Photosynthesis F4

Question 1

How is the epidermis adapted for light absorption?

Answer 1

Transparent and no chloroplast to allow light to pass through.

Question 2

How is the waxy cuticle adapted for gas exchange/light absorption?

Answer 2

Prevents water loss and is thin transparent to let light pass through.

Question 3

How is the palisade mesophyll adapted for light absorption?

Answer 3

Many chloroplasts and cells packed tightly end to end to ensure max. light absorption for P/S.

Question 4

How is the spongy mesophyll adapted for gas exchange?

Answer 4

Fewer cells to facilitate diffusion of gases.

Question 5

How are the intercellular spaces adapted for gas exchange?

Answer 5

Air spaces to facilitate diffusion of CO2 and O2.

Question 6

How are the guard cells adapted for gas exchange?

Answer 6

Regulate opening and closing of stomata.

Question 7

What is an endothermic reaction?

Answer 7

one which takes in energy from the surroundings

Question 8

What is the process of photosynthesis?

Answer 8

light is taken in and reaction occurs in the chloroplasts

Question 9

What is the process of respiration?

Answer 9

glucose is used to produce energy

Question 10

What is the word equation for photosynthesis?

Answer 10

carbon dioxide + water —> glucose + oxygen

Question 11

What is the balanced chemical equation for photosynthesis?

Answer 11

6CO2 + 6H2O —> C6H12O + 6O2

Question 12

Why are plants destarched before the practical?

Answer 12

If the starch test at the end is +ve then it shows starch was produced during the experiment

Question 13

Describe the procedure of the leaf starch test

Answer 13

• boil leaf in water (stops chemical reactions)
• boil leaf in ethanol (removes chlorophyll)
• place leaf back in water (softens leaf)
• add iodine (yellow/brown - blue/black)

Question 14

Why is the leaf destarched for 48hrs?

Answer 14

To give enough time for the starch to be used up

Question 15

Why is it necessary to also test an un-destarched leaf?

Answer 15

To check all starch has been broken down and compare results

Question 16

Describe the procedure to test the need for light and chlorophyll in photosynthesis

Answer 16

• destarch plant for 48hrs
• test leaf from destarched plant for starch. if negative:
• cover a part of leaf with light proof paper
• place plant in bright light for several hours
• test for starch

Question 17

What acts as a control in the test for the need of light and chlorophyll in photosynthesis?

Answer 17

The green part of the leaf

Question 18

How do limiting factors affect photosynthesis?

Answer 18

They slow down and prevent maximum rate of photosynthesis

Question 19

What are the limiting factors of photosynthesis?

Answer 19

• carbon dioxide
• temperature
• light

Question 20

Describe and explain the affect of light intensity in photosynthesis

Answer 20

As light intensity increases, the R.O.P also increases up to a point where the graph levels off and forms a plateau. An increase in light intensity causes an increase in photosynthesis

Question 21

How you increase the amount of carbon dioxide in water?

Answer 21

Blow into the water using a straw

Question 22

How is Sodium Hydroxide used in the production of oxygen?

Answer 22

It absorbs CO2 to act as a control

Question 23

How do you measure the R.O.P?

Answer 23

count the bubbles of oxygen in a set time period

Question 24

How do you change the light intensity?

Answer 24

Move the LAMP at varying distances from the beaker

Question 25

What colour is Hydrogen Carbonate indicator in low levels of CO2?

Answer 25

Purple

Question 26

What level is Hydrogen Carbonate indicator in high levels of CO2?

Answer 26

Yellow

Question 27

What colour is Hydrogen Carbonate indicator at the compensation point?

Answer 27

Red

Question 28

How does dim light affect the R.O.P?

Answer 28

In dim light, the R.O.P becomes equal to the R.O.R so all the CO2 produced by respiration is used in photosynthesis and all the O2 produced by photosynthesis is used in respiration

Question 29

What is the compensation point?

Answer 29

When the R.O.P is equal to the R.O.R and there is no net gaseous exchange