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More complex than Platyhelminthes, these are segmented and symmetrical worms
containing a nervous system, respiratory syst em, and sense organs. Examples include the
common earthworm and leeches.
The second largest phylum by species count , and the largest marine phylum;
Invertebrates with soft unsegmented bodies (usually with shells). It is estimated almost
a quarter of marine life falls in this category. Examples include clams, mussels, and snails
Invertebrate animals with an exosk eleton, segmented bodies and jointed legs. Contains
insects, crustaceans, and arachnids. This is the largest phylum by species count. Examples
include scorpions, butterflies, and shrimp
Vertebrates . Animals that develop a notochord, a cartilaginous skeletal rod that supports
the body in the embryo and can often become a spine. Most animals we are familiar
with, including dogs, horses, birds, and humans fall into this category.
roundworms; unsegmented
spiny body (sea star, sea urchin, sand dollars, sea cucumber, brittle star )
Warm-Blooded vs Cold Blooded
Warm-blooded or endothermic
animals can adjust their body
temperature . Only mammals
and birds in the animal
classifications are warmblooded while cold-blooded or
ectothermic vertebrates are
unable to regulate their body
temperature . Their internal
temperature is dependent on
outside forces. They lay in the
sun and under the shade to cool
down and warm up.
Invertebrate vs Vertebrate
Invertebrates are animals that lack a vertebral column, or backbone while vertebrates are animals that is
distinguished by the possession of a backbone or spinal column
Basic Needs for Animals to Survive
process of taking in, taking apart and taking up the nutrients from a food source.
Food processing has four main stages: Ingestion, Digestion, Absorption and Elimination or Egestion
process of taking in food substances, the animal takes in food in different ways.
Microscopic animals, for instance, can use special cavities which can allow entrance of food or they
can use phagocytosis or pinocytosis wherein food particles are engulfed, thus, creating a food vacuole.
Mechanical Digestion - aids in physically breaking down food particles for easier chemical digestion
Chemical Digestion - process of breaking down complex molecules into simpler molecules through
chemical hydrolysis.
mechanical digestion has an implication in acquisition of energy from our food. The easier to
chemically digest food, the easier to obtain energy from it.
stomach is not only for digestion but also for storage of food
Chemical digestion mainly happens in the small intestine, but it also occurs in the mouth and the
involves either intracellular digestion (Unicellular organisms and members of the Phylum Porifera) or
extracellular digestion or both processes.
Intracellular digestion
Unicellular organisms and members of the Phylum
It involves endocytosis (phagocytosis/pinocytosis)
of basic food molecules which can easily be
broken down through chemical hydrolysis
Extracellular digestion
For animals with complete digested system, where
specialization of organs is possible, extracellular
digestion of food is possible.
Chemical hydrolysis occurs within the lumen or the
space of the digestive system with the aid of various
chemicals, enzymes (speeds up a reaction), and
allows the animals to acquire the necessary energy, organic molecules and essential nutrients from the
digested food
Chemical energy comes from the breakdown of ATP which comes from sources such as sugars from
These organic molecules are the biomolecules that we acquire from food: carbohydrate, protein, fats
and nucleic acids
Carbohydrates - for instant energy, but if not used will be stored and can turn into fats.
Proteins - which are made up of amino acids, are the building blocks of different structures in the
Fats - great source of energy as they can store a lot of energy
Nucleic Acids - important for building blocks of genetic information
Essential Nutrients - substances which the animal’s own body cannot synthesize, thus, comes from the
food source. (vitamins and minerals)
Elimination or Egestion
semi-digested food, which in turn becomes waste is then eliminated or digested
In some animals, such as humans, water is first reabsorbed before it is eliminated or egested out of the
Circulation and Gas Exchange
Animals with thin body rely on diffusion , which is the movement of substances from high
concentration to low concentration, in the transport of substances.
it allows efficient bulk transport of substances
Open-Circulatory System
blood is not fully enclosed in a vessel and is pumped out of the system via an exit called an ostium to a
space which surrounds tissues called a sinus
When the heart contracts, the circulatory fluid goes out of the system, if the heart relaxes the fluid
As the blood goes directly to the tissues, it mixes with the interstitial fluid which surrounds tissue and
cells and is called a hemolymph
circulatory and respiratory systems are independent of each other.
Closed-Circulatory System
the circulatory fluid does not go out of the vessel
Exchange occurs through diffusion via thinner vessels called capillaries across the interstitial fluid
Gas Exchange
uptake of molecular oxygen from the environment and the discharge of carbon dioxide to the
often called respiratory exchange or respiration but it should not be confused with cellular respiration
Oxygen is needed in tissues for aerobic cellular respiration to occur and extract ATP from food
Carbon dioxide must be released to prevent physiological pH in tissues from being very acidic.
Aerobic respiration - when oxygen is present in the production of energy
Anaerobic respiration - process energy production without oxygen
To acquire oxygen, different animals have evolved different adaptations in order to adapt such as:
Thin respiratory structure
Moist respiratory surface
Respiratory structure with high surface area
Air as Respiratory Medium
The problem with air as a respiratory medium is its dehydrating characteristic, thus, terrestrial
organisms keep their respiratory surfaces moist by keeping it within their body
In Insects
tracheal system of insects has a branched network of tracheal tube which responds to the problem of
decreased surface area in the respiratory structure.
The tracheal system opens externally through the side of the insect through a structure called a
Air enters and exit through the spiracles. As the respiratory system of insects are independent from
their circulatory system, gases is directly exchanged through tracheoles which have extensions that are
directly connected to the cells
Air sacs act like aspirator which takes in and push out air out of the body of the insects.
In Mammals
Gases are transported via the bloodstream and are exchanged via diffusion
Gas exchange occurs via the movement of air from the external environment and is exchanged via a
deadend of clusters of thin epithelium of the walls of air sacs called alveoli
Terrestrial Ventilation
Breathing – ventilation in the lungs; the alternating process of inhalation and exhalation
Positive breathing - air is pushed into the lungs, such as in frogs.
Negative breathing - use negative pressure breathing by sucking in air in to the lungs through the
creation of a negative pressure
Exhalation - relaxation of the chest muscles squeezes out air through the process
Homeostasis and Waste Removal
Homeostasis - physiological consistency of the body despite external fluctuations; refers to stability,
balance or equilibrium
Homeostatic regulation - adjustment of physiological systems within the body
Internal environment – the fluid environment that bathes the cells (extracellular fluid) composed of
the interstitial fluid and blood.
Osmosis – the movement of water from a region of higher osmolarity to a region of lower osmolarity
across a selectively permeable membrane.
Osmoregulation – the regulation of water and ion balance
Conformers - animals which copy the environmental factors; osmoconformers (concentration
conformers; allow the osmolarity of their body fluids to match that of the environment) and
thermoconformers (temperature conformers).
Regulators - animals which maintain their body’s internal factors compared to the environment;
osmoregulators (concentration regulators; keep the osmolarity of body fluids different from that of
the environment) and thermoregulators (temperature regulators)
Nervous System - Negative feedback mechanisms regulate reactions while positive feedback ensures
the continuance of the reaction
Negative Feedback
Positive Feedback
Carbon dioxide conce ntration
Blood sugar level
For example, in nerves, a threshold electric potential triggers the generation of a
much larger action potential.
Blood clotting
Events in childbirth
Homeostatic control
A receptor (sense organ) to detect a change
A center of control (the brain or the spinal cord) that will process and integrate what is happening
An effector (muscle cells or organs/ glands) to produce a response appropriate to the change.
Ways in which organisms have adapted to their environment in terms of homeostasis
Physiological and Structural adaptations - observed in the placement of blood vessels for heat
retention, while structures of for osmoregulation such as in the kidneys are also placed adjacent to
each other like the process of countercurrent exchange mechanism
Migration - exhibits migratory response to changing environment by travelling long distances
depending on the climate
The Excretory System
enables it to remove excess salt or water in the body
Nephrons - Materials from the blood are transferred; filtration, reabsorption and secretion will occur.
Urethra – excretion will occur
Filtrate - produced when substances from the blood is filtered in the glomerulus and the Bowman’s
Waste Removal Processes
Filtration - Materials diffuse from the blood capillaries of the g lomerulus into Bowman’s capsule;
diffusion is cause by the high blood pressure in the arteries that supply the capillaries
Reabsorption - The filtrate passing into the Bowman’s capsule contains digested food materials
needed by all the cells of the body; As filtrate passes along the coiled tubules and the loop of Henle,
much of its content is reabsorbed into the capillaries that surround this region of nephron; Water
passes back into the blood by osmosis, but glucose and amino acids move from the cells of the
tubule by active transport.
Secretion - the cells liningthe tubule secrete some substances from the blood into the tubule;
movement is opposite of reabsorption
Excretion - waste disposal
Types of nitrogenous wastes excreted by animals
Ammonia – the primary nitrogenous waste for aquatic invertebrates, teleosts, and larval Amphibians;
it is readily soluble in water but is also highly toxic; it can be excreted from the body only in dilute
Urea – produced by mammals, most amphibians, some reptiles, some marine fishes, and some
terrestrial invertebrates; it is formed by combining ammonia with bicarbonate ion (HCO3 )̄ and
converting the product into urea; although its formation requires more energy compared to ammonia,
it is about 100,000x less toxic than ammonia; its excretion requires only about 10% as much water
compared to ammonia
Uric acid – excreted by birds, insects, and terrestrial reptiles; it is relatively nontoxic but more
energetically expensive to produce than urea; i is largely insoluble in water and it is excreted as a
semisolid paste or precipitate with very little water loss
Excretory systems in invertebrates
Cell surface or cell membrane – allows passage of wastes in unicellular organisms Contractile vacuole –
a specialized cytoplasmic organelle in many freshwater protists (e.g. Paramecium) that expels excess
water out of the cell to prevent lysis
Protonephridia or Flame Bulb System – network of tubules that lack internal openings but have
external openings at the body surface called nephridiopores such as in the flatworm, Dugesia; the
smallest branches of the tubule network end with a large cell called a flame bulb or cell
Metanephridia – the excretory tubule of most annelids and adult mollusks; the tubular network has a
funnel-like internal opening called a nephrostome that collects body fluids
Malpighian Tubules – the excretory tubules of insects and other terrestrial arthropods attached to
their digestive tract (midgut)
Mechanism of urine formation in mammalian nephrons
In filtration , blood pressure forces filtrate (water and small solutes) out of the glomerular capillaries.
o Blood cells, proteins, and other large solutes cannot pass the capillary wall and they remain in the
o Filtrate is collected by the Bowman’s capsule and funneled into the proximal tubule.
