Which one of the following makes use of RNA as a template to synthesize DNA ?
- Reverse transcriptase
- DNA dependent RNA polymerase
- DNA polymerase
- RNA polymerase
The Correct Option is A
Solution and Explanation
Reverse transcriptase is an enzyme found in retroviruses like HIV, and it is capable of reverse transcription, which is the process of using an RNA template to synthesize a complementary DNA strand. This enzyme is essential for the replication of retroviral genomes and is widely used in molecular biology techniques like reverse transcription-polymerase chain reaction (RT-PCR) to convert RNA into DNA for analysis.
So, the correct option is (A): Reverse Transcript
Top Questions on Molecular Basis of Inheritance
Student to attempt either option-(A) or (B):
(A) Write the features a molecule should have to act as a genetic material. In the light of the above features, evaluate and justify the suitability of the molecule that is preferred as an ideal genetic material.
OR
(B) Differentiate between the following:- [(i)] Polygenic Inheritance and Pleiotropy
- [(ii)] Dominance, Codominance and Incomplete dominance
- CBSE CLASS XII - 2025
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Study the given molecular structure of double-stranded polynucleotide chain of DNA and answer the questions that follow.
(a) How many phosphodiester bonds are present in the given double-stranded polynucleotide chain?
(b) How many base pairs are there in each helical turn of double helix structure of DNA? Also write the distance between a base pair in a helix.
(c) In addition to H-bonds, what confers additional stability to the helical structure of DNA?- CBSE CLASS XII - 2025
- Biology
- Molecular Basis of Inheritance
Study the given below single strand of deoxyribonucleic acid depicted in the form of a “stick” diagram with 5′ – 3′ end directionality, sugars as vertical lines and bases as single letter abbreviations and answer the questions that follow.
Name the covalent bonds depicted as (a) and (b) in the form of slanting lines in the diagram.
How many purines are present in the given “stick” diagram?
Draw the chemical structure of the given polynucleotide chain of DNA.- CBSE CLASS XII - 2025
- Biology
- Molecular Basis of Inheritance
Use the given information to select the amino acid attached to the 3′ end of tRNA during the process of translation, if the coding strand of the structural gene being transcribed has the nucleotide sequence TAC.
- CBSE CLASS XII - 2025
- Biology
- Molecular Basis of Inheritance
- Distance between two consecutive base pairs of DNA is \rule{2cm}{0.1mm}
- CBSE Compartment XII - 2025
- Biology
- Molecular Basis of Inheritance
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Concepts Used:
Transcription
The very first stage of gene expression is the procedure of transcription. In this procedure, mRNA is the place where the genetic information is stored which later aids in encoding a protein. In this process, the DNA strand acts as a guide in the making of mRNA. Despite the fact that there is one exception which is adenine base pairs with uracil instead of thymine.
Transcription Unit:
The transcription unit is a set of freshly combined RNA molecules that have been transcribed from DNA. The cause is to encode at least one gene. A protein that has been encoded or encrypted with a DNA transcription unit may have a coding sequence. Transcription has a lower copying fidelity rate when differentiated from DNA replication.
The Stages of Transcription:
The procedure of transcription is enzymatically catalyzed into three steps:
- Initiation
- Elongation
- Termination