Unit 1
Basic Biological Principals
Studying Life
• Biology: The Study of life
• All organisms (a living things) have eight
characteristics that make them living
Studying Life
1. Living things are based on a universal genetic
code.
– All organisms store their information in the form
of DNA
– DNA is copied and passed from parents to
offspring
– http://www.pbs.org/wgbh/evolution/library/04/4/l_044_02.html
Studying Life
2. Organisms Grow and Develop
– Each organism has a specific pattern of growth
and development
– Example: A single egg is fertilized, divides, cells
become specialized to do different functions
– http://www.youtube.com/watch?v=xmsTccmRMh4
Studying Life
3. Organisms Respond to their Environment
– Stimulus: a signal to which an organism responds
– Organisms can respond to a number of stimuli.
Example: Invasion of territory
– http://www.youtube.com/watch?v=XgRHKLyBkMU
Studying Life
4. Organisms are made of cells
– Composed of one or more cells
– Smallest unit of an organism
– Cells can grow, respond to surroundings,
reproduce
– http://www.youtube.com/watch?v=ZK6YP1Smbxk
Studying Life
5. Taken as a group, organisms evolve
– Groups of organism evolve, or change over time.
– Evolution links all life forms to a common origin
more then 3.5 billion years ago
– Evidence: from fossils, proteins, DNA sequence,
similar structures
– http://www.pbs.org/wgbh/evolution/library/11/2/e_s_1.html
Studying Life
6. Organisms obtain and use material and
energy
– Must take in energy and materials to grow,
develop and reproduce
– Metabolism: combination of chemical reactions
through which an organism builds up or breaks
down materials
– http://www.dnatube.com/video/156/introduction-to-metabolism
Studying Life
7. Organism maintain a stable internal
environment
– Homeostasis: Keeping a stable internal
environment even when external conditions
change
– http://www.phys.unsw.edu.au/biosnippets/
Studying Life
8. Organisms reproduce
– Sexual reproduction: Cells from two parents unite
to form the first of a new organism, genetically
different from parents
– Asexual Reproduction: Single organism produces
offspring identical to itself
Check Point
• What eight characteristics do all living things
share?
Life is Cellular
• Brief timeline of the development of life on
Earth:
– 4.6 billion years ago the Earth was formed
– 3.5 billion years ago the first life arose: prokaryotic
bacteria
– 1.5 billion years ago eukaryotic cells arose
– ½ billion years ago the Cambrain explosion: multicelled eukaryotes arose
– 3 million years ago our earliest ancestors, the
hominids, appeared
Life is Cellular
• Types of Cells:
– Prokaryote: Cells that do not separate their
genetic material within a nucleus
– Eukaryote: Cells with a nucleus that separates the
genetic material from the rest of the cell
– http://dsc.discovery.com/videos/assignment-discovery-shortseukaryote-prokaryotes.html
Life is Cellular
• Prokaryotes and Eukaryotes Similarities
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Both have DNA as their genetic material
Both have a plasma membrane
Both contain RNA
Both are made from the same basic chemicals: carbohydrates,
proteins, nucleic acids, lipids
Both have ribosomes
Both regulate the flow of materials into and out of them
Both have similar basic metabolism
(photosynthesis/reproduction)
Both require a supply of energy
Both are highly regulated by sensing systems to sense their
environment
Life is Cellular
• Prokaryotes and Eukaryotes Differences
– Eukaryotes contain a nucleus with DNA, prokaryotes do
not have a nucleus, their DNA floats freely in the
cytoplasm
– Eukaryotes contain many different organelles, prokaryotes
do not, some only contain ribosomes
– Eukaryotes are about ten times larger then prokaryotes
– Both may have cell walls but prokaryotes are made of
different material then eukaryotes
– Flagella (structures that help cells move) are arranged
differently in both types of cells. Far more complex in
Eukaryotic cells them prokaryotic cells
Life is Cellular
• Evolution of cells:
– Present day cells evolved from a common
prokaryotic ancestor
– Endosymbosis: Certain organelles were acquired
into eukaryotes by engulfing prokaryotes. This is
seen with the mitochondria and chloroplast. They
both have separate DNA, are similar in size to
bacteria and reproduce by dividing in two
– Thought to have evolved in aerobic and
photosynthetic bacteria
Check Point
• How are eukaryotic and prokaryotic cells
different?
Cell Structure
• Cell Organization
– The cell is divided into two major parts
• The cytoplasm
• The nucleus
Cell Structure
• The Cytoplasm
– Portion of the cell outside the nucleus
– Prokaryotes and eukaryotes both have a nucleus
– The cytoplasm holds the organelles
– Organelles- structures in the cell that act like
specialized organs that make the cell run correctly
and efficiently
– http://www.youtube.com/watch?v=rABKB5aS2Zg&feature=related
Cell Structure
• The Nucleus
– Contains nearly all the cell’s DNA and, with it,
coded instructions for making proteins and other
important molecules
– Surrounded by a double membrane called the
nuclear envelope with nuclear pores, which allow
materials in and out, like RNA and proteins
Cell Structure
• The Nucleus
– Chromosomes, which carry the cell’s genetic
information, are housed in the nucleus.
