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module 7 Flashcards

cellular respiration (61 cards)

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1
Q

what is the purpose of cellular respiration?

A

converts energy in fuel molecules into atp

uses carbs, lipids, proteins

allows cell to do work

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2
Q

what are the 2 types of cellular respiration

A

substrate level

oxidative

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3
Q

what are the stages of cellular respiration on a high level

A
  1. glycolysis: cytoplasm
    - glucose is broken down to release small amnt of energy
  2. pyruvate oxidation: mitochondria
    - pyruvate is prod from glycolysis which si then converted into acetyl-CoA and CO2
  3. citric acid cycle: mitochondria
    - acetyl-CoA is broken down to release CO2, small amnt of energy, electron carriers
  4. oxidative phosphorylation: mitochondria
    - all electron carriers from 1-3 release high energy electrons to electron transport chain, producing ATP
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4
Q

what are the differences between generating ATP with substrate level phosphorylation and oxidative phosphorylation

A

substrate level:
ATP is synthesized by a hydrolysis reaction involving an enzyme/substrate complex
SMALL amnt of energy

oxidative:
energy is then transferred to electron carriers -> carry ATP from one reaction to another

electron carriers transport electrons to ETC - transfers electrons along emembrane associated proteins to final acceptor

proteins harness energy released to produce ATP -> process

MAJORITY of ATP is produced this way

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5
Q

what are important electron carriers in cellular respiration

A

NAD+/NADH and FAD/FADH2

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6
Q

OIL RIG

A

oxidation is loss of electrons

reduction is gain of electrons

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7
Q

OIL RIG application in cellular respiration

A

energy stored in gluxose is harnessed in electron carriers as glucose is oxidized into CO2

glucose is oxidized to CO2 and O2 is reduced to H2O

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8
Q

______ is the final electron acceptor in cellular respiration

A

oxygen

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8
Q

when O2 is reduced, ______ is formed

A

H2O

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9
Q

how do electrons move from one molecule to the next during cellular respiration

A

via reduction reactions

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10
Q

what are the oxidized and reduced forms of the 2 important electron carriers in cells

A

oxidized: NAD+ and FAD
reduced: NADH and FADH2

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11
Q

the _______ electron carriers become _____ throughout glycolysis, pyruv oxid, and the citric acid cyle

A

oxidized form

reduced

accepts electrons

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12
Q

since the electron carriers become _______, they have high potential energy

A

reduced

used to synthesize ATP in final stage of cellular respiration

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12
Q

is glycolysis catabolic or anabolic?

A

catabolic

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13
Q

why is glycolysis considered universal

A

vast majority of cells use glycolysis to breakdown molecules

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14
Q

how many chemical reactions breakdown glucose and what is the starting product and finishing product

A

10 reactions

6 carbon glucose -> 2 3-carbon pyruvates

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15
Q

what are the 3 phases of glycolysis high level

A
  1. preparatory -> energy is consumed
  2. cleavage -> split into 2
  3. payoff -> ATP is one of the products
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16
Q

where does glycolysis occur, does it need oxygen?

A

in cytosol in presence/absence of O2

considered anaerobic since no oxygen is consumed

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17
Q

what happens in phase 1 of glycolysis

A

preparatory phase

  • prep of glucose for next 2 phases: addition of 2 P grps, producing fructose 1,6-biphosphate, requires input of 2 ATP
  • phosphorylation of glucose traps molecule inside cell and destabilizes it so it is ready for phase 2
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17
Q

what is the space between the 2 membranes in a mitochondrion called

A

intemembrane space

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18
Q

what happens in phase 2 of glycolysis

A

cleavage phase

cleavage of fructose 1,6-biphosphate into 2 molecules:
1. glyceraldehyde 3-phosphate
2. dihydroxyacetone phosphate -> another molecule of glyceraldehyde 3-phosphate

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19
Q

what happens in phase 3 of glycolysis

A

payoff phase

2 pyruvate formed
2 NADH produced
4 ATP produced

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19
Q

does oxygen need to be present for pyruvate oxidation to occur? what is produced if so?

A

yes, pyruvate is oxidized to produce CO2 and NADH, ultimately producing acetyl-CoA

