CHAPTER 6 MOLECULAR BASIS OF INHERITANCE

Transcription

1 CHAPTER 6 MOLECULAR BASIS OF INHERITANCE

2 MOLECULAR BASIS OF INHERITANCES CONTENTS THE DNA THE SEARCH FOR GENETIC MATERIALS REPLICATION TRANSCRIPTION GENETIC CODE

3 MOLECULAR BASIS OF INHERITANCES TRANSLATION REGULATION OF GENE EXPRESSION HUMAN GENOME PROJECT DNA FINGER PRINTING

4 STRUCTURE OF POLY NUCLEOTIDE CHAIN A NUCLEOTIDE HAS THREE COMPONENTS 1. A NITROGENOUS BASES a. PURINES EX- adenine & guanine b. PYRIMIDINES EX- cytosine & thymine Uracil 2. PENTOSE SUGAR deoxyribose & ribose 3. A PHOSPHATE GROUP

5 POLY NUCLEOTIDE CHAIN N B LINKED TO PENTOSE SUGAR THROUGH N- GLYCOSIDIC BOND TO FORM NUCLEOSIDE, WHICH INTURN LINKED TO PHOSPHATE THROUGH PHOSPHOESTER LINKAGE TO FORM NUCLEOTIDE

6 NUCLEOSIDES & NUCLEOTIDES OF DNA NUCLEOSIDES Deoxyadenosine Deoxyguanocine Deoxycytosine Deoxythymidine NUCLEOTIDES Deoxy adenylic acid or damp Deoxy guanylic acid or dgmp Deoxy cytidylic acid or dcmp Deoxy thymidiylic acid or dtmp

7 STRUCTURE OF DNA Two polynucleotide strands running anti parallel Sugar and phosphate Complementary base pairing Chargaff s rule of base equivalence Paired through hydrogen bond 0.34nm. 3.4 nm 10 bp in each turn

8 PACKAGING OF DNA HELIX IN PROKARYOTES THE NEGETIVE CHARGED DNA IS HELD WITH POSITIVE CHARGED SOME PROTEIN TO FORM NUCLEOID IN EUKARYOTES THE NEGETIVE CHARGED DNA IS HELD WITH POSITIVE CHARGED BASIC PROTEINS CALLED HISTONES. THE DNA WRAPPED AROUND AS HISTONE OCTOMER TO FORM NUCLEOSOME.

9 PACKAGING OF DNA HELIX

10 THE SEARCH OF GENETIC MATERIAL TRANSFORMING PRINCIPLE BY- FREDERICK GRIFFITH BIOCHEMICAL CHARACTERISATION OF TRANSFORMING PRINCIPLE THE GENETIC MATERIAL IS DNA HERSHEY & CHASE (1952)

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12 PROPERTIES OF GENETIC MATERIAL IT UNDER GO REPLICATION CHEMICALLY & STRUCTURALLY STABLE UNDERGO MUTATION EXPRESS IT SELF AS CHARACTER

13 REPLICATION COPYING MECHANISM FOR THE GENETIC MATERIAL OR DNA PRODUCE AN EXACT COPY OF ITSELF CALLED REPLICATION REPLICATION IS SEMICONSERVATIVE.

14 STEPS OF REPLICATION ACTIVATION OF NUCLEOTIDE UNWINDING RNA PRIMER ELONGATION TERMINATION

15 TRANSCRIPTION THE PROCESS OF COPYING OF GENETIC INFORMATION FROM ONE STRAND OF DNA INTO RNA IS CALLED TRANSCRITPION. TRANSCRIPTION UNIT

16 TRANSCRIPTION

17 CHARACTERS OF GENETIC CODE Triplet in nature Universal Non-overlapping Degenerate Comma less Non-ambiguous or specific Initiator codon Non-sense or terminator codons

18 trna RNA TRANSFER THE AMINOACIDS FROM AMINOACID POOL IN TO THE SITE OF PROTEIN SYNTHES IS CALLED trna TRANSLATION --The process of polymerisation of amino acids to form polypeptide

19 REGULATION OF GENE EXPRESSION GENE EXPRESSION RESULTS IN THE FORMATION OF POLYPEPTIDES. GENE REGULATED AT 1. TRANSCRIPTIONAL LEVEL 2. PROCESSING OR SPLICING LEVEL 3. TRANSLATIONAL LEVEL

20 REGULATION OF GENE EXPRESSION

21 LAC OPERON CONCEPT (GENE REGULATION)

22 HUMAN GENOME PROJECT GOALS OF HGP METHODOLOGIES SEQUENCING SALIENT FEATURES OF HUMAN GENOME APPLICATION & FUTURE CHALLENGES

