surface area to volume ratio and gas exchnge

Question 1

Below are three 3-D shapes of different sizes for each 3-D shape work out its surface area volume surface area: volume ratio

Answer 1

Below are three 3-D shapes of different sizes for each 3-D shape work out its surface area volume surface area: volume ratio

Question 2

An emperor penguin is much larger than an Adelie penguin

which penguin would you expect to have the larger surface area to volume ratio

which penguin would you expect to find in the coldest regions explain your answer

An adelie penguin has a compact shape with short wings and legs
a Rockhopper penguin is less compact with longer wings and legs

assuming the two penguins are roughly the same size explain which one you would expect to live in the colder regions

Answer 2

An emperor penguin is much larger than an Adelie penguin

which penguin would you expect to have the larger surface area to volume ratio
Adelie penguin the adelie penguin would have the larger surface area to volume ratio because it’s smaller than the Emperor penguin

which penguin would you expect to find in the coldest regions explain your answer
The Emperor penguin because it’s large size means it has a lower surface area to volume ratio than the latter this means it’s harder for it to lose heat from its body so it will be better suited to living in colder and regions

An adelie penguin has a compact shape with short wings and legs
a Rockhopper penguin is less compact with longer wings and legs

assuming the two penguins are roughly the same size explain which one you would expect to live in the colder regions
The adelie penguin because it has a more compact shape, and so has a lower surface area to volume ratio than the Rockhopper penguin therefore it won’t lose heat as easily so it’ll be better suited to living in colder regions than the rockhopper penguin

Question 3

In snowy winter months small animals such as mice and voles live in underground tunnels suggest why they have developed this behaviour

Answer 3

In snowy winter months small animals such as mice and voles live in underground tunnels suggest why they have developed this behaviour

Small animals have a high surface area to volume ratio meaning they will lose heat easily and cold temperatures underground temperatures will be warmer than on the surface so they go underground to keep warm

Question 4

In winter some birds fluff the feathers to trap more warm air close to their body would you expect this physiological adaptation to be more common among small or large birds? explain your answer

Answer 4

In winter some birds fluff the feathers to trap more warm air close to their body would you expect this physiological adaptation to be more common among small or large birds? explain your answer

Small birds as they have a higher surface area to volume ratio so they will lose heat more quickly than larger birds therefore they are more likely to have adaptations to keep warm

Question 5

Some large does it animals such as coyotes sleep during the day and are only active at night suggest why they have this behaviour

Answer 5

Some large does it animals such as coyotes sleep during the day and are only active at night suggest why they have this behaviour

Large animals have a low surface area to volume ratio so they find it hard to lose heat they are active at night because it’s cooler

Question 6

Name two substances an animal needs to take in from its environment and two substances that an animal needs to release into its environment

Answer 6

Name two substances an animal needs to take in from its environment and two substances that an animal needs to release into its environment

Oxygen, and water

Carbon dioxide and urea

Question 7

Do most large animals have a higher or lower surface area to volume ratio than small animals

Answer 7

Do most large animals have a higher or lower surface area to volume ratio than small animals

Lower surface area to volume ratio

Question 8

Give two reasons why diffusion is too slow in multi cellular organisms for them to absorb and excrete substances this way

Answer 8

Give two reasons why diffusion is too slow in multi cellular organisms for them to absorb and excrete substances this way

Some cells are deep within the body so the distance between them and the outside environment is too great for diffusion to take place quickly
large animals have a low surface area to volume ratio which means that they don’t have a large enough area exposed to the environment to be able to exchange all the substances they need quickly enough using diffusion

Question 9

What is meant by a mass transport system?

Answer 9

What is meant by a mass transport system?

A system in a multi cellular organisms that carries substances to and from individual cells

Question 10

Will the rate of heat loss at a given temperature be greater for an animal with a high or low surface area to volume ratio?

Answer 10

Will the rate of heat loss at a given temperature be greater for an animal with a high or low surface area to volume ratio?

