Description : Which of the following regulatory reactions involves a reversible covalent modification of an enzyme? (A) Phosphorylation of serine OH on the enzyme (B) Allosteric modulation (C) Competitive inhibition (D) Non-competitive inhibition
Last Answer : Answer : A
Description : Which one of the following regulatory actions involves a reversible covalent modification of the enzyme? (A) Phosphorylation of ser-OH on the enzyme (B) Allosteric modulation (C) Competitive inhibition (D) Non-competitive inhibition
Description : Which of the following statement(s) is/are true concerning the proliferative phase of wound healing? a. The macrophage is the predominant cell type b. The pink or purple-red appearance of a wound ... amino acids, hydroxyproline and hydroxylysine d. The predominant collagen type in a scar is type 3
Last Answer : Answer: b, c The proliferative phase of wound healing begins with the formation of a provisional matrix of fibrin and fibronectin as part of the initial clot formation. Initially, the provisional ... The principal collagen type scar is type 1, with lesser amounts of type 3 collagen also present
Description : Activation or inactivation of certain key regulatory enzymes is accomplished by covalent modification of the amino acid: (A) Tyrosine (B) Phenylalanine (C) Lysine (D) Serine
Last Answer : Answer : D
Description : Sulphur is made available to the body by the amino acids: (A) Cystine and methionine (B) Taurine and alanine (C) Proline and hydroxyproline (D) Arginine and lysine MINERAL METABOLISM 191
Description : Carnitine is synthesized from (A) Lysine and methionine (B) Glycine and arginine (C) Aspartate and glutamate (D) Proline and hydroxyproline
Description : All the following statement about hydroxyproline are true except (A) There is no codon for hydroxyproline (B) It is present in large amounts in collagen (C) Free proline cannot be hydroxylated to hydroxyproline (D) Hydroxylation of proline residues is catalysed by a dioxygenase
Description : All of the following statements about proline are true except (A) It is an imino acid (B) It can be synthesized from glutamate (C) It can be catabolised to glutamate (D) Free proline can be hydroxylated to hydroxyproline
Description : The amino acid from which synthesis of the protein of hair keratin takes place is (A) Alanine (B) Methionine (C) Proline (D) Hydroxyproline
Last Answer : Answer : B
Description : Regulation of some enzymes by covalent modification involves addition or removal of (A) Acetate (B) Sulphate (C) Phosphate (D) Coenzyme
Last Answer : Answer : C
Description : Which of the following interfere with normal collagen formation or cross-linking? A. Beta-aminopropionitrile. B. Iron chelators. C. Vitamin C depletion. D. Proline analogs (e.g., cis-hydroxyproline). E. D-Penicillamine.
Last Answer : Answer: ABCDE DISCUSSION: Intramolecular and intermolecular cross-links are crucial for collagen structural stability. Formation of cross-links can be inhibited by two ... concentration, proline analogs prevent collagen formation with minimal effects on noncollagenase protein synthesis
Description : Covalent modification of an enzyme generally requires a (A) Hormone (B) cAMP (C) Protein kinase (D) All of these
Description : A ketogenic amino acid among the following is (A) Leucine (B) Serine (C) Threonine (D) Proline
Description : An amino acid required for porphyrin synthesis is (A) Proline (B) Glycine (C) Serine (D) Histidine
Description : An –OH group is present in the side chain of (A) Serine (B) Arginine (C) Lysine (D) Proline
Description : An amino acid having a hydrophilic side chain is (A) Alanine (B) Proline (C) Methionine (D) Serine
Description : The amino terminal of all polypeptide chain at the time of synthesis in E. coli is tagged to the amino acid residue: (A) Methionine (B) Serine (C) N-formyl methinine(D) N-formal serine
Description : I-cell disease results from absence of the following from lysosomal enzymes: (A) Signal sequence (B) Mannose-6-phosphate (C) Sialic acid (D) A serine residue
Description : Phosphorylation is taking place on which amino acid residue?
Last Answer : Serine
Description : Ultraviolet light can damage a DNA strand causing (A) Two adjacent purine residue to form a covalently bounded dimer (B) Two adjacent pyrimidine residues to form covalently bonded dimer (C) Disruption of phosphodiesterase linkage (D) Disruption of non-covalent linkage
Description : Regulation of haem synthesis occurs by (A) Covalent modification (B) Repression - derepression (C) Induction (D) Allosteric regulation
Description : Conversion of pepsinogen to pepsin is (A) Intra molecular rearrangement (B) Breaking of hydrogen bonds (C) Covalent modification (D) Polymerisation
Description : All the following statements about acetyl CoA carboxylase are true except: (A) It is activated by citrate (B) It is inhibited by palmitoyl CoA (C) It can undergo covalent modification (D) Its dephosphorylated form is inactive
Description : Glucose-6-phosphatase and PEP carboxy kinase are regulated by (A) Covalent modification (B) Allosteric regulation (C) Induction and repression (D) All of these
Description : Pyruvate dehydrogenase complex is regulated by (A) Covalent modification (B) Allosteric regulation (C) Both (A) and (B) (D) None of these
Description : Acetyl CoA carboxylase regulates fatty acid synthesis by which of the following mechanism? (A) Allosteric regulation (B) Covalent modification (C) Induction and repression (D) All of these
Description : Give some examples of covalent modification.
