B2 Photosynthesis

Question 1

What is the function of the chlorophyll found in plant cells?

Answer 1

Absorbs light for photosynthesis.

Question 2

Name the sugar made in photosynthesis.

Answer 2

Glucose

Question 3

Name the two chemicals needed for photosynthesis

Answer 3

Water and carbon dioxide

Question 4

Which two tissues in the leaf contains the most chloroplasts?

Answer 4

Palisade mesophyll

Spongy mesophyll

Question 5

How does carbon dioxide enter the leaf?

Answer 5

By diffusion
Through the stomata

Question 6

Give four ways in which the rate of photosynthesis can be increased.

Answer 6

Increase light intensity.
Increase temperature.
Increase concentration of carbon dioxide.
Increase amount of chlorophyll

Question 7

A plants can convert glucose into protein by adding……

Answer 7

Nitrate

Question 8

The glucose produced by a plant can be used for :

Answer 8

Respiration - to release energy

Make starch - used to store glucose

Make cellulose - needed to strengthen cell walls

Make fats and oils

Make proteins

Question 9

Name the chemicals made in photosynthesis

Answer 9

Glucose and oxygen

Question 10

Name the type of energy needed for photosynthesis

Answer 10

Light

Question 11

A plant is given excess carbon dioxide and light. The plant does not photosynthesise at its maximum rate. What is the limiting factor? (Higher only)

Answer 11

Temperature.

Question 12

Give a list of the factors that might limit the rate of photosynthesis

Answer 12

Temperature
Light intensity
Concentration of carbon dioxide
Amount of chlorophyll

Question 13

Name the green pigment found in chloroplasts.

Answer 13

Chlorophyll.

Question 14

Name the chemicals shown below
CO₂
O₂
C₆ H₁₂ O₆
H2O

Answer 14

CO₂ Carbon dioxide
O₂ Oxygen
C₆ H₁₂ O₆ Glucose
H₂O Water

Question 15

Is photosynthesis an exothermic or endothermic reaction?

Answer 15

Endothermic
Energy needs to absorbed for the reaction to occur

Question 16

Give the word equation for photosynthesis

Answer 16

Carbon dioxide + water –> glucose + oxygen

Question 17

Explain how temperature affects the rate of photosynthesis.

Answer 17

As temperature increases the rate of photosynthesis increases.

Diffusion of carbon dioxide into the leaf increases
Molecules will move faster and are more likely to collide and react.
Enzymes catalyse these reactions and have an optimum temperature
At very high temperatures the enzymes will denature and photosynthesis will decrease.

Question 18

Explain how light intensity affects the rate of photosynthesis.

Answer 18

As light intensity increases the rate of photosynthesis increases

Light provides the energy needed for photosynthesis
At very high light intensity not all the light can be absorbed as there is insufficient chlorophyll

Question 19

Explain how carbon dioxide concentration affects the rate of photosynthesis.

Answer 19

As carbon dioxide concentration increases the rate of photosynthesis increases.

More carbon dioxide can diffuse into the leaf
Increases number of collisions that occur between carbon dioxide and water

Question 20

Explain how the amount of chlorophyll affects the rate of photosynthesis

Answer 20

As the amount of chlorophyll increases the rate of photosynthesis increases

More light can be absorbed by the chlorophyll
Light is needed to provide the energy for photosynthesis.

Question 21

Describe and explain how greenhouses are designed to increase the rate of photosynthesis. (Higher)

Answer 21

Large surface area of glass - increase light intensity available to the plant
Temperature monitored - windows opened when too hot. Prevents the denaturation of enzymes
Extra carbon dioxide added - increases amount of carbon dioxide available to the plants.
Plants watered regularly - prevents wilting and provides substrate for reaction
Mineral ions added to the water to provide the nitrate for the plants to make proteins

Question 22

State the law which describes the relationship between the distance of a light source from a plant and light intensity (Higher)

Answer 22

Inverse square law

Light intensity = 1/distance squared

Question 23

How can you show that a plant gives of oxygen during photosynthesis?

Answer 23

Using pond weed,

collect gas produced during photosynthesis,

test the gas to make sure it is oxygen (relights a glowing splint)

Question 24

What is a limiting factor?

Answer 24

An environmental factor which can restrict the rate of photosynthesise

Question 25

Which letter identifies the sub-cellular structure where photosynthesis takes place?

Answer 25

D

Question 26

Name the process shown below

Answer 26

Photosynthesis