Biology
Chapter 1
— Mrs Gren
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Movement
Respiration
Sensitivity
Growth: Permanent increase in size or number of cells
Reproduction: Able to create offsprings of the same species as the parents
Excretion
Nutrition
— Biological classification system
– Species: a group of organisms that can reproduce to produce fertile offspring
– Binomial naming system (always in italics)
— Classification
– Keep pond clean or frog get sick
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Kingdom
Phylum
Class
Oder
Family
Genus
Species
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2
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5
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7
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1
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6
7
. Panthera (genus) - Starts with capital letter
. tigris (species) - Starts with small letter
Animals, plants, fungi, protoctista, prokaryotes
Animals
– Multicellular
– Have a nucleus
– Feed on organic substances made by other living things
Plants
– Multicellular
– Have a nucleus, chloroplast & cellulose cell walls
– Feed by photosynthesis
Fungi (moulds, mushrooms, yeast)
– Main body of most fungi is made up of hyphae (microscopic threads)
– Cell wall not made of cellulose
– Usually multicellular, some (yeast) are unicellular
– Do not have chlorophyll
– Feed by digesting waste organic material
Protoctist 原⽣动物
– Have cells with nucleus
– Some have plant-like cells with chloroplast & cellulose cell wall
– Most protoctist are unicellular but some are multicellular (seaweeds)
– Some feed by photosynthesis / organic substances made by other organisms
– Prokaryote
– Unicellular
– Do not have nucleus, mitochondria
– Have cell wall, not made of cellulose
– Have cytoplasm
– Have a circular loop of DNA
– Have plasmid
— Using DNA to classify organisms
– Organisms share features because they descend from a common ancestor
– DNA base sequencing allow us to classify organisms
— Animal Kingdom
● Vertebrates
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– Have backbone
Mammals
Birds
Reptiles (snake)
Amphibians 两栖动物
Fish
Invertebrates
– Do not have a backbone
– Classified by having how many legs
Myriapods (centipede)
– Many body segments
– Have many jointed legs
– 1 pair antennae
Insects (butterfly, bee)
– 3 parts body (head, thorax, abdomen)
– 3 pairs of jointed legs
– 2 pairs of wings
– 1 pair of antennae
Crustaceans (crab lobster)
– Mostly sea creatures
– More than 4 pairs of legs
– Breathe through gills
– 2 pairs of antennae
Arachnids (spider, scorpion)
– 2 part body [cephalothorax, abdomen]
– 4 pairs of jointed legs
– No antennae
— Plant Kingdom
● Fern
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– Have leaves called fronds
– Do not produce flowers
– Reproduce by spores produced on the underside of fronds
– Plants with roots, stem, leaves (fronts)
Flowering plants
– Plants with roots, stem and leaves
– Reproduce sexually using flower & seeds
– Seeds are produced inside the ovary found at the base of the flower
– Divided into 2 main groups
. Dicotyledon (双叶⽚
– Flowers: multiple of 4 & 5
– Leaves: reticulated (状叶⽚ leaf veins [web-like network throughout the leaf]
. Monocotyledons (单叶⽚
– Flowers: multiples of 3
– Leaves: parallel leaf veins (平⾏叶状
— Viruses
– Not considered as living thing
— Protein coat called caspid
Chapter 2 - Cells
Animal & Plant Cells
. Nucleus (structure containing DNA in the form of chromosomes)
– Largest organelle in the cell
– Control all cellular activities
– Contain genetic materials (DNA)
. Cytoplasm (watery jelly hat fills the cell)
– 70% water in many cells
– Contains many substances dissolved in it (protein)
– Many different metabolic reactions take place in cytoplasm
. Cell Membrane (thin membrane around the cytoplasm of the cell)
– Very thin layer of protein of fat
– Semi/Partially-Permeable
– Separates the contents of a cell from its external environment (surroundings)
– Regulates substances entering and leaving the cell
– Allow allows the exchange of nutrients, respiratory gases and waste products
between the cell and environment
. Cell Wall (a tough layer outside the cell membrane)
– Cells of plants, fungi, bacteria