– Chromosomes are spread out and threadlike
through the nucleus. In this state they are called
chromatin- a complex of DNA bound to proteins
– Nucleolus- small dense region in the nucleus,
where assembly of ribosomes begins
– http://www.youtube.com/watch?v=tRo73dzVfuo
Check Point
• What is the function of the cell nucleus?
Cell Structure
• Vacuoles
– Large, sac-like, membrane enclosed
– Store materials like water, salts, proteins and
carbohydrates
– Central vacuole- In plant cells, filled with liquid to
increase rigidity
– Contractile vacuole- In unicellular organisms and
some animals, pumps excess water out of the cell.
– http://www.youtube.com/watch?v=zW9B3jC-1Xc
– http://www.youtube.com/watch?v=hUkZwSHZjhY
Cell Structure
• Vesicles
– Smaller then vacuoles, membrane enclosed
structures
– Store and move materials between cell organelles
and the cell surface
Cell Structure
• The Cytoskeleton
– Network of protein filaments that give cells their
shape, internal organization and movement
– May carry materials from one part of the cell to
another or move the entire cell
Cell Structure
• The Cytoskeleton
– Microfilaments: Made of a protein called actin, tough
flexible frame work that supports the cell. Also help the
cell move (amoebas crawl along the surface with
cytoplasm movement)
– Microtubules: hollow structure made up of tubulin.
Maintain cell shape, cell division (form mitotic spindle used
to separate chromosomes)
– Centrioles are microtubules found in animal cells only that
help with cell division
– Microtubules also build cilia and flagella which control
movement
– http://www.youtube.com/watch?v=5rqbmLiSkpk&feature=related
Check Point
• What are the functions of vacuoles,
lysosomes, and the cytoskeleton?
Cell Structure
• Ribosomes
– Ribosomes are small particles of RNA and protein
– Proteins are assembled here by following
instructions from DNA
– Protein factory
– http://www.youtube.com/watch?v=Jml8CFBWcDs
Cell Structure
• Endoplasmic Reticulum
– ER is where lipid components of the cell membrane,
proteins and other components are assembled
– Rough ER: Ribosomes are found on its surface. Newly
made proteins leave the ribosomes and are inserted
into the rough ER were they are modified. These
proteins will be released, secreted or transported to
other areas of the cell
– Smooth ER: No ribosomes attached, contain enzymes
that synthesis membrane lipids and detoxify drugs
(liver)
– http://www.youtube.com/watch?v=PASnAaulK-Y
Cell Structure
• Golgi Apparatus
– Proteins from the rough ER come here to get
modified, sorted, and packaged for storage in the
cell or release outside the cell
– Puts the finishing touches on the proteins
– Looks like flattened sacs of membranes
– http://www.youtube.com/watch?v=bD4z27ASN1M
Check Point
• What organelles help make and transport
proteins?
Cell Structure
• Chloroplast
– Solar power for plants
– Capture energy from sunlight and convert in into
food that contains chemical energy in a process
called photosynthesis
– Membrane bound, contain chlorophyll
– Have their own genetic information, DNA,
endosymbiotic with prokaryotes
– http://www.youtube.com/watch?v=LTglday5zak
Cell Structure
• Mitochondria
– Power plants of cell
– Convert chemical energy stored in food into compounds
that are more convenient for the cell to use
– Two membranes with the inner membrane folded to
increase surface area
– Mitochondria only come from the egg during fertilization,
so all the mitochondria in the worlds population come
from the mother
– Have their own genetic information, DNA, endosymbiotic
with prokaryotes
– http://www.youtube.com/watch?v=RrS2uROUjK4
Check Point
• What are the functions of chloroplast and
mitochondria?
Cell Structure
• Cell Wall
– Main function is for support, shape and protect
– Not found in animals cells
– Porous, allow water, oxygen, carbon dioxide and
other substances to pass through easily
– Cell walls are found in all plants. Made of
cellulose
Cell Structure
• Cell Membranes
– Cell membrane regulates what enters and leaves
the cell and protects and supports the cell
– Made of a lipid bilayer which gives the membrane
its chemical properties. Fatty acid head of a lipid
is called hydrophilic (water loving), the tail is
hydrophobic (water hating)
– http://www.youtube.com/watch?v=-aSfoB8Cmic
Cell Structure
• Cell Membrane
– Fluid Mosaic Model: Proteins are embedded in the
lipid bilayer and can “float” so it looks like the
membrane is moving or fluid
– Carbohydrates are attached to the proteins and act as
identification cards, the proteins act as channels or
pumps to get materials through or help change the
shape of the cell
– Selectively permeable: Some material can pass
through the membrane some can not
– http://www.youtube.com/watch?v=ULR79TiUj80
Check Point
• What is the function of the cell membrane?
Cell Specialization/Differentiation
• Cell differentiation starts from a single fertilized egg,
with one set of DNA and cellular components. Each
cell in the organism has the same genetic blueprint.
