chapter 7-metabolism Flashcards

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1
Q

what is metabolism

A

the sum of all chemical rxns that occur in the body

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2
Q

what is carbolic rxns and anabolic runs

A
  • Catabolic rxn: breaks down chemicals and release energy

- Anabolic rxn: synthesize chemicals and require energy

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3
Q

what is cellular respiration

A

describes the biochemical conversion of chemical energy stored in molecular bonds into usable energy (ATP)
-A catabolic process

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4
Q

what are the 2 major pathways of cellular respiration

A

anaerobic and aerobic respiration

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5
Q

what is internal and external respiration

A
  • internal respiration: exchange of gas between individual cells and the extracellular fluid
  • External respiration: inhaling and exhaling of air into and out of the lungs as well as the exchange of gas between alveoli and the blood
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6
Q

which mc are the favoured fuel mc and why

A

carbohydrates and fats bc of the high # of energy rich C-H bonds

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7
Q

end products of metabolisms are?

A

H2O and CO2 –> low energy bonds

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8
Q

during cellular respiration the oxidation of what releases energy

A

C to Co2

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9
Q

what does glycolysis literally mean and what does it lead to

A
  • sugar breaking
  • leads to the oxidative breakdown of glucose into 2 mc of pyruvate, the production of ATP and the reduction of NAD+ to NADH
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10
Q

what gets reduced and what get oxidized during glycolysis

A

glucose is reduced and NAD+ is oxidized

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11
Q

where does glycolysis occur

A

cytoplasms

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12
Q

can prokaryotic and eukaryotic cells undergo glycolysis

A

yes

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13
Q

glycolysis is divided into 3 stages what are they

A

1) energy investment stage
2) cleavage stage
3) energy payout stage

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14
Q

what is the energy investment stage during glycolysis

A

-2 ATPs are used to add 2 phosphate groups to glucose producing fructose 1, 6 biphosphate ( 6 C) and these actions are completed by kinases
oGlucose glucose 6 phosphate fructose 1,6 biphosphate

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15
Q

what is the cleavage stage of glycolysis

A

-splits fructose 1,6 biphosphate into glyceraldehyde 3 phosphate and dihydroxyacetone phosphate
oglyceraldehyde 3 phosphate (PGAL) and dihydroxyacetone phosphate (DHAP) are 3 C cpd with a phosphate added
oDHAP is then isomerized to form a second PGAL

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16
Q

what is the energy payout stage

A

results in the production of ATP
o PGAL–> 1,3 diphosphoglycerate–> 3-phosphoglycerate –>2-phosphoglycerate phosphoenolpyruvate–>pyruvate
oWhen pyruvate gets formed the reduction of NAD+ to NADH occurs which is catalyzed by dehydrogenase) and the production of 2 ATP catalyzed by kinases
o this stage occurs 2 times per mc of glucose

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17
Q

what catalyzes the reduction of NAD+ to NADH during glycolysis

A

dehydrogenase

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18
Q

what catalyzes the production of ATP during the energy payout stage of glycolysis

A

kinase

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19
Q

1 mc of ATP produce
1 ) __ mc of pyruvate
2) __ ATP

A

2 and 2

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20
Q

what is substrate level phosphorylation and an ex

A

ATP synthesis is directly coupled with the oxidation of glucose without participation of an intermediate mc such as NADH or FADH2
- ex is the product of ATP from glycolysis

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21
Q

what is substrate level phosphorylation

A

does require an intermediate e carrier such as NADH or FADH2

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22
Q

what is the net rxn of glycolysis

A

glucose + 2ADP + 2Pi + 2NAD+–> 2 pyruvate + 2ATP + 2 NADH + 2H+ + 2H2O

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23
Q

what are 2 things that can happen to pyruvate after glycolysis

A
  • pyruvate can be reduced during fermentation

- pyruvate is further oxidized during cellular respiration in the mitochondria

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24
Q

what occurs to pyruvate during anaerobic respiration

A

-NAD+ must be regenerated for glycolysis to continue in the absence of O2 which is done by reducing pyruvate into ethanol or lactic acid via fermentation

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25
Q

what are the 2 types of fermentation that occurs to pyruvate

A

alcohol fermentation and lactic acid fermentation

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26
Q

what is alcohol fermentation

A

it occurs in yeast and some bacteria

-The pyruvate produced in glycolysis is converted to ethanol in this way NAD+ is regenerated and glycolysis can continue

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27
Q

what is lactic acid fermentation

A

occurs in certain fungi and bacteria and in human muscles during strenuous activity

  • When O2 supply to muscle cells lag behind the rate of glucose catabolism, the pyruvate generated is reduced to lactic acid
  • The NAD+ is regenerated when pyruvate gets reduced
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28
Q

how many ATP are produced during aerobic respiration and anaerobic respiration

A

36-38 and 2

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29
Q

aerobic respiration an be divided into 3 stages what are they

A

pyruvate decarboxylation, the citric acid cycle, ETC

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30
Q

where does pyruvate decarboxylation, the citric acid cycle, ETC occur in EUK and PROk

