B3.2 Transport Systems In Plants And Animals

Question 1

How does carbon dioxide enter the plant?

Answer 1

Through diffusion in the leaves

Question 2

How do minerals and ions enter the plant?

Answer 2

They are absorbed by the roots.

Question 3

What are stomata?

Answer 3

Tiny pores on the underside of the leaf through which carbon dioxide, oxygen and water vapour can diffuse.

Question 4

What is the function of guard cells?

Answer 4

To control the size of the stomata to control water loss.

Question 5

What happens if the plant loses water faster than it is replaced?

Answer 5

Stomata can close to prevent wilting.

Question 6

How is the surface area of the roots increased?

Answer 6

With root hair cells

Question 7

How is the surface area of the leaves increased? (2)

Answer 7

• Flattened shape

- Internal air spaces (easier gas diffusion)

Question 8

Describe the process of transpiration.

Answer 8

• Water diffuses from the soil into the roots
• Water travels up the stem through the xylem tissue (stuck together - cohesion - easier for water to travel up in a continuous column)
• Water travels up veins into leaves - diffuses out of veins into the leaves by osmosis.
• Water evaporating and diffusing from the leaves sets up a concentration gradient, continuously pulling water from the soil to other parts of the plant.

Question 9

How does increased humidity affect the rate of transpiration?

Answer 9

It decreases it as high levels of water in the air decreases the concentration gradient.

Question 10

How does increased light intensity affect the rate of transpiration?

Answer 10

• It increases it as:
• Photosynthesis increases and plants use more carbon dioxide and water
• Pores on leaves open which let carbon dioxide in cells and more water evaporates out.

Question 11

How does increased temperature affect the rate of transpiration?

Answer 11

• It increases it as water molecules on the edge of the leaf leave because there is more kinetic energy.

Question 12

How does increased wind movement affect the rate of transpiration?

Answer 12

• It increases it as air saturated water vapour moves away from the plant and is replaced with drier, keeping a steep concentration gradient (water conc. outside the leaf is lower than inside)

Question 13

What is the function of the phloem tissue?

Answer 13

To carry dissolved sugars from the leaves to the rest of the plant.

Question 14

Where specifically does the phloem tissue carry dissolved sugars?

Answer 14

• Growing regions e.g shoots

- Storage organs e.g bulbs

Question 15

What is the function of the xylem tissue?

Answer 15

To transport water and mineral ions from the roots to the stem and leaves

Question 16

What are the advantages of artificial hearts?

Answer 16

• Extends lifespan
• No rejection from immune system - no need to take immunosuppressant drugs
• No need for donor/match tissue

Question 17

What are the disadvantages of artificial hearts?

Answer 17

• Parts can wear out/need repair
• Blood doesn’t flow through as smoothly, causes blood clots
• Surgery causes bleeding and infection
• Battery will need changing
• Discomfort from heart controller

Question 18

What is required from artificial heart valves?

Answer 18

• Ability to prevent blood back flow
• Ability to not cause blood clotting
• Long lasting material
• Strength to withstand pressure
• Not to be rejected by the body

Question 19

Why are stents used?

Answer 19

• Coronary heart disease is when arteries supplying the heart are blocked by fatty deposits, restricts blood flow.
• Stents are metal mesh tubes inserted into arteries keeping them open so blood can pass through to the heart muscle.

Question 20

What is the disadvantage to stents?

Answer 20

• Over time, arteries can narrow again as stents irritate and make scar tissue grow.
• Patient has to take drugs to prevent blood clotting.

Question 21

What is artificial blood made of?

Answer 21

A salt solution (“saline”)

Question 22

What is artificial blood for?

Answer 22

It gives patients who have lost blood time to make new red blood cells as it keeps the blood pressure by replacing lost volume.

Question 23

Blood is a t—–?

Answer 23

Tissue

Question 24

What is the purpose of red blood cells?

Answer 24

To carry oxygen from the lungs to the rest of the body

Question 25

What properties to red blood cells have adapting them to their purpose?

Answer 25

• Biconcave surface = higher surface area

- They have no nucleus = more space

Question 26

Describe the reactions that occur when red blood cells transport oxygen.

Answer 26

• In the lungs the oxygen reacts with haemoglobin in the red blood cells to form oxyhaemoglobin.
• In body tissues, oxyhaemoglobin splits into oxygen and haemoglobin and oxygen is released to the cells.

Question 27

What is the purpose of white blood cells?

Answer 27

To mount an immune response against pathogens

Question 28

What do white blood cells have that red blood cells don’t?

Answer 28

A nucleus

Question 29

What are platelets?

Answer 29

Small fragments of cells

Question 30

What is the purpose of platelets?

Answer 30

To help blood clot at the site of a wound

Question 31

What is the purpose of the blood plasma?

Answer 31

To carry:

• Red, white blood cells and platelets
• Urea from the liver to the kidney
• Carbon dioxide from other organs to the lungs
• Soluble products of digestion from the small intestine to body cells.