23 DNA FINGER PRINTING Technique of sequence of DNA to Identify of individual at DNA level.

24 CET CORNER

25 The bond present between nucleoside and phosphate is a. Phosphoester bond b. Phosphodiester bond c. Hydrogen bond d. Ester

26 Transfer message for synthesis of polypeptides during translation, the sequence is a. DNA, t RNA, r RNA, & amino acids b. DNA, t RNA, & m RNA c. DNA, t RNA,amino acids, r RNA, & m RNA d. DNA, m RNA,t RNA & amino acids

27 A portion of DNA molecule is found to contain 200 Adenine and 200 Thymine nucleotides. The total number of base pairs in this DNA fragment is a b. 200 c. 400 d. 520

28 The Ribose sugar is differ from deoxy ribose sugar is a. Additional -OH group at 2 position b. Additional -OH group at 3 position c. Deletion -OH group at 2 position d. Deletion -OH group at 3position

29 Name the basic amino acids residue are rich in Histones a. Lysines & glutamines b. Lysines & arginines c. Lysines & valines d. Lysines & histamines

30 The region of chromatin are loosely packed & less stained & are referred as a. Euchromatin b. Heterochromatin c. Nucleosome d. Chromosome

31 Which of the following experiment on streptococcus pneumonia has proved conclusively that DNA is the genetic material by Avery et. al., a. DNA from S strain + R-strain alive + DNase b. DNA from S strain + Heat killed R-strain + DNase c. DNA from S strain + R-strain alive + RNase d. Denaturized DNA from S strain + R-strain + protease

32 The average of polymerization of nucleotides by DNA polymerase III during replication has to be approximately a. 2000bp / second b bp/ min c. 5000bp/ second d. 5000bp/min

33 A failure in cell division after DNA replication results a. Aneuploidy b. Trisomy c. Polyploidy d. Monosimics

34 The transcription unit in DNA consists of a. A promoter, non coding, initiators b. A promoter, the structural gene & terminator c. A promoter, the structural gene & RNA d. A promoter, RNA & terminator

35 Match the RNAs listed in column I with their Function given in column II: choose the answer which gives the correct combination of alphabets of two columns Column I Column II A RNA pol I p Joining B RNA pol II q Model of t-rna C RNA pol III r Transcribes rrna D DNA ligase s Transcription of trna. t Precursor of mrna

36 a. A= r; B = t; C = s; D = p. b. A = r ; B=q ; C = p: D = t c. A = r; B = s; C = p; D = t. d. A = t ; B= s; C = p ; D = q

37 A classical example of point mutation is change of single base pair in the gene a. Down s syndrome b. Sickle cell anemia c. Turner s syndrome d. Alkeptanueria

38 The management & analysis of the biological information stored in data base called a. Bio formatics b. Bio computers c. Bio systematic d. Bioinformatics

39 Which RNA is present in minimum amount in a cell? a. t RNA b. m RNA c. r RNA d. both a & c

40 The process which involves removal of introns and joining of exons of m RNA is called a) Ligation b) Cleaving c) Splicing d) modification

41 In DNA double helix model, how far is each base pair from the next base pair. a nm b. 34nm c. 3.4 nm d nm

42 The elongation of the leading strand during DNA synthesis a. Progresses away from the replication fork b. Occurs in the 3¹ 5¹ direction c. Does not require a template strand d. Depends on the action of DNA polymerase

43 DNA molecule has uniform diameter due to a. Double stranded nature b. Presence of phosphate c. Specific base pairing between purine and pyrimidine d. Specific base pairing between purine and purine

44 The genetic material must fulfil the following criteria a. It should able produce its replica b. It should be structurally and chemically stable c. It should not changes that leads to evolution d. It express itself in the form of Mendelian characters. 1. Only A, B and C. 2. Only A and B 3. Only C &D. 4. Only A, B and D

45 Identify correct label for alphabets shown in the diagram of transcription of bacteria a. A- Sigma factor, B- RNA polymerase, C- DNA and D- Rho factor. b. A-RNA polymerase, B- Sigma factor, C- DNA and D- Rho factor c. A- RNA polymerase, B-Sigma factor, C- RNA and D- Rho factor. d. A- Rho factor, B- RNA polymerase, C- RNA and D- sigma factor.

