1
Q
what is respiration
A
process that occurs in living cells releasing the energy stores in organic molecules like glucose
2
Q
how do you synthesis (make) ATP
A
ADP + Pi → ATP
3
Q
why is ATP in cells hydrolysed
A
to release energy that is needed to drive biological processes
4
Q
examples of biological processes that use ATP
A
active transport, endocytosis, exocytosis, synthesis of large molecules, DNA replication, cell division, movement and activation of chemicals
5
Q
what did synthesis mean
A
making of a larger molecule from smaller molecules
6
Q
🤔 Muscle cells contain mitochondria with many cristae. Explain the advantage of the mitochondrion containing many cristae.
A
they have a large surface area for oxidative phosphorylation and this provides ATP for contraction of the muscle cells
7
Q
what do you have to remember when answering respiration questions
A
the name of the process - like oxidation, phosphorylation etc
8
Q
what does metabolism or metabolic reactions mean
A
all the chemical reactions that take happen in a cell
9
Q
what is a anabolic reaction
A
a reaction where smaller molecules join together to make larger molecules - ie larger molecules are synthesised from smaller molecules
10
Q
what is a catabolic reaction
A
a reaction where larger molecules are broken down into smaller molecules - ie larger molecules are hydrolysed to smaller molecules
11
Q
what is the structure of an atp molecule
A
adenine (base) + 5 carbon sugar ribose + 3 phosphate groups
12
Q
… + … → ATP
A
ADP + Pi
13
Q
what is Pi
A
inorganic phosphate
14
Q
atp + water → energy what type of reaction is this
A
hydrolysis
15
Q
ATP + water →
A
ADP + Pi + energy
16
Q
what enzyme catalyses the reaction os atp + water
A
atp hydrolase
17
Q
ADP back to ATP is en example of what type of reaction
A
phosphorylation
18
Q
when you add a Pi (phosphate) back to another molecule, what type of reaction is it always calles
A
phosphorylation
19
Q
what are the 2 ways of reforming atp
A
substrate level phosphorylation and oxidative phosphorylation
20
Q
which method provides the fastest way of producing the most amount of atp
A
oxidative phosphorylation
21
Q
what is a dehydrogenation or oxidation reaction
A
breaking down glucose molecules releasing H- ions
22
Q
when a H- ion is released, what is it added to
A
a hydrogen carrier like NAD or FAD
23
Q
NAD + H- →
A
reduced NAD or NADH
24
Q
how many electrons does the H- ion have
A
2 lone electrons
25
what are bonds between the phosphate group
phosphoanhydride bonds
26
why is the heat energy released by the hydrolysis of atp useful for organisms
its keeps the organism warm and enables their enzyme-catalysed reactions to proceed at their optimum rate
27
name the 4 stages of aerobic respiration
Glycolysis
link reaction
krebs cycle
oxidative phosphorylation
28
where does glycolysis happen
cytoplasm
29
is glycolysis aerobic or anaerobic
anaerobic
30
which coenzyme is used in glycolysis
coenzyme NAD
31
outline the main 3 stages in glycolysis
1. phosphorylation of glucose to hexose bisphosphate
2. splitting each hexose bisphosphate molecule into 2 triose phosphate molecules
3. oxidation of triose phosphate into pyruvate
32
what does the cofactor enzyme NAD do
accepts the hydrogen atoms removed during oxidation
33
how may hydrogens can NAD accept
2 hydrogens
34
where is NADH used
in oxidative phosphorylation to generate ATP drom ADP and Pi
35
explain stage 1 (phosphorylation) in glycolysis
glucose + 2APT → hexose bisphosphate (6 carbons and 2 P on either side)
The ATP is hydrolysed to add the phosphate group
ATP → ADP
36
what happens after to the hexose bisphsophate
it splits into 2 molecules of triose phosphate and this is a lysis reaction
37
what happens after to the triose phosphate
phosphorylation happens again where a Pi is added and it becomes triose bisphosphate
38
what happens after to the triose bisphosphate and name of reaction
oxidation reaction
2 hydrogens are removed from the 2 triose bisphosphate and 2NAD → 2NADH
The P is removed and ATP is formed as a result 2ADP + 2Pi → 2ATP
and then finally, 2 molecules of pyruvate is formed (only 3 + 3 carbons left)
39
what is another name for the glycolysis reaction
substrate level phosphorylation
40
what are the final products of glycolysis
2 molecules of pyruvate
2 molecules of net ATP
2 molecules of NADH
41
in the 4 stages of respiration which ones are aerobic and anaerobic
glycolysis = anaerobic
link reaction, krebs cycle and oxidative phosphorylation = aerobic
42
what happens to pyruvate in aerobic conditions
it is actively transported into the mitochondria for the link reaction
43
what happens to pyruvate in anaerobic conditions
it is converted in the cytoplasm to ethanol or lactate
44
what is the inner and outer membrane made from in mitochondria
phospholipid membrane
45
what is the inner membrane of mitochondria folded into and why is this useful
cristae to have a larger surface area
46
what does the mitochondrial matrix contain
mitochondrial looped DNA, mitochondrial ribosomes, enzymes for the link reaction and krebs cycle