– Fully permeable [all molecules & ions can pass through]
– Provide support & protection
– Prevent cell from bursting
. Vacuole (a fluid filled space inside a cell)
– Filled with cell sap containing water, dissolved sugar, salts, pigments, waste
– Store chemical such as organic acids, sugar, amino acid
– Help to keep the cell in shape
. Chloroplast (smart structure found inside some plant cell)
– Never found in animal cells
– Often contain starch grains (made by photosynthesis)
– Contain green pigment called chlorophyll
– Carrying out Photosynthesis
. Rough Endoplasmic Recticulum (Rough ER)
– Has ribosomes on it (small, round organelles) —> make protein
– Transport protein made by ribosome
. Smooth Endoplasmic Recticulum (Smooth ER)
– Does not have ribosome attached
– Synthesis & transport lipids (fat/oil)
– Carries out detoxification of drugs
. Mitochondrion (aerobic respiration)
– Site of cellular respiration
– Produce energy
. Ribosome (Make protein molecules)
– Site of protein synthesis
. Vesicle (Very small vacuole)
– Stores & transport substances throughout the cell
. Golgi Apparatus
– Packaging, processing & transport the vesicle
– Build lysosome
. Lysosome
– Function as digestive
– Enclosed organelles that contain enzymes
Animal & Plant Cells Have:
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Cell membrane
Nucleus (contains DNA)
Ribosomes
Mitochondria
Golgi Apparatus
Endoplasmic Recticulum
Cytoplasm
Difference between animal cells and and plant cell
Animal Cell
Plant Cell
Smaller size
Larger size
Does not have a fixed shape
Has a fixed & regular shape
No cell wall
Cellulose cell wall
No chloroplast
Has chloroplast
Carbohydrate storage glycogen
Carbohydrate storage - starch
Cells & Organisms
● Unicellular Organisms
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– Organisms which consist of a single cell
– E.g Amoeba, Paramecium, Yeast
Multicellular organisms
– Organisms that consist of more than one cell
. Cells (red blood cells transport oxygen, chloroplast does photosynthesis)
. Tissues [Similar cells work together to perform a particular function]
. Organs (heart, flowers & fruit for reproduction)
. Organ System (digestive system requires stomach, intestine, .etc)
. Organisms
Size of Specimens
– Magnification: Size of image / size of an actual object
Cells
● Red blood cell
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– Disc Shaped
– Large surface area
– Does not have a nucleus
– Transport Oxygen
Never cells / neurone
– Send electrical signals through the body
Sperm & Egg Cells
– Together known as gamete
– Fuse together to produce zygote
Ciliated epithelial cells
– lining trachea & bronchi of animals
– Cilia carry hair, muscle, trapped dust and bacteria up to the throat where it can
be swallowed
– Move the ovum through the fallopian tubes to the uterus
Root hair cells
– Large surface area
– To grow easily between the soil particles
– Speed up absorption of water
Palisade cells
– Located under the upper epidermis
– Absorb maximum light
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– Most photosynthesis take place in the palisade cells
– Contain most of leaf’s chlorophyll
Xylem Vessels
– Control water & ions dissolved salts) from the rots, leaves, flowers & fruits
– Formed by dead cells, connecting
Chapter 3 — Movement in and out of the cell
Plasma membrane
– Cell membrane
– Forms a barrier between cytoplasm inside the cell & the environment outside the cell
– Protects & support the cell
– Semi-permeable (only allow certain substance to pass through)
Types of Transport across plasma membrane
. Passive transport
– transport down the concentration gradient (going from regions of high
concentration of some entity to regions of low concentration)
– Simple diffusion, Osmosis
. Active transport
– Molecule transport against the concentration gradient
Simple Diffusion
– Net movement of particles from a region of high concentration to low concentration
– Does not require energy from the cell (passive process)
Factors that influence diffusion
– Surface area to volume ratio
– Bigger cell or structure, smaller surface area to volume ratio
. Distance
– Blood capillaries & alveoli have walls which are one cell thick for faster transport of
oxygen
. Temperature
– Higher temperature, faster molecules move, faster rate of diffusion
