The human chromosomes with the highest and least number of genes in them are respectively:

1

(a)

chromosome 21 and Y

(b)

chromosome 1 and X

(c)

chromosome 1 and Y

(d)

chromosome X and Y

Who amongst the following scientists had no contribution in the development of the double helix model for the structure of DNA?

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(a)

Rosalind Franklin

(b)

Maurice Wilkins

(c)

Erwin Chargaff

(d)

Meselson and Stahl

DNA is a polymer of nucleotides which are linked to each other by 3'-5' phosphodiester bond. To prevent polymerisation of nucleotides, which of the following modifications would you choose?

1

(a)

(a) Replace purine with pyrimidines

(b)

(b) Remove/Replace 3' OH group in deoxyribose

(c)

(c) Remove/Replace 2' OH group with some other group in deoxyribose

(d)

(d) Both 'b' and 'c'

Regulatory proteins are the accessory proteins that interact with RNA polymerase and affect its role in transcription. Which of the following statements is correct about regulatory protein?

1

(a)

They only increase expression

(b)

They only decrease expression

(c)

They interact with RNA polymerase but do not affect the expression

(d)

They can act both as activators and as repressors

Which was the last human chromosome to be completely sequenced:

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(a)

Chromosome 1

(b)

Chromosome 11

(c)

Chromosome 21

(d)

Chromosome X

Which of the following are the functions of RNA?

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(a)

It is a carrier of genetic information from DNA to ribosomes synthesising polypeptides

(b)

It carries amino acids to ribosomes

(c)

It is a constituent component of ribosomes

(d)

All of the above

While analysing the DNA of an organism a total number of 5386 nucleotides were found out of which the proportion of different bases were: Adenine=29%, Guanine=17%, Cytosine=32%, Thymine=17%. Considering the Chargaffs rule it can be concluded that:

1

(a)

it is a double stranded circular DNA

(b)

it is single stranded DNA

(c)

it is a double stranded linear DNA

(d)

No conclusion can be drawn

If Meselson and Stahl's experiment is continued for four generations in bacteria, the ratio of 15_N/15_N :15_N/14_N : 14N/14_N containing DNA in the fourth generation would be:

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(a)

1:1:0

(b)

1:4:0

(c)

0:1:3

(d)

0:1:7

If the sequence of nitrogen base of the coding strand of DNA in a transcription unit is:
5' - A T G A A T G - 3', the sequence of bases in its RNA transcript would be:

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(a)

5' - A  U G A A U G - 3'

(b)

5' - U A C U U A C - 3'

(c)

5' - C A U U C A U -3'

(d)

5' - G U A A G U A - 3'

The RNA polymerase holoenzyme transcribes:

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(a)

the promoter, structural gene and the terminators region

(b)

the promoter,

(c)

the structural gene and the terminators regions

(d)

the structural gene only

If the base sequence of a codon in mRNA is 5' - AUG-3', the sequence of tRNA pairing with it must be:

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(a)

5' - UAC -3'

(b)

5' - CAU -3'

(c)

5' - AUG -3'

(d)

5' - GUA -3'

The amino acid attaches to the tRNA at its:

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(a)

5' - end

(b)

3' - end

(c)

Anti codon site

(d)

DHU loop

To initiate translation, the mRNA first binds to:

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(a)

The smaller ribosomal sub-unit

(b)

The larger ribosomal sub-unit

(c)

The whole ribosomal

(d)

No such specificity exists

The fact that a purine base always paired through hydrogen bonds with a pyrimidine base leads to, in the DNA double helix

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(a)

the antiparallel nature

(b)

the semiconservative nature

(c)

uniform width throughout DNA

(d)

uniform length in all DNA.

The promoter site and the terminator site for transcription are located at

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(a)

3' (downstream) end and 5' (upstream) end, respectively of the transcription unit.

(b)

5' (upstream) end and 3' (downstream) end, respectively of the transcription unit.

(c)

the 5' (upstream) end.

(d)

the 3' (downstream) end.