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IB HL Biology I > Unit 8 > Flashcards

Unit 8 Flashcards

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1
Q

Where is energy stored?

A

ATP

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2
Q

What does ATP do?

A

Provide energy for cellular activities

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3
Q

Cellular Respiration

A

reactions that break down organic monomers to release energy for ATP production

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4
Q

How is ATP (adenosine triphosphate) made?

A

by adding a phosphate group to ADP (adenosine diphosphate)

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5
Q

What does the formation of ATP from ADP require?

A

energy from food/glucose

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6
Q

What is ATP hydrolyzed into? (2)

A
  • phosphate group
  • ADP
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7
Q

What does the break down of ATP into ADP release?

A

Energy that can be used for cellular work

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8
Q

phosphorylate

A

add a phosphate group to a molecue

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9
Q

What happens when a molecule gains a phosphate group? (2)

A
  • becomes unstable
  • becomes highly reactive
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10
Q

What do cells use ATP for? (5)

A
  • skeletal muscle
  • cardiac muscle
  • liver
  • extraocular
  • retinal
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11
Q

What are the reactants for the cellular respiration equation? (2)

A
  • oxygen
  • glucose
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12
Q

What are the products for the cellular respiration equation? (3)

A
  • carbon dioxide
  • water
  • ATP
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13
Q

How are breathing and cellular respiration related? (2)

A
  • breathing bring O2 into the body and distributes it to cells via blood
  • O2 is used in mitochondria to make ATP and breathing disposes of the CO2 waste product
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14
Q

When are electrons moved?

A

when extracting energy

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15
Q

When are electrons gained?

A

when receiving energy

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16
Q

oxidation (2)

A
  • loss of electrons
  • loss of energy
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17
Q

reduction (2)

A
  • addition of electrons
  • addition of energy
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18
Q

What happens when glucose is oxidized? (2)

A
  • loses high energy electrons/H atoms
  • catabolic/glucose is broken down to release energy
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19
Q

What happens when O2 is reduced? (2)

A
  • gains low energy electrons/H atoms
  • oxygen accepts H to make water
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20
Q

What do high energy electron do on their way to oxygen?

A

donate some of their energy to generate ATP

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21
Q

Describe cell respiration in terms of metabolism. (2)

A
  • It is a series of enzyme catalyzed reactions.
  • It is catabolic.
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22
Q

Describe the conversion of ADP into ATP. (3)

A
  • When a phosphate group is added, adenosine diphosphate becomes adenosine triphosphate.
  • Adding a phosphate group is called phosphorylation.
  • ATP production requires energy from food.
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23
Q

List three cellular processes that use ATP as a source of energy. (3)

A
  • Muscular contractions
  • Protein synthesis
  • Active transport
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24
Q

What types of respiration can ATP be made by? (2)

A
  • aerobic
  • anaerobic
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25
Q

Aerobic (3)

A
  • uses oxygen
  • yields more ATP than anaerobic respiration
  • four stages of reaction are used to extract energy from food to make ATP
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26
Q

Anaerobic (3)

A
  • doesn’t use oxygen
  • yields far less ATP than aerobic respiration
  • only one reaction stage is completed
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27
Q

What is the aerobic respiration overall reaction?

A

carbohydrate + oxygen —> carbon dioxide + water + energy (38 ATPs)

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28
Q

What are the stages of aerobic respiration? (4)

A

1) glycolysis
2) link reaction
3) Kreb’s Cycle
4) Electron Transport Chain & Chemiosmosis

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29
Q

What do stages 1-3 aerobic respiration do? (2)

A
  • 4 ATP
  • lots of energized electrons
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30
Q

What does stage 4 of aerobic respiration do?

A

use energized electrons to make 34 ATP

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31
Q

Glycolysis

A

the splitting of sugar

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32
Q

Where does glycolysis occur?

A

cytoplasm

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33
Q

Electron carriers (NADH)

A

carry energy held by energized electrons to the electron transport chain to make ATP

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34
Q

What does glycolysis not require?

