Mixed 2 Flashcards
(100 cards)
1
Q
What enzyme primarily digests lipids in the small intestine?
A) Lingual lipase
B) Gastric lipase
C) Pancreatic lipase
D) Bile salts
A
C) Pancreatic lipase
2
Q
Bile salts help in the digestion of triglycerides by __________ them into smaller units.
A
solubilizing
3
Q
Which lipoprotein is synthesized in the small intestine from dietary fat?
A) LDL
B) VLDL
C) HDL
D) Chylomicrons
A
D) Chylomicrons
4
Q
Lipase action on triglycerides releases monoglycerols, fatty acids, and __________.
A
glycerol
5
Q
Which lipoprotein transports cholesterol from the liver to extrahepatic tissues?
A) HDL
B) LDL
C) VLDL
D) Chylomicrons
A
B) LDL
6
Q
HDL transports cholesterol from extrahepatic tissues to the __________.
A
liver
7
Q
What is the primary role of bile salts in lipid digestion?
A) Emulsification
B) Hydrolysis
C) Absorption
D) Transport
A
A) Emulsification
8
Q
Lipoproteins are made up of lipids, including cholesterol, surrounded by __________ and apolipoproteins.
A
phospholipids
9
Q
Which lipoprotein is known as “good” cholesterol?
A) Chylomicrons
B) LDL
C) HDL
D) VLDL
A
C) HDL
10
Q
VLDL is the transporter of __________ triglycerides.
A
endogenous
11
Q
During the absorptive state, what hormone mediates the increased absorption of glucose into cells?
A) Glucagon
B) Insulin
C) Epinephrine
D) Cortisol
A
B) Insulin
12
Q
A
13
Q
What is the preferred energy source for resting skeletal muscles?
A) Glucose
B) Fatty acids
C) Amino acids
D) Ketone bodies
A
B) Fatty acids
14
Q
The brain relies primarily on __________ as its energy source.
A
glucose
15
Q
Which enzyme catalyzes the conversion of glucose to glucose-6-phosphate in the liver?
A) Hexokinase
B) Glucokinase
C) Phosphofructokinase
D) Pyruvate kinase
A
B) Glucokinase
16
Q
The post-absorptive state is characterized by the return of __________ to normal concentrations in the blood.
A
glucose
17
Q
Which process produces ketone bodies during the post-absorptive state?
A) Glycolysis
B) Gluconeogenesis
C) Beta-oxidation
D) Lipolysis
A
C) Beta-oxidation
18
Q
Glycerol produced by lipase action is converted to __________ as a precursor for glucose synthesis.
A
DHAP (dihydroxyacetone phosphate)
19
Q
What are the two priorities guiding the liver during the post-absorptive state?
A) Fat storage and protein synthesis
B) Glucose maintenance and fat mobilization
C) Energy production and ketone body formation
D) Gluconeogenesis and glycolysis
A
B) Glucose maintenance and fat mobilization
20
Q
Acetyl CoA is a critical junction point for the metabolism of __________ and fats.
A
carbohydrates
21
Q
What molecule is an allosteric regulator of phosphofructokinase-1 (PFK-1)?
A) ATP
B) Citrate
C) Fructose-2,6-bisphosphate
D) Pyruvate
A
C) Fructose-2,6-bisphosphate
22
Q
Pyruvate is converted to __________ in active muscle cells.
A
lactate
23
Q
Which hormone enhances gluconeogenesis and glycogenolysis in the liver?
A) Insulin
B) Glucagon
C) Epinephrine
D) Cortisol
A
B) Glucagon
24
Q
The primary alternative energy source for the brain during fasting is __________ bodies.
A
ketone
25
Which enzyme is involved in the irreversible conversion of pyruvate to acetyl CoA?
A) Pyruvate carboxylase
B) Pyruvate dehydrogenase
C) Lactate dehydrogenase
D) Phosphoenolpyruvate carboxykinase
B) Pyruvate dehydrogenase
26
Succinyl CoA is common to the metabolism of carbohydrates and __________-numbered fatty acids.
odd
27
What is the key junction metabolite that determines the direction of glucose metabolism?