47
where is the electron transport chain found
in the borders of the cristae
48
what does the electron carrier protein contain
a cofactor = non-protein haem group containing an iron ion
49
what does the iron ion as the electron carrier
it becomes Fe2+ when it becomes reduced by gaining an electron
it can become Fe3+ when it becomes oxidised by donating an electron to the next electron carrier
50
what does the coenzyme in the electron carrier do
uses energy released from the electrons to pump protons in the matrix to the intermembrane space causing proteins to accumulate in the intermembrane space. and then this protein gradient causes proteins to flow through the channels in ATP synthase to form ATP
51
what is the process of electron chain transporters called
chemiosmosis
52
what is the second stage in aerobic respiration
link reaction
53
where does the link reaction happen
mitochondrial matrix
54
how does the pyruvate get from the cytoplasm to the mitochondrial matrix
active tranport via specific pyruvate H+ symport transport protein
55
overview of link reaction pleasee 😉
pyruvate + coenzyme A → acetyl coenzyme A + CO2
56
what type of reaction is the link reaction
oxidation because NAD → NADH
57
what 2 things happen to the pyruvate
dehydrogenation and decarboxylation
58
what is the link reaction catalysed by
enzyme pyruvate dehydrogenase
59
what exactly happens in the link reaction
1. carboxyl group is removed and some co2 is produced here
2. decarboxylation of pyruvate and dehydrogenation produces an acetyl group
3. acetyl group combines with CoA to become acetyl CoA
4. NAD → NADH
‼️⚠️this happens 2 times are there are originally 2 pyruvates
60
what type of reaction is the link reaction
oxidative decarboxylation reaction
61
where does the krebs cycle take place
mitochondrial matrix
62
overview of krebs cycle
series of enzyme catalysed reactions that oxidise the acetate CoA from the link reaction to 2 molecules to 2 molecules of co2 whilst reducing NAD and FAD
63
1st part of krebs cycle
acetyl group + oxaloacetate → citrate
2C + 4C → 6C
the coenzyme A is recycled back to the link reaction
64
2nd part of krebs cycle
citrate is decarboxylated (producing co2) and dehydrogenated (NAD → NADH) producing a 5C molecule
65
3rd part of krebs cycle
the 5C molecule is further decarboxylated (producing co2) and dehydrogenated (NAD → NADH) producing a 4C molecule
66
4th part of krebs cycle
substrate level phosphorylation happens again producing 1 ATP and then the 4C is again dehydrogenated (FAD → FADH and NAD → NADH) and this is oxaloacetate (reused again and cycle repeats)
67
products made in the krebs cycle
2 CO2
2 NADH
1 FADH
68
how many times does the krebs cycle happen for each molecule of glucose
2 times because glucose → 2 pyruvates →2 CoA
69
what is the final stage of aerobic respiration
oxidative phosphorylation
70
where does oxidative phosphorylation happen
cristae of the inner mitochondrial membrane
71
overview of oxidative phosphorylation
NADH and FADH are reoxidised when they donate their H ions with the 2e- to the electron transport chain
protons go into the mitchondrial matrix forming a gradient
72
what happens to the electrons from the H ions
they pass along the ETC and each electron carrier has an iron ion that becomes Fe2+ when an e- is added and then it becomes Fe3+ when an e- is donated to the next electron carrier in the chain
73
what else happens as the electrons move through the ETC
some of their energy is used to pump protons fron the inner membrane to the intermembrane space
74
what happens as protons accumulate in the intermembrane space
a proton gradient form across the membrane
75
what does the proton gradient generate
a chemiosmotic potential = known as a proton motive force which is the source of potential energy
76
why can protons not diffuse through the lipid bilayer
the outer membrane has a low permeability to protons and the inner membrane is impermeable to protons
77
how do the protons move
down their conc gradient through protein channels in the inner membrane via ATP synthase
78
what happens as the protons move down their conc gradient
the flow of the protons causes a conformational (shape) change in the ATP synthase allowing ADP + Pi → ATP
79
what is the flow of protons called
chemiosmosis
80
what role does oxygen play here
it is the final oxygen acceptor and combines with the e- coming off the electron transport chain and with protons forming water
81
whats the equation for oxygen in chemiosmosis
4H+ + 4e- + O2 → 2H2O
82
how many molecules of ATP can be produced by oxidative phosphorylation via 1 molecule of glucose
28
83
why is the theoretical yield of 32 molecules of ATP rarely achieved in aerobic respiration
some ATP used to active transport pyruvate into mitochondria and transport NADH made in glycoylsis into the mitochondria and some protons may leak out through the outer mitochondrial membrane
84
what happens if oxygen is absent
no water produced in chemiosmosis as oxygen cannot be the final electron acceptor
