EXAM 3 Flashcards
(149 cards)
1
Q
The reaction pathway that transforms fuels into cellular energy
A
Catabolic
2
Q
The metabolic pathways the require energy and are often biosynthetic processes
A
Anabolic
3
Q
Which energy source is used to regenerate ATP from ADP and Pi
A
oxidation of carbon to CO2
4
Q
What are the major purposes for which organisms require energy
A
- the performance of mechanical work
- active transport
- the synthesis of biomolecules
5
Q
What is the standard-state free energy for the hydrolysis of ATP to ADP
A
-30kJ/mol
6
Q
Electron donor used for reductive biosynthesis
A
NADPH
7
Q
Activated carriers that contain adenosine phosphate groups
A
- NADH
- FADH2
- coenzyme A
8
Q
Metabolic processes are regulated by
A
- Transcriptional regulation of the amount of enzyme
- allosteric control of enzyme activity
- the accessibility of substrates by compartmentalization
9
Q
Organisms that use energy from sunlight and convert to chemical energy
A
Phototrophs
10
Q
Organisms that obtain chemical energy from the oxidation of foodstuffs
A
Chemotrophs
11
Q
Pathways can be either anabolic or catabolic, depending on the energy conditions of the cell
A
Amphibolic
12
Q
In aerobic organisms, the ultimate acceptor of electrons is
A
Oxygen
13
Q
In aerobic metabolism, the product of oxidation of carbon containing fuels is
A
Carbon Dioxide
14
Q
The electron carrier, NADH, is derived from the _______ vitamin
A
Niacin
15
Q
The chemical currency of metabolism
A
ATP
16
Q
FAD is an electron carrier that is derived from the vitamin
A
Riboflavin (B2)
17
Q
NADH and NADPH
A
niacin
18
Q
FADH2
A
riboflavin
19
Q
acetyl CoA
A
pantothenate
20
Q
Biotin
A
biotin
21
Q
Tetrahydrofolate
A
folate
22
Q
The principle carbohydrate in living systems
A
Glucose
23
Q
The product of aerobic glycolysis
A
2 pyruvate
24
Q
The substance _______ must be regenerated for glycolysis to proceed in either aerobic or aerobic conditions
A
NAD+
25
An allosteric activator of glycolysis is
AMP
26
Glycolysis produces a net of ____ moles of ATP
2
27
The key regulatory enzyme for glycolysis is
PFK
28
________ are enzymes that catalyze the transfer of phosphoryl group from ATP to an acceptor
Kinases
29
In alcoholic fermentation, the decarboxylation of pyruvate requires a coenzyme that contains the vitamin_____
Thiamine (B1)
30
A potent allosteric activator of liver PFK if ________, which is produced from fructose-6--phosphate by PFK2
F 2,6-biphosphate
31
_________ mediate the thermodynamically downhill movement of glucose across plasma membranes
Glucose transporters
32
How is glycolysis maintained under anaerobic conditions?
Pyruvate can be reduced to either lactate or ethanol; this reaction is accompanied by the oxidation of NADH to regenerate NAD+
33
Which of the following is a reason that glucose is a common metabolic fuel used by living organisms?
```
Answers:
A.
It has a stable ring structure and is unlikely to glycosylate proteins.
B.
It has been found as one of the monosaccharides formed under prebiotic conditions.
C.
It is the only sugar used by the brain.
D.
A and B
```
A and B
34
```
What is the purpose of phosphorylating glucose in cytosol?
A.
to trap glucose in the cell
B.
to destabilize glucose and facilitate the next series of metabolic steps
C.
to convert it to a more soluble form
D.
A and B
```
A and B
35
What reaction is catalyzed by aldolase
reversible cleavage of F-1,6-BP to DHAP and GAP
36
What is the function of a thirster intermediate such as the one formed from GAP
The thirster allows the two-step reaction to be coupled so that the second reaction, the energetically unfavorable phosphorylation, can proceed
37
What is substrate-level phosphorylation?
ATP synthesis when the phosphate donor is a substrate with high-phosphoryl-transfer potential
38
What type of enzyme catalyzes the intramolecular shift of a chemical group?
Mutase
39
```
What are the primary metabolic fates of pyruvate?
A.
ethanol
B.
lactate
C.
acetyl CoA
D.
All of the above.