46 Q. If sequence of nitrogen bases on coding strand of transcription unit is 5 -TACGTACGTA-3, identify the sequence of nitrogen bases on corresponding mrna produced by it a. 3 UACGUACGUA-5 b. 3 -AUGCAUGCAU-5 c. 5 -UACGUACGUA-3 d. 5 -AUGCAUGCAU-3

47 Removal of RNA polymerase III from nucleoplasm will affect the synthesis of 1. t-rna 2. m-rna 3. r-rna 4. hn-rna

48 DNA sequence is ATG. What would be the sequence of bases in corresponding anticodon of t-rna 1. ATG 2. AUG 3. UAC 4. TAC

49 Teminism need following enzyme 1. RNA dependent RNA polymerase 2. DNA dependent RNA polymerase 3. DNA dependent DNA polymerase 4. RNA dependent DNA polymerase

50 Gene regulation is exerted at following level or levels a. During transcription b. During processing or splicing c. During the transport of m-rna d. At translational level 1. Only A, B and D Only A, C and D 3. Only A and D 4. All these

51 What would happen if in a gene coding a polypeptide of 50 amino acids, 20th codon (UAC) is mutated to UAG a. A polypeptide of 19 amino acids will be formed. b. Two polypeptides of 19 and 30 amino acids will be formed. c. A polypeptide of 49 amino acids will be formed. d. A polypeptide of 20 amino acids will be formed

52 In the following diagram of t-rna, identify correct labels with alphabets and choose the correct answer a. A- amino acid arm, B- DHU arm, C- anticodon arm, D- Variable arm, b. A- amino acid arm, B- anticodon arm, C- Variable arm and D DHU arm. c. A- amino acid arm, C- anticodon arm, D- Pseudo Uridine arm E Variable arm. d. A- anticodon arm, B- DHU arm, C- anticodon arm, D- Pseudo Uridine arm

53 Which of the statement is true DHU loop recognize ribosome & T psi C loop is synthetase site DHU loop is synthetase site & T psi C loop recognize ribosome DHU loop both synthetase & ribosome T psi C loop recognize both ribosome & synthetase

54 DNA replication occurs during which phase of cell cycle a. G1 phase b. S- phase c. G2 phase d. mitosis

55 Non genetic RNA is a. Only one type b. Two types c. Three types d. Four types

56 The enzymes repair & fills the correct nucleotide during DNA replication is a. DNA polymerase I b. DNA polymerase II c. DNA polymerase III d. Helicase

57 In a double strand DNA contains ten turns, the length of DNA strand is a. 100 nucleotides b. 3.4 nm c. 34 nm d nm

58 The replication of DNA is a. Conservative & bidirectional b. Semi Conservative & bidirectional c. Semi Conservative & unidirectional d. Conservative & unidirectinal

59 Radioactive DNA was allowed to replicate in non radioactive medium for three generation. What % of radioactive DNA at the end of third a. 100 % b. 75 % c. 50 % d. 25 % generation.

60 Which group of codons are in same group a. UAA, UAG, UGG b. UAA, UCC, UGA c. UAA, UCC, GGC d. UAA, UAG, UGA.

61 A gene contains 999 nucleotides (including initiator codon & terminator codon). How many amino acids would be there in polypeptide chain a. 333 b. 332 c. 331 d. 999

62 The 3¹ end of the eukaryotic mrna has a. Cap of GPP b. Poly A tail c. Non coding region d. coding region

63 The number of t RNA is equivalent to a. The number of mrna b. The number of Nucleotides c. Number of protein d. Types of amino acids

64 Which of these are true? a. The mrna of prokaryotes is monocistronic b. The same DNA strand is used for synthesis of all RNAs c. The RNAs synthesized on the two strands of DNA are not the same d. RNAs are modified after their transcription 1) a and c 2) b and d 3) a and b 4) c and d

65 The r RNA of E.coli ribosomes has been found to catalyze peptidyl transferase reaction is a) 16 s r RNA b) 23 s r RNA c) 5 s r RNA d) 28 s r RNA

66 Which of the character is not applicable to t RNA? a. It is the smallest of the RNAs b. It acts as an adaptor for amino acid c. It has a clover leaf like structure d. It bears NODOC

67 Which one of the following statements about genetic code is true? a. In between the codons there are punctuations b. Single amino acid is often coded by more than one triplet codon c. The base of one codon is shared by succeeding codon d. Single triplet codon codes for only one amino acids

68 Which of the following are not involved in the formation of aminoacyl t RNA 1. ATP 2. Initiation factors 3. Aminoacyl t- RNA synthetase 4. GTP molecules a)1 and 2 b) 2 and 4 c) 2 and 3 d) 4 only

69 The strand that is used for transcription a) Sense strand b) Both sense and antisense c) Antisense strand d) Primer

70 During initiation of protein synthesis, The methionine t RNA occupies a. P site and then shift to A site b. E site and then shift to P site c. P site and then leaves after depositing amino acid d. A site and then leaves after depositing amino acid

