Test 3 questions and answers Flashcards
1
Q
The main site for gluconeogenesis is:
A. liver
B. muscle
C. kidney
D. brain
A
A. liver
2
Q
The glycosidic bond:
A. in maltose is not hydrolyzed in lactose intolerant humans
B. in sucrose is hydrolyzed by bees
C. joins glucose and fructose to form sucrose
D. both (B) and (C)
A
D. both B and C are correct
3
Q
Glycogen degradation requires the enzymes namely:
A. glycogen synthase and phosphorylase
B. glycogen phosphorylase and glycogen-debranching enzyme
C. glycogen dehydrogenase and glycogen-debranching enzyme
D. glycogen kinase and glycogen splitting enzyme
A
B. glycogen phosphorylase and glycogen-debranching enzyme
4
Q
Two major products of the pentose phosphate pathway are:
A. NADPH and NAD
B. FAD and CoA
C. flavine adenine dinucleotide and glucose 5-phosphate
D. nicotinamide adenine dinucleotide and ribose 5-phosphate
A
D. nicotinamide adenine dinucleotide and ribose 5-phosphate
5
Q
A catabolic intermediate which stimulates phosphofructokinase would stimulate:
A. glycogen synthesis
B. glycolysis
C. gluconeogenesis
D. glycogenolysis
A
B. glycolysis
6
Q
A fatty acid with 14 carbon atoms will undergo how many cycles of beta oxidation?
A. 14
B. 7
C. 6
D. 1
A
C. 6 cycles
7
Q
Which of the following is the primary ketone body?
A. Acetone
B. Acetoacetate
C. Beta-hydroxy buterate
D. Hydroxy Methyl glutarate
A
B. acetoacetate
8
Q
Choose the INCORRECT statement about cholesterol synthesis:
A. All the carbon atoms are derived from Acetyl-CoA
B. Process is cytoplasmic
C. NADPH is the main coenzyme
D. Highly expensive energetically
A
B. process is cytoplasmic
9
Q
Lipolysis of triacylglycerols is stimulated by:
A. insulin
B. glucagon
C. ATP
D. dopamine
A
B. glucagon
10
Q
Which lipoprotein has the highest content of protein?
A. VLDL
B. LDL
C. HDL
D. Chylomicrons
A
C. HDL
11
Q
Which lipoprotein has lowest content of protein
A
Chylomicrons
12
Q
Which fatty acid is this?
A
Stearic acid
13
Q
Which apolipoproteins transport dietary triglycerides from intestines
A
Chylomicrons
14
Q
Hormones stimulating lipolysis
A
Epinephrin
15
Q
How are fatty acids transported in the bloodstream
A
Bound to albumin
16
Q
Number of beta-oxidation cycles needed to oxidise a fatty acid (no, of carbons 12) - 1
A
Depends on the length of the fatty acid and chain, for 12 its 5
17
Q
How many ATP molecules are required for activation of fatty acids?
A
2 ATP
18
Q
Important enzyme in ketogenesis
A
HMG CoA synthase
19
Q
How does dietary glucose enter cytoplasm of enterocytes
A
By symport
20
Q
What phospho sugar is this?
A
Glucose-1-phosphate
21
Q
What is predominant glucose transporter present on surface of erythrocytes
A
Glut 1
22
Q
Glut 2 happens where?
A
In the liver
23
Q
Glut 3 happens where?
A
In the kidneys
24
Q
Alpha - 1,4 bonds are hydrolyzed by enzyme called..
A
Amylase
25
An enzyme phosphoglucomutase transforms
Glucose - phosphate to glucose-6-phosphate
26
Hormones promoting glucagon dehydration
- Glucagon
- Epinephrine
27
Hormones involved in gluconeogenesis
- Glucagon
- Norepinephrine
- Epinephrine
- Cortisol
- Thyroid + growth hormones
28
Choose activated sugar which a substrate of glycogen synthase
UPD glucose
29
Animals which have increased contents of fast twitch myocyte fibres
- Rabbit
- Cat
30
Net energy profit from degradation of one glucose molecule through glycolysis is
- 2 ATP
- 2 NADH
31
Propianate CoA generated after beta oxidation of odd number fatty acids is transformed into..
