Final Exam Flashcards

1
Q

What are the 5 co enzymes included in the pyruvate dehydrogenase complex?

A

TPP, FAD, Lipoate, NAD, COA (co enzyme A)

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2
Q

what are the vitamins needed to make each co enzyme in the Pyruvate dehydrogenase complex?

A

TPP (thiamine)
FAD (Riboflavin)
NAD (Niacin)
COA (Pantothenate)

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3
Q

what is the function of Coenzyme A in acetyl co A production?

A

accepts and carries acetyl groups

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4
Q

PHD is a multi enzyme complex consisting of what 3 enzymes? Each enzyme also has specific co factors, what are they?

A
  1. pyruvate dehydrogenase (TPP)
  2. dihydrolipoyl transacetylase (Lipoate, COA)
  3. Dihydrolipoyl (FAD NAD)
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5
Q

what is the net result of CAC?

A

2CO2, FADH2, GTP

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6
Q

the activity of citrate synthase largely depends on?

A

oxaloacetate

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7
Q

Acetyl CoA oxdation involving citrate synthase is thermodynamically _________ _________

A

favourable/irreverisble

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8
Q

Citrate synthase is inhibitted by?

A

NADH, Citrate, Succinyl COA

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9
Q

what is the difference between the open and closed conformation of citrate synthase?

A

open - free enzyme does not have binding site for acetyl COA

closed- binding of oxaloacetate creates a site for acetyl COA

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10
Q

what is lost and gained during the step of CAC involving isocitrate dehydrogenase?

A

CO2 lost

NADH gained

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11
Q

acetyl COA oxidation involving isocitrate dehydrogenae is thermodynamically ____________ __________

A

favourable/irreversible

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12
Q

Isocitrate dehydrogenase is a major regulatory componant of what?

A

the citric acid cycle

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13
Q

acetyl co A oxidation involving aketoglutarate dehydrogenase is thermodynamically ______ _________

A

favourable/ irreversible

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14
Q

why is FAD reduced instead of NAD in the reaction of CAC with succinate dehydrogenase?

A

because the free energy change is not enough to reduce NAD

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15
Q

Is the step in CAC with malate dehydrogenase favourable or unfavourable?

A

highly thermodynamically unfavourable and reversible

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16
Q

Oxidative decarboxylations in CAC give ?``

A

2 NADH

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17
Q

SLP in CAC gives?

A

GTP

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18
Q

Dehydrogenation gives reduced _______ in CAC

A

FADH2

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19
Q

the Last step in CAC gives _______

A

NADH

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20
Q

There are _____ acetyl COA/pyruvate

A

2

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21
Q

citric acid cycle intermediates are important for many other pathways (4), name each pathway and what is used?

A
  1. Glucose biosynthesis uses oxaloacetate, it is transported as malate
  2. Lipid biosytheis uses acetyl COA from ATP citrate lyase
  3. Amino acid biosynthesis uses aketoglutarate and oxaloacetate
  4. Protein biosynthesis uses succinyl-CoA
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22
Q

in eukaryotes oxidative phosphorylation occurs in the ?

A

mitochondria inner membrane

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23
Q

glycolysis occurs in the __________

A

cytoplasm

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24
Q

citric acid cycle occurs in the _________ ________

A

mitochondrial matrix

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25
Q

What step from CAC is not located in the mitochdrial matrix?

A

succinate dehydrogenase, this step occurs in the inner membrane

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26
Q

the glyoxylate cycle is found where?

A

plants and some microorganisms

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27
Q

what is the net production of the glyoxylate cycle?

A

2 acetyl COA to oxylacetate

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28
Q

the glyoxylate cycle allows a net conversion of acetyla COA to ________________ that does not occur in animals

A

glucose

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29
Q

the glyoxylate cycle is compartmentalized in the glyoxysome and bypasses the ____________ with what enzymes(2)?

A

decarboxylation with isocitrate lyase and malate synthase

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30
Q

what is a major difference between the gyoxylate cycle and the citric acid cycle?

A

there is no CO2 lost

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31
Q

what are two advantages of fats over polysaccharides?

