respiration Flashcards
1
Q
What is respiration?
A
process which releases energy stored in molecules like glucose, through series controlled reactions
2
Q
What is energy from respiration used for?
A
to synthesise molecules of ATP from ADP and inorganic phosphate
3
Q
What is ATP used for?
A
hydrolysed to release energy needed for biological processes
4
Q
What is metabolism
A
collectively all of the chemical processes which occur inside an organisms cells
5
Q
What is an anabolic reaction?
A
large molecules synthesised from smaller ones using energy
6
Q
What is a catabolic reaction?
A
large molecules broken down to smaller molecules releasing energy
7
Q
What type of molecule is ATP?
A
phosphorylated nucleotide
8
Q
Properties of ATP?
A
stable and easily transported, but is readily broken down by enzymes, small manageable amounts of energy
9
Q
How do heterotrophs obtain energy?
A
consumption of food, in lipids and carbohydrates
10
Q
How is energy stored in mammals?
A
as glycogen or in adipose tissues (fats)
11
Q
How many ATP does one molecule of glucose produce?
A
32
12
Q
What types of energy does hydrolysis of ATP release?
A
chemical and heat
13
Q
Why is heat energy from hydrolysis of ATP useful?
A
keeps organisms warm and allows enzyme controlled reactions to take place at optimum temperature
14
Q
What is the word equation for respiration?
A
glucose + oxygen –> carbon dioxide + water + ATP
15
Q
What is the symbol equation for respiration?
A
C6H12O6 + 6O2 -> 6CO2 + 6H2O + 38 ATP
16
Q
What is energy needed for?
A
all metabolic reactions/biological processes
17
Q
Why do mammals need to maintain body temperature?
A
to keep optimum temp for biological processes and enzymes
18
Q
How does SA:V ratio relate to heat loss and respiration?
A
lower SA:V ratio in larger animals means less heat loss and slower rate of respiration, and vice versa
19
Q
Describe the structure of ATP
A
Adenosine and three phosphates
20
Q
What is adenosine?
A
adenine plus ribose
21
Q
What are the four main stages of respiration?
A
glycolysis, link reaction, krebs cycle, electron transport chain
22
Q
Two types of transport which require ATP?
A
active transport, endo/exocytosis
23
Q
Examples of processes ATP is used for
A
synthesis large molecules, cell division, transport
24
Q
Where does glycolysis occur?
A
cytoplasm
25
Where does the link reaction occur?
matrix of mitochondria
26
Where does the krebs cycle occur?
matrix of mitochondria
27
Where does oxidative phosphorylation occur?
cristae of mitochndria
28
Is glycolysis aerobic or anaerobic?
anaerobic (does not need oxygen)
29
Which coenzyme is involved in glycolysis?
NAD
30
What is the role of reduced NAD?
oxidises substrate and becomes reduced gaining two protons during glycolysis, link and krebs, carries them to mitochondria cristae for oxidative phosphorylation
31
What is NAD made up of?
non-protein, made of two ribose sugars, nicotinamide, adenine and two phosphoryl groups
32
What happens to NAD after oxidative phosphorylation?
becomes oxidised and can be used again in glycolysis, link and krebs
33
What are the two stages of glycolysis?
phosphorylation and oxidation
34
where does glycolysis occur
cytoplasm
35
Describe the process of phosphorylation in glycolysis
2 phosphate groups from hydrolysis of 2 ATP added to glucose to form hexose bisphosphate
36
37
What are the products of glycolysis?
2 pyruvate, 2ATP (net), 2 reduced NAD
37
What happens to hexose bisphosphate in glycolysis?
splits into two 3C compounds, triose phosphate
37
Describe the process of oxidation in glycolysis
both TP loses two H atoms to NAD to become reduced NAD, lose two phosphates each, bind to ADP to produce 4ATP, produces 2 pyruvate molecules
38
What is the product of oxidation in glycolysis?
pyruvate
39
What is the net production of ATP in glycolysis?
2ATP
40
What is the end product of glycolysis?
2 pyruvate
41
Describe the whole process of glycolysis
glucose (6C) phosphorylated using 2ATP to form hexose biphosphate (6C). This splits into 2 triose phosphates (3C).