. Concentration Gradient
– Higher concentration gradient, the faster the rate of diffusion
. Size of molecules/ions
– Larger molecules/ions, slower the rate of diffusion
. Pressure
– Higher pressure, faster rate diffusion
Concentration Gradient
Osmosis
– Net movement of water molecules across a partially permeable membrane
– Region of higher water concentration to lower water concentration
– Only for water
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Hypotonic solution
– Lower concentration of solute
– Higher concentration of water
Hypertonic solution
– Higher concentration of solutes
– Lower concentration of water
Isotonic Solution
– Solute concentration inside & outside are the same
– Water molecules diffuses from high concentration to low water concentration
– Across partially permeable membrane
– Water moving down its concentration gradient
– Only allow small molecules (water) through
Osmosis in plant cell
– Water moves into a plant cell —> Vacuole Enlarge —> Pushing cell membrane against the
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wall
Water entering the cell by osmosis makes the cell rigid and firm (turgid)
– Making the plant stand upright with its leaves held out to catch sunlight
– If plant don’t receive enough water, cells cannot remain turgid
Plants cell in solutions of different concentration
● Dilute solution
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– Plant cell will gain water by osmosis (water move into the cell)
– Plant cell get turgid
Concentrated solution
– Plant cell loose water by osmosis
– Plant cell become flaccid & plasmolyse
– Plant loose firmness and ability to support itself, and begin to wilt 植物枯萎
Animal Cells solution of different concentration
● Dilute Solution
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– Animal cell will gain water by osmosis
– the cell may burst as there is no cell wall to create turgor pressure
– burst when cell membrane stretch too far
Concentrated solution
– Animal cell loose water by osmosis
– The cell will become crenated (shrivelled up) [become dry, smaller]
Active Transport
– The movement of molecules or ions trough cell membrane from lower to higher region of
concentration (against the concentration) using energy from respiration
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Protein Carriers
– Protein molecules in cell membranes uses energy to change shape & move ions or
molecules into or out from a cell
Mitochondria
– Carry out respiration
– Provide energy
— Chapter 4: Biological Molecules
Human is made of
● 62% of Water
● 16% of protein
● 16% of fat
● 1% of carbohydrates
● 6% of calcium & phosphorus
Carbohydrates
– Starch, cellulose, sugar
– Made of Carbon, Hydrogen, Oxygen
– Simplest type / smallest molecules: Sugar
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Glucose
– C₆H₁₂O₆
– Used in respiration to release energy
Glycogen
– A carbohydrate that is used as energy stored in animal
Starch
– A carbohydrate that is used as energy store in plant cells
– Can be broken down to form glucose again when the plant needs it
Cellulose
– Made of many glucose molecules linked in a chain
– used on making plant cells
Unit
Description
Chemical
Test
Before
if
positive
Tested
Reducing
Sugar
sugar that
is capable
of acting
as a
reducing
agent
Benedict’s
Solution
Blue
Orange
Iodine
Solution
Brown
Black
Starch
Protein
Long chain Blue
Biuret Test
Violet
of amino
acid
e.g
antibodies,
haemoglobin
haemoglobin
(transport
oxygen)
C₆H₁₂O₆
Lipids
- Fat
(solid), Oil
(liquid)
- Insoluble
in water,
dissolve in
ethanol
- made of
glycerol &
fatty acid
Vitamin C
Ethanol
Emulsion
Test
None
DCPIP test Blue
DNA Base
– A pair with T
– G pair with C
— Chapter 4: Enzyme
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Enzymes are Catalysts (催化剂)
– Substance that speeds up the chemical reaction
– Remain the same after the reaction (reusable)
Enzymes are Protein
Every metabolic reaction is controlled by catalyst called Enzyme
. Reactions would take place very slow or not at all without enzyme
. Needed in small amount
. Reactions are reversible
Milky
emulsion
formed
Colourless
(slightly
pink)
. Can be slowed down or completely stopped by inhibitors (heavy metals: lead, mercury)
. Highly specific (lock & key)
