Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Alevel Biology OCR > 5.2.2 - Respiration > Flashcards

5.2.2 - Respiration Flashcards

(50 cards)

Start Studying
1
Q

What is respiration?

A

a process where glucose is broken down to release energy (generated in the form of ATP)

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

What is the equation for respiration?

A

glucose + oxygen -> carbon dioxide + water

C6H12O6 + 6O2 -> 6CO2 + 6H2O

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

Why is cellular respiration needed?

A 
to produce ATP for processes like...
-active transport
-photosynthesis
-cell division
-movement of vesicles
-phagocytosis
etc
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the structure of a mitochondrion

A
  • double membrane where inner mitochondrial membrane is folded to form cristae
  • matrix containing mitochondrial DNA and ribosomes (needed for protein synthesis to make any enzymes needed)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where does glycolysis occur?

A

cytoplasm

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

What is glycolysis?

A

the breakdown of glucose into pyruvate

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

What are the products of glycolysis (per one molecule of glucose)?

A

2x pyruvate
2x ATP
2x redNAD

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

What happens during glycolysis?

A 
glucose
glucose phosphate
fructose phosphate
fructose bisphosphate
2x triose phosphate
2x triose bisphosphate
2x triose phosphate
2x pyruvate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where does the link reaction occur?

A

matrix of mitochondria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the link reaction?

A

the conversion of pyruvate into acetyl coA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens in the link reaction?

A

pyruvate -> acetyl group -> acetyl CoA

  • dehydrogenation (pyruvate looses Hs and NAD gains them so is reduced)
  • decarboxylation (CO2 is lost)
  • coenzyme A added
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the products of the link reaction (per one molecule of glucose)?

A

2x acetyl CoA

2x redNAD

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

Where does the Krebs Cycle occur?

A

matrix of mitochondria

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

What happens in the Krebs Cycle?

A
  • acetyl CoA and OAA forms citrate
  • citrate is decarboxylated (looses CO2) and dehydrogenated (looses H as NAD is reduced) to form a 5C intermediate
  • 5C intermediate is decarboxylated (looses CO2) and dehydrogenated (looses H as NAD is reduced) to form a 4C intermediate
  • 4C intermediate is converted into a different 4C intermediate as ADP is phosphorylated
  • 4C intermediate is converted into another 4C intermediate as FAD is reduced
  • 4C intermediate is converted into oxaloacetate (OAA) as NAD is reduced
  • OAA can be reconverted into citrate, allowing the cycle to continue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the products of the Krebs Cycle (per one molecule of glucose)?

A

2x ATP
2x redFAD
6x redNAD

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

What coenzymes are used in cellular respiration?

A
  • NAD
  • FAD
  • coenzyme A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is substrate level phosphorylation?

A

phosphorylation when a phosphate group is directly transferred from one molecule to another
eg. during glycolysis and the Krebs Cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is oxidative phosphorylation?

A

phosphorylation when energy from electrons from reduced coenzymes (NAD and FAD) is used to synthesise ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where does oxidative phosphorylation occur?

A

inner mitochondrial membrane (cristae)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What happens in oxidative phosphorylation?

A
  • in the matrix of the mitochondria, redNAD and redFAD are dehydrogenated into NAD and FAD and hydrogen atoms
  • these Hs are dissociated into H+ and e-
  • these e- move down an electron transport chain in the inner mitochondrial membrane, loosing energy as they do so
  • this energy is used by a proton pump move the H+ ions across the inner membrane into the intermembrane space, creating a proton (electrochemical) gradient across the inner membrane
  • the H+ ions then move back across the inner membrane through ATP synthase (known as chemiosmosis)
  • this turns ATP synthase on so that ADP can be phosphorylated into ATP
  • the H+ ions and e- then combine with oxygen (aka the final electron accepter) to produce water (this is catalysed by cytochrome oxidase)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do metabolic poisons disrupt oxidative phosphorylation?

