E. coli fully labelled with N 15 is allowed to grow in N 14 medium. The two strands of DNA molecule of the first generation bacteria have:

Different density but do not resemble with their parent DNA

Same density resemble with their parent DNA

Same density but do not resemble with their parent DNA

Different density but resemble with their parent DNA

EASY

Earn 100

Which statement explains why DNA replication is described as semi-conservative?

50% studentsanswered this correctly

Important Questions on Molecular Basis of Inheritance

HARD

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

Meselson and Stahl carried out centrifugation in CsCl₂ density gradient to separate:

MEDIUM

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

Which one of the following will be the ratio of heavy, intermediate and light bands in Meselson and Stahl's experiment after two generations if

DNA

replication were conservative?

EASY

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

E. coli fully labelled with

{}^{15}N

is allowed to grow in

{}^{14}N

medium. The two strands of DNA molecule of the first generation bacteria have:

EASY

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

Arrange the following events of the replication of DNA. Choose the correct alternative?
(i) Bonds between complementary bases breaks.
(ii) Bonds between complementary bases forms.
(iii) DNA molecules are uncoiled.
(iv) Opposite strands separate.
(v) Sugar phosphate bonds form.
(vi) Free nucleotides align with the complementary nucleotides on each strand.

EASY

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

Taylor conducted the experiments to prove the semiconservative mode of chromosome replication on:

EASY

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

A mixture of equal numbers of fast and slow dividing cells is cultured in medium containing a trace amount of radioactively labeled thymidine for one hour. The cells are then transferred to regular (unlabeled) medium. After 24hrs of growth in regular media

EASY

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

Experiments involving use of radioactive thymidine to detect distribution of newly synthesized DNA in the chromosome was performed on which plant?

HARD

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

What is the significance of Meselson and Stahl's experiment?

EASY

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

E. coli has only

4.6 \times 10^{6}

base pairs and completes the process of replication within

18

minutes; then the average rate of polymerisation is approximately:

MEDIUM

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

Light DNA

(N^{14})

transferred to

(N^{15})

labelled culture medium for replication. The ratio of total number of

N^{15}

and

N^{14}

labelled strands of DNA extracted from the culture after three generations

HARD

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

An E. coli whose DNA is fully labeled by

^{15} N

is grown in a medium containing

^{14} {NH}_{4} Cl

. What will be the percentage of hybrid

(^{15} N /^{14} N)

and light

(^{14} N /^{14} N)

DNA molecules at the end of

80

minutes (assume that doubling time of E. coli is

20

minutes)?

EASY

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

Semiconservative replication of DNA was first demonstrated in

EASY

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

Matthew Meselson and Franklin Stahl grew E.coli (doubling time is

20 \min

) in medium containing

{}^{15}{NH}_{4} Cl

for many generations. Then the E. coli was transferred to medium containing

{}^{14}{NH}_{4} Cl

. After

40

minutes, the cells were harvested and

DNA

was extracted and subjected to caesium chloride density gradient centrifugation. The proportion of light and hybrid

DNA

densities will be:

EASY

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

The experimental proof for semiconservative replication of DNA was first shown in a

HARD

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

"Use of heavy isotope of nitrogen by Meselson and Stahl demonstrated semi-conservative mode of replication of a DNA molecule." Explain how did they arrive at this conclusion.

HARD

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

Describe the semiconservative method of DNA replication with diagram.

HARD

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

Give an account of Meselson and Stahl's experiment.

EASY

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

Which one of the following elements is not directly involved in transcription?

MEDIUM

Biology>Genetics and Evolution>Molecular Basis of Inheritance>Replication

Choose the correct pair from the following.