```
All of the above
40
Lactose intolerance is caused by a deficiency of
Lactase
41
Fructose from table sugar or high-fructose corn syrup and galactose form milk sugar converted to
glycolytic intermediates
42
During exercise, glycolysis is stimulated by a
feed-forward stimulation of pyruvate kinase
43
The process by which non carb precursor molecules are converted into glucose
Gluconeogensis
44
The stores of glucose are enough to support metabolism of a person for
1 day
45
The major tissue in which gluconeogenesis takes place is in the
liver
46
The conversion of glucose 6-phosphate to glucose takes place in the
lumen of the ER
47
The reaction that uses GTP and not ATP as its high-phosphoryl transfer donor is
PEP carboxylase
48
The compound__________ activates glycolysis and inhibits gluconeogenesis via conversion of fructose 1,6-bisphophate
F-2,6-BP
49
controls the synthesis and degradation of F-2,6-BP
PFK2
50
An intermediate that is decarboxylated and phosphorated to produce phophoenopyruvate
oxaloacetate
51
This essential nutrient is required for the carboxylation of pyruvate in human
Biotin
52
The ______ cycle is responsible for converting muscle lactate into glucose in the liver
Cori
53
Glycerol from fats is modified first by glycerol kinase and then a second enzyme to enter gluconeogensis at the intermediate
DHAP
54
How does the liver restore the level of glucose for active muscles
By converting lactate to glucose through the cori cycle
55
Biotin is a _____ for the pyruvate carboxylase reaction
cofactor
56
The phosphoryl donor in the formation of phosphoenolpyruvate is
GTP
57
The phosphorylation of glucose 6-phosphate takes place in which cellular location
The ER lumen
58
```
High levels of ATP and citrate:
Answers:
A.
indicate a high-energy–well-fed state.
B.
promote gluconeogenesis.
C.
inhibits glycolysis
D.
All of the above
```
All of the above
59
What is an inhibitor of PFK?
citrate
60
The major site of gluconeogenesis is in which tissue?
Liver
61
High blood sugar after a meal_______ the level of insulin released by the pancreas
Increases
62
Insulin resistance is a hallmark of
type 2 diabetes
63
Lactate produced in muscle tissue is converted to _____ by ______
glucose by the cori cycle
64
How many high energy-phosphate bonds are expended to make one glucose in gluconeogensis
Six
65
The citric acid cycle is also know as the
Krebs cycle & Tricarboxylic acid cycle
66
Acetyl CoA is
The activated form of acyl groups
| Fuel for the citric acid cycle
67
Which enzyme(s) is/are responsible for the following reaction
Pyruvate + CoA + NAD+ ---> Acetyl CoA + NADH + H+ + CO2
pyruvate dehydrogenase complex
68
What are the steps involved in the conversion of pyruvate to acetyl CoA
1. decarboxylation
2. oxidation
3. transfer to CoA
69
Pyruvate dehydrogenase is _______ when ATP-ADP ratios are high
inhibited
70
Approximately how many ATP or GTP equivalents are produced during one turn of the citric acid cycle
10
71
In which step of the citric acid cycle is FADH2 formed
The conversion of succinate to fumarate
72
In which reaction is ATP directly formed in the citric acid cycle
Conversion of succinyl CoA to succinate
73
Formation of citrate from acetyl CoA and oxaloacetate is a _______ reaction
condensation
74
Which molecule initiates the citric acid cycle by reacting with oxaloacetate
acetyl CoA
75
The activated carrier of acyl groups is
Coenzyme A
76
In the presence of oxygen, pyruvate is converted to
acetyl CoA
77
Large, multi-subunit enzyme complex that links glycolysis and the citric acid cycle under aerobic conditions
Pyruvate dehydrogenase
78
PDH is inactivated when the enzyme is
phosphorylated
79
Caused by a deficiency in vitamin B
Beriberi
80
The function of the citric acid cycle is to ______ high energy electrons
harvest
81
The product found by the condensation of oxalacetate and acetyl CoA
6-c tricarboxylic acid
82
The intermediate between citrate and isocitrate is
cis-aconitate
83
The product of the complete oxidation of carbon in the citric acid cycle
CO2
84
Key control points of the citric acid cycle
1. Isocitrate dehydrogenase
| 2. ketoglutarate dehydrogenase
85
The name applied to metabolic reactions that replenish the citric acid cycle intermediates that are depleted because they were used for biosynthesis
Anapleurotic
86
Electron flow down the electron transport chain leads to
The transport of protons across the inner mitochondrial membrane from inside the matrix to the inter membrane space
87
Coenzyme Q is also called
ubiquinone
88
Which complex does not pump protons
Complex II
89
What is a cytochrome
A protein that transfers elections and that also contains a heme prosthetic group
90
The q cycle
transfers electrons from a two -electron carrier to a one-electrons carrier
91
What pathologic conditions results from free-radical injury
- emphysema
- parkison's disease
- diabetes
- atherogenesis
92
Which enzyme catalyzes the reductions of o2
Cytochrome c oxidase
93
How is light used in photosynthesis
The light is used to generate high-energy electrons with great reducing potential
94
light absorbed by a chlorophyll causes
an electron to move forma ground state to an excited state
95
The rotation of the ______,driven by the proton gradient, powers ATP synthesis
c ring
96
