SIZE AND SURFACE AREA

Question 1

What do most cells need to exchange with the environment (3 points)

Answer 1

1) take in oxygen for aerobic respiration and nutrients
2) excrete waste products (e.g. C02 and urea)
3) heat - to stay at the same temperature

Question 2

What 2 main factors affect the rate of exchange of substances

Answer 2

1) surface area: volume ratio

2) surface thickness

Question 3

How does surface area: volume ratio affect the rate of exchange

Answer 3

bigger SA:V ratio = faster rate of exchange

Question 4

How do you find the volume

Answer 4

the area of the surface of one side times the volume

Question 5

How do you find the surface area

Answer 5

surface areas of all sides added

Question 6

Why do multi-cellular exchange via mass transport rather than diffusing directly

Answer 6

diffusion is too slow

Question 7

Why is diffusion too slow in multi-cellular organisms (2 points)

Answer 7

1) some cells are deep within the body so theres a large distance to travel for diffusion
2) larger animals have a smaller SA:V ratio

Question 8

What is mass transport

Answer 8

an efficient system

Question 9

What is mass transport usually in mammals

Answer 9

circulatory system

Question 10

What does the circulatory system use to transport materials

Answer 10

blood

Question 11

What does the blood in the circulatory system transport (5 points)

Answer 11

1) glucose
2) oxygen
3) hormones
4) antibodies
5) waste - e.g. C02

Question 12

What does the mass transport in plants involve

Answer 12

transport of water and solutes

Question 13

Where does mass transport in plants occur

Answer 13

xylem and phloem

Question 14

What 2 main factors affect heat exchange

Answer 14

1) surface area: volume ratio

2) shape

Question 15

How does body size affect the rate of heat loss

Answer 15

large SA:V ratio = heat lost more easily

Question 16

What do smaller organisms with a larger SA:V ratio need to stay warm

Answer 16

faster metabolic rate

Question 17

How does shape affect the rate of heat loss

Answer 17

1) compact = small SA:V = minimal heat loss

2) less compact = larger SA:V = more heat loss

Question 18

What decides if an animal is compact and give an example

Answer 18

its environment , eg fox - 
arctic fox (cold temp)=small ears, european fox (warm temp)=large ears

Question 19

What other types of adaptations are there (other than physical)

Answer 19

behavioural and physiological

Question 20

What do animals with a high SA:V ratio tend to lose more of, and what do some do to adapt to this

Answer 20

water

they have kidney structure adaptations so that they produce less urine

Question 21

What do animals living in cold regions do to support their higher metabolic rates

Answer 21

eat lots of high energy foods

Question 22

What do some smaller mammals have/do when the weather gets cold

Answer 22

layers of fur or hibernate

Question 23

Give 2 examples of large animal adaptations to increase surface area and lose heat

Answer 23

elephants have large flat ears (physical ) , hippos spend lots of time in water (behavioural)