A) Pyruvate
B) Acetyl CoA
C) Glucose-6-phosphate
D) Fructose-1,6-bisphosphate
C) Glucose-6-phosphate
28
Insulin mediates the activity of __________, enhancing the conversion of glucose to glucose-6-phosphate.
glucokinase
29
Which metabolite acts as an allosteric regulator by increasing the affinity of PFK-1 for its substrate?
A) ATP
B) Fructose-2,6-bisphosphate
C) Citrate
D) Pyruvate
B) Fructose-2,6-bisphosphate
30
In the post-absorptive state, decreased glucose-6-phosphate levels trigger __________ in the liver.
gluconeogenesis
31
Which hormone is known as the "fight or flight" hormone?
A) Insulin
B) Glucagon
C) Epinephrine
D) Cortisol
C) Epinephrine
32
Glucagon enhances the release of glucose from the liver by mediating gluconeogenesis and __________.
glycogenolysis
33
What is the effect of insulin on glucose uptake in cells?
A) Inhibits uptake
B) No effect
C) Mediates uptake
D) Decreases uptake
C) Mediates uptake
34
Key metabolites that regulate carbohydrate and fat metabolism include glucose-6-phosphate and __________.
acetyl CoA
35
Which enzyme is allosterically inhibited by ATP and citrate?
A) Hexokinase
B) Glucokinase
C) Phosphofructokinase-1
D) Pyruvate kinase
C) Phosphofructokinase-1
36
The concentration of substrates and the ratio of reduced and oxidized states of __________ control the flow of intermediates through metabolic pathways.
coenzymes
37
Which hormone-sensitive lipase hydrolyzes triacylglycerols during the post-absorptive state?
A) Lipoprotein lipase
B) Pancreatic lipase
C) Adipose triglyceride lipase
D) Hormone-sensitive lipase
D) Hormone-sensitive lipase
38
The process of β-oxidation involves the breakdown of fatty acids into __________.
acetyl CoA
39
What is the end product of glycolysis?
A) Glucose
B) Acetyl CoA
C) Pyruvate
D) Lactate
C) Pyruvate
40
Epinephrine facilitates the rapid unloading of __________ into cells for energy production.
glucose
41
Which intermediate is formed during the Krebs cycle that is a precursor for gluconeogenesis?
A) Citrate
B) Oxaloacetate
C) Succinyl CoA
D) Alpha-ketoglutarate
B) Oxaloacetate
42
Ketone bodies are produced in the __________ during prolonged fasting or carbohydrate restriction.
liver
43
What enzyme catalyzes the formation of malonyl CoA in fatty acid synthesis?
A) Acetyl CoA carboxylase
B) Fatty acid synthase
C) Carnitine acyltransferase
D) Pyruvate carboxylase
A) Acetyl CoA carboxylase
44
Gluconeogenesis primarily occurs in the __________ and kidneys during prolonged fasting.
liver
45
Which process converts excess carbohydrates into fatty acids?
A) Glycolysis
B) Glycogenesis
C) Lipogenesis
D) Gluconeogenesis
C) Lipogenesis
46
Beta-oxidation of fatty acids generates __________ and NADH for energy production.
FADH2
47
Which lipoprotein contains the highest percentage of protein?
A) LDL
B) HDL
C) VLDL
D) Chylomicrons
B) HDL
48
The synthesis of fatty acids from acetyl CoA occurs in the __________.
cytoplasm
49
What is the major regulatory step in cholesterol biosynthesis?
A) Formation of mevalonate
B) Conversion of HMG-CoA to mevalonate
C) Synthesis of squalene
D) Conversion of lanosterol to cholesterol
B) Conversion of HMG-CoA to mevalonate
50
The enzyme __________ degrades triacylglycerols stored in adipose tissue to release fatty acids.
hormone-sensitive lipase
51
Which pathway is responsible for the production of NADPH?
A) Glycolysis
B) Citric acid cycle
C) Pentose phosphate pathway
D) Beta-oxidation
C) Pentose phosphate pathway
52
The reduction of dihydroxyacetone phosphate (DHAP) forms __________ in lipid metabolism.
glycerol
53
What is the main function of carnitine in lipid metabolism?