– Can only catalyse a single reaction
– Have active side that bind to specific substrate
Naming of Enzymes
– Adding {ase} to the name of the substrates they hydrolyses
Substrate
Enzyme
Carbohydrate
Carbohydrase
Sucrose
Sucrase
Lipid
Lipase
Maltose
Maltase
Protein
Protease
– Protein —> Catalyse by Protease —> Amino Acid
– Protein —> Catalyse by Amylase —> Maltose
– Enzyme breaks down hydrogen peroxide to water & oxygen
– Hydrogen peroxide is produced by many chemical reactions and has to be broken
down because it is high toxic
– Enzyme + Substrate —> Enzyme Substrate Complex —> Product + Enzyme
Factors that influence catalyse of enzyme
. Temperature
– Optimum temperature: 37 Celsius
– High temperature causes enzymes to denature
– Low temperature: less substrate turned into product
– High temperature: more substrate turned into product
. PH
– Optimum pH value: 7 for most enzymes
– Stomach enzymes : pH 2 (acidic)
– Intestinal enzyme: pH 8/9 (alkaline)
– Non optimum pH will cause the change of active side, reducing the rate of activity
– Extreme pH will cause enzymes to denatured
Chapter 6: Plant Nutrition
● Taking in useful substances
Leaf
Adaptation Of Leaf
– Large surface area
– Allow large amounts of sunlight to fall onto the leaf
– helps carbon dioxide to reach all the cells by diffusion
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Cuticle
– Thin layer of wax that covers the upper surface of a leaf
– Waterproof: help prevent excessive water loss
– Transparent: allow light to pass through
Upper Epidermis
– Single layer, thin & transparent
– A barrier against disease organism
Palisade mesophyll
– Beneath upper epidermis
– High density of chloroplast
– Receive CO2 by diffusion from air spaces in spongy mesophyll
Spongy Mesophyll
– Beneath palisade mesophyll
– Contain fewer chloroplast
– Large air space for easy diffusion of water & carbon dioxide through the interior of
the leaf to the palisade cells
Vascular bundle
– Collection of xylem tubes & phloem vessels running side by side
– form vein in a leaf
– Xylem: dead cells (hollow tube) transport mineral ions & water to the leaf
– Phloem: transports photosynthesis products away
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Lower Epidermis
– Does not contain chloroplast
– Protective layer
– Stomata to regulate loss of water —> transpiration
Stomata
– Site of gaseous exchange into and out of the leaf
– Water vapour passes out during transpiration
– CO2 diffuses in & O2 diffuses out
– surrounded by pairs of guard cells that control whether the stomata is close or
open
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Plant Respiration
– Reaction in which plants make carbohydrates from carbon dioxide & water using light as
source of energy
Happens in chloroplast
Enzymes & Chlorophyll are catalysts & supply energy for the reaction
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Carbon Dioxide + Water — Light + Chlorophyll —> glucose + oxygen
6CO2 + 6H2O — Light + Chlorophyll —> C6H12O6 + 6O2
Requirement for Photosynthesis
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Light - Energy for the process
Chlorophyll - Green pigment that absorb energy from light
Carbon Dioxide - Diffuse into leaf from air
Water - absorbed by root in a cell
Products of photosynthesis
. Glucose
– Convert to starch (for energy storage)
– Convert to cellulose (for cell walls)
– Convert to sucrose (for transportation in phloem)
– Convert to other sugar, make nectar (attract pollinator), to make amino acids
(protein), or other substances like chhlorophyll
. Nitrate Ions
Factors affecting photosynthesis
. Supply of raw materials: CO2 & H2O
. Quantity of sunlight
. Temperature (affect the activity of enzymes)
Of photosynthesis increase
— Chapter 7: Human Nutrition
– Balance diet is essential for the healthy growth & development of the body
Nutrients
● Carbohydrate
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– Source of energy
– Bread, pasta, rice
– Starvation
– Excessive: diabetes, obesity
Lipids (fat & oil)
– Source of energy
– Insulation (keep warm)
– Make cell membrane
– Butter, eggs
– Dry scaly skin, poor vitamin absorption
– Excessive: coronary heart disease
Protein
– Metabolic catalysts
– Repairs muscle
– Meat, fish, cheese
– Kwashiorkor, marasmus
