Photosynthesis

Question 1

What is photosynthesis?

Answer 1

The process by which plants use carbon dicxide and water in the presence of sunlight to produce their own source of energy.

Question 2

Give the word and symbol equation for photosynthesis.

Answer 2

6CO2 + 6H20 –> C6H12O6 + 602

carbon dioxide + water –> glucose + oxygen

Question 3

What role does chlorophyll play during photosynthesis?

Answer 3

It absorbs light energy from the sun.

Question 4

What three factors affect the rate of photosynthesis and what do their graphs look like? (3)

Answer 4

1. Light intensity (a cliff)
2. Temperature (a frown)
3. Carbon dioxide concentration (a cliff)

Question 5

Why do these factors affect the rate of photosynthesis?

Answer 5

They are limiting factors, if one is in excess and another is limited, the rate of photosynthesis plateaus.

Question 6

What is the equation for the inverse square law? What does this mean for photosynthesis? (3)

Answer 6

1. Light intensity = 1/d^2
2. . L.I. decreases as distance increases b/c the area it is shared over increases.
3. The rate of photosynthesis decreases as distance increases

Question 7

How do we test for starch in leaves? Give the stages of this process. (4)

Answer 7

1. Leaf in boiling water to break down cell wall and access chloroplasts.
2. Turn off bunsen burner and dry leaf - this increases validity of the results, by preventing the dilution of the ethanol.
3. Put dry leaf in ethanol, to break down double membranes of chloroplast to access starch granules.
4. Spread the leaf and coat in iodine solution, which will turn from a reddish-brown to a blue-ish black in the presence of starch.