Plant Nutrition - Part 2 (T2)

Question 1

Describe photosynthesis in three short points..

Answer 1

• converts carbon dioxide and water into glucose and oxygen
• requires light, which is absorbed by chlorophyll
• takes place in organelles called chloroplasts

Question 2

From where do plants absorb the water and carbon dioxide needed for photosynthesis?

Answer 2

Plants absorb water through their roots and carbon dioxide through the stomata in their leaves.

Question 3

What happened to the glucose and oxygen produced by photosynthesis?

Answer 3

• some glucose is used for respiration and some is converted to starch for storage.
• oxygen is released as a by-product.

Question 4

What part of the plant carries out photosynthesis?

Answer 4

Any green part of a plant can photosynthesise but the main organ of photosynthesis is the leaf.

Question 5

For photosynthesis to take place efficiently what five things are essential?

Answer 5

• a large surface area for absorption of light
• chloroplasts and chlorophyll
• water
• carbon dioxide
• a transport system

Question 6

Briefly, how is a leaf adapted to carry out photosynthesis?

Answer 6

• thin and flat
• usually supported by a stalk which enables the leaf to be angled towards light
• contains layers of cells with specific functions to enable efficient photosynthesis

Question 7

What is the chemical equation for photosynthesis?

Answer 7

6CO2 + 6H2O -> C6H12O6 + 6O2

Question 8

Describe the three main factors that limit the rate of photosynthesis..

Answer 8

LIGHT INTENSITY
- photosynthesis decreases at low light levels and does not take place at all in the dark

CO2 CONCENTRATION
- a plant cannot photosynthesise if there is not enough CO2

TEMPERATURE
- if it gets too cold or hot, the rate of photosynthesis will decrease

Question 9

Give two examples of how seasons affect plant growth..

Answer 9

• in winter, the lawn doesn’t grow due to lack of light and heat
• in summer, the growth slows due to lack of rain

Question 10

How can you overcome the limiting factors of photosynthesis?

Answer 10

• lights can be used to simulate daylight.

- heating a greenhouse, especially if gas or paraffin heaters are used as they produce carbon dioxide as a by-product.

Question 11

What is produced by plants during photosynthesis as a waste product?

Answer 11

Oxygen

Question 12

What is produced by plants during respiration as a waste product?

Answer 12

Carbon dioxide