Chapter 17- Photosynthesis Flashcards

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1
Q

How grana is adapted to its function?

A
  • contains chlorophyll pigments
  • contains e- carriers
  • large SA for light absorption
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2
Q

Why theoretical rate of photosynthesis not achieved at high light intensity?

A
  • another factor becomes limiting factor

- temp becomes limiting as light independent reaction involves enzymes

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3
Q

How till structure of a leaf adapted to living in shade differ from a leaf adapted to living in sunlight?

A
  • larger SA

- Larger chloroplasts

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4
Q

How heterotrophic organisms are dependent on plants?

A
  • plants produce glucose + O2 during photosynthesis
  • these used in respiration by animals
  • animals eat plants to obtain organic materials
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5
Q

Primary pigment?

A

Chlorophyll a

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6
Q

Accessory pigment?

A
  • chlorophyll b
  • xanthophylls
  • carotenoids
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7
Q

Adv of having range of accessory pigments?

A

Can absorb different wavelengths of light

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8
Q

Compound synthesis as a result of an electrical + pH gradient across thylakoid membrane?

A

ATP

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9
Q

Enzyme that catalysts fixation of CO2?

A

Rubisco

Ribulose bisphosphate carboxylase

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10
Q

1st stable product of carbon fixation?

A

GP

Glycerate 3 phosphate

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11
Q

Compound regenerated so more CO2 can be fixed?

A

RuBP

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12
Q

Polysaccharides that can be synthesised from end products of light independent stage?

A
  • amylose

- cellulose

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13
Q

Products of light dependent that is used in light independent?

A

ATP

NADPH

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14
Q

Autotroph?

A

-can make organic molecules from inorganic molecules

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15
Q

Heterotroph?

A

Feeds on + digests organic molecules that have been made by another organism

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16
Q

How light is harvested in chloroplast membrane?

A
  • primary + accessory pigments form a photosystem
  • light energy absorbed by pigment molecules
  • e- excited as move to higher energy level
  • energy passed to chlorophyll a in reaction centre
  • range of pigments allow range of wavelengths to be absorbed
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17
Q

What would happen if movement of e- between e- carriers at PSII was blocked?

A
  • prevents non cyclic phosphorylation

- no ATP + NADPH available for Calvin cycle

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18
Q

What would happen if movement of e- between e- carriers at PSI was blocked?

A
  • prevents cyclic + non cyclic phosphorylation

- no ATP + NADPH available for Calvin cycle

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19
Q

Why herbicide can emit light + heat?

A

-energy given off from excited e-

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20
Q

Why measuring CO2 uptake may or may not give better indication of photosynthesis than measuring O2 production?

A
  • CO2 only used in one stage
  • O2 only produced in one stage
  • O2 produced may be used for respiration
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21
Q

Products of light dependent stage?

A

ATP
NADPH
O2

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22
Q

Graph. What happens at point that plant starts photosynthesising?

A
  • is at compensation point

- rate of photosynthesis = rate of respiration

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23
Q

Graph. What happens at point that rate of photosynthesis starts increasing?

A

Rate of photosynthesis greater than rate of respiration

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24
Q

Function of DNA and ribosomes in chloroplasts?

A
  • DNA to provide coding for protein
  • ribosome for protein synthesis
  • protein can be used for e- carrier
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25
Q

How to supply plant with CO2?

A
  • dry ice

- sodium hydrogen carbonate

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26
Q

Why not all O2 produced collected in capillary tube?

A
  • dissolves in water
  • used in respiration
  • may escape collection apparatus
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27
Q

Assumptions made when carrying out practical forms measure rate of photosynthesis by measuring gas produced?

A
  • all O2 produced by plant collected

- all gas collected is O2

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28
Q

Why nitrogen present in gas given off by plant?

A

Was present in air spaces in the leaf

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29
Q

Why presence of these pigments is an advantage to seaweeds that live in deeper water?

A
  • in dealer water there is lower light intensity

- these pigments can absorb what little light there is

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30
Q

Fate of TP?

