Topic 8- Exchange And Transport In Animals Flashcards
What do cells need for aerobic respiration? What’s the waste product? How do they move?
Oxygen
Carbon dioxide
Diffusion
How’s water taken up by cells? What also moves with it?
Osmosis
Dissolved food molecules and mineral ions
Where and how is urea removed from the body?
It diffuses from cells to blood plasma for removal from body via kidneys.
What affects the ability to exchange substances with its environment?
Surface area to volume ratio
How does size affect surface area to volume ratio?
Larger = smaller surface area to volume ratio
How to calculate surface area to volume ratios
Represent the organism by a block.
Find its area then find its volume.
SA:V
simplify
How do single-celled organisms exchange substances?
Why?
Via direct diffusion into/ out of cell across membrane.
Have high surface area to volume ratio so enough substances can be exchanged to supply full cell volume.
How do multicellular organisms transport substances?
Have smaller SA:V so is hard to exchange enough to supply full cell volume from outside surface alone.
Need exchange surface (efficient diffusion) and a mass transport system to move between exchange surface and body.
Exchange surfaces are adapted to maximise effectiveness
Factors effecting rate of diffusion
DISTANCE- shorter diffusion pathway= quicker
CONCENTRATION GRADIENT- larger gradient = quicker diffusion
SURFACE AREA- more surface area= faster rate of reaction
Where does gas exchange in mammals occur?
Alveoli
Function of lungs
Transfer oxygen to blood and remove waste carbon dioxide.
Characteristics of blood arriving at alveoli
What happens to this blood?
Contains lots of CO2 and not much O2
*Maximises concentration gradient
Oxygen diffuses out of air in alveoli to blood (high to low) CO2 diffuses oppositely to be breathed out.
How are alveoli specialised to maximise diffusion of O2/CO2
Moist lining for dissolving of gases
Large blood supply maintaining gradients
V thin walls (shorter diffusion pathway)
Large surface area (more gas exchange to take place)
Fick’s law
Rate of diffusion (proportional to) surface area*concentration difference/ thickness of membrane
Function of erythrocytes
(Red blood cells)
Carry oxygen from lungs to cells in body
Adaptations of erythrocytes
Are biconcave so have a LARGE SURFACE AREA for absorbing oxygen.
Have NO NUCLEUS so therefore has more room to carry oxygen
Contain HAEMOGLOBIN (containing iron) which binds to oxygen to become oxyhemoglobin and then releases the oxygen at body cells
Function of white blood cells
Defence against infection
2 types of white blood cell
Phagocytes
Lymphocytes
Phagocytes function
Engulfment of unwelcome organisms (phagocytosis)
Lymphocytes function
Production of antibodies (and sometimes antitoxins which neutralise toxins produced by microorganisms) against microorganisms.
What blood test levels of white blood cells will you have when you have an infection?
High as white blood cells multiply during infection to fight it off
Platelets
Small fragments of cells w no nucleus.
Platelets function
Help blood to clot at a wound so blood levels aren’t lost and microorganisms Cant get in.
What can lack of platelets cause?
Excessive bleeding and bruising
Plasma
Pale liquid carrying everything in the blood.
What does plasma hold?
Red/white blood cells Platelets Nutrients (eg glucose/amino acids) (gut to cells) Carbon dioxide (organs to lungs) Urea (liver to kidneys) Hormones Proteins Antibodies/ antitoxins
3 types of blood vessel
Capillaries
Veins
Arteries
Arteries
Vessels carrying blood away from heart.
Capillaries
Vessels involved in exchange of materials at the tissues.
Veins
Vessels carrying blood to the heart.
Artery blood pressure
HIGH
Characteristics of an artery
Lumen w thick, elastic, string walls.
Thick walls in comparison to Lumen.
Muscle (strong walls)
Elastic fibres (allowing to stretch and carry pulse)
Where do capillaries branch off of?
