Topic 8 - Transport in animals

Question 1

Which substances need to be transported in and out of animals

Answer 1

Oxygen, carbon dioxide, water, dissolved food molecules, mineral ions and urea

Question 2

Explain the need for exchange surfaces and transport systems and the relationship with surface area:volume ratio

Answer 2

As organisms get bigger, their surface area to volume ratio gets smaller

Consequently they cant rely on diffusion

This means they need exchange surfaces and transport systems

Question 3

What is oxygen’s site of exchange and reason for exchange

Answer 3

Alveoli in lungs

Needed for respiration

Question 4

What is carbon dioxide’s site of exchange and reason for exchange

Answer 4

Alveoli in lungs

Waste product of metabolism

Question 5

What is water’s site of exchange and reason for exchange

Answer 5

Nephrons in kidney

Needed for cells to function

Question 6

What is dissolved food molecules site of exchange and reason for exchange

Answer 6

Small intestine

Needed for respiration

Question 7

What is mineral ions site of exchange and reason for exchange

Answer 7

Small intestine

Needed for cells to function

Question 8

What is urea’s site of exchange and reason for exchange

Answer 8

Nephrons in kidney

Waste product of metabolism

Question 9

How are some organs adapted for exchange

Answer 9

They’re adapted to make exchange efficient

Lungs adapted to exchange gases
Small intestine adapted to exchange solutes

Question 10

Explain how alveoli are adapted for gas exchange

Answer 10

Adapted by diffusion between air and lungs and blood in the capillaries

Millions of alveoli (air sacs) adapted to create large surface area for gas diffusion

Each closely associated with a capillary. Walls one cell thick, minimising diffusion distance

Question 11

Describe the factors affecting the rate of diffusion

Answer 11

+ surface area (eg alveoli in lungs)

shorter distance for diffusion (eg surfaces one cell thick)

maintenance of a high concentration gradient (eg animals efficient blood supply, ventilated lungs)

Question 12

how do you calculate the rate of diffusion

Answer 12

FICKS LAW:

rate of diffusion α surface area × concentration difference / thickness of membrane

Question 13

explain how the structures in blood are related to function

Answer 13

PLASMA - liquid, carries blood cells through vessels

WHITE BLOOD CELLS - larger than red, has nucleus, immune system attacks pathogens

PLATELETS - causes blood to clot when vessel damaged. clot blocks wound prevents pathogens entering

RED BLOOD CELLS - haemoglobin (carries oxygen), bioconcave shape - larger surface area, easier for oxygen to diffuse in & out, no nucleus more room for oxygen

Question 14

Explain how the structure of the blood vessels is related to their function

Answer 14

VEINS - large space, thinner wall than artery, valves stop blood flowing backward so returns to heart

ARTERIES - carry oxygenated blood away from heart to body

CAPILLARIES - exchange materials with body tissues, capillary only one cell wide, wall one cell thick

Arterues take blood Away, veINs bring it back IN to the heart

Question 15

Explain how the structure of the heart is related to its function

Answer 15

VALVES prevent backflow (backward blood flow)

PULMONARY ARTERY carries deoxygenated blood, heart —> lungs

AORTA carries oxygenated blood, heart —> body

PULMONARY VEIN brings oxygenated blood, lungs —> heart

VENA CAVA brings deoxygenated blood, body —> heart

LEFT VENTRICLE muscle wall thicker than right, bc it pushes blood round body

Question 16

explain how blood moves around the body

Answer 16

1. enters atria
2. atria contract, blood into ventricles
3. ventricles contract, blood into arteries
4. blood through arteries to organs and returns to heart through veins

Question 17

describe cellular respiration

Answer 17

EXOTHERMIC, release energy for metabolic processes, including aerobic, anaerobic respiration

Question 18

describe aerobic respiration

Answer 18

series of chemical reactions, inside mitochondria. glucose completely broken down

exothermic - releases energy used for building larger molecules from smaller, enable muscle contraction, maintain body temp

glucose + oxygen —> carbon dioxide + water

Question 19

describe anaerobic respiration

Answer 19

respiration that occurs in absence of oxygen, doesnt occur in mitochondria

part breakdown of glucose due to lactic acid

produces lactic acid, extra oxygen required to oxidise to co2 and water after exercise

less energy released than aerobic

Question 20

explain advantages and disadvantages of anaerobic respiration

Answer 20

ADVANTAGES:

• useful for muscle cells, can replace aerobic when energy is needed for muscles to contract
• respiration continues in organisms w little/no oxygen

DISADVANTAGES:

• releases less energy
• lactic acid not removed from body, builds up in muscle and blood must be broken down

Question 21

how do you calculate cardiac output

Answer 21

cardiac output = stroke volume × heart rate

Question 22

explain the function of soda lime in the respiration practical

Answer 22

absorbs co2 produced by seeds, so doesnt affect movement of liquid blob

Question 23

explain why the liquid blob moves during the respiration experiment

Answer 23

oxygen is absorbed from surrounding air by germinating seeds.

reduces volume of air in container, so blob moves towards container

Question 24

explain how a respirometer could be used to measure rate of respiration of the seeds

Answer 24

distance liquid blob moves over time could be measured

rate calculated by dividing distance by time

Question 25

describe the controls for the respiration experiment

Answer 25

• TEMPERATURE

- for something other than the study organisms affecting gas volume (eg same volume of substances)