Download central dogma

BIOLOGY
BOTANY
MOLECULAR BIOLOGY
MOLECULAR BIOLOGY
z CONCEPT OF GENE.
z GENETIC CODE
z PROTEIN SYNTHESIS
z LAC OPERON
1. THE CENTRAL DOGMA OF
MOLECULAR BIOLOGY MEANS
1.THE FLOW OF INFORMATION FROM DNA TO POLYPEPTIDE THROUGH mRNA .
2.THE FLOW OF INFORMATION FROM DNA TO mRNA THROUGH POLYPEPTIDE.
3.THE FLOW INFORMATION FROM mRNA TO POLYPEPTIDE THROUGH DNA.
4.THE FLOW OF INFORMATION FROM POLYPEPTIDE TO DNA THROUGH mRNA
2. THE SECTION OF DNA WHICH CODES
FOR A SPECIFIC BIOCHEMICAL
FUNCTION IS
1. CISTRON
2. RECON
3. REPLICON
4. CODON
3. WOBBLE HYPOTHESIS PROPOSED BY CRICK WAS TO EXPLAIN
1. NON OVERLAPPING NATURE OF
GENETIC CODE.
2. NON AMBIGUOUS NATURE OF GENETIC CODE.
3. DEGENERACY OF GENETIC CODE.
4. UNIVERSALITY OF GENETIC CODE.
4. DURING TRANSCRIPTION,ENZYME RNA POLYMERASE UTILIZES
THIS STRAND OF DNA AS A TEMPLATE.
1. CODING STRAND
2. SENSE STRAND
3. ANTISENSE STRAND
4.BOTH STRANDS
1
5. WHICH IS THE ENZYME INVOLVED IN ACTIVATION OF AMINO
ACIDS DURING PROTEIN SYSNTHESIS?
1. PEPTIDYL TRANSFERASE
2. AMINOACYL tRNA SYNTHETASE
3. REVERSE TRANSCRIPTASE
4. RNA POLYMERASE
6. IN CASE OF LAC OPERON THE
REGULATOR GENE REGULATES THE
CHEMICAL REACTION IN E.COLI BY
1. INACTIVATING ENZYMES IN THE REAVTION.
2. INHIBITING THE SUBSTRATE IN THE MEDIUM.
3. INHIBITING THE SYNTHESIS OF mRNA.
4. INHIBITING THE FORMATION OF REPRESSOR INDUCER COMPLEX.
7.THE NOBEL PRIZE FOR DISCOVERY
OF ‘SPLIT GENES’’ WAS AWARDED TO
1. JACOB AND MONAD
2. WATSON AND CRICK
3. P. A. SHARP AND R.J. ROBERTS
4. BEADLE AND TATUM.
8.CHOOSE THE CORRECT ANSWER WITH
RESPECT TO STATEMENTS A AND B.
A. GENETIC CODE HAS TRIPLET CODONS.
B. CODON IS A SEQUENCE OF THREE NUCLEOTIDES IN THE
GENETIC MATERIAL WHICH SPECIFIES AN AMINO ACID.
1. STATEMENT A IS CORRECT.
2. STATEMENT B IS CORRECT.
3. BOTH STATEMENTS ARE CORRECT.
4. BOTH STATEMENTS ARE INCORRECT.
9. AFTER TRANSCRIPTION, THE DNA
MOLECULE
1. MOVES TO A RIBOSOME.
2. REPLICATES ITSELF.
3. DISINTEGRATES ITS COMPONENTS.
4. REASSOCIATES TO FORM ITS ORIGINAL STRUCTURE.
2
10. IN A BACTERIAL CELL THE FIRST AMINOACYL tRNA INVOLVED IN
CHAIN INITIATION CARRIES THIS MOLECULE.
1. FORMYLATED METHIONINE
2. METHIONINE
3. PHENYL ALANINE
4. GLUTAMIC ACID
11. IF YOU COMPARE MATURE mRNA MOLECULES
OF E.COLI AND A PEA PLANT, CONCLUSION
YOU ARRIVE AT WOULD BE
1.THE mRNA OF E.COLI IS POLYCISTRONIC AND mRNA OF PEA PLANT IS
MONOCISTRONIC.
2. THE mRNA OF PEA PLANT IS POLYCISTRONIC AND mRNA OF E.COLI IS
MONOCISTRONIC.
3.THE mRNA MOLECULES OF BOTH ORAGANISMS ARE POLYCISTRONIC.
4 THE mRNA MOLECULES OF BOTH ORGANISMS ARE MONOCISTRONIC.
12. WHAT WOULD HAPPEN IF IN A GENE CODING
A POLYPEPTIDE OF 50 AMINO ACIDS, 25TH
CODON (UAC) IS MUTATED TO ‘UAA’?
1. A POLYPEPTIDE OF 24 AMINO ACID
WILL BE FORMED.