During tubular reabsorption, useful materials such as salts, water, glucose, and amino acids move out
from the renal tubules and into adjacent peritubular capillaries.
Tubular secretion results in movement of surplus hydrogen and potassium ions, uric acid, toxins and
other drugs from the blood into the renal tubules.
Innate and Adaptive Immunity
Innate immunity is the inherent ability of an
organism to fight pathogens which bring about
certain diseases; attacks wider range of
pathogen, thus, is not very specific but
response is rapid
Adaptive immunity can modify its immune
response in defense against the changes which
can occur in the pathogen; specific but has a
slower response rate
Barrier Defenses - made up of the skin, mucus
membranes and various secretions (sweat)
Epithelial cells - physically present in the skin
that prevent the entrance of pathogens
Phagocytic cells - eats pathogens regardless of what they are, which in some cases increases the rate
of infection
Histamines - substances which initiate an inflammatory response, which results in the swelling of an
area and increase in temperature of a localized area or in cases of a fever the increase temperature of
the whole body to neutralize a pathogen
Active Immunity - result to exposure to a specific pathogen. It can either be natural or artificial
Passive Immunity - specific immune response transferred by the mother to a child, which can develop
as the child matures.
Antibody - protein produced by our immune system to specifically bind a target
Antigen - a substance / part of pathogen that generate an immune response
substances which can cause a reaction to a cell , in Greek it literally means to excite
secreted into extracellular fluid such in blood or lymph and transported to target cells to elicit a specific
response, which can be rapid or slow
growth and development of the body are examples of slow and long term effect of a hormone
Circadian rhythm - responsible for the sleep-and-wake cycles respond to a more rapid response to a
can either be water-soluble or fat-soluble which has implication on how response mechanism in cells is
Water-soluble hormones - lipid bilayer of the cell prevent its free movement; requires them to
activate response from outside of the cell; receptor proteins activate cell responses aka signal
transduction pathway
Fat-soluble hormones/Steroid Hormones - can easily pass through a cell membrane; allows them to
initiate cell response inside the cell; receptors are found on the nuclear membrane which can initiate
gene expression; can have a longer, lasting effect than peptide hormones
Reception - process of a signal molecule to bind to receptor molecules
reaction of the contraction of a muscle against an organic lever
Hydrostatic skeleton - occurs in a body compartment in which a volume of fluid is held under pressure;
muscles act on a fluid trapped by a cylindrical muscular structure (body of a worm and the abdomen);
contraction of the muscle creates a strong structure which supports movement and strength of a body
of an organism, an organ or a particular body part.
Exoskeleton – rigid, armor-like coverings characterize; clam shell
Endoskeleton - consists of rigid but flexible support made of bones, cartilage surrounded by masses of
muscles; bones and cartilage in a human; In sponges, cells are supported on spicules. The
endoskeleton of echinoderms is made from calcium plates underneath the skin.
Axial skeleton – skull and backbone (spiral cord); rib cage
Appendicular skeleton – bones of the appendages (arms, legs, fins) and bones linking the appendages
to the axial skeleton – the pectoral and pelvic girdles
Photoreceptors - respond to light
Thermoreceptors - respond to temperature
Mechanoreceptors - respond to physical
Pain receptors- detect possible tissue
stimuli such as sound or touch
Chemoreceptors - detect chemicals
Three types of eyes that have evolved in the animal kingdom
Eye cups in flatworms and other invertebrates
Compound eyes in insects and arthropods
Single lens eyes in squid
Basic Needs For Plants and Animals To Survive
Sexual and Asexual Reproduction
Sexual Reproduction
one parent involved
No need for gamete union
Genetically identical to parent
Mode of reproduction that involves the use of
gametes or sex c ells
Asexual Re production
two parents involved
Present; sperm has to fertilize
the egg
Generally are hybrids of parents
Mode of reproduction that does not involve the use
of gametes or sex cells
o Zygotene (Synapsis Begins) - The homologous chromosome pair (one inherited from each parent)
comes closer and associate along the entire chromosome length, forming a tetrad. Each tetrad is
composed of four chromatids.
o Pachytene (Crossing Over) - The homologous chromosomes exchange parts of DNA with each
other; this process is known as crossing over. The points of physical contact from which the genetic
materials are exchanged are known as chiasmata.
o Diplotene (Synapsis Ends) - Spindle fibers originate from the centrioles on either side of the cell,
getting attached to each chromosome’s centromere.
o Diakinesis (Prophase Ends) - The last step of prophase involves the breakdown of the nuclear
envelope. The chromosomes then start moving towards the middle of the cell.
• Homologous chromosomes align along the center of the
• The centrioles reach the opposite poles of the cell with
the spindle fibers extending from them.
• The centromeres orient themselves towards the opposite
poles of the cell.
The chromosomes with two sister chromatids are separated, and they begin to migrate to the
opposite poles. This separation is achieved because of the contraction of the spindle fibers attached to
each chromosome’s centromere.
The homologous chromosomes start to migrate to the opposite poles.
Telophase •
The chromosomes stopmigrating with each pole containing a haploid number of chromosomes. •
The nuclear envelope is formed around the chromosome, and the spindle fibers disappear.
The chromosomes uncoil and become less dense with the nucleolus appearing within the a
Cytokineses • It involves the division of the cytoplasm to produce two individual daughter cells. In animals,
cytokinesis occurs by constriction of the cell membrane, while in plants, it happens through the
formation of a cell plate. In most cells, cytokinesis occurs at the same time as telophase.
• At the end of cytokinesis I, two different daughter cells are formed, each with half the number of
chromosomes as the parent cell (having 23 chromosomes having 23 pairs of chromatids). Meiosis is
thus also called the reduction division.
Purpose of Meiosis
Maintaining chromosome number in
organisms: In humans, each cell
typically contains 46 chromosomes
organized into 23 pairs . To maintain
the chromosome number generation
after generation, the gametes formed
from the meiotic division should
contain half the number of
chromosomes (23 chromosomes) as
the parent cell. When the sex cells fuse
to form a zygote, the usual
chromosome number of 46
chromosomes is restored in the new
individual. If the chromosomal
reduction process is not maintained, it could cause genetic abnormality in the child.
Creates genetic diversity : The exchange of genetic information between the pair of homologous
chromosomes allows genetic variation among the population. These variations form the basis of the
evolutionary process.
Repairs genetic defects : The process of mixing chromosomes in meiosis, commonly known as
recombination, helps repair genetic abnormalities in individuals produced through meiosis. When one
of the parents has a genetic defect, recombination through meiosis can replace that abnormality in the
next generation, allowing the formation of a healthy individual.
