Photosynthesis

Question 1

What is the equation for photosynthesis?

Answer 1

Question 2

What is the equation for respiration?

Answer 2

Oxygen + glucose —–> Carbon dioxide + water

Question 3

Define photosynthesis.

Answer 3

Photosynthesis is a chemical reaction that takes place in the choloroplasts of green plant cells where light energy is used to convert carbon dioxide and water in to glucose and oxygen.

Question 4

Give four ways in which plants use glucose?

Answer 4

• Combined with minerals. Magnesium and glucose combine to make chlorophyll
• Converted in to insoluble starch for storage
• Used for respiration
• Used to make cellulose. A very tough fiberous carbohydrate material used for makeing new cells to support plant.

Question 5

Describe the way in which we can test for starch.

Answer 5

Iodine tuens starch black. When a leaf has been carrying out photosynthesis glucose is produced. Extra glucose is stored as starch and this is what isodine stains black.

Question 6

What factors can affect the rate of photosynthesis?

Answer 6

• intensity of light
• concentration of CO₂
• temperature

Question 7

Describe the ideal conditions for photosynthesis.

Answer 7

The ideal combination of factors for the maximum rate of photosynthesis is lots of light, lots of carbon dioxide and a warm temperature.

Question 8

What happens to the rate of photosynthesis if one of the factors is restricted?

Answer 8

It limits the rate of photosynthesis and is known as the limiting factor.

Question 9

Describe the graph.

Answer 9

• light is limiting the rate of photosynthesis.
• As light intensity increses, rate of photosynthesis increses.
• Despit the increse of light intensity, the rate of photosynthesis remains constant as the CO₂ concentration or temperature is limiting factor.

Question 10

Describe the graph.

Answer 10

• Increasing the temperature increases the rate of photosynthesis.
• At the peak of the graph, optimum temperature is reachedand the rate of photosynthesis is the highest.
• When increasing the temperature past the optimum, the rate of photosynthesis decreases quickly and stops. This is because the temperature has stopped the enzymes that control photosynthesis from working.

Question 11

Describe the graph.

Answer 11

• CO₂ is the limiting the rate of photosynthesis. As CO2 concentration increases, the rate of photosynthesis increases.
• Despite an increse in CO₂ concentration the rate of photosynthesis remains constant as the light intensity or temperature is limiting the rate of photsynthesis.