– Excessive: kidney stones
Vitamin A
– Protect surface of the eye, connective tissue
– Fish liver oil, carrots
– Vision problems (night blindness)
– Dry cornea, scaly skin
– Excessive: hair loss, vomiting, bone ache, joint pain, liver & bone damage
Vitamin C
– Maintain healthy skin, bone, gum
– Strong antioxidant
– Poor collagen formation, scaly skin, bleeding gums, tooth loss
– Excessive: gastrointestinal
Vitamin D
– Helps in the absorption of calcium & phosphorus ions
– Bone growth
– Egg yolk
– rickets
– Excessive: too much calcium in blood
Calcium
– Bone & teeth formation
– Helps in blood clotting
– Milk, cheese, vegetables
– Rickets, stunted growth, delayed blood clotting
– Excessive: hypercalcemia (too much calcium)
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Iron
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Fibre
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Water
– Component of haemoglobin needed for oxygen transport in the blood
– egg yolk, meat
– anaemia, iron-deficiency
– Maintain peristalsis of intestine (contraction & relaxation)
– Fruits, vegetables
– Constipation
– Formation of blood, cytoplasm & waste product (urine)
– Dehydration
Factors affecting daily energy requirements of individuals
● Age
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– Growing children & teenagers need more energy for growth
Gender
– Metabolic rate in males is much higher than in females (male need more energy)
Occupation
– Active person needs more energy
Pregnancy & lactation
– Pregnant woman needs more energy (to support growing fetuses, and produce milk)
Climate
– People living in cold countries require more energy to maintain body temperature
— Chapter 8: Plant Transport
– All organisms need to obtain substances from their environment
– Plants need carbon dioxide, water & mineral ions
Plans absorb water through their roots and the water must be transported to the leaves
Plant transport system
● Water transport tissue - xylem (root to leaves)
● Sucrose & amino acid transport - phloem (leaves to other parts)
Xylem
– Long drain pipe formed by hollow dead cell
– No cytoplasm and nuclei
– Cell walls are thickened with lignin & cellulose which makes it strong and keep plants
upright
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Xylem vessels helps the leaf to be hell flat, provide large surface area to absorb light
Movement in xylem only takes place in one direction (roots to leaves)
Root Cells
– Plants take in water from the soil through their root hairs
– Root Cap is a layer of cells which protects the root as it grows
– Epidermis is a layer which covers the root
– Each root hair is a long epidermal cell - Root hairs do not lie for very long. As the root
grows, they are replaced by new ones
Functions of Root Hair Cells
– Increase the external surface area of the root for absorption of water (osmosis) & ions
– Provide anchorage (锚地) a place where vessels anchor for the plant
Pathway of water through plant
Root hair cells —> Root Cortex Cells —> Xylem —> Leaf Mesophyll Cell
– Osmosis causes water to pass into the root hair cells and complete the whole process
Transpiration
– Loss of water vapour through evaporation from the surface of plants
– Take place through the stomata of the leaves
Transpiration Stream/Pull
– Loss of water is replaced by the absorption of water from soil by the plant roots
– Water is constantly being taken from the top of the xylem, to supply the cells in the leaves,
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this makes the water flows up and this is known as Transpiration Pull
Movement of water in the transpiration pull is down a water potential gradient
“Driven” by the evaporation of water as each evaporating molecule pulls another one
behind it because of cohesion of water molecules
Mineral ions are taken by active transport into the root hairs, and passively in the
transpiration pull
Importance of transpiration
– Transport mineral ions
– Providing water to keep cells turgid in order to support the structure of the plant
– Providing water to the leaf for photosynthesis
– Keep the leaves cool
Measuring Transpiration Rates
– A photometer (measure rate of transpiration) is a device used for measuring the rate of
water uptake of a leafy plant shoot.
