Photosynthesis

Question 1

Give two examples of photosynthetic organisms

Answer 1

Green plants and algae

Question 2

Where does the energy for photosynthesis come from?

Answer 2

The sun

Question 3

What product is made in photosythesis?

Answer 3

Glucose

Question 4

In which organelle does photosynthesis occur?

Answer 4

Chloroplasts

Question 5

What do chloroplasts contain which absorbs light?

Answer 5

Chlorophyll

Question 6

What is the word equation for photosynthesis?

Answer 6

light
carbon dioxide + water ———–> glucose + oxygen
chlorophyll

Question 7

What is the symbol equation for photosynthesis?

Answer 7

6CO2 + 6H2O ————> C6H12O6 + 6O2

Question 8

What kind of reaction is photosynthesis?

Answer 8

Endothermic

Question 9

What is an endothermic reaction?

Answer 9

A reaction in which energy is taken in.

Question 10

What 3 factors is photosynthesis affected by?

Answer 10

Light intensity, concentration of CO2 and the temperature.

Question 11

What is a limiting factor in photosynthesis?

Answer 11

It is a factor that prevents photosynthesis happening any faster?

Question 12

Why does temperature affect the rate of photosynthesis?

Answer 12

It affects the enzymes involved?

Question 13

Do the enzymes required for photosynthesis work more quickly or more slowly at lower temperatures?

Answer 13

More slowly

Question 14

What happens to the enzymes required for photosynthesis if it gets too hot?

Answer 14

They will become denatured.

Question 15

At what temperature do the enzymes required for photosynthesis denature on average?

Answer 15

45 degrees C.

Question 16

What does not enough light do to the rate of photosynthesis?

Answer 16

It lowers it.

Question 17

What happens at first as you increase the light level?

Answer 17

The rate of photosynthesis increases steadily.

Question 18

What happens after a certain point of increasing the light intensity?

Answer 18

The light intensity will stop making any difference. It’ll be either the temperature or the CO2 which is the limiting factor.

Question 19

In the lab, what can you do to investigate the effects of light intensity on photosynthesis?

Answer 19

You can move a lamp closer to or further away from your plant.

Question 20

What do you need to do if you want to plot your results against light intensity when using the method of moving a lamp further and further away from the plant.

Answer 20

Either use a light meter or use the inverse square law

Question 21

Write the inverse square law

Answer 21

1
light intensity ∝ ——————————-
distance(d) squared

Question 22

What is the inverse square law?

Answer 22

The square of the distance from the light source and the light intensity are inversely proportional to each other - this means as the distance increases, the light intensity decreases. However, light intensity decreases in proportion to the square of the distance.

Question 23

What will happen to the light intensity if you double the distance?

Answer 23

It will be four times smaller

Question 24

What will happen to the light intensity if you halve the distance?

Answer 24

It will be four times larger

Question 25

What result does too little carbon dioxide have on photosynthesis?

Answer 25

It slows photosynthesis down.

Question 26

What happens after a certain point on the graph of the rate of photosynthesis plotted against the level of CO2.

Answer 26

It flattens out.