Succinyl CoA
32
Organs that metabolise ketone bodies
- Brain
- Heart
- Skeletal muscle
33
What is source of two carbon units for fatty acid synthesis
- Acetyl CoA
34
Fatty acid synthase of mammals contains
- 7 enzymatic activities and ACP
35
Common precursor of triglyceride + glycerophospholipid synthesis is
- Phosphatic acid
36
Compound having a major role in regulation of fatty acid synthesis + breakdown
- Molony CoA
37
Glycosidic bonds present in glycogen
- A-1,4
- A-1,6
38
Which organ expresses an enzyme glucose-6-phosphate (gluconeogenesis)
- Liver
39
Products of glucogen hydrolysis
- Glucose
40
Name of protein in center of glucagon
- Glucogenin
41
Hormones stimulating lipolysis
- Cortisol
- Glucagon
- epinephrine
- Norepinephrine
- Growth hormone
42
How are free fatty acids transported in bloodstream
- Bound to albumin
43
How are steroid hormones transported in blood
- bound to globulins
44
Enzymes operating during b-oxidation of fatty acids
- Acyt CoA dehydrogenase
- Thiolase
- Enoyl CoA hydratase
45
How many b-oxidation cycles are necessary to completely degrade one molecule of stearate
- 8
46
2 enzymes requiring the same cofactor + using is the same catalytic mechanism
- pyruvate dehydrogenase
- Alpha-ketoglutarate dehydrogenase
47
Product of fumerase enzyme
- Maleate
48
How many high energy electrons are produced from the oxidation of one acetyl CoA in krebs cycle
- 8
49
Which apolipoproteins transport dietary triglycerols from intestine
- Chylmirons
50
Enzyme playing major role in controlling rate of glycolysis
- Phosphofructo kinase
51
Irreversible glycolysis reaction
- Glucose --> glucose-6-phospate
52
Products of the oxidative phase of pentose phosphate pathway
- nucleotide sugars
- NADPH
53
What enzyme mediates this reaction
- Lactate dehydrogenase
54
Metabolites of non-oxidative phase of pentose pathway that have direct link with glycolysis
- Fructose-6-phosphate
- 3 phosphoglyceraldehyde
55
In the process of glycolysis, 1 glucose molecule converts to..
2 pyruvate molecules
56
Compounds that inhibit activity of phosphofructo kinase
- Citrate
- ATP
57
Metabolic target of oxidative phase of pentose phosphate pathway
- NAD+ reduction
- Synthesis of nucleotide precursors
58
Enzyme of non-oxidative phase of the pentose pathway transferring two-carbon fragments of sugar is
- Transketolase
59
The presence of pyridoxal phosphate (PLP) is necessary for what reaction
- Conversion of glucose-1-phosphate to glucose-6-phosphate
60
In corich cyde, working muscles secrete in blood..