Haploid (n) condition
When a cell has only half the chromosome number
or only one set of
Diploid (2n) condition
When a cell has the full chromosome number or two
sets of chromosomes
Human Development
Fertilization - Occurs in the fallopian tube; results in a unicellular diploid zygote; union of sex cells
(gametes )- union of sperm and egg (ovum)
o In vitro fertilization - Sperm and ovum meet inside the test tube
o In vivo fertilization - Sperm and ovum meet inside the body
Cleavage - Also takes place in the fallopian tube after fertilization
Morula – a human blastula made up of a solid ball of cells
Blastocyst - A human blastula composed of the inner cell mass, which becomes the embryo, and the
trophoectoderm, which becomes the placenta
Implantation - Attachment of blastocyst to endometrium of uterus; start of pregnancy
Gestation - Differentiate embryonic development from fetal development in terms of period covered
during gestation
Menstrual Cycle
Ovarian cycle
Follicular phase- Part of the menstrual cycle of the ovary in humans where the follicles begin to
mature; it is marked by secretions of the follicle-stimulating hormone (FSH) and the leutinizing
hormone (LH) by the anterior pituitary gland and the estrogen by the ovaries; both FSH and LH
stimulate the maturation of the oocytes while estrogen stimulates uterine lining growth in preparation
for implantation of the embryo
Luteal phase- Part of the menstrual cycle of the ovary after the oocytes are released from the follicles;
the remains of the follicle become the corpus luteum, which then secretes progesterone, which
stimulates the uterus to undergo final maturational changes that prepare it for gestation to house and
nourish an embryo
Uterine Cycle
Menstrual phase- Part of the menstrual cycle of the uterus; also known as the “period”; corresponds
to the early part of the follicular phase of the ovaries (days 1-5) when endometrium degenerates and
sloughs off, producing the menstrual discharge
Proliferative phase - Part of the menstrual cycle of the uterus; corresponds to the latter part of the
follicular phase of the ovaries (days 8-14) when the endometrium heals and begins to thicken as a
consequence of estrogen secretion
Secretory phase- Part of the menstrual cycle of the uterus; corresponds to the luteal phase of the
ovaries; the endometrium undergoes final changes before it receives the embryo during implantation
Ovulation - suppressing methods- Oral
Barrier methods - Physical (Condom,
Diaphragm, Cervical cap)
Chemical - Spermicidal jelly and foam
Surgical methods - Vasectomy and Tubal
Implantation - suppressing methods- IUD
and Morning-after pill
Others - Abstinence
Stages of Plant Development
Gametophyte - Stage of the life cycle of a plant that is haploid; stage that produces gametes via
mitosis; these gametes fuse to form a zygote that develops into a sporophyte
Sporophyte - Stage of the life cycle of a plant that is diploid; it is the most recognizable structure in
most flowering plants; it produces haploid spores by meiosis in structures called sporangia
Types of Life Cycles
Haplontic life cycle - Life cycle where the haploid stage (gametophyte) is multicellular and the only
diploid stage is the fertilized egg cell
Haplodiplontic life cycle - Life cycle that includes multicellular diploid (sporophyte) and haploid
(gametophyte) generations
Diplontic life cycle - Life cycle where the diploid stage (sporophyte)is multicellular and the haploid
stage (gametophyte) is represented by the single-celled gametes
The Flower
Four Major Whorls
Sepals - The outermost whorls of a flower; collectively called the calyx
Petals - Whorl inner to the sepals; may be brightly colored in some; collectively called the corolla
Stamen - Whorl inner to the petals; the male reproductive structure of the flower; bears the male
sporangia (also known as microsporangia)
Anther - Part of the stamen that contains the microsporangia that develops into pollen grains
Filament - Part of the stamen that serves as the stalk of the anther
Carpels - Innermost whorl of the flower; the female reproductive structure of the flower; bears the
female sporangia (also known as the megasporangia)
Stigma - Part of the pistil where the pollen grain derived from the microsporangium attaches during
Style - Part of the pistil that serves as the stalk of the stigma; leads to the ovary
Ovary - Found at the base of the pistil; contains one or more ovules; eventually becomes the fruit
Ovule - Contains the female sporangia or megasporangia; eventually becomes the seed
Types of flowers based on the presence of the whorls
Complete - A flower with sepals, petals, stamens and carpels
Incomplete - A flower that lacks one or more of the floral whorls
Types of flowers based on the presence of reproductive whorls
Perfect / Bisexual - A flower that has both stamens and carpels; a bisexual structure
Imperfect / Unisexual - flower that has only either the stamens ( staminate flower ) or the carpels
(carpellate flower ); also known as a unisexual flower
Plant types based on the presence of reproductive structures
Development in flowering plants
Monoecious - A plant having perfect flowers or both staminate and carpellate flowers on the same
Dioecious - A plant having only either the staminate or carpellate flower
Male gametophyte - The microsporangium in the anther contains numerous microsporocytes. Each
microsporocyte will undergo meiosis to produce four haploid microspores each microspore develops
into a pollen grain (containing two sperm nuclei and one tube nucleus)
Female gametophyte - The megasporangium in the ovule contains megasporocytes . One
megasporocyte will undergo meiosis to produce four haploid megaspores three megaspores
degenerate remaining megaspore divides mitotically three times, an embryo sac with eight haploid
nuclei membranes partition to make the embryo sac multicellular
Transfer of pollen grain from the anther to the stigma
May be animal-aided or wind-aided
Double fertilization
Tube Cell – divides to produce two sperm cells
Generative Cell – becomes pollen tube (elongates along the style and penetrates the ovule in the
ovary via the micropyle (an opening); discharges the sperm cells into the embryo sac inside the ovule
one sperm unites with the egg to form the zygote while the other sperm fuses with the polar nuclei to
become the endosperm, which serves as food of the early embryo)
Zygote divides mitotically to produce the proembryo and suspensor, which anchors the proembryo
and transfers nutrients from the parent plant to it cotyledons appear on the proembryo (monocots
have only one cotyledon whereas dicots have two) proembryo elongates into an embryo.
Maturation of ovary and ovule
Ovary matures into fruit while the ovule becomes the seed. The seed may become dormant for some
Seed germination
Transformation of seed to seedling
Seed undergoes imbibition to break dormancy nutrients stored in the endosperm or cotyledons are
digested and transferred to the growing regions of the embryo to primary meristems (protoderm,
ground meristem, procambium) develop to radicle emerges to plumule breaks through the soil surface
o Epigeal germination occurs when the cotyledon
emerges above ground, thereby exposing the
hypocotyl of the plumule.
o Hypogeal germination occurs when the
cotyledon remains below ground, thereby
concealing the hypocotyl.
Seedling growth to mature plant
Primary meristems differentiate to become the
different plant tissues
Cotyledon - Embryonic leaf that forms inside the
Monocot - A plant with only one cotyledon inside
its seed (monocotyledonous)
Dicot - A plant with two cotyledons inside its
seed (dicotyledonous)
Plant Nutrition
Nutrient – refers to any substance required for
the growth and maintenance of an organism. The
two types of organisms based on the mode of
nutrition are:
o autotrophs – organisms that obtain energy from sunlight and chemicals to produce their own food.
Examples: plants; chemosynthetic bacteria
o heterotrophs – organisms that cannot make their own food and obtain their energy from other
organisms. Examples: animals, fungi
Nutritional Requirements of Plants
carbon dioxide - Further, note that water and carbon dioxide are the raw materials needed for
photosynthesis, the process by which plants convert the energy from sunlight into chemical energy.
essential nutrients or elements – which include macronutrients which are normally required in
amounts above 0.5% of the plant’s dry weight; and micronutrients which are required in minute or
trace amounts;
Macronutrients: C, H, O, N, K, Ca, Mg, P, S
Micronutrients: Cl, Fe, B, Mn, Zn, Co, Mo
Routes for Adsorption
▪ Symplast route – through plasmodesmata
▪ Apoplast route – along cell walls
Note that the water and minerals from the soil need to reach the conducting tissues of plants, specifically the
xylem. The two routes mentioned show how this can happen
Specialized absorptive structures
Root hairs – slender extensions of specialized epidermal cells that greatly increase the surface area
available for absorption.
Root nodules – localized swellings in roots of certain plants where bacterial cells exist symbiotically
with the plant. The bacteria help the plant fix nitrogen and in turn, the bacteria are able to utilize some
organic compounds provided by the plant.
Mycorrhizae (singular, mycorrhiza) – a symbiotic interaction between a young root and a fungus. The
fungus obtains sugars and nitrogen-containing compounds from root cells while the plant is able to get
some scarce minerals that the fungus is better able to absorb from the soil.
Nutritional adaptation by plants
Symbiosis of plants and soil microbes
Symbiosis of plants and fungi
Animal Nutrition
Calorie - unit of energy that indicates the amount of energy contained in food
Nutritional requirements of animals
Carbohydrates – serve as a major energy source for the cells in the body. These are usually obtained
from grains, cereals, breads, fruits, and vegetables. On average, carbohydrates contain 4 Calories per
Proteins – can also be used as an energy source but the body mainly uses these as building materials
for cell structures and as enzymes, hormones, parts of muscles, and bones. Proteins come from dairy
products, poultry, fish, meat, and grains. Like carbohydrates, proteins also contain 4 Calories per gram.
Fats – are used to build cell membranes, steroid hormones, and other cellular structures; also used to
insulate nervous tissue, and also serve as an energy source. Fats also contain certain fat- soluble
vitamins that are important for good health. Fats are obtained from oils, margarine, butter, fried foods,
meat, and processed snack foods. They contain a higher amount of energy per gram than
carbohydrates or proteins, about 9 Calories per gram.
Essential Nutrients – include substances that animals can only get from the foods they eat because
they could not be synthesized inside the body. These include:
o Essential amino acids – needed for synthesis of proteins and enzymes; among the 20 amino acids,
eight could not be synthesized by humans: lysine, tryptophan, threonine, methionine,
phenylalanine, leucine, isoleucine and valine.
o Essential fatty acids – used for making special membrane lipids; an example is linoleic acid in
o Vitamins – organic molecules required in small amounts for normal metabolism; examples include
fat-soluble Vitamins A, D, E, K, and water-soluble Vitamins B, B2, B3, B12, C.
o Trace Elements or Minerals – inorganic nutrients needed by the body in minute amounts; these
form part of enzymes, body tissues, and body fluids; examples include: iodine, cobalt, zinc,
molybdenum, manganese, selenium.
Three types of endocytosis: Food Uptake
phagocytosis – engulfment of organic fragments or big particles, eg. Pseudopod formation in Amoeba.
pinocytosis – uptake of extracellular fluid by a cell using small vesicles derived from the plasma
receptor-mediated endocytosis – this relies on membrane receptor recognition of specific solutes
which are then taken up by the cell via receptor-coated pits.
Different types of animals based on feeding mechanisms
substrate-feeders – animals that live in or on their food source. Examples: earthworms that feed
through the soil where they live in; caterpillars that eat through the leaves where they live on.
filter-feeders – include many aquatic animals which draw in water and strain small organisms and food
particles present in the medium. Examples: whales and coelenterates
fluid-feeders – suck fluids containing nutrients from a living host. Examples: mosquitoes, leeches, head
lice, aphids
bulk-feeders – eat relatively large chunks of food and have adaptations like jaws, teeth, tentacles,
claws, pincers, etc. that help in securing the food and tearing it to pieces. Examples: snakes, man, cats
Different kinds of digestive compartments in animals
Food vacuoles in unicellular organisms – these fuse with lysosomes that contain hydrolytic enzymes.
Example: food vacuole in a protozoa like Paramecium
Gastrovascular cavity or incomplete digestive system – composed of a single opening through which
food is taken in and where wastes are disposed of; it is a saclikebody cavity. Examples: in the cnidarian
Hydra and in flatworm Planaria
Complete digestive system – essentially like a tube with an opening at one end for taking in food
(mouth) and an opening at the other end where unabsorbed waste materials are eliminated (anus). In
between the mouth and anus, are specialized organs that carry out transport, processing, and
absorption of digested nutrients
Accessory organs for digestion in a complete digestive system
liver – secretes bile for emulsifying fats
gallbladder – stores bile produced by the liver
pancreas – secretes enzymes that break down all major food molecules; secretes buffers against HCl
from the stomach; secretes the hormone insulin for control of glucose metabolism
Gas Exchange
Stomates in leaves
Lenticels in stems - The lenticels found on the epidermis of different plant organs (stem, petiole, fruits)
made up of parenchymatous cells are pores that always remain open, in contrast to stomata, which
regulate their extent of opening. Lenticels are visible on fruit surfaces, such as mango, apple, and
Root hairs in aerial roots
Pneumatophores or the lateral roots of mangroves
Respiratory surfaces or organs
Cell surface or cell membrane – especially used in unicellular organisms
Integumentary exchange – refers to the general body surface or skin used by animals
with high surface-to-volume ratio; e.g. flatworm and earthworm. Amphibians also use
their skin in addition to lungs as gas exchange surface
External Gills – used by invertebrates that live in aquatic habitats; gills are highly
folded, thin - walled, vascularized epidermis that project outward from the body; e.g.
crayfish, lobster, sea star, nudibranch
Tracheal system in arthropods – utilizes fine air -conducting tubules to provide gaseous
External Gills – thin, vascularized epidermis that project fro m the body surface of a
few amphibians; e.g. larval salamander
Internal Gills – rows of slits or pockets in adult fishes positioned at the back of the
mouth such that water that enters the mouth can flow over them as it exits just behind
the head.
