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Question 1

DONE 2.56 2.57 2.58 2.67 & 2.68

Answer 1

NOT DONE 2.51 2.52 2.53 2.54 2.55 2.59 2.60 2.61 2.62 2.63 2.64 2.65 2.66 & 2.69

Question 2

2.56B the loss of water vapour from the leaves is called

Answer 2

transpiration

Question 3

2.56B examiners definition of transpiration

Answer 3

the evaporation of water from the surface of a plant

Question 4

2.57B how does temperature affect the rate of transpiration

Answer 4

water will evaporate quickly as the water molecules have more kinetic energy

Question 5

2.57B how does humidity affect the rate of transpiration

Answer 5

humid air - water vapour = smaller conc gradient so transpiration slows down

Question 6

2.57B how does wind speed affect the rate of transpiration

Answer 6

moving air - water vapour blown away from leaf - speeds up transpiration

Question 7

2.57B transpiration .. as wind speed ..

Answer 7

transpiration increases as wind speed increases

Question 8

2.57B transpiration .. as humidity ..

Answer 8

transpiration increases as humidity decreases

Question 9

2.57B transpiration .. as temperature ..

Answer 9

transpiration increase as temp increases

Question 10

2.57B light intensity does NOT affect

Answer 10

evaporation

Question 11

2.57B how does light intensity affect the rate of transpiration

Answer 11

in daylight stomata leaves are open to supply CO2 for photosynthesis
allows more water to diffuse out leaves into atmosphere

Question 12

2.58B practical: how to set up a potometer

Answer 12

set up underwater
cut the stem
shoot stem in bung
grease joint w jelly (no air entry/water loss)
bung in potometer
tap closed full of water
lift potometer out of water
leave end of capillary tube out of water until air bubble forms & then put in beaker of water
measure rate as distance bubble travelled in 5 mins

Question 13

2.58B practical: a potometer is to measure

Answer 13

measure the rate of water uptake from a leafy shoot

Question 14

2.58B practical: we can use potometer to collect readings in normal air or windy conditions by

Answer 14

using a hairdryer on cold

Question 15

2.58B practical: we can use potometer to collect readings in temperature

Answer 15

increases and decreases

Question 16

2.58B practical: we can use potometer to collect readings in increased humidity by

Answer 16

using a clear plastic bag

Question 17

2.58B practical: we can use potometer to collect readings by changing the l & d

Answer 17

lightness and darkness

Question 18

2.58B practical: changing the environmental factors stimulates

Answer 18

all the different conditions which affect the rate of transpiration

Question 19

2.67 what are the factors that may increase the risk of developing coronary heart disease?

Answer 19

1. Obesity
2. High Blood pressure
3. High Cholestrol
4. Smoking

Question 20

2.67 how can obesity increase risk of developing coronary heart disease?

Answer 20

Carrying extra weight puts a strain on the heart.
increased weight can lead to Type 2 diabetes which further damages the blood vessels.

Question 21

2.67 How can high blood pressure increase risk of developing coronary heart disease?

Answer 21

High blood pressure increases the force of the blood against the artery walls and consequently leads to damage of the vessels.

Question 22

2.67 How can high cholestrol increase risk of developing coronary heart disease?

Answer 22

High cholestrol speeds up the build up of fatty plaques in the arteries which leads to blockages.

Question 23

2.67 How can smoking increase risk of developing coronary heart disease?

Answer 23

Chemicals in smoke cause an increase in plaque build up and and increase in blood pressure.
Carbon monoxide also reduces the oxygen carrying capacity of the red blood cells.

Question 24

2.68 How many types of blood vessel are there? And name them

Answer 24

3.
Arteries, veins, capillaries.
Each vessel is specifically adapted to carry out its particular function efficiently.

Question 25

2.68 What are the smaller vessels that branch off from the arteries called?

Answer 25

Arterioles (small arteries)

Question 26

2.68 What are the smaller vessels that branch into veins called ?

Answer 26

Venules (small veins)

Question 27

2.68 What are the key features of arteries?

Answer 27

Carry blood at high pressure away from the heart
Carry oxygenated blood (except pulmonary artery)
Have thick muscular walls containing elastic fibres
Have a narrow lumen
Blood flows through at a fast speed.

Question 28

2.68 How is the structure of an artery adapted to its function?

Answer 28

Thick muscular walls containing elastic fibres withstand the high pressure of blood and maintain the blood pressure as it recoils after the blood has passed through
A narrow lumen also helps to maintain high pressure.
See images

Question 29

2.68 What are the key features of veins?

Answer 29

Carry blood at low pressure towards the heart
Carry deoxygenated blood (other than the pulmonary vein)
Have thin walls
Have a large lumen
Contain valves
Blood flows through a slow speed

Question 30

2.68 How is the structure of a vein adapted to its function?

Answer 30

A large lumen reduces resistance to blood flow under low pressure.
Valves prevent the backflow of blood as it is under low pressure

Question 31

2.68 What are the key features of capillaries?

Answer 31

Carry blood at low pressure within tissues
Carry both oxygenated and deoxygenated blood
Have walls that are one cell thick
Have ‘leaky’ walls
Speed of blood flow is slow

Question 32

2.68 How is the structure of a capillary adapted to its function?

Answer 32

Capillaries have walls that are one cell thick (short diffusion distance) so substances can easily diffuse in and out of them.
The ‘leaky’ walls allow blood plasma to leak out and form tissue fluid surrounding cells.