71 The anticodon of a particular t RNA molecule is a. The part of t RNA that binds to a specific amino acid b. Complementary to the corresponding triplet in DNA c. Complementary to the corresponding m RNA codon d. The part of t RNA that binds to ribosome subunit

72 In the lac-operon model, lactose molecules function as a. Repressors which bind with the operator gene b. Inducers which bind with the operator gene c. Co repressors bind with the repressor protein d. Inducers which bind with the repressor protein

73 Which of these is correct a. One gene can produce several different poly peptides b. Normally several genes code for one Polypeptide c. One gene codes for one polypeptide d. Either (a) or (b)

74 The nitrogen base found in RNA but not in DNA is a) Guanine b) Adenine c) Uracil d) Thymine

75 The central dogma of molecular biology is a. DNA m-rna protein b. m RNA DNA protein c. Polypeptide DNA Protein d. Protein m-rna t-rna

76 In prokaryotes, all genes are together transcribed into a single m-rna such m-rna called a) Polycistronic b) Dicistronic c) Monocistronic d) Non-Cistronic

77 Which of the following enzyme activates the amino acid during protein synthesis a. Peptidyl synthetase b. DNA polymerase c. RNA polymerase d. Aminoacyl synthetase

78 Which gene in Lac- Operon of E.coli forms the repressor protein a) Operator gene b) Regulator gene c) Promoter gene d) Structural gene

79 The genes are switched on in response to presence of inducer are known as a. Inducible gene b. Housekeeping gene c. Operator gene d. Promoter gene

80 Read the following statements and choose the correct answer Statement A: DNA finger printing fails to differentiate identical twins Statement B: They are with same VNTR s 1. Both statement A & B are correct and B is correct reason for A 2. Both statement A & B are correct and B is not correct reason for A 3. Only Statement A is correct and B is wrong 4. Only statement B is correct and A is wrong.

81 In transformation experiment, R-strain is converted in to S-strain by formation of a). Cell wall b. Plasma membrane c. Capsule d. All of these

82 In t-rna the amino acid binds at a. CCA 3¹ b. CUA 3¹ c. CGA 3¹ d. ACA 3¹

83 Select the correct answer /answers from thefollowing A. Ligases: - Joins segments of DNA together B. DNA Polymerase: - cuts DNA C. Helicase: - Breaks the hydrogen bonds between complementary pairs during replication D. Gyrase: - Joins weak hydrogen bonds 1. A, B, C and D, are correct 2. A and B are correct, 3. A and C are correct, 4. A, B, C are correct

84 In lac-operon lac Z gene produce a. Beta galactosidase b.permease c. trans acetylase d.. Repressor protein

85 Part of DNA which contains repetitive sequences are called a. Satellite DNA b. Junk DNA c. Repetitive DNA d. Chromosome

86 Meselson and Stahl proved semi-conservative replication of DNA by experimenting with a. E.coli and heavy isotopes of nitrogen b. E.coli and isotopes of Carbon c. E.coli and radioactive phosphorous d. E.coli and radioactive sulphur

87 Process used for amplification of DNA for finger printing a. Polymerase chain reaction b. southern blotting c. polymorphism d. polyploidy

88 Hershey & Chase worked with viruses, that are called a. Plasmids b. Bacteriophages c. Prions d. viroids

89 In the genetic code dictionary, number of sensible codons are a. 20 b. 61 c. 64 d. 03

90 Breaking of hydrogen bond between complementary nitrogenous bases called a. Melting b. Salting c. Aneling d. Tilting

91 The gene which are constantly express themselves in a cells known as a. Inducible gene b. Housekeeping gene c. Operator gene d. Promoter gene

92 Name the enzymes did not affect during biochemical transformation principle a. DN ases & RN ases b. Proteases & RN ases c. DN ases & proteases d. DN ases & ligases

93 Which of the statement is not true a. DNA contains AGTC b. m- RNA carries the message of DNA c. DNA synthesizes RNA d. RNA is double stranded

94 Which of the following group contains purins a. Guanine cytosine b. Uracil cytosine c. Adenine guanine d. Thymine adenine

95 Organisms having either DNA or RNA as genetic material a) Nostoc b) Bacteria c) viruses d) Eukaryotes

96 In protein synthesis, the first initiator codon codes for a) Phenyl Alanine b) Lysine c) Methionine d) Glycine

97 One gene and one enzyme hypothesis was postulated by a. Beadle and Tatum b. R. Franklin c. Hershey and Chase d. Chargaff

98 DNA and RNA are similar in having a. Similar nucleotides b. Similar pyrimidines c. Similar purines d. Similar sugars

99 Which is not true for genetic code? a. It is universal b. It is degenerate c. It is overlapping d. It is unambiguous

100 THANK YOU