A

oxygen

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35
Q

What are key points about glycolysis? (3)

A
  • first occurred before the atmosphere had oxygen
  • uses enzymes to catalyze reactions
  • produces ATP by substrate-level phosphorylation
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36
Q

State the mechanism by which glycolysis produces ATP. (1)

A

Substrate-level phosphorylation

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37
Q

Outline the process of glycolysis. (6)

A

1) Glycolysis occurs in the cytoplasm.
2) Starting off with glucose, that glucose is phosphorylated to become hexose bisphosphate which requires 2 ATPs.
3) Another phosphate is added to the triose phosphate to become triose biphosphate which is then oxidized causing it to lose energy/H+
4) In turn, NAD+ is reduced to NADH and 4 ADPs are reduced to 4 ATPs
5) The rest of what is left from the triose phosphates is two pyruvate molecules
6) Overall, there is a net gain of 2 ATPs.

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38
Q

After glycolysis is that enough?

A

No, there is energy left in the pyruvate

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39
Q

What happens after glycolysis?

A

If oxygen is available, pyruvate will enter the mitochondria where it will be further oxidized.

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40
Q

What happens in cellular respiration is oxygen is present?

A

reactions move to the mitochondria

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41
Q

matrix

A

contains enzymes and solutes for link reaction and Kreb’s Cycle

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42
Q

Inner mitochondrial membrane

A

site for electron transport chain and oxidative phosphorylation

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43
Q

Cristae (2)

A
  • folded inner mitochondrial membrane
  • meant to maximize surface area for reactions
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44
Q

Small inter-membrane space

A

more efficient generation of H+ concentration gradient

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45
Q

Outline the structure of a mitochondrion. (6)

A
  • It is circular
  • It has a smooth outer membrane
  • Within the inner membrane is the matrix - Matrix is the inner compartment within the inner membrane
  • There are ribosomes and circular DNA in the matrix
  • The intermembrane space is between the outer and inner membranes.
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46
Q

70S Ribosomes

A

protein production

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47
Q

What is the step after glycolysis?

A

link reaction

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48
Q

What does the link reaction do?

A

modify pyruvate so it can enter the next stage (Kreb’s cycle)

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49
Q

What are the components of pyruvate?

A

carbons

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50
Q

Explain the link reaction. (6)

A
  • The link reaction can also be known as the oxidative decarboxylation of pyruvates.
  • When a pyruvate enters the link reaction, which occurs when oxygen is present, it attaches to coenzyme A.
  • In the process, it is oxidized and decarboxylated.
  • Where a carboxyl group, CO2 is lost, which becomes a waste product of the link reaction.
  • It also loses electrons/ H atoms/ energy via oxidation which goes to NAD+ which is reduced to NADH.
  • The result from this reaction after happening 2 times is 2 NADH and 2 Acetyl CoA, which was left of the pyruvate after the CO2 was lost. These things go onto the next stage, the Krebs cycle.
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51
Q

decarboxylation

A

removal of carboxyl group and releasing it as CO2

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52
Q

Where does the link reaction occur?

A

matrix of the mitochondria

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53
Q

What is another name for the link reaction?

A

oxidative decarboxylation

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54
Q

What is oxidative decarboxylated in the link reaction?

A

pyruvate

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55
Q

How is pyruvate oxidative decarboxylated? (2)

A

decarboxylated - because CO2 is lost
oxidized - because it loses H atoms/e-/energy

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56
Q

What is the waste from the link reaction?

A

2CO2

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57
Q

What is the net yield from the link reaction? (2)

A
  • 2 acetyl CoA per glucose molecule (because there are two pyruvates to go through the link reaction)
  • 2NADH/2H+
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58
Q

What is stage 3 of cellular respiration?

A

the Krebs Cycle

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59
Q

When does the Kreb’s Cycle occur?

A

when oxygen is present

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60
Q

Where does acetyl CoA come from?

A

the link reaction

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61
Q

What is acetyl CoA used for in the Krebs Cycle?

A

to make citric acid

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62
Q

What happens to citric acid in the Krebs Cycle? (2)

A
  • it is broken down in the Krebs cycle to release energy
  • energy is transferred to electron carriers and used to make ATP directly
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63
Q

Where does the Krebs Cycle occur?

A

the matrix

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64
Q

What are the steps of the Krebs Cycle? (8)

A
  • acetyl CoA brings its carbons to oxaloacetate
  • citric acid is formed
  • the coenzyme goes back to the link reaction
  • citric acid goes through oxidative decarboxylation
    - citric acid is oxidized
    - NAD+ is reduced to NADH H+
    - CO2 is waste product using oxygen
  • 5 carbon is result
  • 5 carbon goes through oxidative decarboxylation (same result as citric acid)
  • 4 carbon goes goes through oxidative decarboxylation
    - ADP –> ATP through substrate level phosphorylation
    - FAD reduced to FADH2
    - NAD+ reduced to NADH H+
  • returns back to oxaloacetate
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65
Q

How many carbons does acetyl CoA have?

