M5 C17: PMT photosynthesis QP1

Question 1

describe 2 ways in which the structure of grana are adapted to their function

Answer 1

• contain chlorophyll a/ photosynthesis
• contain ATP synthase/ ETC
• large surface area for light absorption

Question 2

With REFERENCE to the BIOCHEMISTRY of photosynthesis, explain why the theoretical rate of photosynthesis is not achieved at higher light intensities.

Answer 2

as at higher light intensities other factors such as carbon dioxide concentration become limiting factors as carbon dioxide is required for the Calvin cycle

Question 3

The leaf of a plant that is adapted to living in shade will differ from the leaf of a plant that is adapted to living in sunlight. Suggest one way in which the structure of these leaves will differ

Answer 3

more chloroplast

leaves have larger surface area

Question 4

Plants are autotrophs. Most other organisms are heterotrophs. Outline the ways in which heterotrophic organisms are dependent on plants [3]

Answer 4

heterotrophic organisms need to obtain organic molecules from plants which produce molecules such as glucose from photosynthesis as they are autotrophs. Glucose is used by heterotrophs for respiration (same can be said about oxygen)

Question 5

name an accessory pigment

Answer 5

carotenoid

Question 6

Name the compound that is synthesised in the light-dependent stage as a result of the generation of an electrical and pH gradient across the thylakoid membrane

Answer 6

ATP

Question 7

Identify the enzyme that catalyses the fixation of carbon dioxide.

Answer 7

rubisco

Question 8

Identify the first stable product of carbon dioxide fixation

Answer 8

GP

Question 9

Identify the compound that is regenerated in the Calvin cycle so that more carbon dioxide can be fixed

Answer 9

RuBP