2. TWO POLYPEPTIDES OF 24 AND 25 AMINO ACIDS WILL BE FORMED.
3. A POLYPEPTIDE OF 49 AMINO ACIDS WILL BE FORMED.
4. A POLYPEPTIDE OF 25 AMINO ACIDS WILL BE FORMED.
13. THE CAP STRUCURE OF EUKARYOTIC mRNA
IS OF METHYLE GTP AND THE TAIL IS OF
1.METHIONINE
2.FORMYL METHIONINE.
3.POLY A.
4.AUG CODON.
14.ACTIVATION OF AN AMINO ACID DURING
MECHANISM OF TRANSLATION REQUIRES
THE PARTICIPATION OF SPECIFIC
MOLECULE OF
1.mRNA
2.tRNA
3.rRNA
4.vRNA
3
15. THE GENETIC CODE THAT DIRECTS
PROTEIN SYNTHESIS IN HUMANS IS
FOUND IN
1. NO OTHER KIND OF ORGANISM.
2. VIRTUALLY ALL ORGANISMS.
3. ALL ANIMALS BUT NOT PLANTS.
4. ALL EUKARYOTES BUT NOT PROKARYOTES.
16. ASSERTION: IN A HUMAN CELL
TRANSCRIPTION INVOLVES SPLICING.
REASON: EUKARYOTIC GENES ARE SPLIT
GENES.
1. BOTH THE ASSERTION AND REASON ARE
FALSE.
2. THE ASSERTION IS FALSE BUT THE REASON
IS TRUE.
3. BOTH THE ASSERTION AND REASON ARE TRUE BUT REASON IS NOT A
CORRECT EXPLANATION OF ASSERTION.
4. BOTH ASSERTION AND REASON ARE TRUE AND THE REASON IS THE
CORRECT EXPLANATION OF THE ASSERTION.
17. ASSERTION: GENETIC CODE IS
DEGENERATE.
REASON: A SINGLE AMINO ACID MAY BE
SPECIFIED BY TWO OR MORE CODONS.
1.BOTH THE ASSERTION AND REASON ARE FALSE.
2.THE ASSERTION IS FALSE BUT THE REASON IS TRUE.
3.BOTH THE ASSERTION AND REASON ARE TRUE BUT REASON IS NOT A
CORRECT EXPLANATION OF ASSERTION.
4.BOTH ASSERTION AND REASON ARE TRUE AND THE REASON IS THE
CORRECT EXPLANATION OF THE ASSERTION.
18. DIFFERENT PAIRS OF RIBOSOMES OF
A POLYSOME
1.CONTAIN ESSENTIAL AMINO ACIDS.
2.CARRY THE GENETIC CODE WITHIN THEIR CORE.
3.ARE INVOLVED IN TRANSLATING THE SAME mRNA.
4.ARE CENTRAL PART OF tRNA.
4
19.THE AMINO SEQUENCES OF A BACTERIAL PROTEIN
A HUMAN PROTEIN CARRYING SIMILAR FUNCTIONS
ARE FOUND TO BE 60% IDENTICAL .HOWEVER,THE
DNA SEQUENCES OF THE GENES CODING FOR THESE
PROTEINS ARE ONLY 45% IDENTICAL.THIS IS
POSSIBLE BECAUSE
1.PROTEIN SEQUENCE DOES NOT DEPEND ON DNA SEQUENCE.
2.DNA CODONS HAVING DIFFERENT NUCLEOTIDES IN THE THIRD POSITION
CAN CODE FOR SAME AMINO ACIDS.
3.DNA CODONS HAVING DIFFERENT NUCLEOTIDES IN THE SECOND POSITION
CAN CODE FOR SAME AMINO ACIDS.
4.SAME DNA CODONS CAN CODE FOR MULTIPLE AMINO ACIDS.
20. ASSERTION:A GENE IS A SEGMENT OF DNA
THAT CODES FOR A DEFINED BIOCHEMICAL
FUNCTION.
REASON: NATURE OF THE PROTEIN, THERE-FORE DEPENDS UPON
GENETIC MAKEUP.
1.BOTH THE ASSERTION AND REASON ARE FALSE.
2.THE ASSERTION IS FALSE BUT THE REASON IS TRUE.
3.BOTH THE ASSERTION AND REASON ARE TRUE BUT REASON IS NOT A
CORRECT EXPLANATION OF ASSERTION.
4.BOTH ASSERTION AND REASON ARE TRUE AND THE REASON IS THE
CORRECT EXPLANATION OF THE ASSERTION.
5
21. Codons that do not code for amino acids are
1. Phosphates. 2. ATP. 3. Start and stop signals. 4.Nonsense.
22. In genetic coding,triplet codons make possible 64 types of codons. A
doublet codon system would have made possible
1. 64 types of codons. 2. 4 types of codons.