A

2

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66
Q

How many carbons does oxaloacetate have?

A

4

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67
Q

How many carbons does citric acid have?

A

6

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68
Q

What does the Kreb’s cycle produce for 1 glucose? (3)

A
  • 2 ATP
  • 6 NADH, 2 FADH2 (electron carriers)
  • 4 CO2
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69
Q

What does substrate-level phosphorylation do in the Kreb’s Cycle?

A

produce ATP

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70
Q

Indicate two places where decarboxylation occurs. (1)

A

Going from citric acid to C5 and going from C5 to oxalacetate

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71
Q

What does oxidative decarboxylation make in the Kreb’s cycle? (3)

A

make:
- NADH
- FADH2
- CO2

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72
Q

Which releases more energy to the cell? Glycolysis or Krebs cycle?

A

Krebs cycle

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73
Q

Why does the Krebs cycle produce more energy? (2)

A
  • it produces a lot of NADH and FADH2
  • most of the energy from glucose is still in electrons at the end of the Kreb’s cycle
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74
Q

Where do electron carriers take electrons?

A

the ETC

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75
Q

electron transport chain

A

removes energized electrons from carriers and uses energy to build a concentration gradient

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76
Q

chemiosmosis

A

uses concentration gradient to make ATP

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77
Q

What does ETC + chemiosmosis equal?

A

oxidative phosphorylation

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78
Q

oxidative phosphorylation

A

using energy from oxidation of electron carriers to make ATP

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79
Q

What brings high energy electrons to the ETC? (2)

A
  • NADH
  • FADH2
80
Q

What is the location of the ETC in eukaryotic and prokaryotic cells? (2)

A

eukaryotic cells: mitochondria
prokaryotic cells: plasma membrane

81
Q

Explain how chemical energy for use in the cell is generated by electron transport and chemiosmosis. (8)

A
  • The chemical energy needed can be obtained through the oxidation of NADH and FADH2.
  • When these are oxidized, they donate energy to the ETC.
  • The ETC is a series of protein proton pumps that pump H atoms from the matrix into the intermembrane space.
  • The electrons release energy as they flow along the chain from carrier to carrier.
  • The ETC uses the energy from the high energy electrons to pump the H atoms.
  • When the atoms run out of energy, they are accepted by oxygen which is the terminal electron acceptor.
  • ATP synthase enzymes are located in the inner mitochondrial membrane.
  • The energy is released as protons pass down their gradient through ATP synthase enzymes. ATP synthase converts ADP to ATP.
82
Q

What is the terminal electron acceptor?

A

oxygen

83
Q

What does oxygen accept low energy electrons and protons for?

A

to form water

84
Q

How many ATP are produced from oxidative phosphorylation?

A

34

85
Q

What are the 34 ATP made from?

A

electron carriers from:
-glycolysis
- link reaction
- Krebs cycle

86
Q

Which and how many electron carriers does glycolysis contribute?

A

2 NADH

87
Q

What electron carrier does link reaction contribute?

A

2 NADH

88
Q

What electron carriers does Krebs cycle? (2)

A
  • 6 NADH
  • 2 FADH2
89
Q

How many ATP is made from 1 glucose?

A

38

90
Q

Where to the 38 ATPs come from?

A
  • 2 ATP from glycolysis
  • 2 ATP from Krebs cycle
  • 34 ATP from ETC & chemiosmosis
91
Q

mitochondrion (2)

A
  • produces energy for the cell
  • many in active cells
92
Q

anaerobic respiration

A

occurs when oxygen is absent

93
Q

How much ATP is produced from anaerobic respiration?

A

2 ATP per glucose

94
Q

How many stages of anaerobic respiration are there?

A

2

95
Q

What are the stages of anerobic respiration? (2)

A

1) glycolysis (2 ATP)
2) fermentation (0 ATP)

96
Q

fermentation

A

converts sugar to acids, gasses and/or alcohol

97
Q

What does anaerobic respiration in animals release?

A

lactic acid fermentation

98
Q

When does lactic acid fermentation happen in animals?