A
  1. fatty acids carry more energy per carbon because they are more reduced
  2. fatty acids carry less water because they are non polar
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32
Q

glucose and glycogen are for ______ term energy storage while fats are for ________ term

A

short term, long term

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33
Q

in vertebrates, dietary fatty acids are absorbed in the _______ __________

A

small intestine

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34
Q

NEFA stands for?

A

non esterfied fatty acids or free fatty acids

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35
Q

what is hydrolysis of triglycerides catalyzed by?

A

lipases

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36
Q

some lipases are reuglated by hormones such as _______ and _______

A

glucagon and epinephrin

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37
Q

_______ keeps fats in a stored state

A

perilipin

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38
Q

during mobilization of fats what does a prescence of epinephrin mean? and glucagon?

A

epinephrin means need energy now

glucagon means out of glucose

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39
Q

what are lipid transporters in the blood?

A

chylomicrons

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40
Q

____________act as signals for receptors for uptake of lipids

A

apolipoproteins

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41
Q

in an adipocyte, fats plus glycerol =?

A

triacylglycerols for storage

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42
Q

in myocytes B-oxidation of ______ ______ for ______

A

fatty acids for energy

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43
Q

where are fats degraded into fatty acids and glycerol?

A

cytoplasm of adipocytes

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44
Q

Glycerol kinase activates _______ at the expense of _______

A

glycerol , atp

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45
Q

attatchment of fatty acids to phospholipids requires ?

A

conversion to fatty acetyl COA

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46
Q

descirbe the 3 stages of fatty acid oxydation?

A
  1. oxidative conversion of two carbon units into acetyl COA via B oxidation with concomitant generation of NADH and FADH
  2. oxidation of acetyl COA via citric acid cycle with cincomitant generation of NADH and FADH2
  3. Generates ATP from NADH and FADH2 via respiratory chain
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47
Q

name all 4 enzymes in the beta oxidation pathway?

A
  1. acyl coa dehydrogenase
  2. enoyl coa hydratase
  3. B hydroxyacyl coa dehydrogenase
  4. acyl coa acetyltransferase (thiolase)
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48
Q

to create palmitic acid the B oxidation pathway must be undergone ______ times

A

7

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49
Q

what is formed in each cycle of B oxidation pathway?

A

FADH and NADH so 7 total

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50
Q

how do electrons from FADH and NADH enter the ETC?

A

electron transfering flavoprotein (ETF)

51
Q

after B oxidation what happens to acetyl coa?

A

enters the citric acid cycle and further oxidizes into CO2, this creates more GTP, NADH, FADH2

52
Q

For the oxidation of unstaturated fatty acids what is additionally requires? what does monunsaturated fatty acids need vs poly?

A

two additional enzymes,

  1. isomerase which converts the cis double bond at carbon 3 to trans
  2. reductase, that reduces cis double bonds not at carbon 3
  • monounsaturated fatty acids need isomerase while poly need both
53
Q

what is the difference between mitochondrial acyl COA dehydrogenase and peroxisomal acyl COA dehydrogenase?

A

mitochondrial - passes electron to ETC, energy captured as ATP

peroxisomal - passes electrons straight to molecular oxygen

54
Q

where does B oxidation mainly occur in plants?

A

peroxisomes

55
Q

B oxidation can occur in the peroxisomes in some animals, how?

A

can only occur in specialized tissues such as the liver, and is for very long fatty acids or branched fatty acids

56
Q

do liver peroxisomes contain CAC enzymes?

A

no

57
Q

how are ketone bodies formed?

A

when oxaloacetate is depleted acetyl COA is converted into ketone bodies

58
Q

what gluconeogenic conditions result in ketones?

A

diabetes, starvation, this slows the CAC and results in reduced oxaloactetate

59
Q

_______ is the source of ketone bodies?

A

liver

60
Q

what happens if ketosis is left untreated?

A

diabetes mellitus, blood concentration of 90mg/100ml, urinary excretions of 5000 mg/24hrs

61
Q

what are the 3 metabolic circumstances that lead to amino acid oxidation?