proton conc increases in the matrix and oxidatice phosphorylation stops
NADH and FADH cannot be oxidised and krebs cycle and link reactions stops
85
how can the organisms survive without oxygen
glycolysis can take place but the NADH has to somehow become NAD so it can be reused in glycolysis through another metabolic pathway
86
which pathway do fungi like yeast use for anaerobic respiration
ethanol fermentation pathway
87
which pathway do mammals use for anaerobic respiration
lactate fermentation pathway
88
where does anaerobic respiration happen
cytoplasm of the cell
89
what happens in the ethanol fermentation pathway in fungi like yeast
1. pyruvate → ethanal (produces CO2) and is catalysed by pyruvate decarboxylate
2. ethanal → ethanol by accepting H atoms from NADH (so NADH → NAD) and is catalysed by ethanol dehydrogenase
NADH → NAD which means it can be reused in glycolysis
90
when does lactate fermentation happen in mammals
happens in tissues like the muscles which are used when running etc causing more muscle contractions increasing ATP demand causing an oxygen deficit
91
what happens in the lactate fermentation pathway in mammals
pyruvate → lactate by adding H ion from NADH so NADH → NAD and NAD can be reused again in glycolysis for a short period of time to produce ATP
92
what happens to the lactate when oxygen levels rise
carried away from the muscle in the blood to the liver where it is either converted to pyruvate to be used in the krebs cycle or recycled to glucose and glycogen
93
what would happen if the lactate was not removed
pH would be lowered in the muscle tissue inhibiting enzymes involved in glycolysis and muscle contraction
94
🧐 where does lactic acid in muscles come from
lactic acid is the acidic form of lactate
Lactic acid ⇋ Lactate− + H+
95
why do yeast reproduce faster in aerobic conditions
as they need ATP to divide
96
which molecules can provide respiratory substrates to produce molecules of ATP
lipids, carbohydrates, proteins
they provide energy with lipids providing most
97
how can lipids be used for respiration
triglycerides → glycerol + fatty acid (hydrolysed)
glycerol converted to triose phosphate and respired
fatty acids contain lots of hydrogen atoms used in oxidative phosphorylation
98
when are amino acids used in respiration and where do they come from
they are used when there is not enough glucose of lipids and come from protein in muscles
99
how are amino acids used in respiration
they are broken down into a keto acid → pyruvate, acetyl CoA or krebs cycle acid like oxaloacetic acid then used in respiration
100
complete → the greater the availability of protons....
for chemiosmosis, the more ATP can be produced
therefore, the more hydrogen atoms there are in a molecule, the more amount of atp can be generated per molecule of substrate
101
the more no of hydrogen atoms in a molecule...
the more oxygen will be needed for respiration
102
what the formula for the respiratory quotient (RQ)
RQ = CO2 produced / O2 consumed (no units)
103
what is the RQ value for glucose
1
104
what is the RQ value for fatty acids
0.7
105
what is the RQ value for amino acids
0.8
106
what does it mean if the RQ value is greater than 1
there is some co2 being produced than o2 being consumed showing there is anaerobic respiration taking place
107
explain what is likely to happen to the pH of the solution when light is shone on the chloroplasts
the pH increases and becomes more alkaline because protons move in the chloroplast by diffusing down the concentration gradient
108
where can atp come from in muscle cells particularly during strenous exercise
atp-phosphocreatine which runs out really quickly and is normally used for short bursts of activity
Biology OCR A Level
flashcards
Decks in class (16)
# Cards
-
5.6 Photosynthesis76
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4.2 Biodiversity0
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6.5 Ecosystems79
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6.6 Populations and Sustainability41
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5.7 Respiration108
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5.4 Hormonal Communication64
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5.3 Neuronal Communication69
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5.1 Communication and Homeostasis46
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6.1 Cellular Control40
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5.2 Excretion88
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5.5 Plant and Animal Responses80
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6.2 Patterns of Inheritance20
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6.3 Manipulating Genomes26
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Inheritance Key Terms16
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2.2 Biological Molecules21
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Mistakes from Module 2 Practice Questions12
