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Respiration Flashcards

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1
Q

What is cellular respiration?

A

The process of breaking down glucose to release energy, essentially the reverse of photosynthesis.

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2
Q

What type of sugar is glucose?

A

A hexose (six-carbon sugar).

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3
Q

Where does glycolysis occur?

A

In the cytoplasm of the cell.

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4
Q

Is glycolysis an aerobic or anaerobic process?

A

Anaerobic process as oxidative phosphorylation does not take place oxygen is not required.

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5
Q

What are the products of glycolysis?

A

Two pyruvate molecules, ATP, and reduced NAD.

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6
Q

How many reaction steps are involved in glycolysis?

A

Ten reaction steps.

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7
Q

What is the first step of glycolysis?

A

Phosphorylation of glucose using two ATP molecules.

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8
Q

What is formed during the lysis stage of glycolysis?

A

Two triose phosphate molecules.

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9
Q

What occurs during the dehydrogenation step of glycolysis?

A

Hydrogen atoms are removed from triose bisphosphate, forming pyruvate.

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10
Q

What is substrate-level phosphorylation?

A

The formation of ATP without the involvement of an electron transport chain.

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11
Q

What is the net ATP yield from glycolysis?

A

Two molecules of ATP.

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12
Q

Fill in the blank: The carbon framework of glucose is broken down during respiration to release _______.

A

Energy.

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13
Q

True or False: Reduced NAD produced during glycolysis is used in later stages to synthesize more ATP.

A

True.

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14
Q

What are the three key compounds to recall from glycolysis?

A

Hexose bisphosphate, triose phosphate, and pyruvate.

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15
Q

What molecules are produced from the oxidation of triose bisphosphate?

A

Two pyruvate molecules and two reduced NAD molecules.

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16
Q

What happens to the phosphates during glycolysis?

A

Phosphates from triose bisphosphate are transferred to ADP to form ATP.

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17
Q

What is the role of NAD coenzymes in glycolysis?

A

They accept hydrogen atoms during dehydrogenation and are reduced to form reduced NAD.

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18
Q

What is the Krebs cycle?

A

The Krebs cycle takes place in the mitochondrial matrix and results in the breakdown of an acetyl group.

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19
Q

What are the main processes involved in the Krebs cycle?

A

The Krebs cycle involves decarboxylation, dehydrogenation, and substrate-level phosphorylation.

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20
Q

What coenzymes are involved in the Krebs cycle?

A

The hydrogen atoms released during the Krebs cycle are picked up by the coenzymes NAD and flavin adenine dinucleotide (FAD).

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21
Q

What is produced as a by-product of the Krebs cycle?

A

Carbon dioxide is a by-product of the Krebs cycle reactions.

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22
Q

What is the role of reduced NAD and reduced FAD?

A

Reduced NAD and reduced FAD are used in the final step of aerobic respiration to produce large quantities of ATP by chemiosmosis.

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23
Q

What is the first step of the Krebs cycle?

A

Acetyl CoA delivers an acetyl group to the Krebs cycle, combining with four-carbon oxaloacetate to form six-carbon citrate.

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24
Q

What happens to citrate in the Krebs cycle?

A

Citrate undergoes decarboxylation and dehydrogenation, producing one reduced NAD and carbon dioxide, forming a five-carbon compound.