• There are three basic categories of cells that make up
the mammalian body: Germ cells ( give rise to sperm
and ova), somatic cells (body cells that for different
tissues and organs) and stem cells (able to divide for an
infinite period and give rise to specialized cells)
• During differentiation certain genes are turned on, or
become activated, while other genes are switched off,
or inactivated
• http://www.teachersdomain.org/resource/tdc02.sci.life.stru.differe
nt/
From One Cell To Many
• Embryo: developmental stage from which an
adult organism is gradually produced
• Differentiation: Process by which cells become
specialized. During the development of an
organism, cells differentiate into many types
• Differentiation determines a cells identity, how a
cell will spend its life
• In mammals adult cells do reach a point at which
their differentiation is complete, they can no
longer become other types of cells
Check Point
• How do cells become specialized for different
functions?
Stems Cells and Development
• Totipotent: a cell that can literally do
everything, to develop into any type of cell in
the body. Only the fertilized egg and the cells
after the first few divisions are totipotent
Stem Cells and Development
• Human Development
– Blastocyst: After four days of development a
hollow ball of cells with a cluster of cells inside
known as the inner cell mass.
– The cells begin to specialize, outside cells form
tissues that attach to the mother, inside cells are
called pluripotent, can develop into most, but not
all, of the body’s cell types
Stem Cells and Development
• Stem Cells: the unspecialized cells from which
differentiated cells develop. Sit at the stem of
development from which different cell types form
– Embryonic Stem Cells: they are the pluripotent cells.
Can form into other cells, large amount of research
– Adult Stem Cells: Referred to as multipotent,
meaning they can develop into many types of
differentiated cells. Have limited potential. Example
bone marrow cells
– http://www.youtube.com/watch?v=mUcE1Y_bOQE
Check Point
• What are stem cells?
Stem Cell Research
• Potential benefits
– Stem cells offer the potential benefit of using
undifferentiated cells to repair or replace
damaged cells and tissues
• Ethical Issues
– Human embryonic stem cell research is
controversial because the arguments for it and
against it both involve ethical issues of life and
death. Harvesting embryonic stem cells means
killing the embryo
Check Point
• What are some possible benefits and issues
associated with stem cell research?
Cell Specialization/Differentiation
• Levels of organization
– Somatic cells differentiate into different levels of
organization
• Tissues
• Organs
• Organ Systems
Cell Specialization/Differentiation
• Tissues
– Group of similar cells that perform a particular
function
• Epithelial Tissue: line in interior and exterior of the
body, skin and stomach lining
• Connective tissue: provides support and connects the
body parts, fat cells, bone cells, blood cells. Produce
collagen, give tissues strength and resilience
• Nervous tissue: transmit nerve impulses
• Muscle tissue: provide movement, some we control,
like arm and leg, some we do not, like your pupil
Cell Specialization/Differentiation
• Organs
– A group of different types of tissues that work
together to perform a single function or many
related functions
• Organ Systems
– A group of organs that perform closely related
functions
Check Point
• How does cell differentiation work?
Cell Specialization/Differentiation
• Organ Systems
– Nervous System: Brain, Spinal cord, nerves.
Recognizes and coordinates the body’s response to
changes in its internal and external conditions
– Integumentary System: Skin, hair, nail, sweat and oil
glands. Guard against infection/injury/sunburn,
regulate body temperature
– Immune/Lymphatic System: White blood cells,
thymus, spleen, lymph nodes. Protects the body from
disease, collects fluid lost from blood vessels and
returns it to the circulatory system
Cell Specialization/Differentiation
• Organ Systems
– Muscular System: Skeletal, smooth, cardiac.
Produces voluntary movement, circulate blood, aid in
digestion
– Circulatory System: Heart blood vessels, blood.
Transports oxygen, nutrients, and hormones to cells,
fights infection, removes cell waste, regulates body
temperature
– Skeletal System: Bones, cartilage, tendons. Supports
the body. Protects internal organs, allows movement.
Stores minerals, produces blood cells
Cell Specialization/Differentiation
• Organ Systems
– Respiratory System: nose, pharynx, larynx, trachea,
bronchi, lungs. Brings in oxygen, removes carbon
dioxide
– Digestive System: mouth, pharynx, esophagus,
stomach, small and large intestine, rectum. Breaks
down food, absorbs nutrients, removes wastes
– Excretory System: Skin, lungs, liver, kidneys, ureters,
urinary, bladder, urethra. Eliminates waste products
from the body
Cell Specialization/Differentiation
• Organ Systems
– Endocrine System: Hypothalamus, pituitary,
thyroid, parathyroid, adrenals, pancreas, ovaries,
testes. Control growth, development, and
metabolism, maintains homeostasis
– Reproductive System: Testes, epididymis, vas
deferens, urethra, penis, ovaries, Fallopian tubes,
uterus, vagina. Produces gametes, in females
nourishes and protects the embryo
– http://www.youtube.com/watch?v=po8D290YF9o
Check Point
• How is the human body organized?