A
  • regenerates RuBP so cycle can continue for further carbon fixation
  • formation of glucose
  • formation of amino acids, nucleic acids, lipids
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31
Q

Effect on photosynthesis of an increase in oxygen conc?

A
  • O2 competes with CO2 for active site of Rubisco in Calvin cycle
  • oxygen will be used + less CO2 fixed
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32
Q

How temp can be controlled to increase rate of photosynthesis?

A
  • photosynthesis controlled by enzymes so increasing temp will increase rate
  • heater
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33
Q

How CO2 can be controlled to increase rate of photosynthesis?

A
  • burning paraffin

- increases CO2 fixation

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34
Q

Why there is a difference between max rate of photosynthesis + optimum economic rate?

A
  • maintenance of optimum temp expensive to heat or cool

- cost of maintaining max rate would reduce profits

35
Q

2 graphs showing rate of photosynthesis. Which is more efficient?

A

One which plateaus first

36
Q

How plants can be adapted to diff light conditions?

A
  • large no. Of chloroplasts
  • large SA of leaves to absorb max light
  • large no. Of stomata for max diffusion of CO2
37
Q

Changes in rate of photosynthesis against temp?

A
  • rate of photosynthesis increases as temp increases as enzyme controlled reactions + enzyme activity affected by temp
  • plateaus at high temp as temp mo longer limiting factor. Could be CO2 conc
38
Q

Where is energy needed in the Calvin cycle?

A

Conversion from GP to TP

TP to RuBP

39
Q

Role of rubisco

A

Fix carbon t RuBP

40
Q

What proportion of TP molecules form glucose?

A

1 in every 6. Rest recycled to regenerate RuBP

41
Q

Where does the CO2 come from?

A

Diffuses from environment

42
Q

Why can photosynthesis not take place if light intensity too low?

A

Light dependent reaction cannot take place as light not reaching pigments

43
Q

How does plant respond if CO2 too high?

A

Stomata close

44
Q

How knowledge about limiting factors is useful for farmers?

A

Allows the to create environments with optimum conditions which increases growth + increase yield

45
Q

Where does light dependent reaction take place?

A

Thylakoids

46
Q

Where does light independent reaction take place?

A

Stroma

47
Q

Function of photosystem and how PSI + PSII differ?

A
  • absorb light energy
  • absorb diff wavelengths of light
  • PS2 only non cyclic photophosphorylation
  • Ps1 cyclic + non cyclic
48
Q

Photolysis?

A

Splitting up with light

49
Q

What happens to e- in cyclic photophosphorylation?

A
  • e- excited in chlorophyll are recycled back to chlorophyll molecule
  • not passed to form NADPH
50
Q

E- transport chain?

A

e- carrier proteins transfer e- down chain

51
Q

Why photolysis of water essential?

A
  • photolysis splits water into H+ e- and O2

- e- need to be replaced in PSII

52
Q

How e- transport chain produces ATP?

A
  • light energy enters PSII
  • e- excited + move to higher energy level
  • e- move along e- transport chain
  • his releases energy
  • pumps H+
  • chemiosmosis
  • ATP synthase produces ATP from ADP + Pi
53
Q

Enzyme needed to break down ATP + release energy?

A

ATPase

54
Q

Why ATP is a good immediate energy source?

A
  • easily broken down to release energy
  • small
  • soluble
  • easily transported
55
Q

Why leaves have air spaces?

A

Allow gases to diffuse rapidly

56
Q

How mean cell adapted for maximum photosynthesis?

A
  • many stomata
  • many chloroplasts
  • waxy cuticle
  • thin + flat leaves
57
Q

Metabolic reactions?

A

Series of enzyme controlled reactions

58
Q

Function of coenzyme NADP?

A
  • transfers H from from 1 molecule to another

- involved in redox reactions

59
Q

Importance of pigments in photosynthesis?