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25
What is regenerated at the end of the Krebs cycle?
The cycle regenerates oxaloacetate, allowing the cycle to continue.
26
What is the importance of coenzymes in respiration?
Coenzymes transfer protons, electrons, and functional groups between enzyme-catalyzed reactions in respiration.
27
What are the differences between NAD and FAD?
NAD participates in all stages of respiration while FAD only in the Krebs cycle; NAD accepts one hydrogen and FAD accepts two; reduced NAD synthesizes three ATP while reduced FAD synthesizes two ATP.
28
How is reduced NAD represented?
Reduced NAD can be represented as NADH, NADH + Ht, or NADH+.
29
Why are vitamins essential for coenzymes?
Coenzymes are usually derived from vitamins, making vitamins an essential micronutrient.
30
Which Krebs cycle intermediate compounds should be remembered?
Only oxaloacetate and citrate are the names of Krebs cycle intermediate compounds that need to be remembered.
31
Why is the Krebs cycle termed aerobic?
The Krebs cycle does not use oxygen at any point, but it is termed aerobic because it is part of the aerobic respiration process.
32
What is the Link Reaction?
The Link Reaction is the process that connects glycolysis to the citric acid cycle by converting pyruvate into acetyl-CoA.
33
True or False: The Link Reaction occurs in the cytoplasm.
False: The Link Reaction occurs in the mitochondria.
34
What molecule is produced from pyruvate during the Link Reaction?
Acetyl-CoA.
35
Fill in the blank: During the Link Reaction, each pyruvate molecule loses one molecule of _____ as it is converted to acetyl-CoA.
carbon dioxide.
36
Which coenzyme is involved in the Link Reaction?
Coenzyme A (CoA).
37
What is the role of NAD+ in the Link Reaction?
NAD+ is reduced to NADH during the Link Reaction.
38
What is the primary purpose of the Link Reaction?
To convert pyruvate into acetyl-CoA for the citric acid cycle.
39
How many molecules of acetyl-CoA are produced from one molecule of glucose through glycolysis and the Link Reaction?
Two molecules of acetyl-CoA.
40
True or False: The Link Reaction is an anaerobic process.
False: The Link Reaction is an aerobic process.
41
What are the end products of the Link Reaction for each pyruvate molecule?
One acetyl-CoA, one carbon dioxide, and one NADH.
42
Short answer: What is the significance of the Link Reaction in cellular respiration?
It serves as a crucial link between glycolysis and the Krebs cycle, facilitating the extraction of energy from glucose.
43
Fill in the blank: The Link Reaction occurs after _____ and before the _____ cycle.
glycolysis; Krebs.
44
What enzyme catalyzes the conversion of pyruvate to acetyl-CoA?
Pyruvate dehydrogenase.
45
True or False: The Link Reaction occurs in both prokaryotic and eukaryotic cells.
False: It primarily occurs in eukaryotic cells.
46
What is oxidative phosphorylation?
Oxidative phosphorylation is the process of synthesizing ATP by using high energy electrons from NAD and FAD along the electron transport chain, requiring the presence of oxygen.
47
What happens to hydrogen atoms during oxidative phosphorylation?
Hydrogen atoms dissociate into hydrogen ions and electrons, with the electrons used for ATP synthesis through chemiosmosis.
48
What role do electrons play in the electron transport chain?
Electrons flow along the electron transport chain, releasing energy during redox reactions, which is used to create a proton gradient.
49
What is the final product when electrons combine with hydrogen ions and oxygen?
The final product is water, as oxygen acts as the final electron acceptor.
50
What is substrate level phosphorylation?
Substrate level phosphorylation is the production of ATP through the transfer of a phosphate group from a reactive intermediate, unlike oxidative phosphorylation.
51
Why must hydrogens be actively pumped across the membrane?
Hydrogens must be actively pumped to create a proton gradient that allows protons to diffuse back through ATP synthase for ATP synthesis.
52
Why do electrons from reduced FAD lead to less ATP synthesis than those from reduced NAD?
Electrons from reduced FAD enter the electron transport chain at a later stage, resulting in fewer protons being pumped and less ATP produced.
53
How does cyanide affect respiration?
Cyanide is toxic because it binds to cytochrome c oxidase in complex IV, preventing electron transfer and halting ATP production.
54
Is ATP synthase part of the electron transport chain?
ATP synthase is not part of the electron transport chain; it is a separate enzyme that synthesizes ATP using the proton gradient created by the chain.
55
What is required for the transfer of electrons along the electron transport chain?
Oxygen is required for the transfer of electrons along the electron transport chain.
56
How do hydrogen ions return to the matrix?
Hydrogen ions return to the matrix by facilitated diffusion through ATP synthase.
57
What was the state of the Earth's atmosphere when life began?
There was no oxygen present in the atmosphere.
58
Why was aerobic respiration rapidly selected for?
It is a far more efficient process than anaerobic respiration.
59
How many ATP molecules does aerobic respiration produce per glucose molecule?