They are converted to 2 pyruvate molecules by oxidative dehydrogenation
- 2 molecules of NADH (reduced NAD) produced
- 4 ATP molecules produced
- net production 2 molecules of ATP
42
What happens if no oxygen is available after glycolysis?
anaerobic respiration continues
43
Describe the structure of mitochondria
Double membrane forms envelope. Inner membrane folded into cristae, with embedded electron carriers and protein channels. Matrix is fluid filled space between cristae
44
What does the matrix of mitochondria contain? (5)
mitochondrial ribosomes, DNA and enzymes for link and krebs, coenzymes NAD and FAD, oxaloacetate
45
Where does the link reaction take place?
matrix of mitochondria
45
What is used in the link reaction?
pyruvate, coenzyme A, NAD
45
Describe the link reaction
pyruvate decarboxylated, producing CO2, and is dehydrogenated by reduction of NAD
- produces NADH
, forms acetyl group, binds with coenzyme A to form acetyl coenzyme A
46
Where does glycolysis occur?
CYPTOPLASM
47
Where does oxidative phosphorylation occur?
cristae of the mitochondria
47
Where does the krebs cycle take place?
the matrix of mitochondria
47
For each molecule of glucose, what are the products of the link reaction?
2 CO2, 2 reduced NAD, 2 acetyl CoA
48
What is substrate level phosphorylation?
krebs cycle, ATP produced from 4C compound by binding to and releasing from coenzyme A
48
Describe the krebs cycle
acetyl group (2C) released from coenzyme A, binds with oxaloacetate (4C) to form citrate (6C). reduces NAD and releases CO2, becomes 5C compound. repeats again forming 4C compound.
ATP from ADP and Pi, produced by substrate level phosphorylation
reduced FAD and reduced NAD, produces oxaloacetate to be used again
48
What is the role of coenzyme A?
transports acetyl group from link reaction to krebs cycle
48
How many times does the link reaction occur per molecule of glucose?
2
48
How is ATP produced in the krebs cycle?
4C compound binds temporarily to coenzyme A and released, substrate level phosphorylation takes place producing ATP
49
How many times does the krebs cycle turn for each molecule of glucose?
2
50
For each molecule of glucose, what are the products of the krebs cycle?
6 reduced NAD, 2 reduced FAD, 4 CO2, 2 ATP
51
After glycolysis, link and krebs cycle, what has been produced?
4 ATP, 10 reduced NAD, 2 reduced FAD, 6 CO2
52
Is the Krebs cycle aerobic or anaerobic?
aerobic
53
Is the link reaction aerobic and anaerobic?
aerobic
54
How are the link reaction and krebs cycle aerobic?
require presence of oxygen, although it is not used in reactions. If oxygen not present, glycolysis will repeat
55
How are fatty acids used for respiration?
broken down to molecules of acetate to enter krebs cycle via molecules of acetate coA
56
How is glycerol used for respiration?
can be converted to pyruvate and enter link reaction
57
How can amino acids be used for respiration?
may be deaminated (amino group removed), rest can directly enter krebs cycle or be changed to pyruvate or acetyl CoA
58
What is the definition of oxidative phosphorylation?
the production of ATP in the presence of oxygen
59
What is chemiosmosis?
the flow of protons down a chemiosmotic potential gradient across a membrane by protein channels
60
What is the name of the force created by chemiosmosis?
proton motor force
61
What is the role of oxygen in oxidative phosphorylation?
final electron acceptor, receive electrons from electron transport chain and protons from matrix to produce molecules of water
62
Describe whole process of oxidative phosphorylation
- takes place along electron transport chain
- in cristae of mitochondria
reduced NAD and FAD in matrix oxidised,
produce e- and H+,
- electrons picked up by transport chain and passed by redox reactions.
- releases energy to pump protons across cristae into intermembrane space.
- protons diffuse through stalked particles into matrix by chemiosmosis, activates ATP synthase for phosphorylation.
- oxygen accepts electrons from transport chain and protons from matrix, produces water molecules
63
Describe the electron transport chain
electrons picked up by protein carriers in cristae by reduced FAD and NAD passed along chain by series redox reactions, releases energy to pump protons and electrons picked up by oxygen
64
What happens to aerobic respiration without oxygen
cant accept electrons from transport chain, cant bind with hydrogen to produce water molecules, electron transport chain stops, protons won't be pumped across membrane, oxidative phosphorylation cannot occur, FAD and NAD will remain reduced, stops link and krebs of respiration and run out of NAD and FAD
65
Which stage of aerobic respiration can continue without oxygen?
glycolysis
66
Name two ways reduced NAD can be re-oxidised for anaerobic respiration
Name two ways reduced NAD can be re-oxidised for anaerobic respiration
67
What does glycolysis need to continue anaerobic respiration when oxygen not present?
regenerate NAD from reduced NAD
68
Describe the lactate fermentation pathway
two hydrogen atoms from reduced NAD picked up by pyruvate, catalysed by enzyme lactate dehydrogenase to produce lactate (lactic acid)
69
Which enzyme catalyses the binding of pyruvate and hydrogen atoms in lactate fermentation pathway?
lactate dehydrogenase
70
What does lactate cause?
lowers pH, affects enzymes involved glycolysis and muscle contraction, causes cramp and fatigue in muscles,
71
How is lactate removed?
when oxygen is available, oxidised back to pyruvate, or taken to liver and converted to glycogen/glucose to be recycled
72
Which organisms use the ethanol fermentation pathway?
fungi like yeast and plants
73
Which organisms use the lactate fermentation pathway?
mammals
74
Where does re-oxidisation of reduced NAD occur in anaerobic respiration?
in the cytoplasm
75
Describe the ethanol fermentation pathway
pyruvate decarboxylase catalyses removal of CO2 from pyruvate, producing ethanal. ethanol dehydrogenase reduces ethanal to produce ethanol,
NAD is regenerated by oxidised NADH (reduced NAD)
76
How does oxygen uptake change during and after exercise?
constant before exercise, then increases hugely for aerobic respiration during exercise. Anaerobic respiration causes build of lactate, after exercise, recovery period when oxygen uptake decreases slowly, takes time to return to normal as body is oxidising lactate to become pyruvate
77
Describe anaerobic respiration in microorganisms
pyruvate from glycolysis converted to acetylaldehyde (ethanal) by enzyme pyruvate decarboxylase, releases CO2. Ethanal picks up hydrogen from reduced NAD by enzyme ethanol dehydrogenase to become ethanol
78
Which enzyme produces ethanal from pyruvate?
pyruvate decarboxylase
79
Which enzyme converts ethanal to ethanol?
ethanol dehydrogenase
80
What is a respiratory substrate?
an organic molecule which can be oxidised to make ATP
81
How is glucose stored in plants?
as starch
82
How is glucose stored in mammals?
as glycogen
83
When would you respire lipids and proteins?
when lack of carbohydrates, begin to use other respiratory substrates
84
How are poly/disaccharides used for respiration?
polysaccharides/disaccharides can be hydrolysed to monosaccharides, which can be turned into glucose
85
How are monosaccharides turned into glucose?
by isomerase enzymes
86
Why is glucose important as a respiratory substrate?
produces lots ATP, some cells will only respire glucose
87
How are triglycerides used for respiration?
hydrolyse ester bonds to form glycerol and three fatty acids. Glycerol can be converted to triose phosphate and be used in glycolysis. fatty acids can be hydrolysed to produce acetyl CoA to enter the krebs cycle
88
Why are fatty acids good energy stores?
long with many C-H bonds, which can be hydrolysed into many acetyl CoA molecules
89
What is beta-oxidation?
breakdown of fatty acids to create many molecules of acetyl CoA
90
How can glycerol be used in respiration?
How can glycerol be used in respiration?
91
Which respiratory substrate yields the most ATP?
lipids - depends on amount of H atoms for chemiosmosis
92
What is the Respiratory Quotient?
volume of CO2 produced compared to volume of oxygen taken in
93
What is the formula for the respiratory quotient?
RQ = vol of CO2 produced / vol of O2 taken in
94
what would the respiratory quotient be for glucose?
RQ = 6 (CO2) / 6 (O2) = 1
95
If RQ value is greater than one, it must be?
anaerobic respiration, as producing more CO2 than oxygen taken in
96
What is the RQ value for proteins?
approx. 0.9/0.8
97
What is the RQ value for lipids?
approx. 0.7
98
What is the RQ value for carbohydrates?
1
99
What is the RQ value for anaerobic respiration?
>1
100
Which respiratory substrates can be used in anaerobic respiration?
carbohydrates (glucose), glycerol from triglycerides
101
What does facultative anaerobe mean?
can respire aerobically or anaerobically
102
How does yeast reproduce?
asexually by mitosis
103
State two properties of yeast
single-celled fungus, eukaryotic (has mitochondria)
104
How is lactate transported to the liver?
via the bloodstream
105
How can we use yeast cells to measure the rate of respiration?
mitosis of yeast cells requires ATP - we can assume that the rate of division and number of yeast cells after set time is proportional to the rate of ATP production
106
How many yeast cells would we expect in anaerobic and aerobic conditions?
anaerobic would produce less yeast cells as yields much less ATP, and also produces ethanol which will eventually kill some of the cells. Aerobic much more cells
107
what are obligate anaerobes
- can only respire anaerobically
108
what are obligative areobes
- can only respire aerobically
109
what proteins are found in inner mitochondrial membrane
- channel proteins, associated with ATP synthase enzymes, electron carriers
