Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > A2 CH2 Respiration > Flashcards

A2 CH2 Respiration Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What type of reaction is respiration?

A

Catabolic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does ATP release energy and how is it used?

A
  • ATP releases energy when it is hydrolysed

- The energy is used by the cell or is lost as heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 3 types of phosphorylation?

A
  • Oxidative phosphorylation
  • Photophosphorylation
  • Substrate-level phosphorylation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where does oxidative phosphorylation occur?

A

Occurs on the inner membranes of the mitochondria in aerobic respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does oxidative phosphorylation produce ATP?

A

Energy for making ATP comes from oxidation-reduction reactions and it is released during the transfer of electrons along the electron transport chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where does photphosphorylation occur?

A

Occurs in the thylakoid membranes of the chloroplasts in the light dependent stage of photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does photophosphorylation make ATP?

A

Energy for making ATP comes from light and is released during the transfer of electrons along the electron transport chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

When does substrate-level phosphorylation occur?

A

Occurs when phosphate groups are transferred from donor molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Give two examples of when substrate-level phosphorylation occurs

A
  • glycerate-3-phosphate transferring phosphate to ADP to form ATP in glycolysis
  • Binding of ADP to inorganic phosphate in the krebs cycl
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the three groups of organisms that respire differently?

A
  • Aerobes
  • Facultative anaerobes
  • Obligate anaerobes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are aerobes?

A

Organisms that use aerobic respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are facultative anaerobes?

A

Microorganisms (yeast) respire aerobically but can also respire anaerobically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are obligate anaerobes?

A

Organisms that use anaerobic respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the 3 stages in aerobic respiration?

A
  1. Glycolysis
  2. Link reaction
  3. Krebs cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where does glycolysis occur?

A

Occurs in the cytoplasm of a cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why can’t glycolysis occur in the mitochondria like the other stages of aerobic respiration?

A

because glucose cannot pass through the mitochondrial membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens in glycolysis?

A
  1. Glucose molecules is phosphorylated by two molecules of ATP, making glucose diphosphate
  2. Glucose diphosphate splits into two molecules of triose phosphate (3C)
  3. Two triose phosphate are dehydrogenated and produces pyruvate (3C)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the net products of glycolysis?

A
  • 2 ATP molecules
  • 2 molecules of NADH
  • 2 pyruvate molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

In the beginning of glycolysis, why is it good to phosphorylate glucose to glucose disphosphate?

A
  • The phosphorylated glucose is more reactive so less activation energy is required for reactions with enzymes
  • The phosphorylated glucose is polar so its less likely to diffuse out of the cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why is the net gain of ATP molecules in glycolysis 2?

A

4 ATPs were made by substrate level phosphorylation but 2 were used to phosphorylate glucose molecule so there is a net gain of 2 ATP molecules per glucose molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the series of reactions that occur when 2 triose phosphates are dehydrogenated to form 2 pyruvate molecules?

A
  • Hydrogen is removed from them, oxidizing them to pyruvate
    Hydrogen atoms are transferred to NAD, making NADH
  • This step forms four ATP molecules in total by substrate-level phosphorylation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What occurs in the link reaction?

A
  1. Pyruvate diffuses from the cytoplasm into the mitochondrial matrix
  2. Pyruvate is dehydrogenated and hydrogen released is accepted by NAD to form NADH
  3. Pyruvate is also decarboxylated (removal of a carboxyl group from a molecule, releasing carbon dioxide) and turns into a 2C acetate group which combines with coenzyme a (CoA), forming acetyl coenzyme A which enters the Krebs cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the overall equation of the link reaction?

A

Pyruvate + NAD + CoA → acetyl CoA + NADH + CO2

24
Q

Where does the link reaction occur?

A

In the mitochondrial matrix

25
Q

Where does the Krebs cycle occur?

A

In the mitochondrial matrix

26
Q

The krebs cycle can only occur in the presence of what?

A

oxygen

27
Q

How many times does the krebs cycle occur per glucose molecule and why?

A

twice because there are 2 molecules of acetyl CoA

28
Q

What happens in the Krebs cycle?