A

mitochondria, cytoplasm

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31
Q

what electron carriers

A

NadH and FADH2

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32
Q

what occurs during citric acid cycle

A

Acetyl-coA then undergoes the citric acid cycle producing electron carriers NadH and FADH2 and regenerating oxaloacetate then repeat of cycle

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33
Q

where is the ETC located

A

inter membrane space

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34
Q

where in prokaryotes ETC is located

A

on the bacterial membrane itself

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35
Q

what occurs during pyruvate decarboxylation

A

1) Pyruvate during glycolysis is transported from cytoplasm to mitochondrial matrix where it is decarboxylation: pyruvate is decarboxylated ( loses a CO2)
2) the acetyl group that remains is transferred to coenzyme A to form acetyl-coA
3) in the processes NAD+ is reduced to NADH

36
Q

how many ATP are produced during each round of the CAC

A

1

37
Q

what type of phosphorylation results in ATP production in the CAC

A

substrate level phosphorylation

38
Q

how many ATP are produced from 1 mc of glucose during the CAC

A

2

39
Q

How does the CAC start off

A

acetyl group from acetyl-CoA combine with oxaloacetate to form citrate

40
Q

what 2 electron carriers get regenerated

A

NADH and FADH2

41
Q

what is the net rxn for the CAC per glucose

A

2 acetly-CoA + 6NAD+ + 2FAD +2GDP + 2Pi + 4H2O–>4CO2 + 6NADH +2FADH2 +2GTP + 4H+ 2CO2

42
Q

what happens during oxidative phosphorylation

A

ATP is produced when high-energy potential e are transferred from NADH and FADH2 to oxygen by a series of carrier mc located in the inner mitochondrial membrane
-as e are transferred from carrier to carrier free energy is released which is then used to form ATP

43
Q

what type of mc are most of the mc in the ETC

A

cytochrome

44
Q

what are cytochrome mc

A

electron carriers that resemble hemoglobin in the structure of their active site

45
Q

what is unique about the central iron atom of the functional unit

A

it is capable of undergoing a reversible redox rxn ( can be reduced and oxidized alternatively)

46
Q

what is the final electron acceptor of the ETC

A

oxygen

47
Q

how is water formed during the ETC and what is the rxn

A

O2 picks up a pair of H ions from the surrounding medium forming water
2H+ +2e +1/2O2–>H2O

48
Q

what is the coupling agent of oxidation of NADH and FADH2 to the phosphorylation of ADP

A

a proton gradient across the inner mitochondrial membrane maintained by the ETC

49
Q

how is the proton gradient produced

A

1) s NADH and FADH2 pass their electrons to the ETC, hydrogen ions (H+) ions are pumped out of the matrix across the inner mitochondrial membrane and into the intermembrane space at each of the ETC protein complexes
2) the continuous translocation of H+ creates a positively charged acidic environement in the intermembrane space
3) the electrochemical gradient generates a proton-motive force which drives H back across the inner membrane and into the matrix

50
Q

How does H+ pass through the inner membrane into the matrix when the membrane is impermeable to ions

A

through specialized channels provide by enzyme complexes called ATP synthase

51
Q

as H pass through the ATP synthases enough energy is released to allow for what to occur to ADP

A

phosphorylation of ADP to ATP

52
Q

what is oxidative phosphorylation

A

the coupling of the oxidation of NADH and FADH2 with the phosphorylation of ATP

53
Q

how many ATP are formed during substrate level phosphorylation

A

4 ATP are produced

-1 glucose mc = 2 ATP from glycolysis and 1 ATP for each turn of the citric acid cycle = 4ATP

54
Q

how many ATP are formed during oxidative phosphorylation

A

32 ATP are produced

  • each NADH from the CAC generates 3 ATP and there is 6 so 18 ATP
  • the 2 NADH that were reduced during glycolysis =4ATP
  • the 3NADH during pyruvate decarboxylation generate 3 ATP/NADH=6ATP
  • FADH2 generates 2 ATP and there is 2 so 4 ATP
55
Q

what are the alternate energy sources if glucose is low and their preferential order

A

carbohydrates, fats, proteins
-They are first converted into either glucose or glucose intermediate which can then be degraded into the glycolic pathway and the CAC

56
Q

how is carbohydrates used as an alternative energy source

A
  • Disaccharides are hydrolyzed into monosaccharides & most can be converted into glucose or glycolytic intermediates
57
Q

where is glycogen found and is it a alternative energy source

A
  • stored into liver can be converted when needed into a glycolytic intermediate
58
Q

where are fat mc stored and in what form

A

adipose tissue in the form of triglycerides

59
Q

what hydrolyzes fats when needed for energy

A

lipases to fatty acids and glycerol

60
Q

what glycolytic intermediate is glycerol converted into

A

PGAL

61
Q

how does a fatty acid enter the citric acid cycle

A

1) first gets activated in the cytoplasm which requires 2 ATP
2) once activated the fatty acid is transported into the mitochondrion
3) and taken through a series of beta-oxidation cycles that convert it into 2 C fragments
4) the 2 C fragments are converted into acetyl-CoA which then enters the citric acid cycle

