Microchemistry Objective Questions
Microchemistry Objective Questions with Answers Pdf Download for Freshers Experienced Medical MBBS Students Microchemistry Multiple choice Questions. These Objective type Microchemistry Questions are very important for campus placement Interviews.
1.In electrophoresis, if the pH is above isoelectric point a protein will:
a) Precipitate
b) Not move
c) Form a zwitter ion
d) Migrate to anode
e) Migrate to cathode
2.Regarding iso electric pH, true is (regarding enzymes)
a) All amino acids exit as zwitter ions
b) Net + ve on molecule are equal
c) Enzyme activity maximum
d) None of the above
3.Not produced in Adrenaline synthesis pathway
a) DOPA
b) Dopamine
c) Nor adrenaline
d)Tyramine
4. 17- Alpha hydroxylase deficiency causes:
a) Decreased testosterone
b) Decrease of estrogens
c) Decrease glucagon
d) Increase estrogen
5. In ECF main electrolyte is
a) Na+
b) K+
c) Cl-
d)proteins
6.Norepinephrine is converted to epinephrine by
a) Dopamine hydroxylase
b) Dopa decarboxylase
c) O-mefhylation
d) N-methylation
7.Insulin promotes transport of glucose in which of these
a) Hepatocytes
b) Muscles
c)RBC
8. Regarding uncouple of Oxidative phosphorylation, the following statement is correct
a) ATP production is more in anaerobic metabolism
b) Oxygen is not used and ATP is produced
c) Oxygen is used and ATP is not produced
d) Phosphorylation occurs in cytoplasm
9. Rate limiting step in adrenaline synthesis is conversion of:
a) Tyrosine to Dopa
b) Phenylalanine to tyrosine
c) Dopa to Dopamine
d) Dopamine to Norepinephrine
10.Calcitonin is antagonist to
a) Parathyroid hormone
b) Thyroxine
c) Triiodotyrosine
d) Serotonin
11.Which of the following is precursor of adrenalin and thyroxine synthesis
a) Phenyl alanine
b) Tyrosine
c) Tryptophan
d) None of the above
12.Which of the following about biological membrane is true?
a) Lipid moiety is amphipathic
b) Rigid assembly of protein, lipid and carbohydrate
c) Symmetrical bi leaflet structures
d) Lipid and protein moiety are held by coyalent interactions
13. To keep blood pHat 7.4 the HC03:H2C03 ratio should be
a) 20:1
b) 30:1
c) 15:1
d) 1:1
14. Chemically, oestrogens are characterized by:
a) Absence of 02 at D-17
b) Aromatic character at D-ring
c) Absence of methyl group at C 10
d) A 21 – carbon steroid skeleton
15. Skeletal muscle is deficient in
a) Glucose – 6 – phosphatase
b) Hexokinase
d) Phosphofructokinase
c) Isomerase
16. The most important buffer pair RBCs engaged in maintaining base equilibrium of blood is
a) Bicarbonate
b) Protein
c) Phosphate
d) Haemoglobin
17. Which of the following belongs to steroidal receptor super family
a) Vitamin D3
b)Encephalin
c)GHline
d) Phenylalanine
18.The immediate precursor of norepinephrine is:
a) Epinephrine
b) Tyrosine
c) Dopai
d) Diphosphoglycerate
e) ATP
19.In mature erythrocytes the major available anion is:
a) Haemoglobin
b) Chloride
c) Bicarbonate
d)Bone
20.Ferritin stores are present in following sites except
a) Intestine
b) Liver
c) Spleen
d) Adenyl cyclase
21.Epinephrine activates the enzyme
a) Phosphodiesterase
b) Adenylate kinase
c)GH
d) Cortisone
22.For which is cGMP second messenger
a) Thyroxine
b) Atrial natriuretic peptide
23. pH is maximum in:
a) Pancreatic secretion
b) Intestinal secretions
c) Salivary secretions
d) Gastric secretion
24. S.G. of whole blood is:
a) 1.025-1.035
b) 1.035-1.045