Water fl ows over the gills and blood circulates through them in OPPOSITE
This mechanism, called counter current flow, is highly efficient in extracting oxygen
from water, whose oxygen content is lower than air.
Lungs – internal respiratory surfaces sha ped as a cavity or sac; lungs provide a
membrane for gaseous exchange; since they are not in direct contact with all other
parts of the body, lungs require a circulatory system to transport gases to the rest of
the body; found in birds, reptiles, and mamma ls.
Coordination of Gas Exchange and Circulation
Oxygen Transport
Oxygen diffuses down a pressure gradient from the lungs into the blood plasma → red blood cells →
binds to hemoglobin (4 molecules per hemoglobin to form oxyhemoglobin).
Hemoglobin gives up its oxygen in tissues where partial pressure of oxygen is low, blood is warmer,
partial pressure of carbon dioxide is higher, and pH is lower; these four conditions occur in tissues with
high metabolism.
Carbon Dioxide Transport
Carbon dioxide diffuses down its partial pressure gradient from the tissues into the blood plasma and
red blood cells → air in alveoli.
Seven percent is dissolved in plasma, 23% binds with hemoglobin to form carbaminohemoglobin, and
70% is in bicarbonate form.
Bicarbonate and carbonic acid formation is enhanced by the enzyme carbonic anhydrase, which is
located in the red blood cells
Biology: Genetics
Pedigree Analysis
Pedigree - making use of diagrams showing the ancestral relationships and transmission of genetic
traits over several generations in a family
Proband - individual in the pedigree that led to the construction of the pedigree
Law of Segregation (1st Mendelian Law) - For every trait governed by a pair of alleles, these alleles
segregate or separate during gamete formation in meiosis
Law of Independent Assortment (2nd Mendelian Law) - A pair of alleles for one trait will segregate or
separate independently of another pair of alleles for another trait during meiosis
Autosomal trait - A trait whose alleles that control it are found in the autosomes (body chromosomes/
non-sex chromosomes)
Genotype - The gene pair an individual carries for a particular trait symbolized with a pair of letters; By
convention, uppercase letter (eg. A) for a dominant allele and lowercase letter (eg. a) for the recessive
o For a diploid organism with two alleles in a given gene pair, genotypes may be written as:
o Homozygous dominant, i.e. with two dominant alleles (DD)
o Heterozygous , i.e. with a dominant and recessive allele (Dd). The individual will show the dominant
o Homozygous recessive , i.e. with two recessive alleles (dd)
Phenotype - The observable trait of an individual based on its genotype. Examples: red flower, curly
hair, blood types ( i.e. the blood type is the phenotype)
o For a typical Mendelian trait, phenotypes may either be:
o Dominant. A trait that requires at least one dominant allele for the trait to be expressed, e.g. Dd
o Recessive. A trait that requires two recessive alleles for the trait to be expressed
Phenocopy - A trait that is expressed due to specific environmental conditions (i.e. having hair that is
dyed of a different color) and is not due to the genotype
Identical twins
Also known as monozygotic twins, which are
derived from a single fertilization event . After the
first cleavage or cell divisi on of the zygote, the cells
or blastomeres separate and become independent
blastocysts implanted in the mother’s uterus.
Fraternal twins
Twins that are derived from separate fertilization
events (two eggs fertilized by two sperms) within
the fallopian tube, resulting in t wo separate zygotes;
also known as dizygotic twins
Sex Linkage and Recombination
Females - have two X chromosomes in the nucleus of their cells
Males - have one X chromosome and one Y chromosome in the nucleus of their cells
Sex linked trait . The gene (pair) that determines a character (e.g. hemophilia) is located on the sex
X-linked trait . A sex-linked trait is where the gene or allele for the trait is found on the X chromosome
Color blindness. An X-linked recessive trait where a affected individual could not distinguish red from
green color (red green color blindness)
Hemophilia. An X-linked recessive trait where an affected individual suffers from delayed blood
clotting during injuries because of the absence of certain blood clotting factors
Y-linked trait . A sex-linked trait where the gene or allele for the trait is found on the Y chromosome
Hypertrichosis pinnae auris. A Y-linked trait where affected males have hair growing from their
external ears
Other sex-related traits.
▪ Sex-influenced trait - Any trait in a diploid organism whose expression is affected by an individual’s
biological sex; a trait that occurs at a higher frequency in one sex over the other
▪ Sex-limited trait - Any trait in a diploid organism whose expression is limited to just one biological
Modification to Mendel’s Classic Ratios
Co-dominance - When two contrasting alleles are present in the same locus or trait (heterozygote
genotype), then the phenotype expressed is a “blend” of the two extreme phenotypes. The two genes
interact and the offspring shows the effects of both alleles.
Incomplete dominance - When two contrasting alleles are present in the same locus or trait
(heterozygote genotype), then both alleles are expressed in the same phenotype
Multiple alleles - When there are more than two types of alleles for a given locus or trait, this will
result in more than two kinds of phenotypes that may be expressed for that trait.
Sample Question
In cattle, coat color is inherited in a co-dominant fashion. Homozygous B 1B1 produces black coat, homozygous
B2B2 produces white coat, and the heterozygous B 1B2 produces roan coat. Give the phenotypic ratio of the
offspring of the following crosses:
Molecular Structure of DNA, RNA, and Proteins
Nucleotide - building blocks of any nucleic acid composed of a phosphate group (with negative
charges), a sugar portion and an N-base
double stranded
sugar is deoxyribose
repository of genetic information; sequence of bases encodes the blueprint for life processes
single stranded with Uracil instead of Thymine
sugar is ribose
cellular aerobic respiration : three
anaerobic respiration : one
High-energy molecules: glucose
Low-energy molecules : carbon dioxide and water
Forms of Energy
Kinetic- energy associated with relative motion of objects
Thermal energy-type of kinetic energy associated with random movement of atoms. When thermal
energy is transferred in the form of heat.
Light Energy- main energy source is the sun and powers photosynthesis (anabolic process).
Potential Energy - possessed energy of a matter at rest (non- moving form)
Chemical energy- potential energy released in a chemical reaction
Laws of Energy Transformation
1st Law : The energy of the universe is constant: Energy can be transferred and transformed but it
cannot be created nor destroyed.
Disorder of matter is measured through entropy
2nd Law: Every energy transfer or transformation increases the energy of the universe
Free Energy - Energy that can do work under cellular conditions
Gibbs free energy - the energy in the system that can perform work when temperature and pressure
are uniform throughout the system: ΔG = ΔH – TΔS (Free Energy Change)
Exergonic reactions - energy is released (energy outward), more decrease in free energy= more work
Endergonic reactions - energy is absorbed (energy inward). Plants stores energy in the form of glucose
(from carbon dioxide and water
A cell that reaches the state of equilibrium is DEAD (Equilibrium = NO WORK)
Adenosine Triphosphate (ATP)
Structure composed of: sugar ribose, nitrogen base adenine and a chain of 3-phosphate groups
Mediates most energy coupling in cells
Powers cellular work
3 main kinds of work of a cell: chemical work, transport work and mechanical work. These are possible
through energy coupling, where the cells use and exergonic process to drive an endergonic reactions.
o chemical work: synthesis of polymers from monomers (pushing of endergonic reactions)
o transport work : pumping of substances across membranes (against the direction of spontaneous
o movement)
o mechanical work: beating of cilia, contraction of muscles also used to make RNA (since ATP is used
as one of the nucleoside triphosphate)
Hydrolysis of ATP
process of breaking down bonds between the
phosphate groups this happens when a water
molecule breaks the terminal phosphate bond
HOPO32-, abbreviated P I leaves ATP
Forming Adenosine diphosphate (ADP)
Energy is released. This comes from the chemical
change of the system state of lower free energy
and NOT from the phosphate bonds.
Hydrolysis releases so much energy because of the
negative charges of the phosphate groups. These
charges are crowded together and their mutual
repulsion contributes to the instability of that
region of the ATP. The energy equivalent of the
triphosphate tail of ATP is compared to a compressed spring.
How the Hydrolysis of ATP Perform Work
Proof that ATP releases heat: in a test set up, the
hydrolysis of ATP releases energy in the form of
heat in the surrounding water.
Most of the time when an animal is exposed in a
cold environment, the reaction of the body is
through shivering. In this reaction of the organism,
shivering uses ATP during muscle contraction to
warm the body. Since it will also be a disadvantage
for organisms to generate heat during ATP
hydrolysis, in order to maintain the living conditions
inside the cell, the energy released during ATP
hydrolysis is used by proteins to perform work:
chemical, transport and mechanical
o Hydrolysis of ATP leads to change in the shape
of protein and in its ability to bind to another molecule. Phosphorylation (ADP to ATP) and
dephosphorylation (ATP to ADP) promote crucial protein shape changes during important cellular
The Regeneration of ATP
ATP is a renewable it can be regenerated by the addition of phosphate to ADP
Catabolism (exergonic) provides the free energy to phosphorylate ADP.