Factor Affecting The Rate of Transpiration
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Light Intensity
Temperature
Humidity
Air Movement/Windspeed
Water Supply
Translocation
– Movement of organic food such as sucrose & amino acid in phloem
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Regions of production (source) to regions of storage (sink)
Source is the part of a plant where substances are produced (e.g. leaves)
Sink refers to the part of the plant where the substance can be stored (e.g. roots or stem
for starch)
— Chapter 9: Transport in Animals
– Main transport system of all mammals is the circulatory system, pump and system of tubes
(blood vessels)
Heart
– Made of cardiac muscle
– Usually size of a fist, weight around 250-350 grams
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Activity of the heart can be recorded as ECG (electrocardiograph)
– As the heart contracts, it pumps blood
– When it relaxes, its chambers are filled with blood
– Heart has valve to prevent blood from back flowing
Double circulatory system
– Found in all mammals, birds & reptile
– There are two circuits from the heart
Coronary Artery
– Blood vessels for heart
– Vessels that delivers oxygen blood to the heart muscle
Coronary Heart Disease (CHD)
– Coronary arteries get blocked
– Blood clot/cholesterol deposit build up inside the walls of arteries, including the coronary
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arteries
Deposits make the artery wall stiffer and the lumen narrower, and makes the blood
difficult to flow
Treatment for CHD
● Drugs
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– Asprin: decrease the risk of blood clots
– Statin: Lowers the level of cholesterol
Operation
– Coronary bypass: Replace blood vessel from other part of the body
– Insert Stent/ting ballon to keep artery open
Heart transplant
Blood Vessel
– Types of blood vessel
. Arteries: Carry blood away from heart
. Veins
. Capillary: Join up with one another to form large vessels called vein
Arteries
– Take blood away from heart
– Narrow
– Thick, muscular, elastic artery wall, high pressure
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Pulmonary Artery: Carry deoxygenated blood from heart to lungs
Pulmonary Vein: Carry Oxygenated from lungs to heart
Capillaries
– When arteries reach an organ, it splits into smaller vessels
– Thinnest blood vessels called capillaries
– One cell thick
– Permeable, allow carbon dioxide, oxygen & nutrients to diffuse between cells
– Exchange of substance
– Very narrow
Vein
– Bring blood back to heart
– Vein have thinner walls, not under high pressure
– Have valves to prevent blood back flowing
Content Of Blood
● Blood Plasma [55%]
– 90% water
– Yellowish fluid
– Contains antibodies, clotting factors, nutrients and waste
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Red Blood Cells [45%]
– Carry haemoglobin & oxygen
– Do not have nucleus
– Biconcave shape
– Formed in bone marrow & recycled in liver
White Blood Cells [<1%]
– Fight Infection
– Clear up dead body cells by digesting bacteria phagocytosis
– Formed in bone marrow
Platelets [<1%]
– Clot blood
– Made in bone marrow
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Process Of Blood Clot
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Blood vessel is cut
Platelets react by releasing chemical
Damaged tissues around the blood vessel also release chemical
Chemical released by platelets & damaged tissues set a chain of reaction:
– Fibrinogen —> Fibrin
– Insoluble protein
– Forms fibre mesh across the wound
Blood clot prevent blood lost and entry of pathogens
White Blood Cells
● Phagocytes
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– Engulf 吃 pathogen
– Have nucleus
– Can move around body
Lymphocytes
– Release antibodies
— Chapter 10: Pathogen and Immunity
– Pathogen is a microorganism that causes disease
– Where a pathogen lives and breeds is called a host
– Transmissible disease - can be passed from one host to another
– Pathogens damage our cells by using up our cell’s resources or producing waste products
called toxins
Bacteria
– Single celled organisms without nucleus
– Cholera, syphilis, cough, food infection
Virus
– Non living things
– Influenza, common cold, AIDS
Fungi
– Simple organisms, including mushrooms and yeasts
– Athlete’s foot, ringworm, mushroom poisoning
Protozoa
– Single celled organisms with a nucleus
– Malaria, amoebic dysentery
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Pathogens can be transmitted through direct contact (blood & other fluid) or indirect