A
  • pigments absorb light
  • e- excited + raised to higher energy level
  • accessory pigments pass energy to primary pigment in reaction centre
  • primary pigments pass e- to e- transport chain for light dependent reaction
60
Q

Why some need pigments that are different from those of other photosynthetic organisms?

A

-have to absorb light of shorter wavelengths as some wavelengths may not reach if they are in deep water

61
Q

Process of chemiosmosis?

A
  • occurs on thylakoid membrane
  • involves e- transport chain
  • e- release energy
  • H+ pumped out across membrane
  • proton gradient created and pH gradient
  • H+ pass through hydrophilic channel protein ATP synthase
  • H+ move from area of high conc to area of low concentration
  • ATP synthase produces ATP from ADP + Pi
62
Q

Why temperature has greater effect on light independent stage?

A
  • controlled by enzymes

- increase in temp will increase KE of enzyme molecules, increase no. Of successful collisions + no. Of ESC formed

63
Q

Material that can be used as stationary phase in TLC?

A

Silica gel

64
Q

Location of pigments in chloroplast?

A

Photosystems on thylakoid membrane

65
Q

How grana are adapted to their function?

A
  • contains pigment molecules
  • contains e- carriers
  • large SA for light dependent reaction
66
Q

How will leaf of plant adapted to living in sunlight differ from leaf adapted to living in shade?

A
  • larger chloroplasts
  • more grana in chloroplast
  • larger SA of leaves
67
Q

How are heterotrophic organisms dependent on plants (autotrophs)?

A
  • heterotrophs need to obtain organic materials from autotrophs by eating them
  • plants produce glucose + o2 during photosynthesis
  • organic materials used in respiration by heterotrophs
68
Q

Polysaccharides that can be synthesised from end products of light independent stage?

A
  • Amylose
  • Amylopectin
  • cellulose
69
Q

Compound that can be made from TP?

A

Amino acids

70
Q

PSII blocked. Effect?

A
  • prevents non cyclic phosphorylation
  • no e- available to produce NADPH
  • ATP production by cyclic phosphorylation not prevented
71
Q

Why plants can be seen to emit light and give off heat?

A

Energy given off from excited e-

72
Q

Why measuring CO2 uptake may or may not be better than measuring O2 production?

A
  • O2 only produced in light dependent
  • O2 produced may be used for respiration
  • CO2 only used in 1 stage
73
Q

PSI blocked. Problems?

A
  • inhibits cyclic + non cyclic photophosphorylation

- no NADPH for Calvin Cycle

74
Q

Role of DNA and ribosomes in chloroplast?

A
  • protein synthesis of e- carriers

- enzymes for Calvin Cycle

75
Q

Role of coenzyme NADP?

A
  • accepts H

- supplies H to Calvin Cycle

76
Q

How rate of photosynthesis differs during day?

A
  • increased activity during daylight

- as light intensity increases increased activity of light dependent stage

77
Q

What increases temp does to chloroplasts?

A
  • damage to chlorophyll. Reduce light dependent stage

- damage to membranes. Reduce photophosphorylation. Reduce light dependent stage

78
Q

Several amino acids have similar structures. Why could this be a problem when using TLC to analyse a mixture of amino acids?

A

-amino acids won’t separate because similar compounds have similar Rf values

79
Q

How could you analyse chromatogram to identify amino acids?

A
  • calculate Rf values

- compare Rf values with those known for amino acids

80
Q

Process that TLC separates amino acids?

A

Adsorption

81
Q

Photophosphorylation?

A

Synthesis of ATP using energy from light

82
Q

Effect on rate of photosynthesis if O2 come increases?

A
  • reduces rate
  • less rubisco available for CO2 as more o2 competing with CO2 for rubisco
  • less carbon fixation
83
Q

Why presence of these pigments is an advantage to seaweeds that live deep under water?

A
  • in deeper water there is a lower light intensity
  • these pigments can absorb what little light there is
  • mainly shorter wavelenghts of light that penetrate
  • these pigments can absorb pigments of that wavelength
84
Q

do sieve tube elements have chloroplasts?

A

yes`