Home > Uncategorized > Biochemistry M.Sc Re-test Biochemistry M.Sc Re-test Welcome to your Biochemistry Retest M.Sc. Name email Roll Number Phone # an apoenzyme inhibibotor is cyanide Floride ions Antibiotics Chelates None Inhibitor does not effect the affinity of enzyme to substrate Competitive Non competetive Mixed Uncompetitive Irreversible None An example of hydrogen transferring coenzyme is CoA NAD+ Biotin TPP None Factors affecting enzyme activity Concentration pH Temperature All of these None Disulphuran is an inhibitor used as a drug to prevent alcohol consumption is responsible for Blocking alcohol dehydrogenase Block acetaldehyde dehydrogenase Oxidises acetaldehyde dehydrogenase Oxidises alcohol dehydrogenase None Which one of these was used as nerve gas during first world war Diisopropyl fluorophosphate serine protease Disulphuran Floride ions None Glycolysis is inhibited by floride ions by blocking Hexokinase Enolase Glucokinase Isomerase None the inhibotion in which enzyme only binds to the enzyme inhibitor complex not to the free enzyme Mixed inhibition Non-competitive inhibition Uncompetitive inhibition irreversible inhibition None The enzymatic forms that are produced by post translational changes are Allozymes Ribozymes Prozymes Isoforms None Hexokinase and glucokinase are the two isoenzymes responsible for converting glucose to glucose 6 phosphate, they are present in different organs Hexokinase is present in liver Glucokinase is present in muscles Hexokinase is present in muscles both are isozymes and present in muscles and liver None The restriction enzymes bind to and cut the sequences of DNA which usually are random sequences symmetrical about the midpoint not symmetrical about the midpoint antiparallel None Restriction enzymes are isolated from Virus Bacteria Protozoa Fungi None Restriction enzyme that are extracted from different sources having same recognition and restriction site type I Type II Neoschizomeres isoschizoeres None Not true about restriction enzyme type -II they are multienzyme complex their cleavage site is within the restriction site they recognize, modify and cleave DNA None of these None Isoenzymes are Having the same quaternary structures like the enzymes Catalysing different reactions Different forms of an enzyme similar in all properties Chemically, immunologically and electrophoretically different forms of an enzyme None Beta-oxidation of fatty acids occurs in Peroxisome Peroxisome, Mitochondria and ER Mitochondria Peroxisome and Mitochondria None The acetyl CoA is produced in the mitochondria and must be transported into the cytosol for the synthesis of fatty acid. Which of the following is true regarding its transport? Acetyl CoA is diffused from the mitochondrial membrane Acetyl CoA is transported by its specific transporter protein Acetyl CoA is converted into pyruvate, enters into the cytosol and acetyl CoA is regenerated Acetyl CoA is converted into citrate, enters into the cytosol and acetyl CoA is regenerated All are true None the enzyme that transfers malonyl group from co-A to ACP Malonyl co-A ACP transferase Enoyl-ACP reductase Acetyl co-A ACP transacetylase Acyl carrier protein None Enzymes that break the bond between nucleotides and produce the fragments of DNA are Exonucleases Polymerases Endonucleases Hydorlases None The necessary nucleotides are filled in by ---------between okazaki fragments during replication process DNA Pol I DNA Pol II DNA Pol III All None The average rate of base repair rate of Pol I is 100 to 200 nucleotides per second 10 to 20 nucleotides per second 30 to40 nucleotides per second 1000 to 2000 nucleotides per second None Enzyme having 5' to 3' exonuclease activity DNA Pol I DNA Pol II DNA Pol III All DNA Pol I and II only DNA Pol I and III only None Number of hydrogen bonds between adenine and thymine 1 2 3 None All the following statements describing lipids are true except They usually associate by covalent interactions They are structurally components of membranes They are an intracellular energy source They are poorly soluble in H2O None A nucleoside consists of Nitrogenous base Purine + pyrimidine base + sugar + phosphorous Purine or pyrimidine base + phosphorous Purine or pyrimidine base + sugar None A tightly bound cofactor to protein part of an enzyme is coenzyme Apoenzyme Holoenzyme prosthetic group None Deaminase is an enzyme that removes amino group from amino acids, this enzyme belongs to the ----class of enzymes Isomerases Ligases Oxidoreductases Transferases None of these None Which statement is incorrect about Lock and Key Model? The specific enzyme can transform only a specific substrate The active site of an enzyme is a non-flexible structure. The active site does not change before during or even after the reaction. It explains the mechanism of every chemical reaction None β-Oxidation of fatty acids requires all the following coenzymes except CoA FAD NAD NADP None Activation of fatty acids requires all the following except ATP Coenzyme A Thiokinase Carnitine None Phospholipids are important cell membrane components since They have glycerol Form bilayers in water Have polar and non-polar portions Combine covalently with proteins None True about lock and key model of enzyme action specific substrate having definite active site to fit in active site of enzyme active site is not changeable specific substrate for a specific enzyme all are true about lock and key model None Following reagents are required for Sanger sequencing reaction, each reaction should include template DNA, nucleotides, dideoxynucleotides, buffer, DNA polymerase, and Forward AND reverse primers Forward OR reverse primers Forward AND reverse probes Forward OR reverse probes None What is the difference between a deoxyribonucleotide and a dideoxyribonucleotide? A deoxynucleotide is missing a 3'-hydroxyl group on its sugar. A dideoxynucleotide is missing a 3'- hydroxyl group on its sugar. A deoxynucleotide is missing a 5'-phosphate group. A dideoxynucleotide is missing a 5'-phosphate group. A dideoxynucleotide is missing a 2 and 3'-hydroxyl group. Both (i) and (v) None Which of the following is not required for DNA sequencing? Restriction digestion Electrophoresis Cloning Polymerase chain reaction None What are the basic base – specific cleavage sites used in Maxem and Gilbert method? A, T, G, C C, T, A+G, T+C A, G, A+T, G+C G, C, A+G, C+T None The dideoxy method is also known as …………………………… Maxem and Gilbert method Autosequencing Pyrosequencing Sanger’s enzymatic sequencing None The leading strand of a DNA molecule has the following sequence: 5’-CGCATGTAGCGA-3’ 5'-AGCGATGTACGC-3' 5’-GCGTACATCGCT-3’ 3’-GCGTACATCGCT-5’ 3’-AGCGATGTACGC-5’ None What is the main enzyme component of Sanger sequencing? Helicase Polymerase Nuclease Gyrase None Used as chain terminator Exogenous DNA Deoxynucleotides Dideoxynucleotides None