c) 1.045-1.065
d) 1.065-1.075
25.Which of the following amino acids is involved in the synthesis of thyroxine
a) Glycine
b) Methionine
c) Threonine
d) Tyrosine
26.Oxidative phosphorylation at the level of cytochrome oxidase is inhibited by
a) Carbon monoxide
b) Cyanide
c) Rofenone
d) Oligomycin
27. Hormone substrate concentration affects the velocity of enzymatic action, this is known as
a) Zimmerman reaction
b) Salkowski reaction
c) Michales Menton reaction
d) Lieberman-Burchard reaction
28.The most important buffer in extra cellular fluid is:
a) Hemoglobin
b) Protein
c) Phosphate
d)H203/HC02
29.Keratin in the nail is exceptionally strong than others because of
a) Disulphide bond
b) Van der Wall’s forces
c) Ionic bonds
d) Calcification
30. The normal specific gravity of urine is
a) 1.005-1.015
b) 1.015-1.020
c) 1.030-1.040
d)None
31.The following statement about biological membrane is correct
a)They are symmetric bi leaflet structure
b)Their constituent lipid & protein moieties are held together by covalent teraction
c)They are rigid assemblies of protein, lipid & carbohydrates
d)Their lipid moieties are amphipathic in nature
32.Norepinephrine is converted to Epinephrine by
a) O-methylation
b) N-methylation
c) Dopamine hydroxylase
d) Dopa decarboxylase
33.Disopropyl phosphofluoridate (DFP) reacts with serine proteases irreversibly and therefore is:
a) Allosteric inhibitor
b) Competitive inhibitor
c) Non competitive inhibitor
d) A repressor
34.Calcium as a second messenger in hormone action involves all except:
a) C-GMP
b) Na+ / Ca exchange pump
c)Protein kinase
d) Phosphatidyl inositol
35.The precursor of testosterone is:
a) Aldosterone
b) Methyl testosterone
c) Estrone
d) Pregnenolone
36.Insulin receptors are:
a) Tyrosine Kinase receptors
b) Phosphodiesterase
c) Calcium-calmodulin
d)Lipoprotein lipase
e) All
37.Estrogen receptors are seen in
a) Microsomes
b) Membrane bound
c) Nucleus
d) Mitochondria
38.Insulin helps in all except
a) Glycogen synthesis
b) Gluconeogenesis
c) Lipogenesis
d) Glycolysis
39.All are second messengers, except:
a) c-AMP
b) Calcium
c)m-RNA
d) Phosphatidyl inositol
40.Exogenous catecholamines are metabolized by
a)COMT
b)MAO
c)MOPEG
d) All of the above
41.The major driving force for formation of membrane lipid bilayer is:
a) Hydrogen bonding
b) Hydrophobic interactions
c) Vander wall forces
d) Not known
42.Precursor of Testosterone is
a) Estrone
b) Cholesterol
c) Cortisol
d) Aldosterone
43.Which of the following amino acids is involved in the synthesis of thyroxine?
a) Glycine
b) Methionine
c) Threonine
d) Tyrosine
44.Which of the following is a synthetic reaction?
a) Reduction
b) Acetylation
c) Oxidation
d) Hydrolysis
45.All are physiological buffers, except:
a) Proteins
b) Bicarbonates
c) Hb
d) CLPO,
46.Biosynthesis of oestrogens. Which is true:
a) Phenol end product
b) Aromatization occurs, which requires O, and NADPH
c) Angular methyl at C-10 is lost
d) Androgens serve as precursors
e) All of the above
47.True about Insulin is:
a) Is a glycoprotein
b) Has a half-life of 4 hours after intravenous injection
c)Increase protein synthesis from aminoacids in muscle
d)Increases the activity of glycogen phosphorylase
48.The most important buffer in RBC is
a) 02 Hb + Na Hemoglobinate
b) 0,Hb + K Hemoglobinate
c)H2C03 + KHC03
d)H2C03 + NaHC03
49.Regarding T3 and T4 which is incorrect?
