Exchange and Transport in Animals T8

Question 1

What do cells need for aerobic respiration?

Answer 1

Cells need oxygen for aerobic respiration, which produces carbon dioxide as a waste product. These 2 gases move between cells and the environment by diffusion.

Question 2

How is water taken in by cells in the body?

Answer 2

Water is taken up by cells by osmosis. In animals, dissolved food molecules and mineral ion diffuse with it.

Question 3

How is urea removed from the body?

Answer 3

Urea is removed from the body by diffusing from cells to the blood plasma for removal from the body by the kidneys.

Question 4

Surface area to volume ratio shows what?

Answer 4

How easy it is for an organism to exchange substances with its environment depends on the organism’s surface are to volume ratio

Question 5

How do single celled organisms exchange substances?

Answer 5

In single celled organisms, gases and dissolved substances can diffuse directly into or out of the cell across the cell membrane - it’s because they have a large surface area compared to their volume.

Question 6

How do Multicellular organisms exchange substances?

Answer 6

How do Multicellular organisms (such as animals) have a smaller surface area compared to their volume. This makes it difficult to exchange enough substances to supply their entire volume.

Question 7

What 3 things does the rate of diffusion depend on?

Answer 7

Distance, concentration difference and surface area

Question 8

What is alveoli and what does it do?

Answer 8

Alveoli are tiny air sacs in the lungs which is where gas exchange takes place.

Question 9

What does blood arriving to the lungs contain?

Answer 9

Lots of CO2 and not much O2. This maximises the concentration gradient for the diffusion of both gases.

Question 10

How does diffusion work in alveoli?

Answer 10

O2 diffuses out of the air in the alveoli (where the concentration of O2 is high) and into the blood (where the concentration of O2 is low) CO2 diffuses in the opposite direction to be breathed out.

Question 11

How is the alveoli specialised for maximum diffusion?

Answer 11

• a moist lining for dissolving gases
• a good blood supply to maintain the concentration gradients of O2 and CO2
• very thin walls - minimising the distance that gases have to move
• an enormous surface area (about 75m in humans)

Question 12

How do you calculate the rate of diffusion

Answer 12

Rate of diffusion = (surface area x concentration difference) / thickness of membrane

Question 13

What is another name of red blood cells?

Answer 13

Erythocytes

Question 14

Describe the shape of the red blood cell?

Answer 14

They have a biconcave disc shape to give a large surface area to absorb oxygen.

Question 15

What are the 2 main types of white blood cells?

Answer 15

Phagocytes and lympocytes

Question 16

What do phagocytes remove foreign cells?

Answer 16

They surround foreign cells and digest them.

Question 17

How do lymphocytes remove foreign cells?

Answer 17

Lymphocytes produce proteins called antibodies which stick to the foreign cells and help destroy them.

Question 18

What are platelets?

Answer 18

These are small fragments of cells, the have no nucleus and they help the blood to clot at the wound.

Question 19

What 7 things does plasma carry around the body?

Answer 19

1) red and white blood cells and platelets 2) nutrients like glucose and amino acids 3) carbon dioxide 4) urea 5) hormones 6) proteins 7) antibodies and antitoxins

Question 20

What are arteries?

Answer 20

Blood vessels that carry blood away from the heart

Question 21

What are capillaries?

Answer 21

Blood vessels that are involved in the exchange of materials at the tissues

Question 22

What are veins?

Answer 22

Blood vessels that carry the blood to the heart

Question 23

What are features of the artery?

Answer 23

The heart pumps blood at high pressure so the artery walls are strong and elastic. The walls are thick compared to the size of lumen. They also contain thick layers of muscle to make them strong, and elastic fibres to allow them to stretch and spring back

Question 24

What are features of the capillary?

Answer 24

Arteries branch into capillaries. Capillaries are really tiny - too small to see. They are very narrow, so they can squeeze into the gaps between cells. This means they can carry blood really close to every cell in the body.

Question 25

What are features of the vein?

Answer 25

Capillaries eventually join up to create veins, the blood is at lower pressure in the veins so the walls don’t need to be thick as artery walls. Skeletal muscles help squeeze the veins to create high speeds.

Question 26

What kind of animal has a single circulatory system and what is it?

Answer 26

Fish have a single circulatory system - deoxygenated blood from the fish’s body travels to the the heart, which pumps it right round the body again in a single circuit

Question 27

What is a double circulatory system?

Answer 27

The heart pumps blood in 2 circuits. In the first circuit, the heart pumps deoxygenated blood to the lungs to take in oxygen, oxygenated blood then returns to the heart where it is then pumped to all of the other organs

Question 28

Why is the right and left side flipped around in a heart diagram?

Answer 28

Because the diagram is taken as if the heart was in the persons body

Question 29

What does the right side of the heart do?

Answer 29

Receive and pump deoxygenated blood

Question 30

What does the left side of the heart do?

Answer 30

Receive and pump oxygenated blood

Question 31

What does the atrium do?

Answer 31

Receive blood from the body or the lungs

Question 32

What does the ventricle do?

Answer 32

Pumps the blood to the rest of the body or to the lungs

Question 33

Why is the wall of the left ventricle thicker than the right one?

Answer 33

The left ventricle need to create more pressure to pump the blood throughout the whole body

Question 34

How do you calculate cardiac output?

Answer 34

Cardiac output = heart rate x stroke volume

Question 35

What is respiration?

Answer 35

Its the process of transferring (releasing) energy from the breakdown of organic compounds (usually glucose)

Question 36

What is aerobic respiration?

Answer 36

Aerobic respiration is what happens when there’s plenty of oxygen available
Glucose + oxygen = carbon dioxide + water

Question 37

What is anaerobic respiration?

Answer 37

Anaerobic just means “without oxygen”. It transfers much less energy than aerobic respiration, in anaerobic respiration, the glucose is only partially broken down, and lactic acid is produced.

Question 38

What is anaerobic respiration in plants?

Answer 38

It is similar to animals but it doesn’t produce lactic acid but instead, ethanol and carbon dioxide.