A
  1. leftover amino acids from normal protien turnover
  2. dietary amino acids that exceed bodys protein synthesis needs
  3. proteins in the body can be broken down to supply amino acids for energy when carbs are scarce
62
Q

what is the first step in amino acid oxidation?

A

removal of the amino group (transamination)

63
Q

what is the fate of Nitrogen for aquatic vertebrates?

A

release amonia to environment

64
Q

what is the fate of nitrogen for terrestrial vertebrates?

A

nitrogen in form of urea

65
Q

what is the fate of nitrogen for birds and reptiles?

A

nitrogen as uric acid

66
Q

why is urea better than ammonia?

A

far less toxic than ammonia, high solubility

67
Q

transamination is catalyzed by?

A

aminotransferases

68
Q

what cofactor is used in transamination?

A

pyridoxal phosphate cofactor

69
Q

what accepts the amino groups in transamination?

A

a keto glutarate

70
Q

ammonia added to glutamate makes _______. Where does this product go?

A

glutamine, safely transported into the bloodstream

71
Q

why is glutamine important in transamination?

A
  • glutamine acts as temporary storage of nitrogen
  • can donate amino group when needed for amino acid biosynthesis
  • excess is processed in kidneys, liver and intestines
72
Q

Glutamate can also donate ammonia to pyruvate to make _______

A

alanine

73
Q

what is the importance of alanine with regards to amino acid oxidation?

A

glycolysis makes pyruvate, if pyruvate isnt gotten rid of lactic acid will build up. Oyruvate can be converted to alanine for transport into the liver.

74
Q

what is the second step after transamination?

A

oxidative deamination

75
Q

oxidative deamination occurs in the ______________ -_____________________

A

mitochondrial matrix

76
Q

what happens in oxidative deamination?

A

ammonia is processed as urea for excretion

77
Q

urea cycle enzymes increase when?

A

high protein diet or starvation

78
Q

ammonia is highly toxic and must be ______ or ______

A

utilized or excreted

79
Q

what is the first step of the urea cycle?

A

carbamoyl phosphate synthase 1 captures free amonia in the mitochondrial matrix

80
Q

free ammonia released from glutamate is converted to ______ for excretion

A

urea

81
Q

can all amino acids be synthesized in humans?

A

no some must be obtained through diet

82
Q

what is the chemiosmotic theory?

A

phosphorylation of ATP is not a result of direct reaction between ATP and a high energy phosphate. The energy needed to phosphorylate ADP is provided by the flow of protons (3) down the electrochemical gradient. The energy released by the electron transport is used to transport protons against the graident.

83
Q

carbohydrates, lipids and amino acids are the main source of _____ _____ for the cell to make atp?

A

reduced feuls

84
Q

in eukaryotes what is the ultimate electron acceptor?

A

O

85
Q

What does it mean when a membrane must couple proteins?

A

couple a downhill flow of electrons with an uphill flow of protons across the membrane , membranes must contain a protein that couples the downhill flow of protons to the phosphorylation of ADP

86
Q

What are the 4 compartments of the mitochondrion?

A
  1. outer membrane
  2. IMS
  3. Inner membrane
  4. Matrix
87
Q

The elctron transport chain takes place where?

A

inner membrane of mitochondrion

88
Q

where does the CAC take place ?

A

the mitochndrion matrix

89
Q

what are the initial electron acceptors for complex 1 and 2?`

A

FMN (flavin mononucleotide) FAD (Flavin adenine dinucleotide)

90
Q

each complex containes multiple redox centres consiting of what?

A
  1. FAD, FMN
  2. cytochromes a,b,c
  3. ion sulfur cluster
  4. coenzymes Q
  5. copper proteins
91
Q

describe the electron carrier cytochrome?

A
  • one electron carrier

- iron coordinating phosphoryn ring derivatives, a,b,c differ by ring additions

92
Q

how many electrons do iron sflur clusters carry?

A

one

93
Q

iron sulfur clusters coordinate by?

A

cysteins in the protein

94
Q

iron and sulfur clusters contain an equal amount of iron and slufur ( T or F)

A

T

95
Q

Ubiquinone consists of ____ protons and ____ electrons that give an alcohol called ____________

A

2, 2 , ubiquonol

96
Q

ubiquinone ______ diffuses in the membrane

A

freely

97
Q

what does ubiquinone start as and what does it progress too?