ATP formation is not spontaneous, so there is a need to use free energy for the process to work.
ATP cycle is the shuttling of inorganic
phosphate and energy.
It couples the cell’s energy yielding processes
(exergonic) to energy consuming process
ATP regeneration happens very fast (10M
molecules of ATP used ad regenerated per
If ATP could not be regenerated by
phosphorylation of ADP, HUMANS would use
nearly their body weight in ATP each day.
Energy Transformation
separation technique used to identify various components of mixtures based on the differences in their
structure and/or composition
involves a stationary phase (e.g., paper or any thin layer of an absorbent surface) and a mobile phase
(i.e., solvent containing the dissolved substances).
solvent will move up the paper through capillary action carrying with it the dissolved substances
substances will be carried along at different rates because they are not equally soluble in the solvent
and they will be attracted in different degrees to the paper
substances that
absorb visible light
are the means by
which plants
capture sun’s
energy to be used
in photosynthesis
greenish pigment found in the thylakoid membrane inside the chloroplast of a plant cell
absorbs blue and red light while it transmits and reflects green light
plays the most important role in photosynthesis; directly participates in converting solar energy to
chemical energy.
Structure of chlorophyll
Head—a flat hydrophilic head called porphyrin ring. It has a magnesium atom at its center. Different
chlorophylls differ on the side groups attached to the porphyrin.
Tail —a lipid-soluble hydrocarbon tail.
an aggregate of pigments and proteins in the thylakoid membrane responsible for the absorption of
photons and the transfer of energy and electrons.
Light-harvesting complex — is also called the ‘antenna’ complex and is consisted of several different
pigments (chlorophyll a, chlorophyll b, and carotenoids) bounded with proteins.
Reaction-center complex —is composed of a pair of chlorophyll a and a primary electron acceptor.
Cellular Respiration
ATP in Cellular Metabolism and Photosynthesis
During Photosynthesis:
Energy from sunlight is harvested and used to drive the synthesis of glucose from CO2 and H2O . By
converting the energy of sunlight to a usable form of potential chemical energy, photosynthesis is the
ultimate source of metabolic energy for all biological systems.
Photosynthesis takes place in two distinct stages .
o In the light reactions , energy from sunlight drives the synthesis of ATP and NADPH , coupled to the
formation of O2 from H2O.
o In the dark reactions (named because they do not require sunlight), the ATP and NADPH produced
by the light reactions drive glucose synthesis.
In eukaryotic cells, both the light and
dark reactions of photosynthesis occur
within chloroplasts—the light reactions
in the thylakoid membrane and the dark
reactions within the stroma.
Stages of Cellular Metabolism:
Pyruvate grooming (between Glycolysis
and Citric acid cycle
Kreb’s Cycle/Citric Acid Cycle/Acid Cycle
Electron Transport Chain and Oxidality
Biology: Cell and Molecular Biology
smallest and most basic form of life
basic building blocks of all living things
provide structure for the body, take in nutrients from food, convert those nutrients into energy, and
carry out specialized functions
contain the body’s hereditary material and can make copies of themselves
Robert Hooke , one of the first scientists to use a light microscope, discovered the cell in 1665
Cytology (study of cells); Prokaryotic (Bacteria and Archaebacteria) – true nucleus; Eukaryotic (Protist,
Fungi, Plant, Animal) – do not contain nucleus, have their DNA located in the nuceloid
Cell Theory Principles
Cells are the most basic building units of life.
All living things are composed of cells.
New cells are made from preexisting cells, which divide into two.
Parts of the Cell
nucleus (contains most of the genes (DNAdeoxyribonucleic acid ); cell’s command
center, sending directions to the cell to grow,
mature, divide, or die; Largest organelle in an
animal cell)
mitochondria: Chemical Energy Conversion
(Powerhouse of the cell; which generate
energy; Converts food molecules into energy (ATP) through Cellular Respiration; The waste products of
cellular respiration are water and carbon dioxide gas (CO 2))
ribosomes (which produce protein; carry out protein synthesis (protein factories)
endoplasmic reticulum: Biosynthetic factory (which is a packaging and transport facility; helps process
molecules created by the cell; folded membranes that serves as channels through which materials are
transported in the cell)
golgi apparatus: Shipping and Receiving Center (manufacture, process, and package of certain
macromolecules; which distributes macromolecules; packaging factories of the cell)
lysosomes: Digestive Compartments – Garbage Collector and peroxisomes (a membranous sac of
strong hydrolytic enzymes; helps process molecules created by the cell; break down macromolecules
and destroy foreign invaders)
cytoplasm (made up of a jelly-like fluid (called the cytosol) and other structures that surround the
nucleus; Where organelles are located; compose of water, salts, proteins, fats, carbohydrates, and
other chemicals )
cytoskeleton (network of long fibers that make up the cel l’s structural framewor k; etermining cell
shape, participating in cell division, and allowing cells to move; provides a track-like system that directs
the movement of organelles and other substances within cells)
plasma membrane (functions as a selective barrier (Semipermeable) ; outer lining of the cell;
separates the cell from its environment and allows materials to enter and leave the cell)
Cell wall (located outside the cell membrane, protective layer of the cell; plant cell wall: made up of
cellulose; Fungal cell wall: made up of chitin)
Central vacuoles (found in plants; Hold reserves of important organic compounds and water; Can take
up to 30 %- 90 % of cell's volume)
Cytoskeleton- Mechanical support, network of fibers (Microfilaments (Actin filaments) are the thin
structures essential for cytokinesis, amoeboid movement and)
Cilium- hair-like structure (cilia in paramecium, fallopian tube (oviduct), lungs)
Flagellum-whip-like structure (flagellum in sperm cell, euglena, bacteria)
Functions of Cells
Support and
Transport of
form the structural basis of all the organisms. The cell wall and the cell membrane are the
main components that function to provide support and structure to the organism. For eg.
the skin is made up of a large number of cells. Xylem present in the vascular plants is made
of cells that provide structural support to the plants.
In the process of mitosis, the parent cell divides into the daughter cells. Thus, the cells
multiply and facilitate the growth in an organism.
Various nutrients are imported by the cells to carry out various chemical processes going on
inside the cells. The waste produced by the chemical processes is eliminated from the cells
by active and passive transport.
Active Transport - larger molecules diffuse across the cell membrane through active
transport where the cells require a lot of energy to transport the substances
Passive Transport - Small molecules such as oxygen, carbon dioxide, and ethanol diff use
across the cell membrane along the concentration gradient
Cells require energy to carry out various chemical processes. This energy is produced by the
cells through a process called photosynthesis in plants and respiration in animals
Aids in
A cell aids in reproduction through the processes called mitosis and meiosis. Mitosis is
Reproduction termed as the asexual reproduction where the parent cell divides to form daughter cells.
Meiosis causes the daughter cells to be genetically dif ferent from the parent cells
Types of Cells
Tissues, Organs, Organ Systems, and Organisms
Cells. Cells are the basic structural and functional
unit of all life. Examples include red blood cells and nerve cells.
Tissues. Tissues are groups of cells that share a common structure and function and work together.
There are four types of human tissues: connective, which connects tissues; epithelial, which lines and
protects organs; muscle, which contracts for movement and support; and nerve, which responds and
reacts to signals in the environment.
Organs. Organs are a group of tissues arranged in a specific manner to support a common physiological
function. Examples include the brain, liver, and heart.
Organ systems . Organ systems are two or more organs that support a specific physiological function.
Examples include the digestive system and central nervous system. There are eleven organ systems in
the human body
Organism. An organism is the complete living system capable of conducting all of life’s biologic al
chemical structure consisting of at least two atoms held together by a chemical bond
many molecules that are biologically important are macromolecules
large molecules that are typically formed by combining smaller units called monomers.
give cells the ability to grow and reproduce
overall process of cellular reproduction occurs in two steps: cell growth (cell ingests certain molecules
from its surroundings by selectively carrying them through its cell membrane) and cell division (cell
divides to create two daughter cells)
action of highly specialized, large, elaborately folded molecules
act as catalysts by binding to ingested molecules and regulating the rate at which they are chemically
Cell Division
involves the distribution of identical genetic material or DNA to two daughter cells
Mitosis is the process by which new cells are generated; involves the separation of copied
chromosomes into separate cells
Meiosis is the process by which gametes are generated for reproduction
Cell Cycle
driven by a built-in clock that can be adjusted by external stimuli
Kinase - protein which activates or deactivates another protein by phosphorylating them; give the ‘go ahead’ signals at the G1 and G2 checkpoints
Checkpoint—a critical co ntrol point in the Cell Cycle where ‘stop’ and ‘go -ahead’ signals can regulate
the cell cycle
o The G1 Checkpoint—the Restriction Point
o The G2 Checkpoint—ensures that DNA replication in S phase has been successfully completed
o The Metaphase Checkpoint —ensures that all of the chromosomes are attached to the mitotic
spindle by a kinetochore
nuclear division; the process by
which the nucleus divides to
produce two new nuclei
results in two daughter cells that
are genetically identical to each
other and to the parental cell
from which they came.
important for sexual reproduction indirectly; allows the sexually reproducing organism to grow and
develop from a single cell into a sexually mature individual
preparatory stage; nuclear envelope starts to disappear as chromosomes condensed;
centrioles move towar d opposite sides of the nucleus; initially indistinct chromosomes begin
to condense into visible threads
• Chromosomes first become visible during early prophase as long, thin, and intertwined
filaments but by late prophase, chromosomes are more compacted and can be clearly
discerned as much shorter and rod -like structures.
• As the chromosomes become more distinct, the nucleoli also become more distinct. By the
end of prophase, the nucleoli become l ess distinct, often disappearing altogether.