Last Answer : Glycogen synthase is inactive, in the phosphorylated state, whereas glycogen phosphorylase is active when phosphorylated.
Description : What is covalent modification?
Last Answer : It means, either addition of a group to the enzyme protein by a covalent bond; or removal of a group by cleaving a covalent bond.
Description : The deficiency of copper decreases the activity of the enzyme: (A) Lysine oxidase (B) Lysine hydroxylase (C) Tyrosine oxidase (D) Proline hydroxylase
Description : Post-transcriptional modification of hnRNA involves all of the following except (A) Addition of 7-methylguanosine triphosphate cap (B) Addition of polyadenylate tail (C) Insertion of nucleotides (D) Deletion of introns
Description : Phospholipase A2 is an enzyme which removes a fatty acid residue from lecithin to form (A) Lecithin fragments (B) Phosphotidic acid (C) Glyceryl phosphate (D) Lysolecithin
Description : Vitamin K is involved in posttranslational modification of the blood clotting factors by acting as cofactor for the enzyme: (A) Carboxylase (B) Decarboxylase (C) Hydroxylase (D) Oxidase
Description : The vitamin required for the formation of hydroxyproline (in collagen) is (A) Vitamin C (B) Vitamin A (C) Vitamin D (D) Vitamin E
Description : Collagen and elastin have the following similarity: (A) Both are triple helices (B) Both have hydroxyproline residues (C) Both have hydrolysine residues (D) Both are glycoproteins
Description : A protein rich in hydroxyproline is (A) Prolamin (B) Procollagen (C) Collagen (D) Proinsulin
Description : The following are true about the oxidation of glucose: a. glycolysis produces 3% of the energy ultimately obtained from glucose b. the first stage of glycolysis involves phosphorylation of glucose to 1,6-fructose biphosphate. c. glucose enters the Kreb's cycle as pyruvate d. all above
Last Answer : all above
Description : Oxidative phosphorylation involves (A) Electron transport system (B) Substrate level phosphorylation (C) Reaction catalyzed by succinic thiokinase in TCA cycle (D) None of the above
Last Answer : (A) Electron transport system
Description : In biotin-containing enzymes, the biotin is bound to the enzyme by (A) An amide linkage to carboxyl group of glutamine (B) A covalent bond with CO2 (C) An amide linkage to an amino group of lysine (D) An amide linkage to α-carboxyl group of protein
Description : The acquisition energy by glucose fermentation requires A.substrate-level phosphorylation B.electron transport of electrons from NADH C.long-chain fatty acid oxidation D.the enzyme formic-hydrogen lyase
Last Answer : A.substrate-level phosphorylation
Description : Most of the energy in aerobic respiration of glucose is captured by A- substrate-level phosphorylation B- electron transport of electrons from NADH C- long-chain fatty acid oxidation D- the enzyme formic-hydrogen lyase
Last Answer : electron transport of electrons from NADH
Description : The organophosphates produce irreversible inhibition of cholinesterase because: A. They bind to an allosteric site of the enzyme resulting in unfavourable conformation of esteratic site to bind ... degradation of enzyme molecules D. They are neither metabolized nor excreted from the body
Last Answer : B. Regeneration time of the phosphorylated enzyme is longer than the turnover time of the enzyme molecules
Description : All the following statements describing lipids are true except (A) They usually associate by covalent interactions (B) They are structurally components of membranes (C) They are an intracellular energy source (D) They are poorly soluble in H2O
Description : Synthesis of polyunsaturated fatty acids involves the enzyme systems: (A) Acyl transferase and hydratase (B) Desaturase and elongase (C) Ketoacyl-CoA reductase and hydratase (D) Dihydroxyacetone phosphate
Description : Hereditary fructose intolerance involves the absence of the enzyme: (A) Aldalose B (B) Fructokinase (C) Triokinase (D) Phosphotriose isomerase
Description : Control of urea cycle involves the enzyme: (A) Carbamoyl phosphate synthetase (B) Ornithine transcarbamoylase (C) Argininosuccinase (D) Arginase
Description : Vitamin K is involved in posttranslational modification of the blood clotting factors by acting as cofactor for the enzyme (A) Carboxylase (B) Decarboxylase (C) Hydroxylase (D) Oxidase
Last Answer : (A) Carboxylase
Description : Human insulins are obtained by the following sources/methods except: A. Cadaver pancreas B. Proinsulin recombinant bacterial C. Precursor yeast recombinant D. Enzyme modification of pork insulin
Last Answer : . Cadaver pancreas
Description : (A) Heterolytic fission involves the breaking of a covalent bond in such a way that both the electrons of the shared pair are carried away by one of t
Last Answer : (A) Heterolytic fission involves the breaking of a covalent bond in such a way that both the electrons of ... IF (A) is incorrect but (R) is correct.
Description : What kind of covalent bond involves an even sharing of electron?
Last Answer : A nonpolar covalent bond involves an even sharing ofelectrons.