A) Transports fatty acids into mitochondria
B) Activates fatty acids for degradation
C) Synthesizes fatty acids
D) Degrades fatty acids
A) Transports fatty acids into mitochondria
54
Lipogenesis occurs when the energy state is __________ and there is an excess of carbohydrates.
high
55
Which molecule is a key intermediate in the synthesis of both glycerolipids and sphingolipids?
A) Glycerol-3-phosphate
B) Acetyl CoA
C) Ceramide
D) Palmitate
A) Glycerol-3-phosphate
56
__________, generated by glycolysis, is a precursor for triglyceride and phospholipid synthesis.
Glycerol-3-phosphate
57
Which enzyme catalyzes the committed step in fatty acid synthesis?
A) Fatty acid synthase
B) Acetyl CoA carboxylase
C) HMG-CoA reductase
D) Pyruvate dehydrogenase
B) Acetyl CoA carboxylase
58
During periods of fasting, ketone bodies can be used as an energy source by the __________.
brain
59
Which enzyme converts cholesterol into bile acids?
A) HMG-CoA reductase
B) Cholesterol 7α-hydroxylase
C) Acetyl CoA carboxylase
D) Lipoprotein lipase
B) Cholesterol 7α-hydroxylase
60
The production of ketone bodies from acetyl CoA is called __________.
ketogenesis
61
Which apolipoprotein is primarily associated with HDL?
A) ApoB-100
B) ApoC-II
C) ApoE
D) ApoA-I
D) ApoA-I
62
Lipoprotein lipase, located on the endothelial cells, hydrolyzes __________ in lipoproteins.
triglycerides
63
What is the main function of VLDL?
A) Transport dietary lipids
B) Transport cholesterol to tissues
C) Transport endogenous triglycerides
D) Transport free fatty acids
C) Transport endogenous triglycerides
64
HDL particles are involved in the reverse transport of __________ from tissues to the liver.
cholesterol
65
Which enzyme is responsible for the hydrolysis of triacylglycerol in chylomicrons?
A) Lipoprotein lipase
B) Pancreatic lipase
C) Hormone-sensitive lipase
D) Adipose triglyceride lipase
A) Lipoprotein lipase
66
Cholesterol esters are formed by the enzyme __________ in HDL particles.
LCAT (lecithin-cholesterol acyltransferase)
67
What role does ApoB-100 play in lipid metabolism?
A) Acts as a ligand for LDL receptors
B) Activates lipoprotein lipase
C) Inhibits lipoprotein lipase
D) Activates LCAT
A) Acts as a ligand for LDL receptors
68
Elevated levels of LDL in the blood can lead to __________, a major risk factor for cardiovascular diseases.
atherosclerosis
69
Which lipoprotein is known for transporting cholesterol from peripheral tissues back to the liver?
A) LDL
B) VLDL
C) HDL
D) Chylomicrons
C) HDL
70
The lipoprotein responsible for transporting dietary lipids from the intestines to other locations in the body is __________.
chylomicrons
71
What is the primary cause of familial hypercholesterolemia?
A) Deficiency in lipoprotein lipase
B) Deficiency in LDL receptors
C) Excess production of VLDL
D) Excess production of chylomicrons
B) Deficiency in LDL receptors
72
A deficiency in the enzyme lipoprotein lipase can result in elevated levels of __________ in the blood.
triglycerides
73
Which condition is characterized by the accumulation of cholesterol and cholesteryl esters in macrophages?
A) Atherosclerosis
B) Hepatic steatosis
C) Niemann-Pick disease
D) Tangier disease
A) Atherosclerosis
74
Tangier disease is caused by a defect in the __________ transporter involved in HDL formation.
ABCA1
75
Which genetic disorder is associated with a defect in the enzyme acid sphingomyelinase?
A) Niemann-Pick disease
B) Gaucher disease
C) Fabry disease
D) Tay-Sachs disease
A) Niemann-Pick disease
76
Gaucher disease is caused by a deficiency in the enzyme __________, leading to the accumulation of glucocerebroside.
glucocerebrosidase
77
What is a common symptom of metabolic syndrome?