A

when cells don’t have much oxygen during bursts of high intensity exercise

99
Q

What is the pathway for fermentation in animals?

A

1 glucose –> 2 pyruvates –>lactate

100
Q

When does lactic acid fermentation happen in yeast, bacteria, and plants?

A

when cells lack oxygen

101
Q

What is the pathway for fermentation in yeast, bacteria, and plants?

A

1 glucose –> 2 pyruvates –> ethanol & CO2

102
Q

Describe the relationship between photosynthesis and cellular respiration. (2)

A
  • The products of cellular respiration (CO2 and water) are the reactants of photosynthesis
  • The anabolic pathways of photosynthesis build glucose and the catabolic pathways cell
103
Q

What is the lactic acid fermentation formula?

A

pyruvate + NADH –> lactate + NAD+

104
Q

What is the alcoholic fermentation formula?

A

pyruvate + NADH –> ethanol + CO2 + NAD+

105
Q

How are anerobic and aerobic respiration applied to exercise in humans? (3)

A
  • first few minutes of high intensity exercise is anaerobic, because of a lag in oxygen uptake
  • after sometime of doing the exercise the oxygen intake increases rapidly and eventually becomes steady
  • ATP can be produced through aerobic respiration
106
Q

Within different activities, what differs concerning aerobic and anaerobic respiration?

A

The proportion of aerobic to anaerobic respiration

107
Q

autotrophs (2)

A
  • make their own energy
  • convert energy from the sun or from inorganic compounds into organic compounds rich in energy
108
Q

heterotrophs (2)

A
  • get energy from others
  • consume energy-rich organic compounds from other organisms
109
Q

What is the energetic relationship between autotrophs and heterotrophs?

A

all living things rely on autotrophs to use light energy to make carbohydrates

110
Q

Explain the movement of electrons in the general equation for photosynthesis. (2)

A
  • Water is oxidized (loses electrons/hydrogen/energy)
  • Carbon dioxide is reduced (gains electrons/hydrogen/energy)
111
Q

Photosynthesis (2)

A
  • anabolic pathways
  • photosynthesis build glucose using light energy
112
Q

Cellular respiration (2)

A
  • catabolic pathways
  • respiration break down glucose to extract energy
113
Q

What is CO2 in terms of the photosynthesis equation?

A

a simple, low energy molecule

114
Q

What is light in terms of the photosynthesis equation?

A

an energizer of electrons

115
Q

What is glucose in terms of the photosynthesis equation?

A

high energy glucose is made when energized electrons are transferred to carbon dioxide

116
Q

Why is energy needed for photosynthesis?

A

to build glucose from carbon dioxide

117
Q

What happens when water is oxidized?

A

electrons/H atoms are removed and energized leaving O2 gas

118
Q

What happens when carbon dioxide is reduced?

A

energized electrons/H atoms are transferred to CO2, making sugar

119
Q

Where does photosynthesis occur?

A

chloroplast

120
Q

What is the location of chloroplasts?

A

concentrated in cells of the mesophyll

121
Q

Mesophyll

A

green tissue in interior leaf

122
Q

stomata

A

tiny pores in a leaf through which carbon dioxide enters and oxygen exits

123
Q

Stroma

A

has appropriate enzymes and a suitable pH for the Calvin cycle

124
Q

Double Membrane

A

Evidence for endosymbiosis

125
Q

Thylakoid

A

has ETC and ATP synthase for photophosphorylation

126
Q

Granum

A

flat membrane stacks increase SA:Vol ratio and small internal volumes quickly accumulation ions

127
Q

Lamella

A

connects and separates thylakoid stacks (grana)

128
Q

How many stages does photosynthesis take place in?

A

2

129
Q

Outline the structure of a chloroplast as seen with an electron microscope. (4)

A

An inner and outer membrane - shown as two concentric continuous lines close together
Grana - shown as a stack of several disc-shaped subunits
Thylakoids - one of the flattened sacs
Lamella - shown continuous with thylakoid membrane

130
Q

What are the stages of photosynthesis (2)

A
  • light-dependent reactions
  • light independent reaction
131
Q

Where does the light dependent reaction occur?