a) T3 concentration is more
b) T3 is more potent than T4
c) T3 and T4 have unequal biological activity
d) Concentration of T4 is more than T3
50.Anterior pituitary gland secretes all except:
a)GRH
b)GH
c)TSH
d)LH-FSH
51.Detoxification of d–gs is controlled by:
a) Cytochrome
b) Cytochrome P450
c) Cytochrome C
d) Cytochrome A
52.Glucagon
a) Produces hypoglycaemia
b) Blocks release of catecholamines
c) Increases hyper peristalsis of intestine
d) Acts on heart
53.Which of the following is an effect of dinitrophenoi on oxidative phosphorylation
a) Inhibition of cytochrome b
b) Blockade of both electron transport and ATP synthesis
c)Inhibition of ATP synthesis with normal electron transport
d)Inhibition of electron transport but not ATP synthesis
54.Muscle cannot make use of glycogen for energy due to the absence of
a) Glucose-6-phosphotase
b) Glucokinase
c) Phosphorylase
d) Phosphoglucomutase
55.Insulin has amino acids
a)49
b)50
c)51
d)52
e)62
56.Which of the following hormone does not have a second messenger?
a) Insulin
b) Growth hormone
c) Aldosterone
d) Somatostatin
57.All are true of absorption of calcium from the gut except:
a) Vitamin D increases the absorption
b) Parathormone increase it
c) Calcitonin decreases it
d) An alkaline pH in the gut decreases calcium absorption
58.Which of the following is not a second messenger?
a) cAMP
b) cGMP
c) Phosphatidyl inositol
d) Phosphatidyl glycerol
59.The lipid bilayer of cell membrane exists as
a) Solid
b) Semisolid
c)Gel
d) Fibers
60.Spontaneous chemical reaction means free energy change is
a) Positive
b) Negative
c) Zero
d) Infinity
61.Lamin is present in
a) Basement membrane
b) Inner nuclear membrane
c) Outer nuclear membrane
d) Mitochondria
62.Which of these contain 19 carbon atoms:
a) Estradiol
b) Testosterone
c) Aldosterone
d) Cortisol
63.Which of the following is a direct precursor of hormones
a) Ergosterol
b) Cyclic AMP
c) Cholesterol
d) Tyrosine
64.In cytochrome p 450, P stands for
a) Structural proteins
b) Substrate protein
c) Pigment
d) Polymer
65.A substance having affinity but no intrinsic activity is
a) Agonist
b) Partial agonist
c) Antagonist
d) Physiological antagonist
66. Osmolality is
a) Osmalarity per kg of solvent
b) Osmalarity per liter of solvent
c) Moles per kg of solvent
d) Moles per liter of solvent
67.Thyroxine and catecholamine are .derived from
a) Tyrosine
b) Tryptophan
c) Alanine
d) Leucine
68.Biological cell membrane contains all the following except
a) Steroid receptors
b) Prostaglandins
c) Cholesterol
d) Cytochrome
69.The blood concentration of H2C03 (meq/L) is:
a) 5
b)15
c)20
d)50
70.What is known as the “second messenger”?
a) ATP
b)ADP
c) Cyclic AMP
d)GMP
71. A bilipid layer is most permeable to:
a) Potassium
b) Sodium
c) Glucose
d)Urea
72.A substance having affinity and intrinsic activity is:
a) Agonists
b) Partial agonist
c) Antagonist
d) Physiological antagonist
73.Which of the following hormones are dependent on cyclic AMP?
a) Vasopressin
b) Aldosterone
c) Renin
d) Angiotensin
74.Physiologically, this hormone is superfluous in adult humans
a) Calcitonin
b) Somatotropin
c) Prolactin
d)Somatostatin
75. Which is correct about intracellular fluid
a) Amount less than ECF
b) Amount more than ECF
c) Amount equal to ECF
d) 70% of total body weight
76.Normal blood pH is
a)6.8-7.0
b)7.0-7.12
c)7.38-7.4
d) 7.7-8.0
77.Km decreases but Vmax same-enzyme is
a) Competitive
b) Non-competitive
c) Irreversible
d) Uncompetitive
78.In health the pH of the blood lies between th£ range of
a) 6.5-7.1
b) 7.2-7.3
c) 7.35-7.45
d) 7.45-7.6
79.Hormone that mediates enzymatic action at cellular level is
a) Thyroxine
b) Insulin
c) Cortisol
d) vit-D
80.Multienzyme complex in humans
a) Fatty acid synthetase
b) Malonyl CoA Carboxylase
c) Carbamoyl phosphate synthetase
d) Adenosine phospho ribosyl transferase
81.Fidelity enzyme in protein synthesis
a) DNA polymerase
b) RNA polymerase
c) Amino-Acyl tRNA synthase
d) Amino acyl reductase
82.The enzyme acetylcholine esterase is synthesized in:
a) Liver
b) Plasma
c) Marrow
d) Spleen
e) Ferroprotoporphyrin
83.Dehydrogenases used as coenzymes all of the following, except:
a)FMN
b)FAD
c)NADP
d)NAD
84.Which inhibits adenyl cyclase enzyme
a) Somatostatin
b) Calcitonin
c) Epinephrine
d)Thyroxine
85.Zinc is an essential component of the following enzymes except
a) Carbonic anhydrase
b) Alkaline phosphatase
c) Xanthine oxidase
d) Ethanol dehydrogenase
e)Carboxypeptidase
86.Which of the following enzymes do not need cofactor:
a) Oxidoreductase
b) Isomerase
c) Aldolase
d) Lyases
87. Enzyme that hydrolyzes sucrose is:
a) Invertase
b) Amylase
c) Emulsin
d) Sucrose phosphorylase
e) Saccharase
88.Tyrosinase is
a) Oxidase
b) Tranferase
c) Lyase
d) Sucrose phosphorylase
89.Coenzyme, in an enzymatic reaction usually functions to:
a) Activate the substrate
b) Increase the active sites of apoenzyme
c) Enhance the specificity of apoenzyme
d) Accept one of the cleavage products
90.Lactate dehydrogenase is:
a) Isozyme
b) Coenzyme
c) Antienzyme
d) Zymogen
91. Benzidine test is positive with the enzyme
a) Cytochrome oxidase
b) Dehydrogenase
c) Hydrolase
d) Peroxidase
92. Which of the following is not decreased in diabetes mellitus
a) Glucokinase
b) Acetyl CoA carboxylase
c) Pyruvate carboxylase
d) All
93.Aldolase is an enzyme whose substrate is*
a) Glucose -6 phosphate
b) Fructose-6-phosphate
c) Fructose
d)Fructose- 1,6-biphosphate
94.Insulin stimulates the activity of the following enzymes except:
a) Acetyl CoA carboxylase
b) Pyruvate kinase
c) Hormone sensitive lipase
d) Glycerol kinase
e) Phosphofructokinase
95. True statement regarding Enzyme cascade system is
a) Once activated, continues indefinitely
b) Counter regulation is seen in all
c) Activated by hormones
d) Substrate amplification occurs
96. Coenzymes are-organic compounds:
a) Lipoprotein
b) Proteinaceous
c) Non-protein
d) Any of the above
97. Enzyme deficiency in alkaptonuria is
a) Tyrosine hydroxylase
b) Homogentisic acid oxidase
c) Cystathionine synthase
d) Phenyl alanine hydroxylase
98.Michaelis-Menten hypothesis states that:
a)Rate of enzymatic reaction is independent of substrate concentration
b)Rate of nonenzymatic reaction is proportional to substrate concentration
c)Km is the enzyme-substrate complex association constant
d)Enzyme-substrate complex formation is essential in enzymatic reaction
99.Enzymes not important in testosterone biosynthesis:
a) 5-alpha reductase
b) Delta 5-4 isomerase
c) 18 hydroxylase
d) Alpha hydroxylase
100.When the prosthetic group of an enzyme is an inorganic ion, it is called a
a) Cofactor
b) Coenzyme
c) Apoenzyme
d) Holoenzyme
101. Enzymes stored in muscle is:
a) Alkaline phosphatase
b)SGOT
c)SGPT
d)CPK