- Lactate
61
Steps in glycolysis that lead to breakdown glucose in order
1. Conversion of glucose-6-phosphate to fructose-6-phosphate
2. Cleavage of fructose-1,6-biphosphate to 2 phospho trioses
3. Formation of 1,3-biphosphoglycerate
4. converting 3 phosphoglycerate to 2 phosphoglycerate
5. formation of phosphoenollpyruvate
62
What is cellulose
- Glucose homopolymer
63
What process is the source of the main substrate of the krebs cycle containing 3 carbon
- Glycolysis
64
Compounds that are activators of dehydrogenase
- ADP
- ATP
65
Bloodstream of fasted dogs
- Ketone bodies
66
Primary bile acid
- cholic acids
- chenodeoxycholic acid
67
Common precursor of steroid hormones formed from cholesterol
Pregnenolone
68
Which amino acid does not undergo transmination
- proline
- threonine
69
What cellular compartment is glutamate dehydrogenase present
- mitochondrial matrix
70
What are products of arginase reaction
- amithine and urea
71
During beta-oxidation of fatty acids, propionyl-IN-CoA is converted to
- Something CoA which enters citric acid cycle (succinyl)
72
What enzyme catalyzes more than one reaction during oxidation
- Dehydrogenase
73
When oxaloacetate is unavailable, acetyl-CoA is converted
- Acetone
- Acetylacetate
- B-hydroxybutrate
74
The synthesis of C16 fatty acids proceeds
- in the cytosol, with participation of NADPH
75
Arachidonic acid is not a precursor of..
Cholesterol
76
Non-steroid anti-inflammatory drugs are broad, heterogeneous group of anti-inflammatory, analgesic and antipyretic drugs, work by inhibiting activity of
- Cycloxygenases
77
Statin is a drug used to lower blood cholesterol. Works by inhibiting
- 3-HMG-CoA reductases
- mevalonate formation reaction
78
High density lipoproteins..
- Transport cholesterol from tissue to liver
- Have apoprotein A, E + C in their composition
79
Progesterone in hormone
- Cholesterol derivatives, responsible for maintaining pregnancy
- Allowing implantation of embryo into uterine mucosa
80
The presence of pyridoxal phosphate (PLP) is necessary for what reaction
- Glycogen breakdown catalyzed by glycogen phosphorylase
81
Coric cycle
- Lactate
82
Which process is source of main substrate of krebs cycle containing 3 carbon atoms
- Glycolysis
83
Product of glycogen hydrolysis
- Glucose
84
Irreversible glycolysis reaction
- Phosphoenolpyruvate -> pyruvate
85
Production from oxidate of PPP
- nucleotide sugars
- NADPH
86
Glucagon + Epinephrine
- Stimulates gluconeogenesis + inhibits glycolysis
86
Catabolic intermediate stimulating phosphofructokinase will also stimulate
- Glycolysis
87
Arachidonic acid is a precursor of
- Prostaglandins
- Leukotrienes
- Prostacyclin
88
In which cell does the rapapo-lubering shunt operate
- Erythrocytes
89
In liver, dietary fructose is converted to
Fructose-1-phosphate
90
Enzyme mediating this reaction
- Pyruvate carboxylase
91
Products of oxidative phase of pentose phosphate pathway
- NADPH
- Nucleotide sugars
92
Enzyme controlling rate of pentose phosphate pathway
- Glucose-6-phosphate dehydrogenase
93
Beta oxidation of fatty acids takes place in
- Mitochondrium
94
Synthesis of fatty acids takes place in
- Cytoplasm
95
Krebs cycle takes place in
- Mitochondrium
96
Biological functions of cholesterol
- Precursor of bile acids
- Precursor of vitamin D
- Precursor of steroid hormones
- Component of lipid rafts
97
What is the proportion of de novo cholesterol synthesis relation to dietary cholesterol uptake
- 85%
98
Lipoprotein that has the highest cholesterol contents
- LDL
99
Lipids in the bilayer
- Inner
--> Phosphatidylserine
--> Linositol
--> Lethanolamine
- Outer
--> Phosphatidylcholine
--> Glycolipids
--> Glycoproteins
- Both
--> Cholesterol
100
Key enzyme that allows the use of ketone bodies as an energy source in extracellular tissues