Metaphase chromosome pairs align at the equatorial plate ; is when chromosomes become arranged so
that their centromeres become aligned in one place, halfway between the two spindle poles ;
long axes of the chrom osomes are 90 degrees to the spindle axis; plane of alignment is called
the metaphase plate
spindle fibers pulls the sister chromatids apart towards the opposite poles ; is initiated by the
separation of sister chromatids at their junction point a t the centromere; daughter
chromosomes then move toward the poles
Telophase sister chromatids are now on opposite poles ; is when daughter chromosomes complete their
migration to the poles ; two sets of progeny chromosomes are assembled into two -groups at
opposite ends of the cell; chromosomes uncoil and assume their extended form during
interphase; soon, the nucleolus reforms
telophase stage of mitosis is accompanied by cytokinesis
In animal cells, cytokinesis occurs by the formation of a constriction in the middle of the cell until two
daughter cells are formed; constriction is often called cleavage, or cell furrow
in most plant cells this constriction is not evident. Instead, a new cell membrane and cell wall are
assembled between the two nuclei to form a cell plate; Each side of the cell plate is coated with a cell
wall that eventually forms the two progeny cells
Transport Mechanisms
Phospholipids - foundation of all known biological membranes
Diffusion - natural tendency for molecules to move constantly and to spread out evenly into the
available space
Facilitated diffusion - utilizes protein transmembrane channels that are specific to certain molecules;
passive process driven by the concentration of molecules both inside and the outside of the
membrane; Aided by transport proteins
Passive Transport - heat energy of the cellular environment provides all of the energy, hence, this is
not energy-costly to the cell/ no energy investment ; Move from high to low concentration
(concentration gradient); Can be diffusion, facilitated diffusion, osmosis
Active Transport - Certain molecules are transported in and out of the cell, independent of
concentration; process requires the expenditure of energy in the form of ATP
Endocytosis - Large molecules enter the cell by this generalized nonselective process
o Phagocytosis - endocytosis of a particulate material
o Pinocytosis - endocytosis of liquid material
o Exocytosis – reverse process
o Receptormediated Endocytosis - complicated mechanism involving the transport of materials via
coated vesicles
Osmosis - special type of diffusion specifically
associated with the movement of water molecules
Biology: Microbiology and Parasitology
a living thing that is too small to be seen with the naked eye
exist as unicellular, multicellular, or cell clusters
widespread in nature and are beneficial to life, but some can cause serious harm
Types of Microbes
microscopic, single-celled organisms that have no nucleus and a cell wall made of peptidoglycan
direct descendents of the first organisms that lived on Earth, with fossil evidence going back about 3.5
billion years
usually do not have any membrane-wrapped organelles (e.g., nucleus, mitochondria, endoplasmic
reticulum), but they do have an outer membrane
Most bacteria are also surrounded by at least one layer of cell wall
cells are described as prokaryotic because they lack a nucleus
exist in four major shapes: bacillus (rod shape), coccus (spherical shape), spirilla (spiral shape), and
vibrio (curved shape).
Most bacteria have a peptidoglycan cell wall ; they divide by binary fission
may possess flagella for motility
aerobic (living in the presence of oxygen), anaerobic (living without oxygen), and facultative
anaerobes (can live in both environments)
According to the way they obtain energy, bacteria are classified as heterotrophs or autotrophs
Bacteria that use decaying life forms as a source of energy are called saprophytes
microscopic, single-celled organisms that have no nucleus and an outer membrane containing unique
on the surface, archaea look a lot like bacteria
surrounded by a membrane made up of a type of lipid that isn’t found in any other organism
Most archaea also have a cell wall, but theirs is very different from the peptidoglycan cell wall of
best known for living in extreme environments , but they also live in non-extreme environments,
including the human gut and skin
use different energy sources like hydrogen gas, carbon dioxide, and sulphur
absorb sunlight using their membrane pigment, bacteriorhodopsin
can be divided into the following groups
o methanogens (methane-producing organisms),
o halophiles (archaeans that live in salty environments),
o thermophiles (archaeans that live at extremely hot temperatures), and
o psychrophiles (cold-temperature Archaeans).
single-celled or multicellular organisms with nuclei and with cell walls made of chitin
eukaryotic cells (with a true nucleus)
also have membrane-wrapped organelles, including mitochondria
cannot make their own food
important decomposers in most ecosystems
obtain nutrients by absorbing organic material from their environment ( decomposers), through
symbiotic relationships with plants ( symbionts), or harmful relationships with a host (parasites )
form characteristic filamentous tubes called hyphae that help absorb material. The collection of
hyphae is called mycelium
reproduce by releasing spores
include yeasts, molds, and mushrooms
single-celled or multi-cellular, microscopic organism with cell nuclei, and which aren't plants, animals,
or fungi
Multi-cellular protists live as colonies, without specialization
category of leftovers and oddballs that don’t fit into other groups, and taxonomists are c ontinually
reorganizing them
Some make their own food using chloroplasts, but most don’t
have many ways of moving around, including flagella (produce their own food and use their whip-like
structure to propel forward) , cilia (have tiny hair that beat to produce movement) , amoeboid action
(have false feet or pseudopodia used for feeding and locomotion) and sporozoans (non-motile)
have membrane-wrapped organelles and an outer cell membrane
Several parasitic protists can cause deadly diseases, including malaria, amoebic dysentery, and giardia
microscopic particles made of nucleic acids, proteins, and sometimes lipids
noncellular (acellular) entities that consist of a nucleic acid core (DNA or RNA) surrounded by a protein
can’t reproduce on their own. Instead, they reproduce by infecting other cells and hijacking their host’s
cellular machinery
specialized to infect a certain host, and often a specific cell type within that host
Viruses that infect bacteria are called bacteriophage
Viruses that infect archaea come in unusual shapes: some have two tails, others are shaped like bottles
or flowers
Microscopic Animals
their cells have membrane-wrapped compartments, including nuclei
include mostly arthropods, crustaceans, and rotifers
Microscopic Plants (Algae)
Most microscopic plants are counted among the “green algae” (a general term), and they live as single
cells (sometimes with flagella) or long fibers
important food sources for animals in both freshwater and saltwater ecosystem
Bacteria, protists, and viruses and their effects on
Microbes that cause disease are called
Notes to Remember
A pathogen is a micro-organism that has the
potential to cause disease.
An infection is the invasion and
multiplication of pathogenic microbes in an
individual or population.
Disease is when the infection causes damage
to the individual’s vital functions or systems.
An infection does not always result in disease!
Biology: Anatomy and Physiology
Systems of the Body: Functions, Diseases, and Care
The Digestive System
uniquely constructed to do its job of turning your food into the nutrients and energy you need to
survive. And when it’s done with that, it handily packages your solid waste, or stool, for dis posal when
you have a bowel movement
Oral Cavity
it is where food is initially chewed into shreds by the teeth, and mixed with saliva by the
tongue. Saliva is secreted into the mouth by three pairs of salivary glands located above the
upper jaw and below the lower jaw
responsible for ingestion ; humans, the mouth have specialized dentition for mechanical
digestion of food
With the aid of the salivary gland, food is softened and rolled by the tongue, which results in a
round, semi-digested food called the bolus
Some animals do not have teeth, such as birds and earthworms, they use a structure called
gizzard, a muscular organ which grinds food with the aid of ingested pebbles or stones.
cross-road of food and air
To prevent food from entering the respiratory system, the epiglottis covers the opening (called
the glottis) to the respiratory when swallowing.
has voluntary muscles that allows the movement of bolus to the stomach by lubricating its
walls with mucus produced by goblet cells
Movement of food is caused by peristalsis
Mucus protects the lining of esophagus from acids of the stomach
bag which mainly functions in the storage of food; gastric juice (combination of HCl and acidstable proteases)
Chemical digestion of food starts here through the action of pepsin (an enzyme for protein
digestion) and hydrochloric acid (HCl) helps in breaking cells, activating pepsinogen to pepsin,
and denaturing proteins.
Denaturation is the process of breaking the bonds of protein, through acids, bases, heavy
metals, high temperature and others
product of its digestion called chyme or acidic chyme (due to its acidic nature) moves to the
small intestines
Small Intestine
has the largest surface area among the organs in the digestive system
approximately 6 meters long and is composed of three regions: the duodenum, jejunum, and
chemical digestion of the four biomolecules occur
Bile - substance produced by the liver and stored by the gall bladder which aids in the digestion
of fats by emulsification of fat molecules
Villus (plural- villi) and microvillus (plural- microvilli) - structures responsible for the efficient
absorption of the digested molecules
secretes digestive enzymes into the duodenum that break down protein, fats and
makes insulin (chief hormone in your body for
metabolizing sugar), passing it directly into the
Large Intestine
responsible for water reabsorption and temporary
storage of feces; about 1 meter
water is recycled by the large intestine by reabsorbing
Appendix – a vestigial organ
Rectum - temporary store feces; it is where the
compacted undigested food from the colon are
pushed via persitaltic contractions
Anus – regulates the movement of the feces; terminal
opening of the digestive system through which feces
are expelled
Diseases, Condition and Disorder
acute inflammation of vermiform appendix
happens when you go poop (have a bowel movement) less frequently than you normally
do; poop is often dry and hard and it’s difficult and painful for your poop to pass
loose or watery poop ; can be caused by many things, including bacteria
uncomfortable burning feeling in your chest that can move up your neck and throat ;
happens when acidic digestive juices from your stomach go back up your esophagus
swollen, enlarged veins that form inside and outside of your anus and rectum ; can be
painful, uncomfortable and cause rectal bleeding
infection of the stomach and upper part of the small intestine ; virus
Stomach flu
(gastroenteritis )
Peptic ulcer
a sore that develops on the lining of the esophagus, stomach or small intestine ; bacteria
(Helicobacter pylori (H. pylori) ) and long-term use of anti-inflammatory drugs such as
ibuprofe n
Irritable bowel
syndrome (IBS)
Crohn’s disease
Celiac disease
small pieces of solid material formed from digestive fluid that form in your gallbladder
condition in which acid -containing contents in your stomach frequently leak back up into
your esophagus
condition in which your colon muscle contracts more or less often than normal
unable to digest lactose, the sugar primarily found in milk and dairy products
occur in your large intestine ; pockets or bulges that form in the wall of your colon
affect tissues and organs in the digestive system ; esophageal cancer, gastric (stomach)
cancer, colon and rectal (colorectal) cancer, pancreatic cancer and liver cancer
lifelong form of inf lammatory bowel disease (IBD); the condition irritates the digestive
autoimmune disorder that can damage your small intestine ; damage happens when a
person with celiac disease consumes gluten, a protein found in wheat, barley and rye
Care and Medication
Drink water often
Include fiber in your diet
Eat a balanced diet
Eat foods with probiotics or take probiotic
Eat mindfully and chew your food
Avoid alcohol and smoking
Manage your stress
Circulatory System
provide oxygen, nutrients and hormones to muscles, tissues and organs throughout your body
How does it Work
1. The heart’s bottom right pumping chamber (right ventricle) sends blood that’s low in oxygen (oxygen poor blood) to the lungs. Blood travels through the pulmonary trunk (the main pulmonary artery).
