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AL Biology > 13) Photosynthesis > Flashcards

13) Photosynthesis Flashcards

1
Q

4 main structures of the chloroplast

A
  • double membrane
  • photosystems I & II
  • thylakoid
  • fluid stroma
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2
Q

what is the function of the double membrane

A
  • contains grana & stroma
  • permeable to CO2, 02, ATP, sugars
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3
Q

what is the function of the photosystems

A
  • provide huge surface area for maximum light absorption
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4
Q

what is the function of the thylakoid related to its structure

A
  • stacked/large sa to increase light absorption
  • membrane (w pigments to absorb light) for light-dependent reaction
  • space for accumulation of H+ = proton gradient
  • green so chlorophyll absorbs red & blue light
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5
Q

what is the function of the fluid stroma

A
  • light-independent reaction/calvin cycle
  • has enzymes (RuBP, NADP)
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6
Q

where is the site of Light Dependent Stage (cyclic/non-cyclic phosphorylation)

A

Thylakoids (grana)

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7
Q

where is the site of Light Independent Stage (calvin cycle)

A

Stroma

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8
Q

where is the precise location of chlorophyll

A

Thylakoid membrane

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9
Q

Explain Non-Cyclic Phosphorylation (LDR)

A
  • Accessory pigments in photosystem II absorbs photons of light.
  • energy passed onto primary pigment & chlorophyll photoactivated.
  • diff wavelengths absorbed.
  • photolysis
  • O2 production
  • energised electrons pass along ETC then to PSI
  • ETC sets up proton gradient = chemiosmosis
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10
Q

Explain Cyclic Phosphorylation (LDR)

A
  • only PSI used
  • light energy absorbed by primary pigment
  • electron excited
  • electron emitted from chlorophyll passed along ETC
  • protons pumped into thylakoid space
  • protons diffuse back to stroma by ATP synthase
  • ATP synthesis
  • electron returns to PSI
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11
Q

How many photosystems are used in cyclic & non-cyclic phosphorylation

A

Cyclic = 1
Non-cyclic = both (2)

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12
Q

What are the products in cyclic & non-cyclic phosphorylation

A

Cyclic = ATP
Non-cyclic = ATP, O2, NADPH

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13
Q

What is the role of NADP reductase

A
  • transfers electrons to NADP
  • to form NADP
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14
Q

Chlorophyll A reflects & absorbs what colours ?

A

absorbs = blue & little violet/orange
reflects = green & little yellow

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15
Q

Chlorophyll B reflects & absorbs what colours ?

A

absorbs = violet & red
reflects = green & yellow

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16
Q

Cartenoids absorb what colours ?

A

colours that chlorophyll cannot absorb.
(can be seen in fall when chlorophyll breaks down)

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17
Q

why do plants appear green?

A

reflection of green light by chlorophyll

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18
Q

Shorter the wavelength, _____ the energy

A

higher

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19
Q

Longer the wavelength, ____ the energy

A

lower

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20
Q

Compare red light with blue light

A
  • lower energy
  • longer wavelength
  • lower frequency
21
Q

What happens to an electron when light strikes it?