A

thylakoid membrane

132
Q

Explain how light energy is converted into chemical energy in the light-dependent reactions. (10)

A
  • Starting with photoactivation, light shines on the pigment in photosystem II
  • the electrons to become excited and pass it on to chlorophyll.
  • The excited electrons move on to the ETC where a gradient is being formed in the process as H atoms are being pumped into the thylakoid space using energy from the energized electrons.
  • Then ATP is formed via chemiosmosis using ATP synthase.
  • Photophosphorylation is also used, which is the use of light energy to energize electrons whose energy will be used to form a concentration gradient that will be used to phosphorylate ATP.
  • Eventually, electrons in the ETC run out of energy
  • go to photosystem I where they are reenergized through photoactivation.
  • NADP+ is reduced to NADPH using electrons from photosystem I.
  • The H atoms that are needed for the cycle to continue are replenished through photolysis
  • water is broken down causing the loss of energy/H atoms/ electrons that are used for photosystem II.
133
Q

Photoactivation (3)

A
  • light is absorbed by pigment molecules in photosystem II
  • this causes electron to be excited (higher energy level)
  • energy is passed to chlorophyll
134
Q

How is NADPH helpful to the light-dependent reaction?

A

it helps maintain the H+ concentration gradient because it binds excess H+

135
Q

photophosphorylation

A

using light energy to make ATP in the light dependent reactions

136
Q

What happens in photophosphorylation? (8)

A
  • photosystem II absorbs light
  • photoactivation produces an excited electron
  • H+ is pumped across thylakoid membrane
  • The absorption of light in photosystem I gives an electron to a carrier (NADP+ becomes NADPH)
  • Protons pass through ATP synthase
  • ATP is produced by chemiosmosis
  • Photolysis occurs
  • Photolysis of water produces H+/O2/e-
137
Q

What is the biproduct of electrons being replaced through the photolysis of water?

A

oxygen

138
Q

What is the result of the light dependent reaction? (2)

A
  • ATP
  • NADPH
139
Q

Where do ATP and NADPH go after the light dependent reaction?

A

the light independent reactions in the stroma to make glucose

140
Q

Outline what molecules are oxidized and reduced in the Krebs cycle and how energy is transferred by these processes. (3)

A
  • When molecules are oxidized they lose energy
  • Citric Acid, a 6 carbon molecule, and a 4 carbon molecule are oxidized and decarboxylated causing for a loss of energy/electrons/H atoms
  • The lost energy/electrons/H atoms go to FAD2 and NAD+ which are reduced to FADH2 and NADH which are electron carriers.
141
Q

Give one example of oxidative decarboxylation in the Krebs cycle. (4)

A
  • Enzymes in the matrix remove one carbon dioxide and H/energy/electrons from citric acid.
  • Oxidative decarboxylation is when a molecule is oxidized causing it to lose electrons/energy/hydrogen atoms, but it also loses a carboxyl group coming as the form of CO2.
  • With citric acid, it is oxidized and loses its electrons/energy/hydrogen atoms (oxidation)
  • which goes to an electron carrier (NADH), but it also loses CO2 causing it to become a 5 carbon molecule (decarboxylation).
142
Q

Describe how the link reaction and the Krebs cycle are related. (3)

A
  • The link reaction brings the Acetyl CoA
  • used in the Krebs cycle to join with a 4 carbon compound
  • Both of these processes occur in the matrix of the mitochondria
143
Q

Outline the molecules oxidized and reduced in the ETC and how energy is transferred by these processes. (3)

A
  • NADH and FADH2 are oxidized meaning they lose energy/electrons/H atoms
  • Proton pumps are reduced in ETC meaning they gain energy/electrons/H atoms
144
Q

Explain how the structure of a mitochondrion is adapted for its function. (3)

A
  • The large inner surface area of the cristae is to hold more electron transport chains and make more ATP by chemiosmosis.
  • The matrix contains DNA and ribosomes for protein (enzyme) synthesis and Krebs cycle enzymes.
  • The double membrane isolates metabolic processes/chemical reactions from the rest of the cytoplasm. The small intermembrane space between the inner and outer membranes allows for the rapid accumulation of protons/hydrogen ions.
145
Q

Outline the process of aerobic respiration. (6)

A
  • The first step is glycolysis which takes place in the cytoplasm.
  • Glucose is split and oxidized leaving two pyruvates
  • a net gain of 2 ATP.
  • Next, the pyruvates move to the matrix of the mitochondria if oxygen is present.
  • CO2 is produced.
  • 38 ATPs are produced per glucose molecule.
146
Q

Distinguish between anaerobic and aerobic cell respiration in eukaryotes. (4)

