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Mcqs MBBS Exams India
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(Single Best Answer) Question 41: Acetyl Co-A acts as a substrate for all the enzymes except ?
A) HMG-CoA synthase
B) Malic enzyme
C) Malonyl CoA synthetase
D) Fatty acid synthetase
Answer (Select an option above to get the answer):
(Single Best Answer) Question 42: The activity of the following enzymes is affected by biotin deficiency ?
A) Transketolase
B) Dehydrogenase
C) Oxidase
D) Carboxylase
Answer (Select an option above to get the answer):
(Single Best Answer) Question 43: Km of an enzyme is ?
A) Dissociation constant
B) The normal physiological substrate concentration
C) The substrate concentration at half maximal velocity
D) Numerically identical for all isoenzymes that catalyze a given reaction
Answer (Select an option above to get the answer):
(Single Best Answer) Question 44: At the physiological pH the DNA molecules are ?
A) Positively charged
B) Negatively charged
C) Neutral
D) Amphipathic
Answer (Select an option above to get the answer):
(Single Best Answer) Question 45: Cholesterol present in LDL ?
A) Represents primarily cholesterol that is being removed from peripheral cells
B) Binds to a receptor and diffuses across the cell membrane
C) On accumulation in the cell inhibits replenishment of LDL receptors
D) When enters a cell, suppresses activity of acyl-CoA: cholesterol acyltransferase ACAT
Answer (Select an option above to get the answer):
(Single Best Answer) Question 46: A newborn infant refuses breast milk since the 2nd day of birth, vomits on force-feeding but accepts glucose-water, develops diarrhoea on the third day, by the 5th day she is jaundiced with liver enlargement and eyes show signs of cataract. Urinary reducing sugar was positive but blood glucose estimated by glucose oxidation method was found low. The most likely cause is deficiency of ?
A) Galactose-1-phosphate uridyl transferase
B) Beta galactosidase
C) Glucose-6-phosphatase
D) Galactokinase
Answer (Select an option above to get the answer):
(Single Best Answer) Question 47: Various cells respond differently to a second messenger (such as increased cAMP) because they have different ?
A) Receptors
B) Enzymatic composition
C) Nuclei
D) Membrane lipids
Answer (Select an option above to get the answer):
(Single Best Answer) Question 48: Which of the following is LDL lipoprotein ?
A) Apo B 100 & Apo C
B) Apo B 48
C) Apo C
D) Apo A
Answer (Select an option above to get the answer):
(Single Best Answer) Question 49: Which one of the following acts to increase the release of Ca2+ from endoplasmic reticulum ?
A) Inositol triphosphate
B) Parathyroid hormone
C) 1,25-dihydroxy cholecalciferol
D) Diacyglycerol
Answer (Select an option above to get the answer):
(Single Best Answer) Question 50: Xeroderma Pigmentosum is caused due to a group of closely related abnormalities in ?
A) Mismatch repair
B) Base excision repair
C) Nucleotide excision repair
D) SOS repair
Answer (Select an option above to get the answer):