62
Q

how many NADH and FADH2 are produced after one round of beta oxidation of a saturated fat

A

1 of each

63
Q

___ meets the long term energy need for a month

A

fats

64
Q

there is enough ___ stored in humans to meet the short term energy needed for a day

A

glycogen

65
Q

what type of mc yields the greatest number of ATP per gram

A

fats

66
Q

when will your body degrade proteins

A

only when enough carbohydrate or fat is available

67
Q

what is a transamination reaction

A

when a.a lose an amino group to form a alpha-keto acid

68
Q

how does a protein enter the CAC and produce ATP

A

the C atom of most a.a are converted into acetyl-coA, pyruvate or one of the intermediates in the CAC which enter their respected metabolic pathways allowing cells to produce fatty acids, glucose, or energy in the form of ATP

69
Q

what is oxidative deamination

A

removes an ammonia mc directly from the amino acid

70
Q

where does photosynthesis take place

A

chloroplasts

71
Q

the reduction of what occurs in photosynthesis

A

CO2 to carbohydrates

72
Q

net rxn of photosynthesis

A

6CO2 +12H2O +light energy–>C6H12O6 +6O2 + 6H2O

73
Q

what occurs when water is split during photosynthesis

A

released their electrons are donated to form ATP and NADPH

74
Q

what happens to the H atom after water splits during photosynthesis

A

the H atom combines with C an dO atom from CO2 to form carbohyydrates and more water

75
Q

is O2 a waste product during photosynthesis

A

yes

76
Q

what occurs in light (photolysis rxn) vs dark rxn (reduction synthesis)

A

the light rxn=split water and produce ATP and NADPH

the dark rxn=form sugar from CO2 and the energy produced in the light rxn

77
Q

describe cyclic e flow for light rxn

A

1) absorption of a photon of light by a chlorophyll mc when light strikes P700 ( a special mc in PSI)
2) electrons are excited to a higher energy level and can either flow to cyclic or noncyclic
cyclic:
1) the excited e move along a chain of e carries
2) a series of redox rxn return the e to P700
3) the reactions are harnessed using an ETC, a proton gradient, and ATP synthase to produce ATP from ADP and Pi which is called cyclic photophosphorylation

78
Q

describe noncyclic e flow for light rxn

A

1) absorption of a photon of light by a chlorophyll mc when light strikes P700 ( a special mc in PSI)
2) electrons are excited to a higher energy level and can either flow to cyclic or noncyclic
non cyclic:
1) the excited e move to the e acceptor NADP+ which is similar to NAD+ ( that functions in cellular respiration) and forms NADPH
2) light stikes PSII P680 and electrons are excited and move down the same electro carrier chain used in cyclic e flow until they reach PSI and fill in the electron holes
3) ATP is produced by noncyclic photophosphorylation
4) now PSII has holes and is strong enough oxidatzing agent to oxidize wawter and fill the holes
5) water splits into 2 H and 1 O atom and e produced reduce PSII
6) oxygen atoms combine to form O2

79
Q

what is the net result of noncyclic e flow

A

NADPH, ATP, and photolysis of water

80
Q

what does noncyclic e flow produce that cyclic does not

A

O2 or NADPH

81
Q

when does the dark rxn occur and why

A
  • during the day when the light rxn are replenishing the supply of ATP and NADPH
82
Q

what is the source of carbon carbohydrate production in the Calvin cycle

A

CO2

83
Q

what is the product of the Calvin cycle

A

3 C sugar phosphoglyceraldehyde (PGAL)

84
Q

how many times does the calvin cycle take place

A

3 times

85
Q

steps of the calvin cycle

A

1) CO2 is fixed to RBP ( ribulose bisphosphate) a 5C sugar resulting in a 6 C unstable mc
2) that mc splits to form 2 mc of PGA ( phosphoglyceric acid)
3) PGA is phosphorylated and reduced by ATP, NADPH to form PGAL
4) most of PGAL is recycled to RBP by a complex series of rxn
5) 6 turns of the cycle 12 PGAL ar formed from 6CO2 and 6 RBP
5) the 12 PGAL and 6RBP combine to form glycose the net product

86
Q

what can PGL be used for

A

as an intermediate food nutrient, combined and rearranged to form monosaccharide sugars that can be transported to other cells or packaged for storage in insoluble pholysaccharide such as starch

87
Q

how many cycles of calvin cycle needs to occur to make 1 glucose mc

A

6