A

starts as a liquid soluble compund that rapidly accepts electrons, then becomes mobile electron carrier transporting electrons from complexes 1 2 and 3

98
Q

what are proton wires and where are they located?

A

complex one, series of amino acids under go protonation and deprotonation to get net transfer of proton from one side of membrane to other

99
Q

describe what happens in complex one?

A

FMN accepts 2 e from NADH, iron sulfur centers pass one e at a time toward ubiquinone binding site, this electron transfer causes protons to move from the matrix to IMS. appoximtely 4 protons are translocated by proton wires.

100
Q

describe what happens in complex 2?

A

FAD accepts 2 electrons from succinate, elelctrons passed one at a time via iron sulfer centres to ubiquinone which becomes reduced QH2.

*reaction of succinate to fumarate with succinae dehydrogenase

101
Q

does complex 2 transport protons?

A

no

102
Q

What happens in complex 3?

A

two electrons from QH2 reduce cytochrome c, the Q cycle results in 4 additioal protons transported

103
Q

During the Q cycle ____ protons are transported per ___ electrons for Cytc

A

4, 2

104
Q

during the Q cycle __ protons come from QH2 and __ protons are picked up from the matrix

A

2, 4

105
Q

during the Q cycle two molecules of QH2 become oxidised resulting in what?

A

releasing protons into IMS

106
Q

during the Q cycle ___ QH2 becomes reduced resulting in a net transfer of ____ protons per reduced coenzyme Q

A

1, 4

107
Q

what is cytochrome C and what does it do in the ETC?

A

the second mobile electron carrier, it is a heme containing protein in the IMS, it carries a single electron from the cytochrome bc1 complex to cytochrome oxidase

108
Q

what is heme iron?

A

can be ferrous or feric (reduced) oxide

109
Q

mammalian cytochrome oxidase is a membrae protein with _____ subunits

A

13

110
Q

cytochrome oxidase has ___ heme groups which are____ and _____

A

2, a3 and a3

111
Q

describe the function of the copper ions in cytochrome oxidase?

A

CUA - two ions that accept electrons from Cyt c

CUB - bonded to heme a3 and transfers 4 electrons to oxygen

112
Q

what happens in complex 4?

A

cytochrome oxidase passes electrons to o2, 4 electrons reduce one oxygen molecule into 2 water molecules, 4 protons picked up from matrix

113
Q

complex 3 and 4 associate together to form a __________

A

respirasome

114
Q

the protons in the ETC created the electrochemical proton gradient by 3 means, what are they?

A
  1. active transport of protons across the membrane
  2. chemically remove protons from the matrix
  3. release protons into the inter membrane space
115
Q

_________ -________ sets up proton motive force

A

electron transports

116
Q

what is the purpose of DNP?

A

transports protons down the gradient during uncoupling oxidative phosphorylation

117
Q

what is the uncoupling protein?

A

thermogenin

118
Q

how does UCP-1 generate heat?

A

short circuiting the mitochindrial protein battery

119
Q

the mitochondrial ATP synthase complex has two subunits what are they?

A

f1- soluble part in matrix, individually catalyzes hydrolysis of ATP
f0- integral membrane complex, transports protons from IMS to matrix, dissipating proton gradient

120
Q

the f1 subunit has 3 ab dimers what are they?

A

open - empty
loose -binding ADP and Pi
tight - catalyzes ATP formation and binds product

121
Q

_____ H needed to synthesize 1 ATP

A

4

122
Q

oxidation of 1 glucose molecule to CO2 yeilds ___ or ___ ATP

A

30, 32

123
Q

glycolysis under anearobic conditions ( fermentation) yeilds how many ATP?

A

2

124
Q

what are 3 ways oxidative phosphorylation is regulated?

A
  1. substrate availibility
  2. inhibitor IF1, onyl active at low pH, prevents hydrolysis of ATP
  3. inhibition of Oxphos leads to accumulation of NADH