Brainscape's Knowledge GenomeTM

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


See full index

Biology Core Idea 3 > Respiration > Flashcards

Respiration Flashcards

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

Cellular respiration

A
  • Process by which chemical energy in organic molecules is released by oxidation
  • Aerobic (presence of O₂) → cytosol and mitochondria
  • Anaerobic (absence of O₂) → cytosol
  • Produce ATP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Mitochondria

A
  • Cristae → inholdings of inner membrane
  • Circular DNA, 70S ribosomes
  • Inner & outer membrane
  • Intermembrane space vs mitochondrial matrix
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Aerobic respiration (4)

A
  1. Glycolysis (In cytosol, rest in mitochondria)
  2. Link reaction
  3. Krebs cycle
  4. Oxidative phosphorylation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Key molecules besides ATP

A
  • NADH (Reduced nicotinamide adenine dinucleotide)
  • FADH₂ (Reduced flavin adenine dinucleotide)
  • Serve as mobile electron carriers → transport high-energy electrons and protons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Glycolysis (4)

A
  1. Phosphorylation of glucose
  2. Lysis
  3. Oxidation by dehydrogenation
  4. Substrate-level phosphorylation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Phosphorylation of glucose

A
  • Initial investment of 2 ATP molecules
  • Glucose phosphorylated → fructose 1,6-bisphosphate
  • Activate sugar, make it more reactive, commit it to glycolytic pathway
  • Catalysed by phosphofructokinase (addition of 2nd phosphate group)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Phosphofructokinase (PFK)

A
  • Allosteric enzyme
  • Inhibited by excess ATP/citrate
  • End product inhibition (allosteric inhibition)
  • Stimulated by AMP and ADP (allosteric activators)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Lysis

A
  • Fructose 1,6-bisphosphate split → glyceraldehyde-3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP)
  • G3P and DHAP are isomers → can be converted by isomerase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Other names for G3P (2)

A
  1. Triose phosphate (TP)

2. Phosphoglyceraldehyde (PGAL)

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

Oxidation can be defined in 3 ways

A
  1. Addition of oxygen
  2. Removal of hydrogen (dehydrogenation)
  3. Removal of electrons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Oxidation by dehydrogenation

A
  • G3P oxidised by dehydrogenation
  • Coenzyme NAD⁺ reduced to NADH
  • Highly exergonic, energy released adds 2nd phosphate group to G3P → 1,3-bisphosphoglycerate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Substrate-level phosphorylation

A
  • 1,3-bisphosphoglycerate dephosphorylated → glycerate phosphate (GP) → pyruvate
  • 2 ATP formed via substrate-level phosphorylation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Glycolysis overview

A
  • Net gain of 2 ATP and 2 NADH per glucose
  • Glucose + 2ADP + 2Pi + 2NAD⁺ → 2 pyruvate + 2ATP + 2NADH
  • Energy transferred from glucose to pyruvate, ATP and NADH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Link reaction/oxidative decarboxylation

A
  • Transport protein in mitochondrial membrane translocates pyruvate from cytosol to mitochondria via active transport
  • Pyruvate decarboxylated → loss of CO₂
  • Oxidation by dehydrogenation → NADH + 2C compound
  • 2C compound combines with coenzyme A → acetyl CoA
  • 2 acetyl CoA, NADH and CO₂ per glucose/pyruvate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Krebs cycle (3)

A
  1. Acetyl CoA (2C) + oxaloacetate (4C) → citrate (6C)
  2. Citrate decarboxylated & dehydrogenated → α-ketoglutarate (5C) + NADH
  3. Oxaloacetate (4C) regenerated → 1 decarboxylation step (1CO₂), 3 dehydrogenation (2NADH, 1FADH₂), 1 substrate-level phosphorylation (1ATP)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Krebs cycle overview

A
  • 2 rounds to completely oxidise 1 molecule of glucose

- 2 CO₂, 3NADH, 1 FADH₂, 1ATP per acetyl CoA

17
Q

Inner mitochondria membrane (cristae)

