The experimental proof for semiconservative replication of DNA was first shown in a
- Virus
- Fungus
- Plant
- Bacterium
The Correct Option is D
Solution and Explanation
The experimental proof for semiconservative replication of DNA was first demonstrated using bacteria by Matthew Meselson and Franklin Stahl in 1958. They conducted an experiment using the bacterium Escherichia coli (E. coli)
Here is a step-by-step explanation of the process involved:
- The semiconservative model of replication suggests that during DNA replication, the two strands of the DNA molecule separate, and each acts as a template for the synthesis of a new, complementary strand. Thus, each new DNA molecule consists of one original strand and one newly synthesized strand.
- Meselson and Stahl grew E. coli bacteria in a medium containing a heavy isotope of nitrogen, ^{15}N, which was incorporated into the bacterial DNA, making it denser.
- They then shifted the bacteria to a medium containing the normal lighter isotope, ^{14}N. As the bacteria replicated, the newly synthesized DNA incorporated lighter nitrogen.
- They extracted the DNA from the bacteria at various time intervals and subjected it to ultracentrifugation, which allowed them to separate DNA molecules based on density.
- The results showed that after one replication cycle in ^{14}N, all DNA molecules had an intermediate density, indicating that each incorporated an old strand and a newly synthesized strand, consistent with semiconservative replication.
- In successive generations, they observed a hybrid (intermediate density) and a light-band (pure ^{14}N DNA), confirming the model of semiconservative replication.
The significance of this experiment lies in its direct proof of how genetic information is accurately transferred from one generation to the next. The use of the bacterium E. coli made it possible to effectively demonstrate semiconservative DNA replication due to its rapid rate of replication and ease of handling in a laboratory setting.
Thus, the correct answer is: Bacterium.
Top NEET Biology Questions
- In spite of interspecific competition in nature, which mechanism the competing species might have evolved for their survival?
- Which of the following is a correct sequence of steps in a PCR (Polymerase Chain Reaction)?
- Mutations in plant cells can be induced by :
- Chordae tendineae are found in
- Glycolysis takes place in
Top NEET The DNA Questions
- The association of histone H1 with a nucleosome indicates
- Which scientist experimentally proved that DNA is the sole genetic material in bacteriophage ?
- The final proof for DNA as the genetic material came from the experiments of :
- Hind II always cuts DNA molecules at a particular point called recognition sequence and it consists of:
- What is the fate of a piece of DNA carrying only gene of interest which is transfered in to an alien organism?
A. The piece of DNA would be able to multiply itself independently in the progeny cells of the organism.
B. It may get integrated into the genome of the recipient.
C. It may multiple and be inherited along with the host DNA.
D. The alien piece of DNA is not an integral part of chromasame.
E. It shows ability to replicate.
Choose the correct answer from the options given below:
Top NEET Questions
- In spite of interspecific competition in nature, which mechanism the competing species might have evolved for their survival?
- A coil of inductive reactance $31\, \Omega$ has a resistance of 8 $\Omega$. It is placed in series with a condenser of capacitative reactance $25 \,\Omega$. The combination is connected to an a.c. source of 110 V. The power factor of the circuit is :-
- A car starts from rest and accelerates at $5\, m / s ^{2}$ At $t=4\, s$, a ball is dropped out of a window by a person sitting in the car. What is the velocity and acceleration of the ball at $t =6\, s$ ? (Take $\left. g =10\, m / s ^{2}\right)$
- A liquid compound (x) can be purified by steam distillation only if it is
- In an a.c. circuit with phase voltage V and current I, the power dissipated is
Concepts Used:
Discovery of DNA
DNA - Discovery
Many individuals believe that American biologist - "James Watson" and English physicist - “Francis Crick” discovered DNA in the 1950s. Actually, this is not the case. Preferably, DNA was first recognized in the late 1860s by Swiss chemist - “Friedrich Miescher”.
Read More: Structure of DNA
What actually DNA is?
DNA is self-replicating material that exists in every living organism. In easiest terms, it is a carrier of all genetic information. It contains the instructions required for organisms to develop, grow, survive, and reproduce. It’s one of the longest molecules that contain our genetic “code,” or recipe. This recipe is the initial point for our development, but DNA’s interaction with outside impacts such as our lifestyle, environment, and nutrition ultimately forms human beings.
DNA is a composition of molecules known as nucleotides. Each nucleotide comprises a sugar and phosphate group, also nitrogen bases. These nitrogen bases are further tumbledown into four types, including:
- Adenine (A)
- Cytosine (C)
- Guanine (G)
- Thymine (T)