Study These Flashcards
A
  • they bind to electron carriers, which inhibits the electron transport chain
  • reduces chemiosmosis
  • inhibits Krebs Cycle as NAD and FAD are not regenerated
22
Q

How much ATP is produced across all of aerobic respiration?

23
Q

Why is less ATP produced than the theoretical maximum?

Study These Flashcards
A
  • some ATP is used for active transport (of pyruvate and H+ ions from glycolysis into the mitochondrion)
  • some energy is released to surroundings (eg. as heat)
  • not all of the H+ ion movement across the membrane is used to generate ATP/goes through ATP synthase (eg. H+ leak through membrane)
  • not all redNAD produced is used to make ATP
24
Q

What are the stages in aerobic respiration?

Study These Flashcards
A
  • glycolysis
  • link reaction
  • Krebs Cycle
  • oxidative phosphorylation
25
What are obligate anaerobes?
organisms that only respire anaerobically | eg. prokaryotes like clostridium
26
What are obligate aerobes?
organisms that only respire aerobically | eg. mammals
27
What are facultative anaerobes?
organisms that can respire both aerobically and anaerobically (depending on the conditions) eg. yeast
28
What are the two types of anaerobic respiration?
lactate fermentation | alcoholic fermentation
29
Where does lactate fermentation occur?
cytoplasm of muscle cells | in mammals
30
What happens in lactate fermentation?
- pyruvate is converted into lactate (lactic acid) - catalysed by lactate dehydrogenase - redNAD is oxidised
31
What happens to the lactate produced from lactate fermentation when there is oxygen again?
-lactate is converted back into glucose in the liver
32
Where does alcoholic fermentation occur?
yeast
33
What happens in alcoholic fermentation?
- pyruvate is decarboxylated to form ethanal (catalysed by pyruvate dehydrogenase and pyruvate decarboxylase) - ethanal is reduced to ethanol (catalysed by ethanal dehydrogenase) - redNAD is oxidised
34
What would happen if too much ethanol was produced in alcoholic fermentation?
-cell membranes would dissolve in the ethanol
35
Why do organisms respire anaerobically?
- 2xATP are still produced in glycolysis | - NAD is regenerated (which is needed in glycolysis, so allows glycolysis to continue)
36
Why does anaerobic respiration produce less ATP than aerobic respiration?
- ATP is only produced from glycolysis (only 2 molecules of ATP) - Krebs cycle, oxidative phosphorylation, etc can't occur (oxygen is needed as a final electron acceptor)
37
RQ=
volume of CO2 produced ____________________ volume of O2 used
38
What molecules are normally used in respiration?
carbohydrates and lipids
39
When are proteins used in respiration?
during starvation
40
What substrate is being used for respiration if there is a RQ value of 1?
carbohydrates
41
What substrate is being used for respiration if there is a RQ value of 0.7?
lipids
42
What substrate is being used for respiration if there is a RQ value of 0.8-0.9?
proteins -range because there are different R groups in different amino acids (or a mixture of carbohydrates and lipids)
43
Why do lipids release more energy than carbohydrates when used as a respiratory substrate?
- lipids have more H atoms - so can form more redNAD - which forms more ATP
44
What does a RQ value of more than 1 mean?
anaerobic respiration is occuring
45
What is a respirometer used for?
to find the rate of respiration | -measured the volume of O2 produced/CO2 used
46
What is the function of soda lime in a respirometer?
absorbs CO2
47
What is the function of the syringe in a respirometer?
used to reset the respirometer at the end of each trial
48
What does it mean when the bubble/coloured liquid in the glass tube of the respirometer moves left?
- more O2 is used than CO2 is produced (in aerobic conditions - how much O2 is absorbed (in anaerobic conditions)
49
What does it mean when the bubble/coloured liquid in the glass tube of the respirometer moves right?
-more CO2 is produced than O2 is used (in aerobic conditions)
50
What causes the bubble/coloured liquid to move in a respirometer?
changes in pressure from O2/CO2 being used/produced

Alevel Biology OCR (26 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions