1. MCQs on Neurotransmitters 2.Carbohydrate Absorption
3. MCQs on the chemical properties of neurotransmitters
1. MCQs on Neurotransmitters
1. Which of the following is an excitatory neurotransmitter in the central nervous system?
A) Glycine
B) GABA
C) Glutamate
D) Serotonin
Ans - C
2. Which neurotransmitter is primarily associated with mood regulation and is targeted by SSRIs?
A) Dopamine
B) Serotonin
C) Acetylcholine
D) Norepinephrine
Ans - B
3. GABA is synthesized from which precursor molecule?
A) Glutamate
B) Tyrosine
C) Tryptophan
D) Histidine
Ans - A
4. Which neurotransmitter is associated with the "reward pathway" in the brain?
A) Dopamine
B) Serotonin
C) Norepinephrine
D) Acetylcholine
Ans - A
5. What type of receptor does acetylcholine bind to at neuromuscular junctions?
A) Nicotinic
B) Muscarinic
C) Adrenergic
D) GABAergic
Ans - A
Neurotransmitter Synthesis and Pathways:
6. Dopamine is converted to norepinephrine by which enzyme?
A) Tyrosine hydroxylase
B) Dopamine beta-hydroxylase
C) Monoamine oxidase
D) COMT
Ans - B
7. Which amino acid is the precursor for serotonin synthesis?
A) Tyrosine
B) Glutamine
C) Tryptophan
D) Glycine
Ans - C
8. Norepinephrine is degraded primarily by which enzyme?
A) Acetylcholinesterase
B) Monoamine oxidase (MAO)
C) COMT
D) Glutaminase
Ans - B
9. Which neurotransmitter is synthesized from histidine?
A) Dopamine
B) Histamine
C) Serotonin
D) Glycine
Ans - B
10. What is the rate-limiting enzyme in the synthesis of catecholamines?
A) Dopamine beta-hydroxylase
B) Tyrosine hydroxylase
C) Monoamine oxidase
D) Phenylethanolamine-N-methyltransferase
Ans - B
Neurotransmitter Functions:
11. Which neurotransmitter is involved in the regulation of circadian rhythms?
A) Serotonin
B) Melatonin
C) Dopamine
D) Glutamate
Ans - B
12. Acetylcholine plays a key role in which of the following?
A) Memory and learning
B) Pain regulation
C) Hunger signaling
D) Stress response
Ans - A
13. Which neurotransmitter is inhibitory in the spinal cord?
A) GABA
B) Glycine
C) Glutamate
D) Dopamine
Ans - B
14. Which neurotransmitter is associated with alertness and the "fight or flight" response?
A) Acetylcholine
B) Dopamine
C) Norepinephrine
D) Serotonin
Ans - C
15. Which neurotransmitter is primarily released during muscle contraction?
A) GABA
B) Acetylcholine
C) Dopamine
D) Glutamate
Ans - B
Disorders Related to Neurotransmitters:
16. A deficiency in dopamine production in the substantia nigra is linked to which disorder?
A) Schizophrenia
B) Parkinson’s disease
C) Alzheimer’s disease
D) Depression
Ans - B
17. Excess dopamine activity in certain brain regions is associated with which condition?
A) Schizophrenia
B) Anxiety
C) Epilepsy
D) ADHD
Ans - A
18. A deficit in serotonin levels is most commonly linked to:
A) Anxiety disorders
B) Depression
C) Bipolar disorder
D) Parkinson’s disease
Ans - B
19. GABA dysfunction is most likely to result in which condition?
A) Schizophrenia
B) Anxiety disorders
C) ADHD
D) Alzheimer’s disease
Ans - B
20. Which neurotransmitter is decreased in Alzheimer’s disease?
A) Dopamine
B) Acetylcholine
C) Serotonin
D) Norepinephrine
Ans - B
21. Endorphins primarily modulate which sensation?
A) Vision
B) Pain
C) Hunger
D) Temperature
Ans - B
22. Which neurotransmitter acts as a retrograde messenger, influencing presynaptic neurons?
A) Glutamate
B) GABA
C) Nitric oxide
D) Acetylcholine
Ans - C
23. Which of the following is a gas neurotransmitter?
A) Serotonin
B) Dopamine
C) Nitric oxide
D) Acetylcholine
Ans - C
24. What is the primary inhibitory neurotransmitter in the brain?
A) Glutamate
B) GABA
C) Glycine
D) Norepinephrine
Ans - B
25. Substance P is primarily associated with which function?
A) Memory enhancement
B) Pain transmission
C) Sleep regulation
D) Hunger suppression
Ans - B
26. Which one of the following small molecule neurotransmitters is not synthesized from tyrosine?
A) Epinephrine
B) Dopamine
C) Serotonin
D) Norepinephrine
Ans - C
2. Carbohydrate Absorption:
1. Which enzyme breaks down starch into maltose and dextrins?
A) Sucrase
B) Lactase
C) Amylase
D) Isomaltase
Ans C
2. Which disaccharide is broken down by lactase?
A) Maltose
B) Sucrose
C) Lactose
D) Cellobiose
Ans - C
3. Which monosaccharides are produced by the hydrolysis of sucrose?
A) Glucose and galactose
B) Glucose and fructose
C) Glucose and glucose
D) Glucose and maltose
Ans - B
4. Which transporter is responsible for fructose uptake into intestinal epithelial cells?
A) SGLT1
B) GLUT2
C) GLUT5
D) GLUT4
Ans - C
5. What is the primary site of carbohydrate digestion?
A) Stomach
B) Mouth
C) Small intestine
D) Large intestine
Ans - C
Transporters and Mechanisms:
6. Which transporter mediates sodium-dependent glucose absorption in the small intestine?
A) GLUT2
B) GLUT5
C) SGLT1
D) GLUT4
Ans - C
7. What type of transport mechanism does SGLT1 use?
A) Simple diffusion
B) Facilitated diffusion
C) Primary active transport
D) Secondary active transport
Ans - D
8. GLUT4 is primarily found in which tissues?
A) Liver and kidney
B) Adipose tissue and skeletal muscle
C) Intestinal epithelial cells
D) Red blood cells
Ans - B
9. Which transporter is insulin-dependent?
A) GLUT2
B) GLUT5
C) GLUT4
D) GLUT1
Ans - C
10. GLUT1 is primarily involved in glucose transport to which tissues?
A) Liver
B) Brain and red blood cells
C) Skeletal muscle
D) Adipose tissue
Ans B
11. Insulin promotes glucose uptake by which transporter?
A) GLUT2
B) GLUT3
C) GLUT4
D) GLUT5
Ans - C
12. Which transporter plays a key role in glucose absorption in hepatocytes?
A) GLUT2
B) GLUT5
C) SGLT1
D) GLUT4
Ans - A
13. A deficiency in lactase leads to which condition?
A) Celiac disease
B) Lactose intolerance
C) Fructose malabsorption
D) Glycogen storage disease
Ans - B
14. Which transporter is affected in fructose malabsorption?
A) GLUT2
B) GLUT5
C) SGLT1
D) GLUT4
Ans - B
15. A mutation in SGLT1 can lead to which disorder?
A) Diabetes mellitus
B) Fanconi syndrome
C) Glucose-galactose malabsorption
D) Hereditary fructose intolerance
Ans - C
Advanced Questions on Carbohydrate Absorption
16. The apical uptake of glucose and galactose is mediated by:
A) GLUT2
B) GLUT5
C) SGLT1
D) GLUT4
Ans - C
17. Which enzyme is involved in the breakdown of maltose?
A) Amylase
B) Sucrase
C) Maltase
D) Lactase
Ans - C
18. Which monosaccharide is absorbed without sodium co-transport?
A) Glucose
B) Galactose
C) Fructose
D) Maltose
Ans - C
19. Where is GLUT2 localized in the intestinal epithelial cells?
A) Apical membrane
B) Basolateral membrane
C) Cytoplasm
D) Endoplasmic reticulum
Ans - B
20. In a fasting state, which GLUT transporter maintains basal glucose uptake?
A) GLUT2
B) GLUT3
C) GLUT4
D) GLUT1
Ans - D
21. Which transporter is overexpressed in cancer cells to meet energy demands?
A) GLUT1
B) GLUT2
C) GLUT3
D) GLUT4
Ans - A
22. Glucose transport into the brain occurs primarily through:
A) GLUT2
B) GLUT3
C) GLUT4
D) SGLT1
Ans - B
23. Which of the following is a passive glucose transporter?
A) SGLT1
B) GLUT1
C) SGLT2
D) Na+/K+ pump
Ans - B
24. High blood glucose levels primarily stimulate which transporter?
A) GLUT1
B) GLUT2
C) GLUT4
D) GLUT3
Ans - C
25. The primary glucose transporter in the liver is:
A) GLUT1
B) GLUT2
C) GLUT3
D) GLUT4
Ans - B
26. Absorbed monosaccharides in intestinal epithelial cells exit via which one of the following transporters?
A) GLUT1
B) GLUT2
C) GLUT3
D) GLUT4
Ans - B
30 multiple-choice questions (MCQs) based on glucose transporters (GLUT)
-
Which GLUT transporter is primarily responsible for glucose uptake in the brain?
A. GLUT1
B. GLUT2
C. GLUT3
D. GLUT4
Ans - C
-
Which GLUT isoform is insulin-dependent?
A. GLUT1
B. GLUT2
C. GLUT3
D. GLUT4
Ans - D
-
Which gene encodes GLUT2 in humans?
A. SLC2A1
B. SLC2A2
C. SLC2A3
D. SLC2A4
Ans - B
-
Where is GLUT5 predominantly expressed?
A. Liver
B. Brain
C. Small intestine
D. Muscle
Ans - C
-
Which GLUT isoform has the highest affinity for glucose?
A. GLUT1
B. GLUT3
C. GLUT4
D. GLUT2
Ans - B
-
What is the primary substrate of GLUT5?
A. Glucose
B. Fructose
C. Galactose
D. Mannose
Ans - B
-
Which disease is caused by mutations in the SLC2A1 gene?
A. Diabetes mellitus
B. GLUT1 deficiency syndrome
C. Alzheimer's disease
D. Obesity
Ans - B
-
What is the Km value of GLUT2, indicating its affinity for glucose?
A. High (10–20 mM)
B. Low (1–3 mM)
C. Medium (5–10 mM)
D. Very low (<1 mM)
Ans - A
-
Which tissue predominantly expresses GLUT4?
A. Brain
B. Liver
C. Skeletal muscle
D. Pancreas
Ans - C
-
What type of transporter is GLUT?
A. Symporter
B. Antiporter
C. Facilitated transporter
D. ATP-dependent transporter
Ans - C
-
Which GLUT isoform is expressed in pancreatic β-cells?
A. GLUT1
B. GLUT2
C. GLUT3
D. GLUT4
Ans - B
-
Which signaling pathway regulates GLUT4 translocation?
A. MAPK pathway
B. PI3K-Akt pathway
C. Wnt pathway
D. JAK-STAT pathway
Ans - B
-
Which GLUT isoform is involved in glucose transport across the blood-brain barrier?
A. GLUT2
B. GLUT1
C. GLUT4
D. GLUT5
Ans - B
-
Which GLUT transporter is most involved in fructose metabolism in the liver?
A. GLUT3
B. GLUT2
C. GLUT5
D. GLUT1
Ans - C
-
What is a major consequence of GLUT1 deficiency syndrome?
A. Hyperglycemia
B. Seizures
C. Insulin resistance
D. Obesity
Ans - B
-
Which GLUT isoform is expressed in adipose tissue?
A. GLUT1
B. GLUT4
C. GLUT3
D. GLUT2
Ans - B
-
Which GLUT transporter is essential for glucose sensing in the hypothalamus?
A. GLUT1
B. GLUT2
C. GLUT3
D. GLUT4
Ans - B
-
What happens to GLUT4 expression in type 2 diabetes?
A. Increased
B. Decreased
C. Unchanged
D. Completely absent
Ans - B
-
Which GLUT isoform is expressed in erythrocytes?
A. GLUT1
B. GLUT2
C. GLUT3
D. GLUT4
Ans - A
-
Which GLUT isoform is expressed in cancer cells and linked to the Warburg effect?
A. GLUT1
B. GLUT2
C. GLUT3
D. GLUT4
Ans - A
-
What is the primary function of GLUT8?
A. Fructose transport in testes
B. Glucose transport in skeletal muscle
C. Insulin secretion in β-cells
D. Glucose uptake in adipocytes
Ans - A
-
Which GLUT transporter is responsible for transporting glucose during embryogenesis?
A. GLUT3
B. GLUT1
C. GLUT4
D. GLUT2
Ans - B
-
Which GLUT isoform is highly expressed in neurons?
A. GLUT1
B. GLUT2
C. GLUT3
D. GLUT4
Ans - C
-
How many transmembrane helices do GLUT transporters typically have?
A. 6
B. 12
C. 8
D. 10
Ans - B
-
GLUT9 is associated with the transport of which molecule?
A. Glucose
B. Uric acid
C. Fructose
D. Galactose
Ans - B
-
Which GLUT isoform is expressed in the kidney and regulates glucose reabsorption?
A. GLUT4
B. GLUT5
C. GLUT9
D. GLUT2
Ans - D
-
What is the role of the N-terminal region in GLUT transporters?
A. Substrate binding
B. Regulation of translocation
C. ATP binding
D. Channel gating
Ans - B
-
Mutations in which GLUT isoform are linked to gout?
A. GLUT2
B. GLUT4
C. GLUT9
D. GLUT5
Ans - C
-
Which GLUT transporter is found in placental trophoblasts?
A. GLUT1
B. GLUT3
C. GLUT4
D. GLUT5
Ans - A
-
GLUT12 is predominantly expressed in which tissue?
A. Brain
B. Muscle
C. Liver
D. Pancreas
Ans - B
3. MCQs on the chemical properties of neurotransmitters:
1. Epinephrine is classified as which type of neurotransmitter?
A) Amino acid
B) Catecholamine
C) Indoleamine
D) Peptide
Ans - B
2. The functional group that defines catecholamines like dopamine and norepinephrine is:
A) Amide
B) Catechol (benzene with two hydroxyl groups)
C) Carboxylic acid
D) Phenyl
Ans - B
3. Serotonin is derived from which amino acid?
A) Tyrosine
B) Tryptophan
C) Phenylalanine
D) Histidine
Ans - B
4. Dopamine contains which chemical functional group that allows it to bind to its receptor?
A) Phenolic hydroxyl group
B) Amine group
C) Carboxyl group
D) Both A and B
Ans - D
5. The chemical precursor to epinephrine in its biosynthesis is:
A) Dopamine
B) Norepinephrine
C) L-DOPA
D) Phenylalanine
Ans - B
Chemical Pathways:
6. Which enzyme catalyzes the conversion of norepinephrine to epinephrine?
A) Monoamine oxidase (MAO)
B) Phenylethanolamine-N-methyltransferase (PNMT)
C) Tyrosine hydroxylase
D) Dopamine beta-hydroxylase
Ans - B
7. Serotonin belongs to which class of neurotransmitters based on its chemical structure?
A) Catecholamines
B) Indoleamines
C) Purines
D) Amino acids
Ans - B
8. Which cofactor is required for the hydroxylation of tyrosine in the synthesis of dopamine?
A) NADH
B) FAD
C) Tetrahydrobiopterin (BH4)
D) Pyridoxal phosphate
Ans - C
9. What is the major degradation product of serotonin?
A) Homovanillic acid (HVA)
B) 5-Hydroxyindoleacetic acid (5-HIAA)
C) Vanillylmandelic acid (VMA)
D) Dopacetic acid
Ans - B
10. The methylation of norepinephrine to form epinephrine requires which methyl donor?
A) ATP
B) S-adenosylmethionine (SAM)
C) Tetrahydrofolate (THF)
D) NADPH
Ans - B
Molecular Structure and Stability:
11. The catechol structure in dopamine makes it susceptible to oxidation. This property is responsible for:
A) Its stability in the synaptic cleft
B) Its degradation into reactive oxygen species (ROS)
C) Its inability to cross the blood-brain barrier
D) Its enhanced receptor binding affinity
Ans - B
12. Which neurotransmitter contains an imidazole ring?
A) Serotonin
B) Dopamine
C) Histamine
D) Epinephrine
Ans - C
13. The ionization state of the amine group in neurotransmitters affects:
A) Their receptor binding
B) Their ability to cross membranes
C) Their enzymatic degradation
D) All of the above
Ans - D
14. The degradation of dopamine is primarily catalyzed by:
A) Catechol-O-methyltransferase (COMT)
B) Phenylethanolamine-N-methyltransferase
C) Glutamate dehydrogenase
D) Acetylcholinesterase
Ans - A
15. The zwitterionic form of serotonin exists at:
A) Acidic pH
B) Basic pH
C) Physiological pH
D) Extreme alkaline pH
Ans - C
Receptors and Ligand Interactions:
16. Epinephrine’s interaction with adrenergic receptors is primarily mediated by which functional group?
A) Hydroxyl group
B) Catechol ring
C) Amine group
D) Both B and C
Ans - D
17. Dopamine receptors are classified as:
A) Ionotropic receptors
B) G-protein coupled receptors (GPCRs)
C) Ligand-gated ion channels
D) Nuclear receptors
Ans - B
18. Which neurotransmitter binds to both alpha and beta-adrenergic receptors?
A) Dopamine
B) Serotonin
C) Epinephrine
D) GABA
Ans - C
19. The oxidation of serotonin to its inactive form is mediated by:
A) MAO-A
B) MAO-B
C) COMT
D) GAD
Ans - A
20. Which neurotransmitter requires vesicular monoamine transporters (VMATs) for storage?
A) Acetylcholine
B) GABA
C) Dopamine
D) Glutamate
Ans - C
21. Norepinephrine has limited ability to cross the blood-brain barrier due to:
A) Its size
B) Its polar catechol structure
C) Its lack of a lipid-soluble form
D) Both B and C
Ans - D
22. Which structural property of serotonin makes it soluble in water?
A) Hydroxyl group on the indole ring
B) Amine group
C) Its polar nature
D) Both A and B
Ans - D
23. Dopamine cannot cross the blood-brain barrier, but its precursor L-DOPA can. This is because:
A) L-DOPA has a smaller molecular weight
B) L-DOPA is actively transported across the barrier
C) Dopamine is too polar
D) Dopamine binds to plasma proteins
Ans - B
24. The oxidative deamination of norepinephrine by MAO produces:
A) DOPAC
B) Homovanillic acid
C) 3,4-Dihydroxyphenylglycol (DHPG)
D) Vanillylmandelic acid
Ans - C
25. The high lipid solubility of dopamine analogs like apomorphine increases:
A) Receptor binding affinity
B) CNS penetration
C) Degradation rate by MAO
D) Neurotoxicity
Ans - B
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