A

gets excited and jumps to a higher energy level

22
Q

What are the accessory pigments

A
  • chlorophyll B
  • cartenoids (B carotene & xanthophyll)
23
Q

where is chlorophyll A (primary pigment) found

A

reaction centre

24
Q

Outline the role of accessory pigments in the Light Dependent Stage

A
  • Absorb light/wavelengths not absorbed by primary pigment
  • Passes energy to primary pigment/reaction centre
  • Absorb different wavelengths of light
25
How to calculate Rf value?
distance moved by pigment/ distance moved by solvent front
26
Describe the steps of Chromatography (5)
- Place a capillary tube in the pigment, and put one spot on the centre of the line (on chromatograph paper). - Repeat this to make the spot concentrated. - Place end of the paper into solvent. - Mark solvent front after some time. - Remove chromatogram before solvent reaches top. - Calculate Rf value by measuring distances. - Compare with known Rf values to identify the pigment.
27
what are the 3 limiting factors of photosynthesis ?
- light intensity - CO2 concentration - temperature
28
what is a limiting factor ?
the factors that prevents any further increase in the rate of the process
29
when there is no further increase in the rate, what is the limiting factor at the increasing point compared to the straight line
increasing point = factor on X axis straight line = one of the other 2 limiting factors
30
Effect of light intensity
At low light intensities : - decreased photolysis/energy absorbed - less production of oxygen - less ATP & glucose - slower rate At high light intensities : - some other factor is limiting photosynthesis
31
Effect of CO2 concentration
At low CO2 concentration: - enzyme used to fix CO2 (Rubisco) not effective - rate of successful collisions between CO2 molecules & active site of the enzyme is lower - ATP & high-energy electrons not used as rapidly - lower oxygen production - slower rate At high CO2 concentration: - some other factor is limiting
32
Effect of temperature
At low temps: - enzymes work slowly At high temps : - less production of oxygen/slower photosynthesis - Rubisco/enzyme decreasingly effective/ denatured - change in active site = fewer ESCs - CO2 cannot be fixed - less ATP produced - stomata close - reduction in CO2 uptake - loss of turger At intermediate temps: some other factor is limiting
33
where are accessory pigments found
surrounding the reaction centre
34
what is photoactivation
excitation of an e- to a higher energy level, causing it to escape a chlorophyll molecule
35
what happens to electrons in cyclic vs non-cyclic phosphorylation
cyclic = returns to same photosystem (PSI) non-cyclic = emitted from PSII absorbed into PSI
36
Explain the Calvin Cycle (light-independent stage)
- NADPH reduces hydrogen to give glycerate 3 phosphate. - forming Triose Phosphate - fixation of CO2 by Rubisco - rubisco catalyses reaction between RuBP and CO2 to give 2 GP. - GP to TP uses ATP & NADPH - TP --> glucose --> starch
37
Describe the process that produces oxygen during non‑cyclic photophosphorylation
- light absorbed by photosystem II (photoactivation) - photolysis - water-splitting enzyme - water splits into protons, electrons & oxygen
38
Describe how photoactivation of chlorophyll results in the synthesis of ATP in photophosphorylation
- electrons excited - electrons travel along ETC and energy released - energy used to pump H+ into thylakoid space - creates proton gradient - H+ diffuse through ATP synthase to stroma - chemiosmosis
39
why might a membrane have many diff coloured pigments to function efficiently ?
- to absorb light energy - more wavelengths can be absorbed - faster rate of photosynthesis
40
name the process that involves Rubisco in the Calvin Cycle
CO2 Fixation
41
what are some molecules produced from Triose Phosphate (TP) & GP molecules
- RuBP - hexose (glucose) - starch - amino acids - glycerol/fatty acids
42
why is the Calvin cycle described as a "cycle"
- no start & end point - all molecules present all the time - RuBP regenerated
43
suggest the imp of glucose/sugars to ecosystems
- oxygen linked to aerobic respiration - store of energy/ATP - energy flows through food chain/web
44
what is the function of the DNA in chloroplasts
make chloroplast proteins
45
function of lipid droplets in chloroplast
store products of photosynthesis
46
difference between absorption spectrum & action spectrum
- absorption spectrum = shows how much each wavelength/colour is absorbed - action spectrum = shows RATE of photosynthesis for light/wavelengths of colours
47
describe chemiosmosis
- H+ ions move out of stroma into thylakoid space - increased H+ concentration in thylakoid space - H+ diffuse back into stroma through ATP synthase
48
what is the colour change in DCPIP/Methylene blue when oxidised --> reduced
oxidised = blue reduced = colourless
49
what does sodium hydrogencarbonate do?
provides CO2

AL Biology (9 decks)

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