3. 24 types of codons. 4. 16 types of codons.
23.Choose the correct answer wrt statements A and B
A= The interrupted gene of eukaryotes is longer than its final mRNA
and the protein it codes for.
B= Prokaryotic gene is not a split gene.
1. Statement A is correct.
2. Statement B is correct.
3. Both the statements A and B are correct.
4. Both the statements A and B are incorrect.
24. structural genes of the Lac operon
1.Synthesise the repressor protein.
2.Synthesise the enzyme involved in lactose metabolism.
3.Activate tRNA.
4.Determine how fast the operon should function.
25.In split genes the coding sequences are
1.Cistrons 2.Operons. 3.Exons. 4.Introns
26. The inducer which inactivates the repressor by causing configurational
changes to it in the lactose metabolism is
1. Lactose sugar. 2. RNA polymerase
3. Glucose.
4. Promotor site.
27.The messenger RNA formed in Lac operon model from the structural
genes is
1.Polycistronic. 2. Dicistronic.
3.Monocistronic. 4. Acistronic.
28. Enzymes synthesized in Lac operon are
1.Lactose,Galactose,Hexokinase.
2.Permease,Galactose,Lactose.
3.Lactase,Permease,Galactosidase.
4.Permease,Galactosidase,Transacetylase.
29. In Lac operon the repressor comprises
1.DNA. 2. RNA. 3.Protein. 4. Lactose.
6
30.Lac operon model was proposed by
1.Jacob and Monad.
2.Jacob and Watson.
3.Jacob and Wilkins.
4.Jacob and Nirenberg.
31. The region of Lac operon which must be free for structural gene
transcription to occur
1. Operator. 2. Promotor. 3. a Gene. 4. Regulator.
32. mRNA is a complemetary copy of
1. 5’-3’ DNA strand.
2. 3’-5’ DNA strand.
3. antisense DNA strand.
4. tRNA strand.
33. A particular gene has 600 DNA nucleotides;ignoring introns;stop and
Start signals how many polypeptide coded for by this gene?
2.600. 3. 900. 4. 400.
34. Polysomes lack
1.Proteins. 2. mRNA. 3. DNA. 4. t and rRNA.
35.Genes that are involved in turning on or off the transcription of a set of
structural genes are called
1.Polymorphic genes. 2. Operator genes.
3.Redunant genes.
4. Regulatory genes.
36.What will the RNA code,if the DNA codes ATG?
1.ATG. 2.AUG. 3.UAC 4.TAC.
37. The codon for anticodon 3’UUA5’ is
1.5’AAU3’. 2.3’AAU5’. 3.5’AAT3’. 4.3’AAG5’.
38.Amino acid sequence in protein synthesis is decided by
1.tRNA 2.rRNA 3.mRNA 4.DNA.
39. One of these is not associated with termination of protein synthesis
1.UAA. 2. UAG. 3. UGA. 4. AUG.
40. Which of the following is initiation codon?
1.AUG. 2.AUU. 3. UAG. 4.UUU.
7
41. During protein synthesis the anticodon on tRNA pairs with
1. codon on tRNA.
2.codon on mRNA.
2. ribosome unit.
4.codon on rRNA.
42. In the genetic code dictionary,how many codons are used to code for
all the 20 essential amino acids?
1.20. 2.64. 3.61. 4.60.
43. Degeneration of genetic code is attributed to the
1.first member of a codon.
2.second member of a codon.
3.entire codon.
4.third member of a codon.
44. The terminator codons are
1.UAA,UAG,UGA. 2.AUG,UAG,UGA.
3.UAC,UAG,UAG. 4.DCC,UAA,CAC.
45. Which of the following is the Pribnow box?
1.5’TAATTA3’.
2.5’TATAAT3’.
3.5’ATATTA3’.
4.5’AATAAT3’
46.Transcription is initiated by
1. RNA polymerase.
2. DNA polymerase.
3.Kornberg’s enzyme.
4.ligase.
47.After transcription of m RNA,splicing takes place to eliminate
1.exons.
2.introns. 3.mutons. 4.recons.
48. The triplet codon comprising the bases represents
1.protein. 2.amino acid.
3.enzyme. 4.hormone.
49. Genetic code determines
1.structure of proteins.
2.structure of amino acids.
3.sequence of amino acids.
4.metabolic pathways.
50. In lac operon model, the inducer is
1.promotor gene. 2.operon.
3.glucose.
4.lactose.
KEY
21-4, 22-4, 23-3, 24-2, 25-3, 26-1, 27-1, 28-4, 29-3, 30-1,31-1, 32-2,33-1, 34-3, 35-4, 36-3, 37-1,
38-4, 39-4, 40-1, 41-2, 42-3, 43-4, 44-1, 45-2, 46-1, 47-2, 48-2, 49-3, 50-4.
8
9