A
  1. Acetyl CoA (2C) enters the krebs cycle by combining with a 4C compound, forming a 6C compound, CoA is regenerated
  2. 6C compound is dehydrogenated, making NADH. It is also decarboxylated making CO2 and resulting in a 5C compound
  3. 5C compound is dehydrogenated, making NADH. It phosphorylates ADP producing one ATP.It is also decarboxylated to make CO2 and forms a 4C compound
  4. 4C compound gets dehydrogenated twice forming FADH and NADH
  5. 4C compound combines with Acetyl CoA again and cycle repeats
29
Q

What type of reactions occur in the krebs cycle and how many times?

A
  • Decarboxylation happens twice

- Dehydrogenation happens 4 times

30
Q

What are the products of one kreb cycle?

A
  • 1 ATP by substrate-level phosphorylation
  • 3 molecules of NADH
  • 1 molecules of FADH
  • 2 molecules of CO2
31
Q

Where is the electron transport chain located?

A

On the cristae of the inner mitochondrial membrane

32
Q

How are hydrogen atoms brought to the ETC?

A

By coenzymes FAD and NAD

33
Q

How many proton pumps does NADH and FADH use? and how many ATP molecules do they synthesise?

A

NADH uses three proton pumps on the ETC so it synthesizes 3 ATPs
FADH passes its hydrogen atoms directly to the second proton pump on the ETC so it only synthesizes 2 ATPs

34
Q

What happens in the electron transport chain in respiration?

A
  1. NADH joins the first proton pump and is dehydrogenated, releasing hydrogen atoms which split into protons and electrons
  2. The electrons provide energy for the proton pumps to pump protons across the inner mitochondrial membrane to the intermembrane space
  3. Electrons pass along the ETC, they provide more energy to pump protons from the matrix to the intermembrane place
  4. The inner membrane is impermeable to protons so the protons pumped into the inter membrane space accumulate and create an electrochemical gradient
  5. At the end of the ETC, the final electron acceptor which is oxygen takes the electrons
  6. Two protons diffuse down the concentration gradient through a channel with enzyme ATP synthetase by chemiosmosis, where ADP is phosphorylated to ATP
  7. The protons join with the electrons and oxygen to form water
35
Q

In the ETC, what maintains the electrochemical gradient?

A

Proton pumps

36
Q

What happens to the oxygen when it joins with electrons and protons to form water at the ETC?

A

The oxygen is reduced by the addition of hydrogen ions and electrons

37
Q

What does cyanide do at the ETC? What happens what it is present?

A
  • Cyanide is a non-competitive inhibitor of the final electron acceptor in the ETC
  • When cyanide is present, electrons cant pass to the final electron acceptor. So electrons at the end of the chain will accumulate and the flow of electrons in the ETC will stop, which prevents the proton pumps from working
  • The electrochemical gradient will be destroyed so ATP synthetase won’t operate and no ATP will be produced there
  • The cell dies quickly.
38
Q

How many ATP molecules does 20 NADH generate at the ETC?

A

20*3 = 60 ATP molecules

39
Q

How many ATP molecules does 10 FADH generate?

A

10*2 = 20 ATP molecules

40
Q

In aerobic respiration, how many ATP molecules are produced in glycolysis per glucose molecule? And how are they produced?

A

8

  • 2 from substrate-level phosphorylation
  • 6 from oxidative phosphorylation (ETC) as there are 2 NADH molecules and they use 3 proton pumps on the ETC
41
Q

In aerobic respiration, how many ATP molecules are produced in the link reaction per glucose molecule? And how are they produced?

A

6
- 6 from oxidative phosphorylation (ETC) as a total of 2 NADH molecules are produced and they use 3 proton pumps on the ETC

42
Q

In aerobic respiration, how many ATP molecules are produced in the Krebs cycle per glucose molecule? And how are they produced?

A

24

  • 18 from oxidative phosphorylation (ETC) as a total of 6 NADH molecules are produced and they use 3 proton pumps on the ETC
  • 4 from oxidative phosphorylation (ETC) as a total of 2 FADH molecules are produced and they use 2 proton pumps on the ETC
  • 2 from substrate-level phosphorylation
43
Q

What is the total number of ATP molecules produced per glucose molecule in aerobic respiration?