High surface area : volume ratio

Question 11

Explain how an animal’s shape can help to control its temperature

Answer 11

Explain how an animal’s shape can help to control its temperature

An animal with a compact shape has a low surface area to volume ratio which means they lose less heat
an animal with the less compact shape has a higher surface area to volume ratio which means they lose heat more easily

Question 12

Other than body size or shape give two adaptations a small animal may have to survive in a cold environment

Answer 12

Other than body size or shape give to adaptations a small animal may have to survive in a cold environment

Thick layer of fur and they might hibernate

Question 13

Other than body size or shape give two adaptations a large animal might have to survive in a hot environment

Answer 13

Other than body size or shape give two adaptations a large animal might have to survive in a hot environment

Spend a lot of time in the water and might have features that increase the surface area for example large ears

Question 14

The photographs below show sections of leaves from two different plants

which leaf belongs to a xerophyte
explain your answer

Answer 14

The photographs below show sections of leaves from two different plants

which leaf belongs to a xerophyte
explain your answer

B, as the leaf is curled with the stomata inside, protecting them from the wind so less water is lost

there are lots of hairs on the epidermis to trap water vapour reducing the concentration gradient of water between the leaf and the air

Question 15

In polluted water, the dissolved oxygen concentration is lower than it is in clean water
explain how this would affect the gas exchange across the gills of a fish

Answer 15

In polluted water, the dissolved oxygen concentration is lower than it is in clean water
explain how this would affect the gas exchange across the gills of a fish

A concentration gradient would still be maintained between the water in the blood but it would be less steep
this means the fish wouldn’t be able to take in as much oxygen as they would in clean water

Question 16

What happens to the oxygen concentration of blood as it moves along the lamella?

Answer 16

What happens to the oxygen concentration of blood as it moves along the lamella?

It increases steadily

Question 17

What happens to the oxygen concentration of water as it moves along to lamella?

Answer 17

What happens to the oxygen concentration of water as it moves along to lamella?

It decreases steadily

Question 18

Use evidence from the graph to explain why the oxygen concentration of the blood increases straight after point X

Answer 18

Use evidence from the graph to explain why the oxygen concentration of the blood increases straight after point X

Because at point X the oxygen concentration of the water is higher than in the blood so oxygen has diffused into the blood down its concentration gradient

Question 19

Give two things that all gas exchange surfaces have in common

Answer 19

Give two things that all gas exchange surfaces have in common

They have a large surface area and their thin

Question 20

Explain why single celled organisms don’t need a gas exchange system

Answer 20

Explain why single celled organisms don’t need a gas exchange system

Single celled organisms can exchange gases directly through the cell membrane this has a large surface area, is thin and has a short diffusion pathway so there’s no need for a gas exchange system

Question 21

Describe the structure of fish gills

Answer 21

Describe the structure of fish gills

Each gill is made of lots of thin plates called Gill filaments these are covered in lots of tiny structure called lamella

Lamella have a thin surface layer of cells and a good blood supply

Question 22

Describe how the counter current system in fish aids gas exchange

Answer 22

Describe how the counter current system in fish aids gas exchange

The counter current system works by maintaining a steep concentration gradient between the water and the blood along the entire length of the gill
blood flows through the lamella in One Direction and water flows over the lamella in the opposite direction
this means that water with a relatively high oxygen concentration always flows next to blood with a lower oxygen concentration oxygen then defuses into the blood from the water down the concentration gradient

Question 23

What is the main gas exchange surface for a dicotyledonous plant?

Answer 23

What is the main gas exchange surface for a dicotyledonous plant?

The surface of the mesophyll cells in the leaf

Question 24

Where do you gases move in and out of a leaf?

how does air get into an insects trachea?

Answer 24

Where do you gases move in and out of a leaf?
Through the stomata in the epidermis

how does air get into an insects trachea?
Through the spiracles on the surface of the insects body

Question 25

Describe how carbon dioxide moves out of an insect cells into the atmosphere

Answer 25

Describe how carbon dioxide moves out of an insect cells into the atmosphere
Carbon dioxide from the cells moves down it’s concentration gradient through the tracheoles towards the spiracles to be released into the atmosphere

Question 26

What is a xerophyte

Answer 26

What is a xerophyte

A plant specially adapted for life in a warm, dry or windy habitat

Question 27

Give three adaptations that Xerophytic plants have to reduce water loss

Answer 27

Give three adaptations that Xerophytic plants have to reduce water loss

Stomata sunk in pits
Curled leaves with stomata inside
A layer of hairs on the epidermis

Question 28

How does carbon dioxide diffuse into the alveolus

Answer 28

How does carbon dioxide diffuse into the alveolus

CO2 Defuses out of the capillary endothelium and into the alveolar epithelium and into the alveolus

Question 29

A mountain climber is climbing at an altitude, where there is less oxygen suggest how this will affect gas exchange in the alveoli

Answer 29

A mountain climber is climbing at an altitude, where there is less oxygen suggest how this will affect gas exchange in the alveoli

Less air and so less oxygen would be in held in each breath
this means the concentration gradient of oxygen between the alveoli and the capillaries will be less steep slowing the rate of diffusion

Question 30

Describe what happens to make the volume of the thorax increase during inspiration

Answer 30

Describe what happens to make the volume of the thorax increase during inspiration

The external intercoastal and diaphragm muscles contract which causes the ribcage to move upwards and outwards and the diaphragm to flatten

Question 31

What happens to make air leave the lungs during forced expiration

Answer 31

What happens to make air leave the lungs during forced expiration

During forced expiration the external intercostal muscles relax and internal intercostal muscles contract pulling the ribcage further down and in

Question 32

Describe how oxygen gets from the lungs into the blood

Answer 32

Describe how oxygen gets from the lungs into the blood

Oxygen diffuses out of the alveoli, across the alveolar epithelium and the capillary endothelium and into haemoglobin in the blood

Question 33

describe the features of Alveoli and explain how they affect the rate of diffusion

Answer 33

describe the features of Alveoli and explain how they affect the rate of diffusion

Alveoli have a thin exchange surface which means there is a short diffusion pathway the speeds up the rate of diffusion into the blood
there is a large number of Alveoli so there is a large surface area for gas exchange, which speeds up the rate of diffusion.
there’s also a steep concentration gradient of oxygen and carbon dioxide between the alveoli and the capillaries which increases the rate of diffusion

Question 34

Percentage change =

Answer 34

Percentage change = final - original / original x 100

Question 35

Which one of the Spirometer traces below is from a patient with TB? A or B Explain your answer

Answer 35

Which one of the Spirometer traces below is from a patient with TB? A or B Explain your answer

Question 36

(a) Describe the main difference between the healthy lung tissue and diseased lung tissue from a patient with emphysema
(b) Use your answer to part (a) to explain my people with emphysema have a lower level of oxygen in the blood the normal

Answer 36

a) Describe the main difference between the healthy lung tissue and diseased lung tissue from a patient with emphysema
(b) Use your answer to part (a) to explain my people with emphysema have a lower level of oxygen in the blood the normal

Question 37

What is forced vital capacity

Answer 37

What is forced vital capacity

The maximum volume of air it is possible to breathe forcefully out of the lungs after a really deep breath in

Question 38

A person with fibrosis scar tissue has a reduced tidal volume explain why

Answer 38

A person with fibrosis scar tissue has a reduced tidal volume explain why

Scar tissue is thicker and less elastic than normal lung tissue which means that the lungs are less able to expand and so can’t hold as much error as normal so the tidal volume is reduced

Question 39

Explain why the rate of gaseous exchange in someone with fibrosis is slower than in a healthy person

Answer 39

Explain why the rate of gaseous exchange in someone with fibrosis is slower than in a healthy person

Scar tissue is thicker than normal lung tissue so diffusion of gases is slower

Question 40

What happens to FEV1 during an asthma attack

Answer 40

What happens to FEV1 during an asthma attack

Reduced air flow means that FEV1 is severely reduced