Arteries
Function of capillaries
Supply food/ oxygen
Take away waste like CO2
Characteristics of capillaries
V tiny and narrow
Permeable walls
Thin walls (one cell thick)
Adaptations of capillaries
NARROW (can carry blood v close to every cell to exchange substances) PERMEABLE WALLS (allowing diffusion) THIN WALLS (short diffusion pathway)
What do capillaries join up to form?
Veins
Blood pressure in veins
Lower
Vessel w valves
Veins
Characteristics of veins
Large Lumen
Valves
Thinner walls w elastic fibre and muscle
Adaptations of veins
Thin walls (as blood is lower pressure) Big Lumen (helps blood flow despite lower pressure) Valves (keep blood flowing in right direction)
Mammals circulatory system type
DOUBLE CIRCULATORY SYSTEM
(Heart pumps blood around body in 2 circuits
1 deoxygenated blood to lungs to heart
2 oxygenated blood to organs to return to heart deoxygenated)
Fish circulatory system
SINGLE CIRCULATORY SYSTEM
(Deoxygenatedblood to heart to round body in single circuit)
Picks up oxygen at gills
4 chambers of heart
Right atrium
Left atrium
Right ventricle
Left ventricle
4 major blood vessels
Aorta
Pulmonary artery
Pulmonary vein
Vena cava
Right atrium function
Receives DEOXYGENATED blood from body through vena cava
Function of right ventricle
Receives deoxygenated blood from right atrium, flowing through tricuspid valve to lungs via PULMONARY ARTERY
Left atrium function
Receives OXYGENATED blood from lungs through pulmonary vein and pushes down into left ventricle
Function of left ventricle
Receives OXYGENATED BLOOD from left atrium and gives to whole body via aorta
Which atrium has the thickest wall?
Why?
Left
Because it needs more muscle to pump blood around whole body at high pressure while right ventricle only has to pump into lungs.
Valves function
Prevent back flow of blood around heart
Cardiac output
Total volume of blood pumped by left ventricle per minute
Equation for cardiac output
Heart rate (bpm) * stroke volume (cm cubed)
Heart rate
Number of beats per minute
Stroke volume
Volume of blood pumped by one ventricle each time it contracts
Respiration
Process of transferring (releasing) energy from the breakdown of organic compounds (usually glucose).
What’s energy from respiration used for?
Metabolic processes (making larger molecules from smaller ones) Muscle contractions Maintaining steady body temp
What type of reaction is respiration
Exothermic
Transfers energy to environment via heat
2 types of respiration
Aerobic and anaerobic
Aerobic respiration
Respiration in presence of plenty of oxygen.
Equation for aerobic respiration
Glucose + oxygen»_space; carbon dioxide + water
C6H1206 + 6O2»_space; 6CO2 + 6H2O
Anaerobic respiration
Respiration in presence of limited oxygen supply
Anaerobic respiration equation
Glucose»_space; lactic acid
Why’s lactic acid produced in anaerobic respiration?
Because glucose is only partially broken down
Plant anaerobic respiration equation
Glucose»_space; ethanol + carbon dioxide
Equipment to measure rate of respiration
Respirometer
Woodlice
Water bath
Investigation of temperature’s effect on rate of respiration of woodlice.
- ) put SODA LIME GRANULES in 2 test tubes
- ) put cotton wall above soda lime in each test tube. Woodlice in one and same mass glass beads in control test-tube.
- ) set up RESPIROMETER
- ) use SYRINGE to set fluid in manometer to a known level.
- ) leave in water bath at 15 degrees c
- ) distance moved by red manometer liquid allows you to calculate volume of oxygen taken in by woodlice per minute (rate of respiration)
- ) repeat w different temps
What do soda lime granules do
Absorb CO2 produced by respiring woodlice
Hazards of experiment of temp’s effect on respiration
Soda lime is corrosive so wear goggles when handling w gloves
Don’t leave woodlice in respirometer for too long or will suffocate, make sure they don’t come in contact w soda lime
