biochemistry Mcqs
101. Rate limiting step in adrenaline synthesis is conversion of____________?
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A. Dopamine to nor epinephrine

B. Tyrosine to dopa

C. Phenylalanine to tyrosine

D. Dopa to dopamine

102. Benzidine test is positive with the enzyme______________?
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A. Hydrolase

B. Cytochrome oxidase

C. Dehydrogenase

D. Peroxidase
104. Glycogen synthesis is increased by_____________?
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A. Insulin

B. Epinephrine

C. Cortisone

D. GH

105. Which of the following is precursor of adrenaline and thyroxine synthesis ?
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A. Tyrosine

B. Phenyl alanine

C. None of the above

D. Tryptophan

106. Coenzyme, in an enzymatic reaction usually functions to_____________?
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A. Activate the substrate

B. Accept one of the cleavage products

C. Increase the active sites of apoenzyme

D. Enhance the specificity of apoenzyme

107. All are true regarding glucose 6 phosphate deficiency except______________?
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A. Hyperuricemia

B. Increased mobilization of glycogen from liver

C. Defective cori cycle

D. Hyperglycemia
108. The deficiency of thiamine can be identified by measuring the red cell______________?
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A. Alpha ketoglutarate dehydrogenase

B. Transketaolase

C. Transaldolase

D. Pyruvate dehydrogenase

110. The immediate precursor of norepinephrine is______________?
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A. Tyrosine

B. Phenylalanine

C. Epinephrine

D. Dopamine
111. The enzyme that splits hydrogen peroxide into water and oxygen is_____________?
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A. Cytochrome P 450

B. Cytochromes

C. Super oxide dismutase

D. Catalase
114. Biotin is required for the activity of_____________?
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A. Phosphohexose isomerase

B. Pyruvate carboxylase

C. Succinate thiokinase

D. Lactate dehydrogenase

115. The main pathways of metabolism in brain are______________?
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A. Glycolysis and citric acid cycle

B. Embden-Meyerhof Pathway and H.M.P shunt

C. Glycogenolysis and Gluconeogenesis

D. Glycogenolysis and Citric and cycle

117. Enzymes involved in degradation of epinephrine_____________?
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A. Oxidases

B. Anticholinesterases

C. Cholinesterase

D. Catechol 0-transferase
118. Calcitonin is antagonist_______________?
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A. Thyroxine

B. Parathyroid hormone

C. Serotonin

D. Triidothyronine

120. Which of the following is NOT a characteristic feature of allosteric enzymes ?
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A. Give sigmoid shaped curve

B. Presence of Modulator site

C. Follow Michaelis-Menton Kinetics

D. They are multienzyme complex

121. NADPH is generated by the action of____________?
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A. Glucose 1 phosphate dehydrogenase

B. Glucose 1,6 diphosphate dehydrogenase

C. Glucose 6 phosphate dehydrogenase

D. All of the above

122. Lactate dehydrogenase is____________?
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A. Zymogen

B. Isozyme

C. Coenzyme

D. Antienzyme

123. Ribosomes are usually associated with______________?
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A. Nucleolus

B. Mitochondria

C. Plasma membrane

D. Endoplasmic reticulum
124. Muscle glycogen cannot contribute directly to blood glucose level because___________?
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A. Absence of glucokinase

B. Muscle does not contain glycogen phosphorylase

C. Muscle lacks glucose 6 phosphatase

D. Muscle lacks phospho gluco isomerase

125. Normal blood PH is______________?
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A. 7.7 8.0

B. 7.0 7.12

C. 6.8 7.0

D. 7.38 7.4
127. The precursor of testosterone is_____________?
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A. Methyl testosterone

B. Pregnenolone

C. Estrogen

D. Aldosterone

128. In glycolysis ATP is produced by the following enzyme______________?
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A. Hexokinase

B. Phosphoglycerate kinase

C. Phosphohexose isomerase

D. Enolase

129. Enzyme + coenzyme constitutes_____________?
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A. Protoenzyme

B. Apoenzyme

C. Holoenzyme

D. Proenzyme

130. Normal blood bilirubin level is______________?
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A. 0.5 1 mg%

B. 4 5.5 mg%

C. 1 3 mg%

D. 3 4 mg%

131. Acetyl Co-A acts as a substrate for all the enzymes except______________?
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A. Malonyl CoA synthetase

B. HMG-Co A synthase

C. Fatty acid synthetase

D. Malic enzyme
132. Which of the following is false about starvation ketoacidosis ?
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A. Smell of acetone in breath

B. Metabolic acidosis

C. Rotheras test is +ve

D. Benedicts test +ve
133. The combination of main supporting enzyme is called______________?
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A. Apoenzyme

B. Coenzyme

C. Constitutive enzyme

D. Holoenzyme
134. Which of the following about biological membrane is true ?
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A. Lipid moiety is amphipathic

B. Symmertrical bi leaflet structures

C. Rigid assembly of protein, lipid and carbohydrate

D. Lipid and protein moiety are held by covalent interactions

135. The first product of glycogenolysis is_____________?
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A. Glucose 6 phosphatase

B. Glucose 1,6 diphosphatase

C. Glucose 1- phosphatase

D. Fructose 1- phosphatase

137. The monsaccharide glucose is best described by which one of the following statements ?
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A. It is a ketose

B. It possessesan anomeric C-2 carbon atom

C. It usually exists in the furanose form

D. It formspart of the disaccharide sucrose
138. Insulin increase the following pathways in liver EXCEPT____________?
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A. Protein syntehsis

B. Fatty acid synthesis

C. Glucose synthesis

D. Glycogen synthesis

140. In Cytochrome p450, P stands for____________?
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A. Substrate protiens

B. Pigment

C. Structural proteins

D. Polymer

143. Elevated levels of serum glutamic oxaloacetic transaminase in indicative of______________?
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A. Deficiency of glutamic acid

B. Liver disease

C. Deficiency of oxaloacetic acid

D. All of the above

144. Bilirubin is produced from________________?
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A. Haemoglobin

B. Gall bladder

C. Myoglobin

D. A & B
145. Which of the following is inclusion of cytoplasm ?
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A. Endoplasmic reticulum

B. Golgi body

C. Ribosome

D. Glycogen
146. The most abundant protein present in body is_____________?
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A. Albumin

B. Collagen

C. Globulin

D. Hemoglobin

147. Which of the following combination is correct ?
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A. Thiamine Acyl CoA

B. All of the above

C. Biotin-CO2

D. ATP-Hydrogen

148. Mutation in the oxidative enzymes (peroxisomes) could lead to_______________?
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A. Lebers neuropathy

B. Zellwegers syndrome

C. Gauchers disease

D. Epidermolysis bullosa

149. Type II glycogen storage disorder is due to deficiency of______________?
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A. Alpha galactosidase

B. Alpha -Glucosidase

C. Muscle phosphorylase

D. Acid Lipase

150. The uptake of glucose by the liver increase following a carbohydrate meal because____________?
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A. GLUT-2 stimulated by insulin

B. Glucokinase has a low Km for glucose

C. There is increase in phosphorylation of glucose by glucokinase

D. Hexokinase in liver has a high affinity for glucose