contact (contaminated surface, food, air)
Body defences
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Skin - Prevents pathogens from entering the body
Hairs in nose - Filter out particles from the air that could contain pathogens
Mucus in the airway - Traps bacteria, swallowed rather than into lungs
Stomach acid - Hydrochloric acid kills bacteria
White Blood Cells
Control Spread Of Disease
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Clean Water Supply
Hygienic food preparation
Good personal hygiene
Proper waste disposal
Sewage treatment
Diarrhoea
– Infection of colon lead to diarrhoea (watery feaces) partly because water is not being
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absorbed, but also because water is being drawn from the cells in the wall of the colon
which might help to ‘flush out’ the pathogens
Oral Rehydration Therapy (ORT) is a treatment for diarrhoea
One of these is infection by bacterium which causes the disease cholera
Antigen
– Molecules found on the outside of a pathogen
– Each pathogen has its own antigen, which have specific shape
– To destroy a particular pathogen, antibody molecules must be made which are a perfect
complementary shape to the antigen on the pathogen
– Lymphocytes react to pathogens by producing antibodies (immune response)
– Lymphocytes divide rapidly by mitosis, making clone of itself to fight pathogens
Memory Cells (immune system)
– Memory cells are produced when an individual’s specific immune system responds to a
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pathogen (the response involving lymphocytes and anti body production)
Memory cells can stay in blood for many years, it can react faster when the same
pathogen infects again
– Memory cells plays an important role in vaccination
— Chapter 11 - Respiration & gaseous exchange
Nose
– Hair in the nose trap dust particle
– Lining of the nose contain mucus which traps bacteria
– Blood vessels beneath nasal lining release heat that warm the air
Trachea
– It provides support and prevents the tubes collapsing when the air pressure inside is low
– Trachea has mucus secreting cells & ciliated epithelial cells
Lungs
– Provide the body with oxygen and removal of carbon dioxide
– Right Lung: 3 lobes
– Left Lung: 2 lobes
Bronchi
– Trachea divides into two smaller tubes called bronchi (bronchus)
Adaptation of the alveoli
– Thin - faster diffusion
– Large surface area - sufficient amount of gases able to be exchanged
– Moist - Gases can dissolve before diffusing
– Good Blood Supply - They are richly supplied with capillaries for rapid transport of gases
— Alveoli is where the actual gaseous exchange takes place
– Oxygen from the inhaled air dissolves in the moist alveolar lining and moves by diffusion
through the walls of the alveolus and the capillary next to it
– Oxygen diffuses into the blood and enters the red blood cells, which contain haemoglobin
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(transport oxygen)
The oxygen that combines with the haemoglobin to make oxyhemoglobin (haemoglobin
with oxygen) which is bright red in colour
Blood that received oxygen is known as oxygenated blood
The Diaphragm
– Large sheet of muscle attached to the edges of the tenth pair of ribs and backbone
Gas
Inspired Air
Expired Air
Oxygen
20%
16%
Carbon Dioxide
0.04%
4%
Argon/Noble
1%
1%
Water (humid)
Variable
Always High
Temperature
Variable
Always Warm
Aerobic Respiration 有氧呼吸
– Process in which sugar (glucose) are converted into usable energy (ATP)
– Sugar (C6H12O6) + Oxygen (O2) —> Carbon Dioxide (CO2) + Water (H2O) + Energy (ATP)
– Involve mitochondrion
Anaerobic Respiration ⽆氧呼吸
– Breaking down of sugar to produce energy where oxygen is absence
– Takes place in cytoplasm
– Incomplete oxidation
Oxygen Debt
– Muscle initially respire aerobically when oxygen is present, as soon as oxygen is used up
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as the blood cannot supply oxygen fast enough, anaerobic respiration will be used.
When muscles are in a state of oxygen deficiency, an oxygen debt occurs
Use of anaerobic respiration produces lactic acid which when it reaches high level of
concentration will cause muscle cramp and fatigue
Oxygen debt will be paid off when there is enough oxygen to oxidise the accumulated
lactic acid to carbon dioxide and water
– Oxygen debt is the amount of oxygen needed to remove lactic acid from the muscle
cells
Similarities of Anaerobic & Aerobic Respiration
– Both are cellular respiration
– Both involve breaking down of glucose
– Both releases energy that is stored in the ATP molecules