A

38

44
Q

Why is the true number of ATP molecules produced per glucose molecule in aerobic respiration less?

A
  • ATP is used to move pyruvate, ADP, NADH, FADH across the mitochondrial membrane
  • Protons may leak across the inner mitochondrial membrane rather than passing through ATP synthetase
  • Molecules may leak through membranes
45
Q

In anaerobic respiration, why doesn’t the ETC function?

A
  • Because there is no oxygen to make water

- No oxidative phosphorylation will occur so no ATP is formed

46
Q

In anaerobic respiration, why cant the link reaction and krebs cycle take place?

A

NADH cannot be oxidised at the ETC so NAD is not regenerated to pick up more hydrogen. Therefore, the link reaction and krebs cycle won’t function without oxygen

47
Q

In animals, muscle cells may not get enough oxygen during exercise, in order for glycolysis to continue, what happens?

A
  1. Hydrogen from NADH is used to reduce pyruvate to lactate, regenerating NAD, so ATP can be produced.
  2. Anaerobic respiration creates an oxygen debt so when oxygen becomes available again later, lactate is respired to carbon dioxide and water, releasing more energy
  3. The only ATP that can be made is by substrate-level phosphorylation
48
Q

When plants and yeast are in anaerobic conditions, what happens so that glycolysis can continue?

A
  1. Pyruvate is decarboxylated by decarboxylase to ethanal,
  2. Ethanal gets reduced to ethanol by accepting the hydrogen from NADH, regenerating NAD
  3. This process is not reversible, so if oxygen is available again, ethanol is not broken down and accumulates in the cells which can rise to toxic concentration
  4. ATP is only made by substrate-level phosphorylation
49
Q

Why is the efficiency of anaerobic respiration much less than aerobic respiration?

A

Because anaerobic respiration only has glycolysis where aerobic respiration has glycolysis, the link reaction, krebs cycle, and the ETC. Glycolysis in anaerobic respiration only generates ATP through substrate level phosphorylation whereas glycolysis in aerobic respiration generates ATP through substrate level phosphorylation and oxidative phosphorylation

50
Q

What is used as an alternative respiratory substrate when carbohydrates (glycogen and glucose) in the body are low?

A

Fat provides an energy store and is used as a respiratory substrate when carbohydrates in the body (glycogen and blood glucose) are low

51
Q

How are lipids used as an alternative respiratory pathway?

A
  1. Fat is hydrolysed into glycerol and fatty acids
  2. Glycerol is phosphorylated with ATP and dehydrogenated by NAD forming a 3C compound, triose phosphate which enters glycolysis
  3. Fatty acids are split into 2C compounds that enter the krebs cycle as acetyl CoA
52
Q

What are lipids with more carbon and hydrogens on the fatty acid chains produce more ATP as an alternative respiratory pathways?

A
  • Fat is hydrolysed into glycerol and fatty acids
  • Fatty acids split into 2C compounds that enter the krebs cycle as acetyl CoA
  • Fatty acids are made of carbon and hydrogen atoms. The more carbon it has, the more CO2 is produced.
  • The more hydrogen it has, more NAD is reduced, so more ATP is produced. As well as more water is produced (final electron acceptor). This is why desert animals respire fat, because they need metabolic water
53
Q

Why do desert animals respire fat?

A

Because they need metabolic water.
The hydrogen from the fatty acids from the lipid molecules reduce NAD to NADH, so ATP is and water is produced and can be used by the animal

54
Q

What are two alternative respiratory substrates?

A

Lipids and proteins

55
Q

What can be used as a respiratory substrate when fats and carbohydrates are unavailable, or when protein intake is high?

A

Protein

56
Q

How can protein be used as a respiratory susbtrate?

A
  1. Protein is hydrolysed into amino acids which are deaminated in the liver
  2. The NH2 (amino group) is converted into urea and excreted
  3. The leftovers are converted to acetyl CoA, pyruvate or different krebs cycle intermediates

Biology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions