Description : A provitamin D synthesized in human beings is (A) Ergosterol (B) 7-Dehydrocholesterol (C) Cholecalciferol (D) 25-Hydroxycholecalciferol
Last Answer : Answer : B
Description : Provitamin D3 is (A) Cholecalciferol (B) Ergosterol (C) 7-Dehydrocholesterol (D) Ergocaliferol
Last Answer : Answer : C
Description : The ‘Committed step’ in the biosynthesis of cholesterol from acetyl CoA is (A) Formation of acetoacetyl CoA from acetyl CoA (B) Formation of mevalonate from HMG CoA (C) Formation of HMG CoA from acetyl CoA and acetoacetyl CoA (D) Formation of squalene by squalene synthetase
Description : Calcitriol inhibits the conversion of (A) Cholesterol into 7-dehydrocholesterol (B) Cholecalciferol into 1-hydroxycholecalciferol (C) Cholecalciferol into 25-hydroxycholecalciferol (D) 25-Hydroxycholecalciferol into 1,25- dihydroxycholecalciferol
Last Answer : Answer : D
Description : Parathormone is required for the conversion of (A) Cholecalciferol into 1-hydroxycholecalciferol (B) Cholecalciferol into 25-hydroxycholecalciferol (C) 25-Hydroxycholecalciferol into calcitriol (D) Cholesterol into 7-dehydrocholesterol
Description : A hydrocarbon formed in cholesterol synthesis is (A) Mevalonate (B) HMG CoA (C) Squalene (D) Zymosterol
Description : The β-ring of 7-dehydrocholesterol is cleaved to form cholecalciferol by (A) Infrared light (B) Dim light (C) Ultraviolet irridation with sunlight (D) Light of the tube lights
Description : The structure shown below is of (A) Cholecalciferol (B) 25-Hydroxycholecalciferol (C) Ergocalciferol (D) 7-Dehydrocholesterol
Last Answer : Answer : A
Description : One international unit (I.U) of vitamin D is defined as the biological activity of (A) 0.025 µg of cholecalciferol (B) 0.025 µg of 7-dehydrocholecalciferol (C) 0.025 µg of ergosterol (D) 0.025 µg of ergocalciferol VITAMINS 113
Description : Which of the following metabolite integrates glucose and fatty acid metabolism? (A) Acetyl CoA (B) Pyruvate (C) Citrate (D) Lactate
Last Answer : A
Description : The most potent Vitamin D metabolite is (A) 25-Hydroxycholecalciferol (B) 1,25-Dihydroxycholecalciferol (C) 24, 25-Dihydroxycholecalciferol (D) 7-Dehydrocholesterol
Description : In the pathway leading to biosynthesis of acetoacetate from acetyl-CoA in liver, the immediate precursor of aceotacetate is (A) Acetoacetyl-CoA (B) 3-Hydroxybutyryl-CoA (C) 3-Hydroxy-3-methyl-glutaryl-CoA (D) 3-Hydroxybutyrate
Description : The cyclisation of squalene in mammals results in the direct formation of the sterol. (A) Cholesterol (B) Lanosterol (C) Sistosterol (D) Zymosterol
Description : The active transport of ‘Ca’ is regulated by __________ which is synthesized in kidnyes. (A) Cholecalciferol (B) Ergosterol (C) 25-OH cholecalciferol (D) 1, 25-di OH-Cholecalciferol
Description : Cells must constantly manage metabolic pathways, and this is often done by balancing specific biochemical reactions within a pathway. For example, the metabolic product of one pathway may block the formation ... the pathway to prevent a buildup of that specific product. What is this process called?
Last Answer : Feedback inhibition
Last Answer : (B) 1,25-Dihydroxycholecalciferol
Description : In the biosynthesis of cholesterol, the rate limiting enzyme is (A) Mevalonate kinase (B) HMG-CoA synthetase (C) HMG-CoA reductase (D) Cis-prenyl transferase
Description : In the biosynthesis of cholesterol, the step which controls the rate and locus of metabolic regulation is (A) Geranyl pyrophosphate farnesyl pyrophosphate (B) Squalene → lanosterol (C) HMG CoA → mevalonate (D) Lanosterol → 1, 4-desmethyl lanosterol
Description : The rage limiting step cholesterol biosynthesis is (A) Squalene synthetase (B) Mevalonate kinase (C) HMG CoA synthetase (D) HMG CoA reductase
Description : All statements regarding 3-OH-3 methyl glutaryl CoA are true except (A) It is formed in the cytoplasm (B) Required in ketogenesis (C) Involved in synthesis of Fatty acid (D) An intermediate in cholesterol biosynthesis
Description : What reductive biosynthesis pathways need NADPH?
Last Answer : Fatty acid biosynthesis, synthesis of cholesterol, steroid hormones.
Description : The source of all the carbon atoms in cholesterol is (A) Acetyl-CoA (B) Bicarbonate (C) Propionyl-CoA (D) Succinyl-CoA
Description : The acetyl CoA formed on β-oxidation of all long chain fatty acids is metabolized under normal circumstances to (A) CO2 and water (B) Cholesterol (C) Fatty acids (D) Ketone bodies
Description : Acetyl CoA formed from pyruvate can be used for the synthesis of all the following except (A) Glucose (B) Fatty acids (C) Cholesterol (D) Steroid hormones
Description : An enzyme required for the synthesis of ketone bodies as well as cholesterol is (A) Acetyl CoA carboxylase (B) HMG CoA synthetase (C) HMG CoA reductase (D) HMG CoA lyase
Description : Acetyl CoA is not used for the synthesis of (A) Fatty acid (B) Cholesterol (C) Pyruvic acid (D) Citric acid
Last Answer : C
Description : Steroid hormones are synthesised from (A) Cholesterol (B) 7-Dehydrocholesterol (C) Calcitriol (D) 7-Hydroxycholesterol
Description : This interferes with cholesterol absorption (A) Lipoprotein lipase (B) Creatinase (C) 7-dehydrocholesterol (D) β-sitosterol
Description : Insulin regulates fatty acid synthesis by (A) Dephosphorylating of acetyl CoA carboxylase (B) Activating phosphorylase (C) Inhibiting malonyl CoA formation (D) Controlling carnitine-Acyl CoA transferase activity
Description : Formation of acetyl CoA from pyruvate for de novo synthesis of fatty acids requires (A) Pyruvate dehydrogenase complex (B) Citrate synthetase (C) ATP citrate lyase (D) All of these
Description : The coenzyme not involved in the formation of acetyl-CoA from pyruvate is (A) TPP (B) Biotin (C) NAD (D) FAD
Description : The initial step of the citric acid cycle is (A) Conversion of pyruvate to acetyl-CoA (B) Condensation of acetyl-CoA with oxaloacetate (C) Conversion of citrate to isocitrate (D) Formation of α -ketoglutarate catalysed by isocitrate dehydrogenase
Description : Fatty acids can not be converted into carbohydrates in the body, as the following reaction is not possible: (A) Conversion of glucose-6-phosphate into glucose (B) Fructose 1, 6 diphosphate to ... phosphate (C) Transformation of acetyl CoA to pyruvate (D) Formation of acetyl CoA from fatty acids
Description : In the extra mitochondrial synthesis of fatty acids, CO2 is utilized (A) To keep the system anaerobic and prevent regeneration of acetyl CoA (B) In the conversion of malonyl to CoA hydroxybutyryl CoA (C ... of acetyl CoA to malonyl CoA (D) In the formation of acetyl CoA from 1 carbon intermediates
Description : A soluble system for synthesis of fatty acids have been isolated from avian liver, required for the formation of long chain fatty acids by this system is (A) ATP (B) Acetyl CoA (C) NADPH (D) All of these
Description : The formation of citrate from oxalo acetate and acetyl CoA is (A) Oxidation (B) Reduction (C) Condensation (D) Hydrolysis CARBOHYDRATES AND CARBOHYDRATE METABOLISM 17
Description : Fatty acids cannot be converted into carbohydrates in the body as the following reaction is not possible. (A) Conversion of glucose-6-phosphate into glucose (B) Fructose 1,6-bisphosphate to fructose- ... (C) Transformation of acetyl CoA to pyruvate (D) Formation of acetyl CoA from fatty acids
Description : By which of the following means antifungal chemotherapeutic agents may affect fungi? A- Interfere with nuclear division by preventing the aggregation of microtubules needed for mitosis B- ... membrane-bound enzymes like thoseinvolved in nutrient transport and chitin synthesis D- all of these
Last Answer : all of these
Description : The cyclooxygenase isoenzymes COX-1 and COX-2 differ from each other in that (a) They catalyse different pathways in prostanoid biosynthesis (b) COX–1 is inhibited by aspirin but not COX–2 (c) COX–2 is inhibited by ibuprofen but not COX–1 (d) COX–1 is constitutive while COX–2 is inducible
Last Answer : Ans: D
Description : The cyclooxygenase isoenzymes COX-1 and COX-2 differ from each other in that: A. They catalyse different pathways in prostanoid biosynthesis B. COX-1 is inhibited by aspirin but not COX-2 C. COX-2 is inhibited by ibuprofen but not COX-1 D. COX-1 is constitutive while COX-2 is largely
Last Answer : D. COX-1 is constitutive while COX-2 is largely
Description : The metabolite which sustains urea cycle is (A) Ornithine (B) Citrulline (C) Carbamoyl phosphate (D) n-acetyl glutamate
Description : Methylmalonyl CoA is a metabolite of (A) Valine (B) Leucine (C) Isoleucine (D) All of these
Description : The precursor of bile salts, sex hormones and vitamin D is (A) Diosgenin (B) Cholesterol (C) Campesterol (D) Ergosterol
Description : For each of the first 7-acetyl-CoA molecules formed by α-oxidation of palmitic acid, the yield of high energy phosphates is (A) 12 (B) 24 (C) 30 (D) 35
Description : In the biosynthesis of heme, condensation between succinyl CoA and glycine requires (A) NAD+ (B) FAD (C) NADH + H+ (D) B6-phosphate
Description : In the biosynthesis of the iron protoporphyrin, the product of the condensation between succinyl-CoA and glycine is (A) α-Amino β-ketoadipic acid (B) δ-Aminolevulinate (C) Hydroxymethylbilane (D) Uroporphyrinogen I
Description : In the biosynthesis of triglycerides from glycerol 3-phosphate and acyl-CoA, the first intermediate formed is (A) 2-Monoacylglycerol (B) 1, 2-Diacylglycerol (C) Lysophosphatidic acid (D) Phosphatidic acid
Description : The rate limiting step in cholesterol biosynthesis is one of the followings : (A) LDL-receptor concentration (B) VLDL secretion (C) Mevalonic acid formation (D) Co-enzyme A formation
Last Answer : (C) Mevalonic acid formation
Description : The following is not true of the cytochrome P450 isoenzyme CYP2D6: A. It generates the hepatotoxic metabolite N-acetyl benzoquinone immine from paracetamol B. It is involved in demethylation of ... for poor capacity to hydroxylate many drugs including metoprolol D. It is inhibited by quinidine
Last Answer : A. It generates the hepatotoxic metabolite N-acetyl benzoquinone immine from paracetamol
Description : N-acetyl cysteine is beneficial in acute paracetamol poisoning because: A. It reacts with paracetamol to form a nontoxic complex B. It inhibits generation of the toxic metabolite of ... scavenger D. It replenishes hepatic glutathione which in turn binds the toxic metabolite of paracetamol
Last Answer : D. It replenishes hepatic glutathione which in turn binds the toxic metabolite of paracetamol