Question

A Bar body is an example of what? A) Constitutive euchromatin B) Facultative heterochromatin c) Constitutive heterochromatin D) Facultative euchromatin What were the conclusions of Franklin's work regarding the structure of DNA? A) The helix contained about 1 bases pertum B) The helix had more than one strand. c) The helix had only one strand D) It did not have a helical structure. 3) According to Chargaff's nie, if the DNA of a species contains 20% adenine, what percent of quanine will it contain? B) C) D) 50% 20% 30% How does DNA differ from RNA? A) RNA has multiple bases attached to the sugar. B) RNA uses a different five-carbon sugar. C) RNA uses only purines. D) RNA has a contains different sized phosphate groups. 5) Attaches adjacent Okazaki fragments, forming a continuous DNA strand. A) DNA ligase B) Topoisomerase C) DNA primase D) DNA polymerasel E) DNA polymerase III 6) The helical shape of the DNA contains major and minor grooves, which assist in the regulating of gene expression. o true false 7) Synthesizes the lagging strand of the DNA.

Answer 1

1. C. Constitutive heterochromatin. Highly condensed and non transcribed region which is permanently inactive region of female x chromosome.

The region contain repetitive DNA sequence.

2. B. X-ray diffraction data was produced by Maurice Wilkins and Rosalind Franklin demonstrated the double helical structure of DNA.

3.D.For double stranded DNA the ratios between adenine and thymine , and guanine and cytosine are constant and equal one . so , 4.B. RNA contain ribose sugar which is pentose sugar

(A + T = (G+C) = 1 A = 20% 20+20= 40% 100% -40% -60 G+C = 60 60 - 30 G =C = 30%

DNA is hexose sugar compound which is 2- deoxy ribose sugar.

5.D. It is DNA polymerase I which fills the gaps and join adjacent okazaki fragments and thus forming continuous stands.The enzyme possess 3'-5' proof reading and 5'-3' exonuclease activity that synthesise continuous stands.

6.True.

The replication and transcription of gene is mediated. By this groves. It is in these major groves protein interact with based.

The specificity of these grooves vary depending on protein

7.synthesis of lagging strand.

Legging strand is the discontinuous strand which had 3'-5' polarity.

The DNA polymerase enzyme can only initiate new strand synthesis in 5'-3' direction (template strand should be 3'-5')The primase enzyme first recognise the parental strand and synthesis RNA primer .

dNTPs are added onto 3' end by DNA polymerase and this initiate synthesis of lagging strand. The primer is extended upto 1000 nucleotide . And when this DNA polymerase encounters the primer at 5' end they get dissociated then the primer gets removed by specialised polymerase enzyme then the gaps are filled and okazaki fragments are joined by DNA polymerase I enzyme and the lagging strand synthesis is completed.