13-photosynthesis

Question 1

Chlorophyll a(main pigment)

Answer 1

absorbs red+blue light, REFLECTS green

Question 2

Chlorophyll b: accessory pigment
(with chlorophyll a in light harvesting complexes)

Answer 2

Xanthrophyll/Carotenoids

Question 3

role of accessory pigments

Answer 3

• pass energy to primary pigment/reaction centre
• absorb light wavelengths not absorbed by main
• forms part of photosystem/light harvesting cluster

Question 4

photosystems(pigment clusters)

Answer 4

light harvesting system- absorbs energy (containing pigments)

Question 5

thylakoid grana function

Answer 5

light dependent reaction

Question 6

thylakoid membrane

Answer 6

contain pigment/photosystems - electron carriers

Question 7

thylakoid grana

Answer 7

large SA to absorb more light

Question 8

stroma

Answer 8

• for light INDEPENDENT reaction
• has RuBP, NADPH

Question 9

stroma colourless/contains water SO

Answer 9

light reaches thylakoids
as medium for photolysis

Question 10

DNA/ribosomes

Answer 10

produces proteins for photosynthesis

Question 11

starch grains/lipid droplets

Answer 11

store energy

Question 12

why is calvin cycle a cycle

Answer 12

• no start+end points
• RuBP regenerated
• all molecules present at same time

Question 13

explain why light intensity can be a limiting factor in photosynthesis

Answer 13

• not enough light energy for photoactivation of electrons
  -> to make NADP/ATP
• to open stomata for CO2 to enter

Question 14

explain how very dry conditions cause CO2 concentration to become the main limiting factor of photosynthesis in plants

Answer 14

• less CO2 diffuse into air spaces/stroma
• stress response by ABA
• CA2+ second messenger
  stomata CLOSE

Question 15

how does nitrate deficiency limit quantity of SBPase made by Sox4 plants

Answer 15

• nitrogen needed to produce NUCLEOTIDES for transcription of SBPase gene
• amino acids for protein synth/SBPase production