2. Blood cells pick up oxygen in the lungs.
3. Pulmonary veins carry the oxygenated blood from the lungs to the heart’s left atrium (upper heart
4. The left atrium sends the oxygenated blood into the left ventricle (lower chamber). This muscular part
of the heart pumps blood out to the body through the arteries.
5. As it moves through your body and organs, blood collects and drops off nutrients, hormones and waste
6. The veins carry deoxygenated blood and carbon dioxide back to the heart, which sends the blood to
the lungs.
7. Your lungs get rid of the carbon dioxide when you exhale.
allows substances to travel long distances with the aid of the vessels, which acts like a hi way for
Atrium- receives blood
Ventricle - pumps blood
Artery- transports blood away from the heart, muscular
Vein - transports blood back to the heart, has valves and thinner in structure
Capillary- exchange of substances, has very thin walls
Venule - small vein
Arteriole- small artery
a) The pulse is the wavelike force which is a result of the pumping of blood through an artery with
decreasing diameter. As the diameter of the artery decreases, the walls of the artery stretch to
accommodate the blood that is passing through it.
Care and Medication
Drink plenty of water : Staying hydrated will flush out your system and can help you prevent kidney
stones and UTIs. You can try drinking cranberry juice to ward off a UTI. Compounds in cranberries may
stop bacteria from growing.
Eat a healthy diet : Low sodium, high-calcium foods may prevent kidney stones.
Wipe the right way : Women should always wipe front to back after using the toilet. Proper wiping
reduces the risk of bacteria getting into the vagina and causing a UTI.
Empty your bladder after sex : If you’re a woman, you should use the bathroom after having sex.
Peeing promptly can clear out bacteria and reduce your risk of a UTI.
Practice safe sex : Protect yourself from an STI with a condom. But be careful with spermicides because
they can cause bacteria to flourish.
Do pelvic floor exercises : Also called Kegel exercises, these can reduce your risk of urinary
incontinence by strengthening the muscles in your pelvic floor.
Endocrine System
made up of several organs called glands
Hormones are chemicals that coordinate different functions in your body by carrying messages
through your blood to your organs, skin, muscles and other tissues
continuously monitors the amount of hormones in your blood
o Metabolism (the way you break
o Emotions and mood.
down food and get energy from
o Fertility and sexual function.
o Sleep.
o Growth and development.
o Blood pressure.
Hypothalamus - located in
your brain and controls your
endocrine system ; mood,
hunger and thirst, sleep
patterns and sexual function
Pituitary - only about the size
of a pea; makes hormones
that control several other
glands such as the thyroid
gland, adrenal glands,
ovaries and testicles
Thyroid - butterfly-shaped
gland in the front of your
neck; metabolism
Parathyroid - four tiny
glands; control the level of
calcium in your body
Adrenal - control your
metabolism, blood pressure, sexual development and response to stress
Pineal - manages your sleep cycle by releasing melatonin, a hormone that causes you to feel sleepy
Pancreas - makes a hormone called insulin that controls the level of sugar in your blood
Ovaries - release sex hormones called estrogen, progesterone and testosterone
Testes - make sperm and release the hormone testosterone
Diseases, Condition and Disorder
affects the way your body uses the energy from the food you eat ; develops when the
pancreas doesn’t make enough of a hormone called insulin
abnormal enlargement of the thyroid glan d
Thyroid disorders Hypothyroidism happens when the thyroid doesn’t produce enough hormones.
Hyperthyroidism occurs when it creates too many hormones
(low testosterone )
Polycystic ovary
syndrome (PCOS)
can cause erectile dysfunction; cause memory and concentration problem s, changes
in muscle strength and low sex drive
hormonal imbalance causes women with PCOS to have irregular periods, abnormal
hair growth, excess acne and weight gain
When a woman’s ovaries don’t produce en ough estrogen, bones become brittle and
Care and Medication
Your endocrine system needs the same things the rest of your body needs to stay healthy. You should
exercise, eat right and see your healthcare provider regularly.
Nervous System
composed of circuits of nervous tissue and supporting cells.
has evolved in increasing complexity throughout the different groups of animals
controls complicated processes like movement, thought and memory
further distinguished by the location of the neurons within the system
Motor neurons tell your muscles to move
Sensory neurons take information from your senses and send signals to your brain
Nerve – functional unit; composed of neurons that have extensions for transmission of messages
Dendrites - extensions of neurons; transmit messages towards the cell body of neurons
Axons – transmit message away from the cell body of the neuron
Supporting Cells/Glial Cells - function in metabolic, structural, metabolic and other activities of the
Schwann cells - example of a glia, which surrounds the axon of neurons for more efficient transmission
of message
Central nervous system - composed of
the brain and spinal cord; responsible
for data/information processing which
is gathered by the peripheral nervous
Peripheral nervous system - composed
of corresponding structures outside of
this two organs of the nervous system;
further divided, based on its function,
into the motor system (guides your
voluntary movements) and the
autonomic nervous system (controls the activities you do without thinking about them)
Motor system - controls skeletal muscles or voluntary muscles
Autonomic nervous system - functions in the control of involuntary muscles (cardiac, smooth muscles)
and glands
Sympathetic and parasympathetic divisions - mostly have antagonistic functions
Enteric division - function in digestive control
Diseases, Condition and Disorder
Disease: diabetes, lupus
and rheumatoid arthritis ;
multiple sclero sis
Accidental injury
inflammation of the meninges
can cause nervous system problems ; causing tingling and pain in the legs and
feet; attacks the myelin around nerves in the CNS
happens when one of the brain’s blood vessels becomes blocked or suddenly
bursts; cause nerve damage ranging from mi ld to severe.
Car crashes and falls are common injuries that can damage nerves anywhere
in your body
Toxic substances
Aging process
Nerves can be pinched or trapped for many reasons, such as overuse (as in
carpal tunnel syndrome), a tumor, or structural pr oblems like sciatica
can cause peripheral neuropathy or nerve damage ; Chemotherapy medicines,
illegal drugs, excessive alcohol and poisonous substances
As you get older, your neurons’ signals may not travel as fast as they used to
Care and Medication
See your doctor regularly, eat a healthy diet, avoid drugs, and only drink alcohol in moderation. The
best way to avoid nerve damage from disease is to manage conditions that can injure your nerves, such
as diabetes.
Reproductive System
Testis - Where sperms are produced
Epididymis- Where sperms are temporarily stored
Scrotal sac/scrotum - Supports the testis and epididymis
Vas deferens - Where the sperm passes through from the testis before it joins the urethra
Urethra - Connected to the urethra and the urinary bladder; serves as passageway of both sperm and
urine and terminates in the external urinary meatus of the penis
Seminal vesicle - Secretes fluid that forms part of the semen; secretion gives the semen its alkaline
characteristic to counteract the acidity of the vaginal tract and therefore protect the sperm; the fluid
also contains sugars like fructose
Prostate gland - Secretes fluid that also provides alkalinity to the semen; it also contains proteolytic
enzymes, citric acid, phosphatases, and lipids
Bulbourethral glands - Paired glands that produce clear, viscous secretion known as pre-ejaculate that
helps to lubricate the urethra for sperm to pass through, neutralizing traces of acidic urine in the
urethra, and helps flush out any residual urine or foreign matter
Clitoris- The homologue (equivalent) of the penis in females
Vagina - Main entrance to the female reproductive tract; receives the penis during sexual intercourse
Cervix- Where the vagina ends; projection of the uterus into the vagina; leads to the uterus UterusAlso known as the womb; where the embryo develops; with thick muscular walls, blood vessels; and
the endometrial lining
Endometrial lining/endometrium- Innermost lining of the uterus where the embryo implants and
Fallopian tubes - Also known as oviducts; paired tubes that are connected to the uterus and terminate
near the ovaries; this is where fertilization takes place
Ovaries- Female gonads that release the oocytes during ovulation, which are then caught by the
fimbrae of the fallopian tubes in order for the oocytes to pass on to the fallopian tubes
average menstrual cycle takes about 28 days and occurs in phases
o The follicular phase (the egg develops).
o The ovulatory phase (release of the egg).
o The luteal phase (hormone levels decrease if the egg doesn’t implant ).
four major hormones (chemicals that stimulate or regulate the activity of cells or organs) involved in
the menstrual cycle
o Follicle-stimulating hormone.
o Estrogen.
o Luteinizing hormone.
o Progesterone.
Diseases, Condition and Disorder
severe menstrual cramping ,
or dysmenorrheal
Ovarian cancer ; cancer of the fallopian tube ; primary peritoneal cancer;
cervical cancer
sexually transmitted diseases ; genital herpes, gonorrhea and syphilis ;
most common disease of the reproductive system occurs with a woman's
monthly menstrual period
affect the body’s appearance,
structure and function
A wide range of diseases affect
how bones, muscles and
connective tissues work
Hundreds of injuries can affect
bones, cartilage, muscles and
connective tissues
Some, such as osteonecrosis, cause bones to
deteriorate and die. Other disorders, such as
fibrous dysplasia and brittle bone disease
(osteogenesis imperfecta), cause bones to
fracture easily. Conditions that affect the
skeletal muscles ( myopathies ) include more
than 30 types of muscular dystrophy .