A
  • Anaerobic respiration does not require oxygen, but aerobic does
  • Anaerobic happens in the cytoplasm, while aerobic happens in the mitochondria.
  • Anaerobic respiration yields 2 ATP, aerobic yields 38 ATP
  • Anaerobic has a product of acids, gasses, or alcohol, aerobic has a product of CO2 or water.
147
Q

Outline anaerobic cell respiration in plant cells. (2)

A
  • Anaerobic respiration in a plant still results in 2 pyruvates from glycolysis.
  • The result is the production of CO2 or ethanol from fermentation.
148
Q

Explain the movement of electrons in the general equation for photosynthesis. (2)

A
  • Water is oxidized (loses electrons/hydrogen/energy)
  • Carbon dioxide is reduced (gains electrons/hydrogen/energy)
149
Q

Photosystems

A

groups of photopigments (including chlorophyll) in the thylakoid membrane

150
Q

What happens when a photosystem absorbs light energy? (2)

A
  • When a photosystem absorbs light energy, electrons within the pigments become energized
  • Excited electrons are transferred to carrier molecules
151
Q

What kind of light can photopigment electrons absorb?

A

certain wavelengths of visible light.

152
Q

What light on the visible light spectrum has the shortest wavelength?

A

violet light

153
Q

What light on the visible light spectrum has the longest wavelength?

A

red light

154
Q

What are the primary pigments of photosynthesis? (2)

A
  • Chlorophyll a
  • Chlorophyll b
155
Q

Chlorophyll (2)

A
  • Absorbs blue-violet and red light, reflects green light
  • Transfers excited electrons to electron carriers (NADP+)
156
Q

Chlorophyll b (2)

A
  • Absorbs blue and
    orange light, reflects
    yellow-green
  • Gives excited electrons
    to chlorophyll a
157
Q

Absorption spectrum

A

shows wavelengths of light absorbed by a single photosynthetic pigment

158
Q

What do chlorophyll a and b mainly absorb?

A

blue-violet and red-orange wavelengths

159
Q

action spectrum

A

show the wavelengths of light over which photosynthesis is most active

160
Q

Where does the light-independent reaction occur?

A

stroma

161
Q

light independent reactions (3)

A
  • use CO2, ATP, and NADPH to make a sugar called triose phosphate
  • ATP and NADPH from light dependent reactions
  • triose phosphate used to make glucose/other carbs.
162
Q

What are the phases of the Calvin cycle? (3)

A
  • carbon fixation
  • reduction
  • regeneration
163
Q

Carbon fixation (3)

A
  • taking carbon from the atmosphere and changing it into organic sugar
  • 3 CO2 + 3 RuBP = 6 glycerate 3-phosphate
  • reaction is catalyzed by rubisco
164
Q

Rubisco (carboxylase)

A
  • enzyme that catalyzes the carboxylation of ribulose bisphosphate
165
Q

Reduction (Calvin Cycle) (4)

A
  • glycerate 3-phosphate is reduced to triose phosphate using NADPH and ATP
  • 6 glycerate 3-phosphates → 6 triose phosphates
  • 6 ATP and 6 NADPH are oxidized
  • The energy from ATP and NADPH causes glycerate 3-phosphate molecules to react/rearrange
166
Q

Regeneration (3)

A
  • some triose phosphate & ATP is used to regenerate ribulose biphosphate (RuBP)
  • some triose phosphate also exits the cycle
  • 3 ATP are oxidized
167
Q

How much does the Calvin cycle use to make a triose phosphate? (3)

A
  • 3 CO2
  • 9 ATP
  • 6 NADPH
168
Q

How much does the Calvin cycle use to make a glucose? (3)

A
  • 6 CO2
  • 18 ATP
  • 12 NADPH
169
Q

Outline the relationship between a photopigment and a photosystem. (2)

A
  • Photopigments are molecules that trap light energy.
  • A photosystem is composed of a cluster of photopigments and an electron acceptor.
170
Q

Describe the absorption spectrum for chlorophyll a. (4)

A
  • Wavelength or color of light is plotted on the x-axis.
  • Absorbance of light is plotted on the y-axis.
  • On an absorption spectrum, there would be a curve over the blue-violet light and a curve over the red light.
  • There would not be a curve over the green light because it is not absorbed.
171
Q

Explain the relationship between the absorption spectrum for chlorophyll and action spectrum of photosynthesis for green plants. (3)