A) Low blood pressure
B) High HDL levels
C) Insulin resistance
D) Low triglyceride levels
C) Insulin resistance
78
The clinical condition characterized by excessive fat accumulation in the liver is called __________.
hepatic steatosis
79
Which enzyme deficiency leads to the lysosomal storage disorder Tay-Sachs disease?
A) Hexosaminidase A
B) Glucocerebrosidase
C) Acid sphingomyelinase
D) Alpha-galactosidase
A) Hexosaminidase A
80
Deficiency in the enzyme alpha-galactosidase causes __________ disease.
Fabry
81
What is the primary site for beta-oxidation of fatty acids?
A) Cytoplasm
B) Mitochondria
C) Endoplasmic reticulum
D) Peroxisomes
B) Mitochondria
82
Beta-oxidation of odd-chain fatty acids produces acetyl CoA and __________.
propionyl CoA
83
Which enzyme catalyzes the first step of beta-oxidation?
A) Acetyl CoA carboxylase
B) Carnitine acyltransferase
C) Fatty acyl-CoA synthetase
D) Acyl-CoA dehydrogenase
D) Acyl-CoA dehydrogenase
84
Peroxisomes are involved in the oxidation of very __________-chain fatty acids.
long
85
Which disorder is characterized by the inability to transport long-chain fatty acids into the mitochondria?
A) Carnitine deficiency
B) Niemann-Pick disease
C) Fabry disease
D) Tay-Sachs disease
A) Carnitine deficiency
86
Refsum disease is caused by a defect in the metabolism of __________ fatty acids.
branched-chain
87
Which enzyme deficiency leads to the disorder MCAD (Medium-chain acyl-CoA dehydrogenase) deficiency?
A) Acyl-CoA dehydrogenase
B) Acetyl CoA carboxylase
C) Carnitine acyltransferase
D) Fatty acyl-CoA synthetase
A) Acyl-CoA dehydrogenase
88
Zellweger syndrome is a disorder of __________ biogenesis affecting the oxidation of long-chain fatty acids.
peroxisome
89
What is the primary symptom of carnitine deficiency?
A) Hyperglycemia
B) Muscle weakness
C) Hypercholesterolemia
D) Hypotension
B) Muscle weakness
90
Adrenoleukodystrophy is a peroxisomal disorder that affects the metabolism of very long-chain __________.
fatty acids
91
Which tissue is primarily responsible for the synthesis and release of ketone bodies?
A) Brain
B) Liver
C) Muscle
D) Adipose tissue
B) Liver
92
The Cori cycle involves the transport of __________ from muscles to the liver, where it is converted back to glucose.
lactate
93
What is the primary function of adipose tissue in energy metabolism?
A) Store glycogen
B) Produce glucose
C) Store triglycerides
D) Release ketone bodies
C) Store triglycerides
94
The urea cycle, which eliminates excess nitrogen, takes place primarily in the __________.
liver
95
Which enzyme is a key regulator of the citric acid cycle and is inhibited by high levels of ATP?
A) Citrate synthase
B) Isocitrate dehydrogenase
C) Alpha-ketoglutarate dehydrogenase
D) Succinate dehydrogenase
B) Isocitrate dehydrogenase
96
Fatty acids are broken down by beta-oxidation in the __________ of cells.
mitochondria
97
What is the role of malonyl CoA in fatty acid metabolism?
A) Inhibits beta-oxidation
B) Activates lipolysis
C) Synthesizes ketone bodies
D) Transports fatty acids into mitochondria
A) Inhibits beta-oxidation
98
During prolonged fasting, __________ becomes the major energy source for the brain after glucose is depleted.
ketone bodies
99
Which enzyme is involved in the activation of fatty acids for beta-oxidation?
A) Fatty acid synthase
B) Acetyl CoA carboxylase
C) Fatty acyl-CoA synthetase
D) Carnitine acyltransferase
C) Fatty acyl-CoA synthetase
100
Glucose-6-phosphatase is an enzyme involved in the final step of __________, converting glucose-6-phosphate to glucose.
gluconeogenesis
