Photosynthesis

Question 0

Light on the calvin cycle

Answer 0

• requires products from light dependent stage to get GP to TP
• if dark GP builds up and NO TP produced
• used when light levels increase

Question 1

CO2 concentration on the calvin cycle

Answer 1

• needed to make GP
• so if conc is low
• less GP = less TP
• RUBP can build up, but also less TP to replace it but replacing is prioritised over glucose production
• some RUBP levels fall under prolonged lack of CO2

Question 2

Limiting factor

Answer 2

• a factor preventing a reaction or process from going any faster
• increase factor = increase rate

Question 3

Factors affecting photosynthesis

Answer 3

• UNTIL ANOTHER LIMITING FACTOR
• light intensity - increased light intensity = increases rate of photosynthesis
• CO2 conc - increased CO2 conc = rate of photosynthesis
• temperature -increased temp = increased collisions = rate of photosynthesis (in light independent)
• BUT too high enzymes denature rubisco catalyses O2 = photorespiration

Question 4

The light independent stage

Answer 4

• in the stroma
• produces organic molecules
• RUBP (ribulose bisphosphate) -> CO2 + rubisco -> intermediate-> GP (2 x glycerate-3-phosphate) -> amino acids/fatty acids OR + ATP-ADP NADPred-NADP -> TP (2 x triose phosphate)-> glucose/sucrose -> ATP-ADP -> ribulose bisphosphate

Question 5

Non- cyclic photophosphorylation

Answer 5

• PS1and PS11
• produces ATP, NADPred, O2
• light that hits PS11 activates enzyme that causes photolysis
• H+ ions form NADPred with e from PS1
• e from PS11 replaces the one in PS1
• produces ATP as the electrons travel down the etc

Question 6

Cyclic photophosphorylation

Answer 6

• PS1
• produces ATP
• light energy excites an electron that leaves the chlorophyll molecule
• the electron travels along the electron transport chain losing energy thats used to produce ATP
• e returns to PS1

Question 7

Photophosphorylation

Answer 7

• phosphorylation using light
• adding a phosphate group to ADP to form ATP using light energy
• as the electron passes along ETC loses energy that can be used for phosphorylation

Question 8

Photosystems

Answer 8

• contain proteins and pigment molecules
• across the thylakoid membrane
• light energy captured by accessory pigments and funnelled to reaction centre
• PS1 - P700
• PS11 - P680

Question 9

Light dependent reactions

Answer 9

• in the thylakoid membrane
• involves cyclic and non- cyclic photophosphorylation
• Input - light, H2O, NADP
• output- ATP, oxygen, NADPred

Question 10

Accessory pigments

Answer 10

• ie carotenoids and xanthophyll
• they absorb wavelengths of light other pigments cant
• funnelled the light energy to the reaction centre
• probably protect chlorophyll from intense light

Question 11

Photosynthetic pigment

Answer 11

• A substance that absorbs sone wavelengths of light
• the light reflected creates the colour of the pigment
• ie chlorophyll carotenoids and xanthophyll

Question 12

Thylakoid

Answer 12

• the fluid filled sacs inside lamellae
• can be arranged in stacs to form grana
• sight of light dependent reactions

Question 13

Chloroplasts

Answer 13

• in palisade mesophyll tissues and spongy mesophyll tissue
• contain circular DNA & ribosomes
• surrounded by 2 membranes = envelope
• lamellae sheets form a membrane around thylakoids
• contain starch grains
• site of photosynthesis

Question 14

Stroma

Answer 14

• background material inside the chloroplast

- site of the light independent reactions

Question 15

Grana

Answer 15

• stacks of thylakoid discs

Question 16

Lamellae

Answer 16

• the membrane that encloses thylakoid in chloroplasts

Question 17

Autotrophs

Answer 17

• an organism that makes its own complex organic molecules from an inorganic source
• ie plants photosynthesise light energy

Question 18

Heterotrophsp

Answer 18

• an organism that requires organic nutrients to supply it with a source of carbon