ADP transport into the mitochondria is coupled to the export of ______
ATP
97
Dihdroxyacetone phosphate is part of the_______ shuttle
glycerol 3-phosphate
98
The number of ATP molecules produced by the transfer of electrons from NADH
2.5
99
The membrane protein ________ couple the entry of ADP into the mitochondrial matrix with the exit of ATP
ADP-ATP translocase
100
A molecular assembly in the inner mitochondrial membrane that carries out the synthesis of ATP
ATP synthase
101
Which form of the subunit is responsible for phosphorylation of ADP
tight
102
The proton gradient generated form the oxidation of NADH and FADH2 is called the
proton-motive force
103
The F0 portion of ATP synthase contains the
proton channel
104
Which form of the ATP subunit is responsible for trapping nucleotides in the subunit B
loose
105
What type of gradient is critical to ATP formation by oxidative phosphorylation
proton
106
When glucose is totally oxidized to CO2 and H2O, how many ATP molecules are made by oxidative phosphorylation out of a maximum yield of how many ATP molecules
26 out of 30
107
The F1 component of ATP synthase is composed of
- Three alpha subunits
- Three beta subunits
- Delta subunit
108
The 3 beta subunits of the F1 component can exist in
Open, Loose, Tight
109
The proton-motive force consists of
chemical and proton gradient
110
The subunit of the ATPase embedded in the inner mitochondrial membrane is the
F0 subunit
111
The rate of oxidative phosphorylation is determined by the need for
ATP
112
What are the driving force for the ATP-ADP translocase
membrane potential from electron transport
113
What is the net ATP obtained form 1 cytoplasmic NADH when it is oxidized by the ETC, using the glycerol 3-phospahte shuttle
1.5
114
Where oxidative phosphorylation occurs in eukaryotes
Mitochondria
115
________ is an ATP-generating process in which an inorganic substance such as oxygen serves as the ultimate electron acceptor
Respiration
116
The electron carrier _______ is a derivative of quinine and has a isoprenoid tail
Coenzyme Q
117
The citric acid cycle enzyme ______ is also a part of and electron-transport complex
Succinate dehydrogenase
118
Complex_____ also know as _________ accepts electrons from NADH
1, NADH-Q oxidoreductase
119
Complex that is not a proton pump
Complex 2
120
A strong oxidizing agent has a strong tendency to __________ electrons
accept
121
___________ are the result of uncontrolled electron transfer to oxygen
oxygen radicals
122
In the cytochrome c oxidase reaction ____ protons are removed from the matrix
8
123
In the overall stoichometry of the light reactions, 8 photons of light generate ____ molecules of ATP
3
124
The primary photoreceptor in the chloroplasts of green plants is
Chlorophyll
125
Photosystem 1 generates biosynthetic reducing power in the form of
NADPH
126
Photosystem II replenishes the ________ of photosystem I while generating a _______ that is used to synthesize ______
Electrons, Proton Gradient, ATP
127
In the light reaction of photosynthesis, the cooperation between photosystem I and photosystem II creates a flow of electrons from H2O to ____
NADP+
128
The oxidative phase of the pentose phosphate pathway produces_____,which is required for lipid biosynthesis
NADPH
129
The net result in sugars of the non oxidative phase of the pentose pathway is the conversion of 3______ into 2 _____ and 1_____
Pentoses, hexoses, Triose
130
The enzyme at the committed step of the pentose phosphate pathway
Glucose 6- phosphate dehydrogenase
131
The key source of biosynthetic reducing equivlanents
Pentose Phosphate Pathway
132
The two key comments required for growth are _______ and biochemical reducing powers
Ribose sugars
133
Most of the glucose residues in glycogen are linked by this bond
Alpha 1,4 glycoside
134
The _________ enzyme catalyzes the phosphorylation of glycogen phosphorylation
Phosphorylase Kinase
135
The hormone _____ signifies the starved or low glucose state
glucagon
136
The ______ enzyme serves are the glucose "sensor" enzyme in liver cells
Phosphorylase
137
Markedly increases glycogen breakdown in muscle by initiating a cAMP signal-transduction cascade
Epinephrine
138
The hydrolysis catalyzed by a alpha-1,6 glucosidase releases a ______ molecule
free glucose
139
_____ is the monomer that is used to extend the chain in glycogen synthesis
UDP-glucose
140
The complete oxidation of a glucose residue from glycogen produces ____ATP
31
141
The key regulatory enzyme in glycogen synthesis
Glycogen synthase
142
The major site of glycogen storage
Liver and skeletal muscle
143
The key regulatory enzyme in glycogen degradation is
Glycogen phosphorylase
144
How is phosphorylase b converted into phosphorylase a?
Through the addition of a phosphate to a serine residue
145
Two critical hormones that signal for glycogen breakdown are
glucagon and epinephrine
146
What is required to remove branches in glycogen
debranching enzyme
| transferase enzyme
147
What enzyme id required to synthesize alpha-1,4-glycosidic bods in glycogen
glycogen synthase
148
The enzyme that begins the kinase cascade, activating glycogen degradation
protein phosphatase 1
149
What happens after a carbohydrate rich meal?
blood-glucose levels rise, leading to glycogen storage in the liver