A
  • Highly folded to increase surface area to accommodate:
    1. Electron transport chains (ETC) → series of electron carriers with increasing electronegativity
    2. ATP synthase → synthesise ATP
18
Q

Function of NAD⁺ and FAD

A
  • Serve as mobile electron carriers
  • Transport high energy e⁻ from organic molecules to ETC
  • Pass electrons to ETC → oxidised → regenerated → pick up more electrons and protons
19
Q

Oxidative phosphorylation

A
  1. NADH and FADH₂ transfer high energy electrons to electron carriers of ETC
  2. As electrons travel down ETC, energy released coupled to pumping of H⁺ from mitochondrial matrix into intermembrane space → builds up proton gradient across cristae
  3. As H⁺ flows through ATP synthase back into matrix down the gradient, ATP is produced from ADP and inorganic phosphate via chemiosmosis
  4. O₂ acts as final electron acceptor, accepting electrons and combines with H⁺ to produce H₂O
20
Q

Chemiosmosis

A

Mechanism by which energy stored in proton gradient drives ATP synthesis

21
Q

Importance of O₂ (4)

A
  1. Final electron acceptor that accepts electrons from the ned of the electron transport chain where it will combine with electrons and protons to form water
  2. Allows electron carriers NADH and FADH₂ to continue donating their electrons to the chain by re-oxidising ETC, thereby generating ATP via chemiosmosis, allowing oxidative phosphorylation to continue
  3. Allows regeneration of NAD⁺ and FAD → pick up more electrons and protons from glycolysis, link reaction and Krebs cycle
  4. Reduction of O₂ to water removes H⁺ from matrix → contributes to generation of proton gradient
22
Q

ETC Function (2)

A
  1. Generate proton motive force to produce ATP

2. Regenerate coenzymes NAD⁺ and FAD

23
Q

ATP produced per glucose molecule (Theoretical)

A
  • NADH → 3ATP, FADH₂ → 2ATP (enters chain at lower energy potential)
  • Glycolysis → 2ATP, 2NADH → 8 ATP
  • Link reaction → 2NADH → 6 ATP
  • Krebs cycle → 2ATP, 6NADH, 2FADH₂ → 24 ATP
  • Total: 38 ATP
24
Q

ATP produced per glucose molecule (Reality)

A
  • 36-38 ATP
  • Mitochondrial membrane impermeable to NADH → cannot enter from glycolysis
  • Electrons, H⁺ carried across via shuttle system → either to NADH or FADH₂
25
Q

What happens when there is no O₂

A
  • No final e⁻ acceptor → e⁻ carriers remain reduce → NADH and FADH₂ can no longer donate e⁻ to ETC
  • NAD⁺ and FAD not regenerated to pick up more e⁻ from glycolysis, link reaction and Krebs cycle → 3 processes come to a halt
26
Q

Anaerobic respiration

A
  • Takes place in cytosol
  • Glycolysis followed by fermentation
  • Produce small yield of energy
  • Regenerate NAD⁺ from NADH
27
Q

Fermentation

A
  • Pathways to regenerate NAD⁺ from NADH → ensure steady supply of NAD⁺ for glycolysis to continue
  • Alcohol
  • Lactic acid
  • Pyruvate/ethanal become final e⁻ acceptor
28
Q

Alcohol fermentation

A
  1. Pyruvate decarboxylase coverts pyruvate (3C) → ethanal/acetaldehyde (2C)
  2. Alcohol dehydrogenase reduces ethanal to ethanol, removing H⁺ from NADH → NAD⁺
29
Q

Lactic acid fermentation

A
  • When muscles contract, exceptionally high demand for ATP → dramatic increase in rate of glycolysis → rapidly depletes limited supply of NAD+ → oxidative phosphorylation may not be able to replenish NAD+ quickly enough
  • Lactate dehydrogenase reduces pyruvate → lactic acid/lactate
  • No CO₂ produced
  • Lactate carried to liver → converted back to pyruvate

Biology Core Idea 3 (2 decks)

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