Around 38 molecules of ATP.
60
How many ATP molecules does fermentation produce?
Only two molecules of ATP (net).
61
What do eukaryotic cells do if enough oxygen is available?
They respire aerobically.
62
What is anaerobic respiration?
It occurs in the absence of oxygen and results in the synthesis of smaller quantities of ATP.
63
What are obligate anaerobes?
Organisms that cannot survive in the presence of oxygen.
64
Give an example of an obligate anaerobe.
Clostridium (bacteria that cause food poisoning).
65
What are facultative anaerobes?
Organisms that synthesize ATP by aerobic respiration if oxygen is present but can switch to anaerobic respiration in its absence.
66
Give an example of a facultative anaerobe.
Yeast.
67
What are obligate aerobes?
Organisms that can only synthesize ATP in the presence of oxygen.
68
Give an example of an obligate aerobe.
Mammals.
69
What is fermentation?
The process by which complex organic compounds are broken down into simpler inorganic compounds without the use of oxygen.
70
What are the end products of alcoholic fermentation?
Ethanol (an alcohol) and carbon dioxide.
71
What does lactate fermentation produce?
Lactate.
72
What happens when there is no oxygen in oxidative phosphorylation?
The flow of electrons stops, halting ATP synthesis by chemiosmosis.
73
What is the role of pyruvate in lactate fermentation in mammals?
It acts as a hydrogen acceptor, converting to lactate and regenerating NAD.
74
What happens to lactic acid after it is produced?
It is converted back to glucose in the liver, requiring oxygen.
75
What causes oxygen debt after exercise?
The need to convert lactic acid back to glucose.
76
Why can't lactate fermentation occur indefinitely?
The reduced quantity of ATP and the accumulation of lactic acid leading to a fall in pH.
77
What is the main aim when improving physical fitness?
To increase the blood supply and flow through muscles for better lactic acid removal.
78
What is the first step in alcoholic fermentation?
Pyruvate is converted to ethanal, catalyzed by the enzyme pyruvate decarboxylase.
79
What happens to ethanal in alcoholic fermentation?
It accepts a hydrogen atom from reduced NAD, becoming ethanol.
80
What is anaerobic respiration?
Anaerobic respiration is a process that can continue indefinitely in the absence of oxygen.
81
What is a toxic waste product of yeast during anaerobic respiration?
Ethanol is a toxic waste product to yeast cells.
82
What happens to yeast cells if ethanol accumulates above 15%?
Yeast cells are unable to survive if ethanol accumulates above approximately 15%.
83
What does the apparatus measure in the investigation of yeast respiration?
The apparatus measures the rate of carbon dioxide production, which is equivalent to the rate of anaerobic respiration or alcoholic fermentation.
84
What provides a respiratory substrate in the yeast respiration experiment?
The glucose in solution provides a respiratory substrate.
85
Why is the flask sealed during the yeast respiration experiment?
The flask is sealed to ensure anaerobic conditions.
86
How is the increase in volume of gas measured in the yeast respiration experiment?
The distance moved by the liquid in the capillary tube, along with the diameter of the tube, can be used to calculate the increase in volume of gas.
87
What is a factor that affects the efficiency of respiration?
Respiration is not 100% efficient and energy is lost as heat.
88
What does the temperature sensor measure during the yeast respiration experiment?
The temperature sensor measures changes in temperature due to heat produced by yeast respiration.
89
What was the duration for which the data logger recorded readings in the yeast respiration experiment?
The data logger recorded readings every 50 seconds for 1,600 seconds.
90
Why did the student cover the yeast solution with liquid paraffin?
Covering the solution with liquid paraffin helps to maintain anaerobic conditions.
91
What adaptations do animals have for surviving anaerobic respiration?
Animals have various adaptations to survive periods of anaerobic respiration while underwater.
92
What do some bacteria use as final electron acceptors in anaerobic respiration?
Different groups of bacteria have evolved to use nitrate ions, sulphate ions, and carbon dioxide as final electron acceptors.
93
What role do methanogens play in the digestive systems of ruminants?
Methanogens digest cellulose from grass cell walls into products that can be further digested and absorbed.
94
What is bradycardia in marine mammals?
Bradycardia is the slowing of the heart rate by up to 85% during dives.
95
How do marine mammals reduce energy demand while diving?
They exhibit peripheral vasoconstriction to shunt blood to vital organs and reduce energy demand.
96
What is the significance of higher concentrations of haemoglobin and myoglobin in marine mammals?
Higher concentrations maximize oxygen stores, delaying the onset of anaerobic metabolism.
97
Why are larger lungs a disadvantage for whales?
Larger lungs would increase buoyancy, making it harder for whales to dive.
98
What compound is **NOT** a product of the link reaction?
ATP.

Biology (18 decks)

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