- CoA transferase
101
What is the source of Acetyl-CoA needed for synthesis of fatty acids in cytoplasm
- Citrate
102
What is function of APO-11
- Activates lipoprotein lipase
103
Factors that promote cholesterol synthesis in liver
- Insulin
- Low concentration of non-steroidal mevalonate metabolism
104
HMG-CoA synthase is involved in synthesis of
- Cholesterol
- Ketone bodies
105
Name of aminotransferase that performs following RXN
- Aspartate aminotransferase
106
Correct type of LDL update mechanism
- Receptor-mediated endocytosis
107
Consequences of LDL receptor deficiency
- increased plasma cholesterol levels
- Increased probability of coronary heart disease
- Common xanthomas
108
Organs in which cholesterol synthesis occurs
- Liver
- Ovaries
- Adrenal cortex
109
Enzyme targeted by statins
- HMG-CoA reductase
110
Correct rotation for squalene synthase reaction
- CIS + CIS --> C30
111
Factors inhibiting HMG-CoA reductase
- Fasting
- Cholesterol intake
- Phosphorylation
112
Primary bile acids
- Cholic acid
- Chenodeoxycholic acid
113
Mineralocorticoid
- Aldosterone
114
Calcitriol (activate form of vit D) is generated from vitamin D3 by following modifications
- Successive hydroxylations
115
Steroid + peptide hormones are equally well cell permeable
- false
116
Peptide hormones more diverse than steroid
- true
117
Steroid hormones are same from species to species
- true
118
Steroid hormones can be stored in place of synthesis
- false
119
Peptide hormones are always bound to carrier protein
- false
120
Glycolysis stage 1
- 2 ATP invested
- Glucose is phosphorylated
- Converted to fructose
- Cleaved into 2 molecules = glyceraldehyde + 3 Phosphate
121
Glycolysis stage 2
- Glyceraldehyde 3 phosphate converted to pyruvate
- Generates 4 ATP + 2 NADH = only 2 ATP used
122
How is glycolysis regulated
- substrate + enzyme is limited
123
Enzymes regulated in glycolysis
- Hexokinase
- Phosphofructo kinase
- Pyruvate kinase
124
ATP in glycolysis + gluconeogenesis
- 2 ATP made in glycolysis
- 4 ATP used in gluconeogenesis
125
How does fructose 2,6-biphosphate regulate glycolysis + gluconeogenesis
- Activates phosphofructokinase-1
- Activates transcription of hexokinase
- Inhibits fructose 1,6-biphosphate
126
3 fates of glucose 6-phosphate
- glycolysis
- glycogenolysis
- pentose phosphate pathway
127
Enzyme for glycogenesis
- glycogen synthase
128
Enzyme for reverse of glycogenesis
- UDP glucose pyrophospyrase
129
How is glycogen synthase regulated
- Phosphorylation leads to inactivation
130
Regulation of pentose phosphate pathway
- first step irreversible
- NADPH is inhibitor of glucose 6-phosphate dehydrogenase
- Induced by insulin
131
How many ATP molecules required for activation of fatty acids
2 ATP
132
Location of ketogenesis
- mitochondria
133
Enzyme in ketogenesis
- HMG CoA synthase
134
Final product of lipogenesis
- palmitic acid C16
135
What activates lipogenesis
- Insulin
- High blood glucose
136
Coenzymes of lipogenesis
- NADPH
- NADP+
137
Regulation of lipogenesis
- activated by insulin
- deactivated by glucagon epinephrine
138
LDL
Low Density, more lipid than protein
139
HDL
High density protein + lipoprotein, low lipid content
140
VLDL
Very Low Density, high lipid content, low protein
141
excess fat stored in
Lipocytes
142
Location of de nobo synthesis of cholesterol
- liver
- secondary sites: adrenal cortex, ovaries and testes
143
Energetic cost of de novo synthesis of cholesterol
18 ATP
144
Enzyme in de novo synthesis of cholesterol
HMG CoA synthase
145
Regulating step of de novo synthesis of cholesterol
HMG CoA to mevalonade
146
HMG CoA inhibited by
Statins
147
Location of HMG CoA enzyme
- Endoplasmic reticulum
148
How many steps needed to convert squaline to cholesterol
19
149
Half life of HMG - CoA
2 hours
