Photosynthesis

Question 1

Where does photolysis occur

Answer 1

Thylakoid space

Question 2

How are electrons replaced in the chlorophyll

Answer 2

Electrons removed from water in photolysis- water split using light energy

replaced electrons lost in chlorophyll from photoionisation

Question 3

What enzyme required to reduce NADP + FAD+NAD

Answer 3

Dehydrogenase

Question 4

Factors affecting rate of photosynthesis

Answer 4

Temperature
Light intensity
Co2 concentration
*if one of these variable tested on graph with rate
IF ITS DIRECTLY PROPORTIONAL its LF
Once rate plateaus something else LF

Question 5

Where is the enzyme rubisco found

Answer 5

Stroma

Question 6

What products from the LDR required in the LIR

Answer 6

Reduced NADP
ATP
* so in absence of light rate of LIR falls rapidly

Question 7

In plants Atp produced in LDR
Suggest why this not a plants only source of ATP

Answer 7

Plants don’t photosynthesise in the dark
Not all parts of the plant photosynthesise (roots)
Plants require more ATP than produced in the LDR
ATP used in AT

Question 8

Describe the effect of introducing a herbicide on the electron transport chain

Answer 8

Reduces transfer of protons across thylakoid membrane
Less ATP produced
Less reudced NADP produced
Slower LIR
Less reduction of GP into TP

Question 9

How reduced NADP FORMED

Answer 9

proton and associated electron used to reduce NADP catalysed by dehydrogenase enzyme
Oxygen waste product (photolysis)

Question 10

Co2 conc in the air at different heights changes over a period of 24 hours
How and why

Answer 10

High conc of of CO2 at night
No photosynthesis in the dark
In the dark plants respire
In light net uptake of co2 by plants
Decrease in co2 conc with height
At ground level fewer leaves so less photosynthesis

Question 11

Where does LDR take place

Answer 11

Grana

Question 12

When producing chromatogram explain why origin is marked using pencil not ink

Answer 12

Ink and leaf pigments would mix

Question 13

While makin chromatogram describe how to separate pigments after solution of pigment had been applied to origin

Answer 13

Level of solvent below origin
Then remove before solvent reaches top

Question 14

Suggest and explain advantage of plants to havin different colour pigments in leaves

Answer 14

Absorb more wavelengths of light for faster photosynthesis

Question 15

When the plants absorb the light energy
What is it converted into

Answer 15

Chemical potential energy

Question 16

Explain relationship between stomatal opening and photosynthesis

Answer 16

Stomata allow uptake of CO2
Co2 used in photosynthesis

Question 17

Photoionisation

Answer 17

Chlorophyll absorbs light
Which excites electrons

Question 18

Describe the effect of introducing a herbicide on the ETC

Answer 18

Reduced transfer of protons across thylakoid membrane
Less atp produced
Less reduced NADP produced
LIR slows

Question 19

Atp produced in LDR suggest why this is not a plant’s only source of ATP

Answer 19

Plants do not photosynthesise in the dark
Not all parts of the plantphotosynthesise
Plants require mor ATP than produced in LDR
ATp uses in AT

Question 20

Explain why plants that have more chlorophyll will grow faster than plants w less chlrophyll

Answer 20

Faster production of ATP + REDUCED NADP
Faster LIR
So produce more sugars which can be used in respiration
More energy for growth
Faster synthesis of organic materials

Question 21

Describe LDR

Answer 21

Chlorophyll absorbs light energy+ excited electrons
Electrons removed via photoionisation
Electrons move along ETC releasing energy thru a series of redox reactions
Energy released by electrons to form a proton gradient
Protons move through atp synthase
Providing energy to join ADP+PI to form ATP
Photolysis of water produced 2 protons 2 electrons + 1/2 oxygen
NADP reduced by electrons

Question 22

describe LIR

Answer 22

Co2 combines with RUBP
Produces 2X GP using rubisco
2Gp reduces to 2XTriose phosphate
Using reduced NADP
Using energy from ATP
triose phosphate converted to RUBP

Question 23

Explain why rate of oxygen production is measures

Answer 23

Oxygen produced in the LDR
Faster oxygen produced faster LDR

Question 24

Where is rubisco found

Answer 24

Stroma

Question 25

How is ATP produced in LDR

Answer 25

Photophosphorylation of ADP
Protons diffuse through atp synthase
Releasing energy to join ADP+Pi
Into ATP

Question 26

How to increase light intensity to optimum levels

Answer 26

Artificial light can be used to increase light intensity to optimum levels

Blinds may be used to shade plants if light intensity is high as very high light intensity may damage chlorophyll

Question 27

Increasing CO2 for optimum levels

Answer 27

Burn fossil fuels

Question 28

Raising heat to optimum level

Answer 28

Heaters can be used to increase temp
(Night time lower temp)
Prevents temp falling to levels where plants may be damaged

Question 29

Why wud reducing light intensity reduce oxygen released

Answer 29

light intensity limiting factor
Fewer electrons released from chlorophyll less photolysis so less oxygen

Question 30

Evaluate suggestion that increase in temp will not affect oxygen released

Answer 30

No affect because photolysis does not require an enzyme
May affect because increased temperature increases oxygen
Oxygen used in respiration

Question 31

Describe how NADP reduced in LDR

Answer 31

Electrons
From chlorophyll