Injuries can result from overuse, such as carpal
tunnel syndrome, bursitis and tendinitis.
Sprains, muscle tears, broken bones and injuries
to tendons, ligaments and ot her soft tissues can
result from accidents and trauma
Care and Medication
Exercise regularly , and be sure to include a combination of weight-bearing exercises and
cardiovascular activity. Strengthening your muscles can support your joints and protect them from
Get plenty of sleep so your bones and muscles can recover and rebuild.
Maintain a healthy weight . Extra pounds put pressure on your bones and joints, causing a range of
health problems. If you carry extra weight, talk to your provider about a healthy weight-loss plan.
Make healthy food choices , including a balanced diet of fruits and vegetables, lean protein and milk
for strong bones.
Quit smoking and avoid tobacco . Smoking decreases blood flow throughout your body. Your bones,
muscles and soft tissues need adequate blood flow to stay healthy.
Have regular checkups and age-appropriate health screenings . If you’re over 65, talk to your provider
about getting bone density tests.
Skeletal System
206 bones in an adult human skeleton
Bone Layers
o Periosteum : The periosteum is a tough membrane that covers and protects the outside of the
o Compact bone: Below the periosteum, compact bone is white, hard, and smooth. It provides
structural support and protection.
o Spongy bone: The core, inner layer of the bone is softer than compact bone. It has small holes
called pores to store marrow.
Functions as
o Allows movement: Your skeleton supports your body weight to help you stand and move. Joints,
connective tissue and muscles work together to make your body parts mobile.
o Produces blood cells: Bones contain bone marrow. Red and white blood cells are produced in the
bone marrow.
o Protects and supports organs : Your skull shields your brain, your ribs protect your heart and lungs,
and your backbone protects your spine.
o Stores minerals : Bones hold your body’s supply of minerals like calcium and vitamin D.
Cartilage - enables bones to move without friction (rubbing against each other)
Ligaments - Bands of strong connective tissue called ligaments
hold bones together.
Tendons - Tendons are bands of tissue that connect the ends of
a muscle to your bone.
Joints - is where two or more bones in the body come together
o Immovable joints: Immovable joints don’t let the bones
move at all, like the joints between your skull bones.
o Partly movable joints : These joints allow limited
movement. The joints in your rib cage are partly movable
o Movable joints: Movable joints allow a wide range of
motion. Your elbow, shoulder, and knee are movable joints.
Diseases, Condition and Disorder
Age, injury, and medical conditions such as can lead to arthritis, a painful wearing down
of joints; Lyme disease
Disease, a tumor, or trauma can put stress on a bone, causing it to break
Cancer that forms in the bones can cause tumors that may weaken and break bones
Bone loss caused by not getting enough calcium can lead to fragile and brittle bones
Sprains and
Age, disease and trauma can cause connective tissue to overstretch and tear
Lordosis – also called swayback, spine curves significantly inward at the lower back.
Kyphosis – abnormally rounded upper back.
Scoliosis – sideways curve to their spine.
Care and Medication
Get plenty of vitamin D and calcium in your diet (try milk, yogurt or almonds) to keep bones strong.
Drink plenty of water to help keep tissues healthy.
Exercise regularly to strengthen bones and joints.
Stay at a healthy weight to avoid putting extra pressure on your bones and cartilage.
Wear protective gear during contact sports such as football and hockey.
Be cautious on stairs to avoid falls.
Integumentary System
consists of your skin, hair, nails and glands
first line of defense against bacteria and help protect you from injury and sunlight
helps regulate your body temperature and allows you to feel skin sensations like hot and cold
Skin - largest and heaviest organ in your body
o Epidermis: The top layer of your skin. This is the part of your skin that you can see and touch. It’s
made up of three types of cells: melanocytes, keratinocytes and Langerhans. It gives your skin its
color and provides a waterproof barrier.
o Dermis: The middle layer of your skin. This layer is the thickest. It contains sweat and oil glands and
hair follicles.
o Hypodermis: The bottom layer of your skin. It’s the fatty layer of your skin that helps insulate your
Nails - protect the ends of your fingers and toes
o Nail plate : The hard part of your nail you can see.
o Nail bed: The skin under your nail plate.
o Cuticle: The thin skin at the base of your nail plate.
o Matrix: The “root” of your nail responsible for making it grow.
o Lunula: The white, moon-shaped part of your nail plate.
Hair - helps keep heat in your body; help protect your eyes from dirt and water
o Hair shaft : The part of your hair you can see, touch and style.
o Hair follicle: The tube-like structure that keeps your hair in your skin.
51 o
Hair bulb: Located under your skin and responsible for hair growth.
Glands - release materials like water, salt or oil from under your skin to the surface of your skin o
Sudoriferous glands: These are the glands that secrete sweat through your skin. There are two types of
sweat glands: eccrine glands and apocrine glands. Eccrine glands are all over your body and open to
your pores, while apocrine glands open into your hair follicles. o Sebaceous glands: These glands
produce sebum (oil) and give your face its oil. o Ceruminous glands: These are the glands in your ear
that secrete ear wax.
o Mammary glands: These are the glands on a person’s chest. In people assigned female at birth
(AFAB), mammary glands produce milk after giving birth.
Diseases, Condition and Disorder
tissue damage that results from heat, overexposure to the sun or other radiation, or chemical or electrical
• 1st-degree burn. This minor burn affects only the outer layer of the skin (epidermis). It may cause
redness and pain.
• 2nd-degree burn. This type of burn affects both the epidermis and the second layer of skin (dermis).
It may cause swelling and red, white or splotchy skin. Blisters may develop, and pain can be severe.
Deep second-degree burns can cause scarring. The most painful type of burn.
• 3rd-degree burn. This burn reaches to the fat layer beneath the skin. Burned areas may be black,
brown or white. The skin may look leathery. Third-degree burns can destroy nerves, causing
Allergies like contact dermatitis and poison ivy rashes.
Blisters from trauma.
Bug bites, such as spider bites, tick bites and mosquito bites.
Skin cancer, including me lanoma.
Skin infections like cellulitis.
Skin rashes and dry skin.
Skin disorders like acne, eczema, psoriasis and vitiligo.
Skin lesions like moles, freckles and skin tags.
Wounds, burns (including sunburns) and scars.
Hair loss is the most common condition that affects your hair. Some types of hair loss are temporary,
disorders while others are permanent. The most common types of hair loss include:
• Alopecia areata: Patches of hair loss caused by an autoimmune disease.
• Androgenic alopecia: Baldness in both genders/sexes that’s based on genetics.
• Anagen effluvium: Loss of hair during its growth phase; this often occurs during medical treatments
like chemotherapy.
• Telogen effluvium: Loss of hair during its rest phase. It typically shows up a few months after your
body goes through something stressful or from hormonal changes.
• Traumatic alopecia: Hair loss due to damage to your scalp from hair styling, through rubbing your
scalp repeatedly against a surface or hat or by playing with and breaking your hair.
• Dandruff: It causes white or yellow flakes on your scalp and hair shaft. It’s also known as seborrheic
• Head lice: Tiny, crawling insects that live in a person’s head hair.
• Hirsutism: Excessive hair growth in people assigned female at birth.
• Onychomycosis: Nail fungus in your fingernails or toenails. Onycholysis: When your nail separates
from your nail bed.
• Psoriasis of the nails: skin condition that causes pitting, nail discoloration and other symptoms.
• Lichen planus: A rash that appears as ridges or grooves on your nail.
Paronychia: An inflammation or infection of the tissue directly surrounding your nail.
disorders •
Hyperhidrosis: Excessive sweating.
Seborrheic dermatitis: Scaly, red patches that affect your face, chest or back. When it’s on your head,
it’s called dandruff.
Sebaceous hyperplasia: A skin condition common in people who are older that causes small,
yellowish bumps on your skin.
Care and Medication
Maintaining good hygiene
Practicing good skincare habits, such as using gentle products to wash and moisturize
Using sun protection
Wearing clothing that doesn't cause irritation
Getting regular checkups
Recent inventions that have improved the health and longevity of life
innovations have the potential to greatly enhance medical treatments and improve people's quality of
CRISPR-Cas9 gene editing technology - has the potential to cure genetic diseases at their source.
Artificial intelligence in medical diagnosis - can help doctors make more accurate diagnoses
Wearable fitness trackers/health monitoring devices - can help people maintain healthy lifestyles.
Robotic surgical systems and 3D printing in prosthetics and implant manufacturing - have
revolutionized surgical procedures and the production of medical devices.
Telemedicine platforms and non-invasive glucose monitoring devices - have made healthcare more
accessible and convenient
Advanced cancer treatments such as immunotherapy and personalized medicine - have improved the
chances of survival for cancer patients.
High-resolution imaging technologies like MRI and PET scans - provide detailed views of the body
Stem cell research and regenerative medicine - have the potential to repair or replace damaged
tissues and organs.
Hyperbaric oxygen treatment (HBOT) - involves breathing in oxygen in a chamber where atmospheric
pressure is raised up to three times higher than normal. This type of treatment is usually used to treat
decompression sickness or sporting injuries.
mRNA vaccine technology - has been around for a while, but it is only recently that we have begun to
overcome its drawbacks and see promising results from its use in animals and humans. Our progress
came to a head this year with the development of the Pfizer/BioNTech and Moderna COVID-19
vaccines – the former being the first mRNA vaccine to be used in humans outside of human trials.
Neurotechnology - holds boundless potential to improve many aspects of life. It is already being
practically applied in the medical and wellness industries, but also has many future implications for
other contexts including education, workplace management, national security, and even sports; holds
boundless potential to improve many aspects of life. It is already being practically applied in the
medical and wellness industries, but also has many future implications for other contexts including
education, workplace management, national security, and even sports