Biology Chapter 20
CHAPTER NO. 20 BIOLOGY
1)
In semi-conservatives replication
a)
Sequence of original duplex is conserved after one
round of replication
b)
Generate DNA copies of entirely new molecules
c)
Parental DNA become completely dispersed
d)
Each strand of daughter molecules will be a mixture of
old and new
2)
The true E-coli replicating enzyme is
a) DNA polymerase I b) DNA polymerase II
c) DNA polymerase III d) All of the above
3)
Which statement is correct?
a)
Leading strand elongates away from the replication fork
b)
Lagging strand elongates towards the replication fork
c)
Lagging strand elongates away from the replication fork
d)
Both A and B
4)
In alkaptonuria
a)
Patient’s urine contains homogenetisic acid
b)
Urine becomes black
c)
Both A and B
d)
Patient does not produce urine
5)
The sequence of nucleotides that determines the
amino acid sequence of a protein is
a) Chromosome b) DNA
c) RNA d) Gene
6)
Central dogma is
a)
Transfer of information from DNA to mRNA
b)
Basic mechanism of reading and expressing genes
c)
Transfer of information from RNA to proteins
d)
Synthesis of all three types of RNA
7)
In eukaryotes newly synthesized mRNA
a)
Travels a large distance from nucleus to cytoplasm
b)
Is directly released into the cytoplasm
c)
Contains a cap and tail
d)
Both A and C
8)
Which 3 codons are nonsense codons?
a) UAA, UAU, UUA b) UGA,
UAG, UAA
c) UGG, UGA, UAU d) UGG,
UAA, UAG
9)
In mitochondria UGA is / specifies
a) Stop codon b) Tryptophan
c) Initiation codon d) Nonsense codon
10)
Initiation complex in translation is composed of
a)
Ribosome and aminoacyl-tRNa
b)
Ribosome and tRNA
c)
tRNa and aminoacyl-tRNa
d)
None of the above
11)
Examples of chromosomal aberrations are
a) Sickle cell anemia b) Phenylketonuria
c) down’s syndrome d) Both
A and B
12)
Strand
of DNA which is not transcribed is called
a) Antisense b) Template
c) Coding d) None of these
13)
Which is incorrect about nucleosome
a) 2 turns of DNA coiled round b) 8
histones as acidic proteins
c) 200 nucleotides d) None
of these
14)
DNA histone complex is called
a) Nucleotides b) Chromatin
c) Nucleolus d) None
of these
15)
The phenomenon in which heat killed bacteria of
one type could have hereditary effect on bacteria of another type is called:
a) Transaction b) Translocation
c) Transformation d) Transduction
16)
Nucleotides are joined with one another through:
a) Phosphoric acid b) Ribonucleic
acid
c) Deoxyribonucleic acid d) Nucleic
acid
17)
DNA molecule is a / an:
a) Mononucleotide b) Dinucleotide
c) Polynucleotide d) All
of the above
18)
are made up of half RNA and half protein:
a) Ribosomes b) Mitochondria
c) Thylakoid d) Nucleus
19)
When some extra segment of chromosome is found,
is the situation is called:
a) Deletion b) Addition
c) Inversion d) Transduction
20)
Genes are made up of:
a) Histones b) Polynucleotides
c) Hydrocarbons d) Lipoproteins
21)
Beads in chromosomes are formed by:
a)
DNA molecule taking one turn
b)
DNA molecule taking two turns
c)
RNA molecule taking one turn
d)
RNA molecule taking two turns
22)
Which one of the following amino acids replaces
glutamic acid in sickle cell?
a) Valine b) Glycine
c) Lysine d) Alanine
23)
The base sequence on one strand of DNA is
A-T-T-G; the sequence for mRNA is:
a) T-A-A-C b) U-A-A-C
c) A-T-T-G d) T-U-U-C
24)
The potentiality for replication of deoxyribose
nucleic acid depends on
a)
Covalent bonds between bases.
b)
Electrovalent bonds between base and phosphate groups
c)
High energy bonds between phosphate groups
d)
Hydrogen bonds between bases.
25)
The complementary messenger RNA triplet for the
DNA triplet GAT would read
a) CTA b) CTC
c) CUA d) TAG
26)
If 30% of the bases in a DNA molecule are
adenine, what percentage of the bases are guanine?
a) 15% b) 40%
c) 20% d) 70%
27)
Which one of the following statements correctly
describes the transcription of DNA?
a)
It produces amino acids
b)
It results in an increased DNA synthesis
c)
It produces messenger RNA
d)
It is a semi-conservative process
28)
Which of the following basis is never found in
RNA?
a) Adenine b) Uracil
c) Cytosine d) Thymine
29)
Which of the following is involved in the
inter-chain linkage between complementary strands of DNA?
a)
Covalent bonding between the sugar and nitrogenous
bases
b)
Covalent bonding between the sugar and the phosphate
groups
c)
Covalent bonding between adjacent sugar groups
d)
Hydrogen bonding between the nitrogenous bases
30)
The insulin molecule is composed of two
polypeptide chains, one consisting of 20 amino acids and the other consisting
of 31. What is the minimum number of base pairs of DNA required to code for
this molecule?
a) 20 b) 51
c) 102 d) 153
31)
One complete turn of the double helix of DNA
contains 10 pairs of bases and is 3.4 nm long. What is the approximate length
of the DNA coding sequence of lysozyme, a protein of 129 aminoa cids?
a) 132 nm b) 113 nm
c) 66 nm d) 44 nm
32)
What is the effect of the enzyme DNA ligase?
a)
DNA is broken up at specific sites
b)
DNA fragments are joined together
c)
DNA replication occurs
d)
DNA transcription occurs
33)
Chromosomes acquire different shapes such as
that of I, j and v at the time of
a) Prophase b) Metaphase
c) Anaphase d) Interphase
34)
The first evidence of hereditary nature of DNA
was provided by
a) McLeod b) McCarty
c) Griffith
d) Avery
35)
Which of the followings is not true about DNA?
a) C = G b) A = T
c) %G = %C d) %A = %G
36)
One of the followings is not a monomer of RNA
a) Guanine ribonucleotide b) Cytosine
ribonucleotide
c) Cytosine ribonucleotide d) Adenine
deoxyribonucleotide
37)
The enzyme that plays supporting role in DNA
replication
a) DNA polymserase I b) DNA polymerase II
c) DNA polymerase d) DNA
polymerase III
38)
An RNA primer is constructed by
a) DNA polymerase III b) Rna polymerase
c) Primase d) DNA
ligase
39)
Which strand elongates toward the replicating
fork during replication of DNA
a) Lagging strand b) Okazaki fragments
c) Leading strand d) Both
a and c
40)
Genetic code depends on
a) Three nucleotides b) The kind of nucleotide
c) Specific sequence d) All of these
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