Photosynthesis

Question 1

Describe two ways in which the structure of the Thylakoids stack is adapted to its function (2 marks)

Answer 1

1. contains pigment
2. contains electron carriers
3. it has a large surface area for light absorption

Question 2

Explain why the theoretical rate of photosynthesis is not achieved at higher light intensities (2 marks)

Answer 2

1. at high light intensity, light is no longer the limiting factor
2. temperature becomes the limiting factor - calvin cycle relies on kinetic e of molecules

Question 3

Explain the difference of structure of leaves that have lived in the shade from a plant living in sunlight (3 marks)

Answer 3

shade part :

1. more chloroplast
2. more thylakoids in chloroplast
3. larger surface area in leaves

Question 4

Outline the ways in which heterotrophic organisms are dependent on plants (3 marks)

Answer 4

1. animals eat plants
2. plants produce organic molecules during photosynthesis
3. plants produce oxygen during photosynthesis

Question 5

Name the primary photosynthetic (1 mark)

Answer 5

Chlorophyll a

Question 6

Name an accessory pigment (1 mark)

Answer 6

chlorophyll b

Question 7

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 (1mark)

Answer 7

ATP

Question 8

state the advantage to the plant of having a range of accessory pigment in photo systems (1mark)

Answer 8

about to absorb a range of different light wavelengths

Question 9

Explain what is meant by the terms autotroph and heterotroph (2 marks)

Answer 9

AUTOTROPH:
can make organic molecule from inorganic molecules
HETEROTROPHS:
relies on food for organic molecules

Question 10

Suggest why fat droplets may be used for in the chloroplast (1 mark)

Answer 10

1. for membrane formation
   OR
2. phospholipid for membrane

Question 11

Describe how light is harvested in the chloroplast membrane (5 marks)

Answer 11

1. pigments are in antenna complex
2. photon absorbed by pigment
3. electrons is excited and returns to pigment
4. photon passed from one pigment to another
5. photon passed to chlorophyll a
6. accessory pigments allow range of wavelengths to be absorbed