B4 The Rate of Photosynthesis (page 51)

Question 1

What provides the energy needed for Photosynthesis?

Answer 1

Light

Question 2

As the light level is raised, what happens with photosyntheses?

Answer 2

The rate of photosynthesis increases steadily (but only up to a certain point)

Question 3

Why won’t it make any difference as light intensity increases with photosynthesis?

Answer 3

The rate will no longer increase, this is because the temperature or CO2 level is now the limiting factor - not light.

Question 4

In the lab, how can you change the light intensity for photosynthesis?

Answer 4

by moving a lamp closer to, or further away from your plant.

Question 5

What happens plotting the rate of photosynthesis on your graph against ‘distance of lamp from the plant’?

Answer 5

You would get a weird shaped graph

Question 6

Look at the diagram 1 on page 51, what would you need to do to get a graph like this?

Answer 6

you either need to measure the light intensity at the plant using a light meter, or do a bit of nifty math with your result.

Question 7

What can slow down the ‘Rate of Photosynthesis?

Answer 7

Not enough light
Too little carbon dioxide
the temperature.

Question 8

What is one of the raw materials needed for photosythesis?

Answer 8

CO2

Question 9

What will happen with the amount of CO2 when it increases for photosynthesis? (on graph pg 51)

Answer 9

As with light, co2 will only increase the rate up to a point. After this, the graph flattens out - as the amount of co2 increases the rate no longer increases. This shows that co2 is no longer the limiting factor.

Question 10

As long as light and co2 are plentiful supply, what might the limiting factor of photosynthesis be?

Answer 10

it must be temperature.

Question 11

If the temperature is to low of the limiting facor, what do this mean?

Answer 11

the temperature must be too low - the enzymes needed for photosynthesis work more slowly at low temperature