exchange and transport in animals

Question 1

why do multicellular organisms need exchange surfaces

Answer 1

multicellular organisms have a smaller surface area to volume ratio - this makes it harder to the exchange enough substances to supply their entire volume using their outside surface area
they need an exchange surface therefore for efficient diffusion as well as a mass transport system

Question 2

surface area (formula)

Answer 2

2((l x w) + (w x h) + (h x l))

Question 3

volume (formula)

Answer 3

l x w x h

Question 4

surface area : volume ratio

Answer 4

divide both sides of the ratio by the volume to simplify

Question 5

what happens in the alveoli

Answer 5

gas exchange in mammals
blood arrives at the alveoli from the rest of the body with a high concentration of CO2 and a low concentration of O2
this maximises the concentration gradient for the diffusion of both gases
O2 diffuses out of the air and into the blood
CO2 diffuses out of the blood and into the air to be breathed out

Question 6

what are 3 adaptations of the alveoli

Answer 6

good blood supply to maintain concentration gradient
one cell thick walls minimises diffusion distance
large surface area

Question 7

diffusion

Answer 7

the net movement of particles from an area of high concentration to an area of low concentration

Question 8

what 3 factors affect rate of diffusion

Answer 8

diffusion distance
concentration gradient
surface area

Question 9

how does diffusion distance affect rate of diffusion

Answer 9

the shorter the distance that substances have to travel, the greater the rate of diffusion

Question 10

how does concentration gradient affect rate of diffusion

Answer 10

the greater the concentration gradient, the higher the rate of diffusion

Question 11

how does surface area affect the rate of diffusion

Answer 11

the larger the surface area for particles to move across, the greater the rate of diffusion

Question 12

Fick’s law

Answer 12

describes the relationship between the rate of diffusion and the factors affecting it

Question 13

Fick’s law formula

Answer 13

rate ‘∝’ surface area x concentration gradient / diffusion distance

Question 14

respiration

Answer 14

the process of transferring/releasing energy from the breakdown of organic compounds, generally glucose

Question 15

what kind of reaction is respiration

Answer 15

exothermic , transferring energy to the environment

Question 16

what is energy from respiration used for

Answer 16

metabolic processes such as protein synthesis
contracting muscles
maintaining body temperature (thermoregulation)

Question 17

aerobic respiration

Answer 17

respiration using oxygen

Question 18

symbol equation aerobic respiration

Answer 18

C6H12O6 + 6O2 —> 6CO2 + 6H2O

Question 19

anaerobic respiration

Answer 19

respiration without oxygen

Question 20

word equation anaerobic respiration animals

Answer 20

glucose -> lactic acid

Question 21

word equation anaerobic respiration (plants/yeast)

Answer 21

glucose -> ethanol + carbon dioxide

Question 22

respirometer

Answer 22

a piece of equipment that allows you to measure the effect of temperature on the rate of respiration

Question 23

method to investigate the uptake of oxygen in a given time to work out the rate of respiration

Answer 23

1) add soda lime granules to both test tubes to absorb CO2 produced by the respiring insects (or cotton wool soaked in potassium hydroxide solution)
2) insects are placed on the cotton wool in one tube and the same mass of glass beads on cotton wool on cotton wool in the other tube
3) set up respirometer
4) syringe is used to set the fluid in the MANOMETER to a known level
5) leave apparatus for a set amount of time with the water bath at 15°C
6) the distance moved by the liquid in the given time is measured and can be used to calculate the volume of oxygen taken in by the insects per minute
7) repeat at different temperatures

Question 24

why does the manometer move

Answer 24

in the time that the apparatus is left, there will be a decrease in the volume of air in the test tube containing the eggs as they will have used up oxygen as they respire
this decreases the pressure in the tube, causing the manometer fluid to move towards the insect test tube

Question 25

what are the 4 parts of the blood

Answer 25

erythrocytes white blood cells - phagocytes and lymphocytes platelets plasma

Question 26

erythrocytes

Answer 26

red blood cells carry oxygen from the lungs to all other cells in the body

Question 27

adaptations of erythrocytes

Answer 27

biconcave disc shape - increases surface area for absorbing oxygen no nucleus - increases room for carrying more oxygen contain haemoglobin - binds to oxygen to form oxyhaemoglobin which then splits up at the cells

Question 28

phagocytes

Answer 28

white blood cells that change shape to engulf unwanted microorganisms - PHAGOCYTOSIS

Question 29

lymphocytes

Answer 29

white blood cells that produce antibodies against microorganisms some produce antitoxins to neutralise toxins made my microorganisms

Question 30

platelets

Answer 30

small fragments of cell | help the blood to clot at a wound, preventing all the blood from pouring out and microorganisms from entering

Question 31

what happens if you have a shortage of platelets

Answer 31

can lead to excessive bleeding and bruising

Question 32

plasma

Answer 32

a pale straw-coloured liquid that carries everything in the blood

Question 33

what are 9 things carried by the plasma

Answer 33

``` erythrocytes white blood cells platelets nutrients (soluble products of digestion such as glucose and amino acids) CO2 urea hormones proteins antibodies/antitoxins ```

Question 34

3 types of blood vessel

Answer 34

arteries veins capillaries

Question 35

arteries

Answer 35

carry blood away from the heart | arteries branch into capillaries

Question 36

capillaries (role)

Answer 36

involved in the exchange of materials at the tissues | supply food and oxygen and transport waste products away

Question 37

veins

Answer 37

carry blood back to the heart | capillaries join back up to form veins

Question 38

structure of an artery (4 points)

Answer 38

- strong, elastic artery walls to cope with blood being pumped out of the heart at a high pressure - thick walls compared to the lumen (small lumen) - thick layers of muscle make them strong - elastic fibres allow the artery walls to stretch and spring back

Question 39

structure of capillaries (3 points)

Answer 39

- very narrow so can squeeze in gaps between cells allowing them to carry blood close to every cell in the body - permeable walls for diffusion that are one cell thick - very small lumen

Question 40

structure of veins (4 points)

Answer 40

- less thick walls as blood is travelling at a lower pressure - larger lumen than arteries to help blood flow despite lower blood pressure - thin layer of elastic fibres and smooth muscles - valves to prevent backflow

Question 41

how does blood flow through the heart (blood vessels and chambers)

Answer 41

vena cava -> right atrium -> right ventricle -> pulmonary artery -> *TO THE LUNGS* -> pulmonary vein -> left atrium -> left ventricle -> aorta -> *TO THE BODY*

Question 42

how does the wall of the left and right ventricle differ and why

Answer 42

the left ventricle has a much ticker wall than the right ventricle as it has to pump blood around the body at a much higher pressure so needs more muscle

Question 43

cardiac output formula

Answer 43

cardiac output (cm^3min^-1) = heart rate x stroke volume (cm^3)