A
  • An absorption spectrum depicts the wavelengths of light that chlorophyll will absorb while an action spectrum depicts the wavelengths of light at which photosynthesis is most active.
  • Photosynthesis is most active when light is being absorbed because it excites the electrons in the photopigments, so the points where the chlorophyll absorbs light will be where the absorption spectrum peaks.
  • The difference in the absorption spectrum of chlorophyll and the action spectrum for photosynthesis is due to the absorption by pigments other than chlorophyll such as carotene.
172
Q

Define carboxylation, reduction, and carbon fixation. (3)

A
  • Carboxylation - when a carboxyl group from the atmosphere is added to another molecule
  • Reduction - When an electron/hydrogen atom/energy is gained as a result of another molecule being oxidized. In the light dependent reaction, 6 ATP and 6 NADPH donate their electrons/energy/hydrogen atoms to the 6 glycerate 3-phosphate turning it into a triose phosphate.
  • Carbon fixation - taking carbon from the atmosphere and making it an organic sugar
173
Q

Explain the relationship between the structure and function for the thylakoid membranes and stacks (grana) (3)

A
  • large surface area for light absorption and reactions
  • membrane-bound ATP Synthase and photosystems
  • High density of chlorophyll for light absorption
174
Q

Explain the relationship between the structure and function for the low volute thylakoid spaces

A

rapid generation of H+ gradient for chemiosmosis

175
Q

Explain the relationship between the structure and function for the enzyme rich stroma (2)

A
  • contains rubisco for carboxylation of RuBP
  • fluid easy for diffusion
176
Q

What is the chloroplast’s equivalent to the outer mitochondrial membrane?

A

chloroplast envelope

177
Q

What is this chloroplast’s equivalent to the thylakoid membrane?

A

inner mitochondrial membrane

178
Q

What is this chloroplast’s equivalent to the matrix?

A

the stroma

179
Q

What are direct ways photosynthesis can be measured? (2)

A
  • rate of oxygen production
  • rate of carbon dioxide uptake
180
Q

What are indirect ways photosynthesis can be measured?

A

tracking changes in plant biomass/ mass of organically bound carbon

181
Q

What is the formula for measuring the rate of oxygen produced?

A

oxygen produced
time

182
Q

How is the rate of gas produced measured and what are some methods? (4)

A
  • Oxygen gas production is measured over a period of time
  • counting oxygen bubbles
  • collecting oxygen gas in a syringe - using oxygen sensors
183
Q

What is the formula for measuring the rate of carbon dioxide produced?

A

carbon dioxide used
time

184
Q

How is the rate of CO2 used measured and what are some methods? (3)

A
  • CO2 usage or increases in pH are measured over time
  • pH of water surrounding a plant using pH meter or pH paper
  • Decreases in CO2 are measured by using a CO2 sensor
185
Q

What is the formula for measuring the rate in change in biomass?

A

change in biomass
time

186
Q

How is the rate of change in body mass measured and what are some methods? (2)

A
  • Biomass increase can be used as an indirect measure of the production of glucose
  • Biomass can be measured by drying a plant to remove water and then finding its mass.
187
Q

What is a limiting factor?

A

factor is closes to its minimum

188
Q

Are limiting factors of photosynthesis?

A
  • light intensity
  • carbon dioxide concentration
  • temperature
189
Q

When is light intensity limiting?

A

at night

190
Q

What is the result of low light intensity?

A
  • affects light-dependent stage
  • creates insufficient ATP and NADPH production
  • stops the Calvin cycle from operating at maximum rate
191
Q

Why does a graph expressing light intensity plateau?

A

at high light intensity, further increase has no effect on rate of reaction, as all chloroplasts are working at full efficiency

192
Q

When is CO2 concentration limiting? (2)

A
  • in bright light
  • in warm temperatures
193
Q

How is low CO2 concentration limiting? (2)

A
  • it limits carbon fixation
  • results in low glucose production
194
Q

Why does the graph expressing CO2 concentration plateau?

A

at high concentration, further increase has no effect on rate of reaction, as CO2 is being fixed at the maximum rate of efficiency

195
Q

When is temperature limiting?

A

in colder climates

196
Q

What is the result of low temperatures?

A
  • affect light-independent stage
  • affect enzyme activity (less active at low temps)

IB HL Biology I (10 decks)

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