Photosynthesis

Question 1

Compensation point

Answer 1

The light intensity level in which the rate of photosynthesis exactly matches the rate of respiration

Question 2

Photosynthetic pigments

Answer 2

Coloured substances that absorb the light energy needed for photosynthesis.

They are light harvesting

Question 3

Example of photosynthetic pigment

Wavelengths of light absorbed in two photosytems

Answer 3

Chlorophyll A

PS1 700nm
PS2 680nm

Question 4

Stroma

Answer 4

It contains enzymes, sugars and organic acids

Question 5

What does reductase do

Answer 5

Accepts protons from the atp synthase pump and joins them with NADP to produce reduced NADP

Question 6

What does ferredoxin do

Answer 6

Accepts e- from PS1 and combines them with NADP in the stroma to make reduced NADP

Question 7

What uses cyclic photophosphorylation

Answer 7

Guard cells

They produce ATP which brings potassium ions into the cells, lowering the water potential so that water follows by osmosis. Swell and opens stomata.

Question 8

How many turns of the calvin cycle is needed for 1 hexose sugar

What can TP be made into

Answer 8

6

Carbohydrates, lipids and amino acids

Carbohydrates= two triose phosphate molecules form a hexose sugar

Lipids= glycerol and fatty acids. Glycerol synthesised from triose phosphate, where as fatty acids from glycerine 3 phosphate

amino acids= glycerine 3 phosphate

Question 9

What colour sunlight does chlorophyll A and B absorb

Answer 9

Red and blue

Question 10

What is the saturation point

Answer 10

Where a factor is no longer a limiting factor

For example, increasing light past this point makes no difference as something else has to be a limiting factor

Question 11

What is a limiting factor

Answer 11

Variable that can slow down the rate of reaction