Photosynthesis Weak Areas

Question 1

Suggest why soda lime is not placed in the respirometer when photosynthesis is occurring

Answer 1

Photosynthesis is a reactant so is removed
Soda lime increases the absorption of CO2
So CO2 becomes a limiting factor

Question 2

Online the importance of photosynthetic pigments in photosynthesis

Answer 2

Pigments absorb light energy to excite electrons to higher energy levels
Accessory pigments pass energy on to the primary pigment centre
Primary pigments become oxidised and lose electrons along the electron transport chain
For photophosphorylation

Question 3

State the precise location of photosynthetic pigments in a chloroplast

Answer 3

Photosystems on the thylakoid membrane

Question 4

What is the role of sucrose in photosynthesis

Answer 4

Prevents damage to the chloroplasts
Sometimes not needed when measuring photosynthesis as damage to chloroplast membranes allow greater access to NADP to be reduced

Question 5

What is the compensation point

Answer 5

The point at which the rate of production of products in respiration equals the rate of production of products in photosynthesis

Question 6

Describe how the rate of photosynthesis differs at different light intensity on both the upper surface and lower surface of the leaf

Answer 6

The leaf is thin so there is small difference in rate of photosynthesis as light can diffuse down
At lower light levels the rate of photosynthesis in the upper surface is greater as the palisade cells containing chlorophyll are closer to the upper surface of the leaf
Also greater stomata on the upper surface so greater CO2 concentrations
There is no difference in rate at higher light intensity as light can diffuse through the leaf to the lower surface easily