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20
Q

what is the net products after glycolysis

A

2 ATP (4-2)

2 NADH

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21
what is the space inside the inner membrane of a mitochondrion called
mitochondrial matrix
22
where does pyruvate oxidation occur
in mitochondrial matrix
23
what enzymes catalyze the reactions in pyruvate oxidation
pyruvate dehydrogenase complex
24
what does 1 molecule of pyruvate produce
1 CO2 1 NADH 1 acetyl-CoA
25
what happens after initial production of CO2 and acetyl grp in pyruvate oxidation
acetyl grp is transferred to coenzyme A, which carries the acetyl grp to the citric acid cycle
26
why is the citric acid cycle a "cycle"
because the first reactant (oxaloacetate) in the process is also regenerated at the end
26
what are other names for citric acid cycle
krebs cycle tricarboxylic acid cycle (TCA cycle)
27
where does the citric acid cycle occur
matrix of mitochondria
28
what happens to the fuel molecules in TCA cycle
completely oxidized
29
what happens during the citric acid cycle
completes oxidation of glucose to produce CO2 substrate level phosphorylation is used to produce ATP NADH and FADH2 are also produced
30
why do we exhale CO2
oxidation of acetyl-CoA produces CO2 transfer of potential energy stored within acetyl-CoA to be transferred and stored in NADH and FADH2 production of GTP is catalyzed by substrate level phosphorylation
31
can organisms use products from diff steps in the TCA cycle as intermediates in metabolic pathways?
yes! ex. alpha-Ketoglutarate can be mod to form other amino acids/purine bases
32
what reactions create electron carriers NADH and FADH2?
redox reactions
33
where does the ETC occur?
mitochondrial inner membrane -> electrons enter and move from donors to acceptor
34
what is the final electron acceptor in the ETC? what does it become?
final acceptor -> O2 becomes reduced to H2O
35
what occurs in the etc?
electrons are moved from energy storage molecules to proteins in the ETC
36
what processes do electrons in the ETC move through in a sequence? what is the purpose of this
electrons move thru sequence of redox processes helps form proton gradient, storing potential energy for ATP synthesis
37
what is the distribution of protons in the mitochondria?
intermembrane space: high protons mitochondrial matrix: low protons
38
can protons diffuse across the membrane of the mitochondria?
no, proton concentration gradient contains high potential energy -> proton motive force (concentration gradient)
39
what does the proton gradient supply power to?
atp synthase -> molecular machine
40
what are the 2 subunits of atp synthase? what are their purposes
F0: bottom (intermembrane), forms a channel that rotates as protons pass thru it F1: top (matrix), uses rotational energy from F0 to catalyze synthesis of ATP
41
summary of cellular respiration
energy of glucose is released slowly in a series of reactions: - substrate level phosphorylation - redox reactions that transfer energy to NADH & FADH2 - electron carriers donate electrons to ETC, forming proton gradient for atp synthase: oxidative phosphorlyation - overall 32 molecules of ATP
42
how does ATP synthase work?
protons flow down concen gradient as protons pass thru channel, rotates ATP synthase, converting one form of energy into energy in bonds of ATP
43
how much ATP is generated from the full process of cellular respiration
32 molecules = 2 ATP from glycolysis + 2 ATP from citric acid cycle + 28 ATP from oxidative phosphorlyation
44
what happens if oxygen is unavailable in a bacterial/animal cell?
cell is under anaerobic conditions pyruvate can be reduced in lactic acid by a fermentation process regenerates NAD+ -> reduced in glycolysis ATP is still synthesized in small amnts for use by cell glucose + 2 ADP + 1Pi -> lactic acid + ATP + H2O
45
what happens if oxygen is unavailable in a plant/fungi cell?
anaerobic conditions -> ethanol fermentation pyruvate releases CO2 to form acetaldehyde -> electrons from NADH are transferred to acetaldehyde to prod ethanol and NAD+ regeneration of NAD+ is important so small amnts of ATP can be generated during ethanol fermentation glucose + 2ADP + 2Pi -> ethanol + CO2 + ATP + H2O
46
what happens if there is excess glucose?
can be stored for later as branched polymers of glucose monomers are cleaved 1 at a time, entering glycolysis as an intermediate
47
how do plants store excess glucose
starch
48
what is the difference between starch and glycogen
starch -> how glucose is stored in plants, just large branched chain of glucose glycogen -> how glucose is stored in animals, large branched chain of glucose attached to a central protein
49
how do animals store excess glucose
glycogen stored in muscle cells as energy to power contraction stored in liver for whole body
50
what are examples of other sugar sources
carbs -> can produce a variety of disaccharides and monosaccharides, can produce glucose or other glycolysis intermediates
51
what are examples of disaccharides
maltose (barley), lactose (milk), sucrose (candy)
52
what are examples of monosaccharides
galactose (milk), fructose (apple), mannose (apple)
53
what are other sources of energy
lipids fatty acids absorbed after a meal, or produced from excess glucose
54
how are lipids used for energy sources
lipids: excellent energy source, rich in C-C and C-H bonds
55
how are fatty acids used as an energy source
fatty acids absorbed after a meal, or produced from excess glucose: - shortened thru beta-oxidation which breaks down lipids into glycerol and acetyl-coA - does not prod atp directly, but prod NADH and FADH2 which can enter ETC
56
what are the products of each of the stages of cell. respiration
1. glycolysis: - pyruvate, 2 ATP, reduced electron carriers 2. pyruvate oxidation: - acetyl CoA, reduced electron carriers, CO2 3. citric acid cycle: - 2 ATP, reduced electron carriers, CO2 4. oxidative phosphorlyation: - 28 ATP, O2 -> H2O
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