exchange and transport in animals

Question 1

what is the equation for cardiac output?

Answer 1

cardiac output= stroke volume x heart rate

Question 2

what are 2 examples of exchange surfaces?

Answer 2

• root hair cells in plants: large surface area and thin walls in order to take up water and nutrients from the soil and thin so that diffusion across the wall happens quicker
• walls of nephrons in the kidney: thin walls and large surface area because they need to reabsorb substances like water and glucose

Question 3

what is diffusion?

Answer 3

the movement of particles from a high concentration to a low concentration

Question 4

what are alveolis?

Answer 4

small air sacs in the lungs that allow gas exchange between the lungs and blood

Question 5

what are 2 adaptations of alveolis?

Answer 5

• they are very small meaning there is more space for diffusion to take place around
• thin walls so there is a short diffusion pathway

Question 6

how does the difference in concentration affect the rate of diffusion?

Answer 6

the more difference in concentration, the faster the rate of diffusion

Question 7

how does temperature affect the rate of diffusion?

Answer 7

the higher the temperature, the more movement of particles and more collisions so a faster rate of diffusion

Question 8

how does surface area affect diffusion?

Answer 8

the greater the surface area, the more space for particles to move so a faster rate of diffusion

Question 9

how do you calculate the rate of diffusion?

Answer 9

rate of diffusion= surface area x concentration difference/ thickness of membrane

Question 10

what are the 4 things that blood is made up of?

Answer 10

• plasma
• red blood cells
• white blood cells
• platelets

Question 11

what are the features of red blood cells?

Answer 11

• they carry oxygen
• they have a bi concave shape which has a large surface area to carry more oxygen
• no nucleus, more room for oxygen to be carried
• they contain haemoglobin which binds to oxygen

Question 12

what are the features of white blood cells?

Answer 12

• part of the immune system that defends against pathogens
• they have a nucleus

Question 13

what are the 2 main types of white blood cells?

Answer 13

• phagocytes: engulf the pathogen
• lymphocytes: produce antibodies

Question 14

what are platelets?

Answer 14

small fragment of cells that help the blood to clot when there is a wound, the clot dries to form a scab where new skin grows

Question 15

what are the 3 types of blood vessels

Answer 15

• arteries
• veins
• capillaries

Question 16

what do arteries do?

Answer 16

• carry blood away from the heart
• carry oxygenated blood except the pulmonary artery
• carry blood under high pressure
• thick walls
• narrow blood vessel

Question 17

what do veins do?

Answer 17

• carry blood to the heart
• carry deoxygenated blood except the pulmonary vein
• carry blood under low pressure
• thin walls
• wide blood vessel

Question 18

what do capillaries do?

Answer 18

allow the blood to flow very close to the cells to enable substances to move between them

Question 19

what are the differences between aerobic and anaerobic respiration?

Answer 19

aerobic:
- used oxygen
- needs the most energy
- mainly happen in the mitchondria
- glucose + oxygen –> carbon dioxide + water

anaerobic:
- happens when there is not enough oxygen
- used as a last resort e.g when sprinting and its hard to breathe
- glucose gets converted into lactic acid which makes the muscles ache

Question 20

draw and label the heart

Answer 20

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