Biology

Molecular Genetics

917 Questions

Molecular genetics explores the mechanisms of genetic information transfer, including DNA replication, transcription, and translation. It is a core component of biology syllabi. These concepts frequently appear in general science sections of major competitive exams.

DNA replicationTranscription processTranslation processRNA typesCentral dogma

Molecular Genetics Questions

Multiple choice

Which of the following statements about transcription is not correct?

  1. Transcription is the first step of gene expression.

  2. Transcription is a process that involves the transcribing of genetic information from DNA to RNA.

  3. The coding region of a gene is bounded near the 5' end by a start codon.

  4. The regulatory sequence before the coding sequence is called the 3'UTR.

  5. DNA is read from 3'UTR → 5'UTR during transcription.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is correct because the regulatory sequence before the coding sequence is called the five prime untranslated region (5'UTR).

Multiple choice

A nematode Meloidegyne incognitia infects the roots of tobacco plants and causes a great reduction in yield. It can be prevented by RNA interference (RNAi). What does this method involve?

  1. Silencing of a specific DNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA.

  2. Silencing of a specific tRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA.

  3. Silencing of a specific mRNA due to a complementary ssRNA molecule that binds to and prevents translation of the mRNA.

  4. Silencing of a specific mRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA.

  5. Silencing of a specific rRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

RNA interference (RNAi) involves silencing of a specific mRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA.

Multiple choice

Which of the following PCR formats is/are used in the detection of both DNA and RNA viruses?

P. RT-PCR Q. IC-PCR R. IC-RT-PCR

  1. Only P

  2. Only Q

  3. Only R

  4. P and Q

  5. Q and R
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Correct answer. Nucleic acid based detection systems were greatly improved following the development of the polymerase improved following the development of the polymerase chain reaction (PCR). PCR is able to detect pathogens by targeting their genetic material (RNA/DNA). Real time PCR (RT-PCR) is used to combine amplification, detection and quantification in a single step for RNA as target. Immunocapture PCR (IC-PCR) is used to combine the advantages of serology and is a very sensitive method of detection the diseases by targeting both DNA and RNA as genetic material. Multiplex PCR (IC-RT-PCR) allows for simultaneous and sensitive detection of different DNA and RNA as genetic material in the detection of plant diseases in a single reaction.

Multiple choice

Large eukaryotic ribosome’s sub-unit consists of__________.

  1. 23S rRNA + 5S rRNA + 4.5 rRNA + 33 proteins

  2. 23 rRNA + 5.8 S rRNA + 33 proteins

  3. 28S rRNA + 18S rRNA + 41 proteins

  4. 28S rRNA + 5.8S rRNA + 5S rRNA + 49 proteins
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Large eukaryotic ribosome’s sub-unit consists of 28S rRNA + 5.8S rRNA + 5S rRNA + 49 proteins.

Multiple choice

A precise evidence, which states that in particular cases, RNA produces genetic hereditary material comes from the fact that__________.

  1. RNA initially enters genes followed by DNA

  2. when virus particles are extracted individually from infected host, only RNA is present to form infection

  3. RNA is capable of dissociating itself & can enter the genetic materials

  4. RNA codes for DNA, which then produces protein molecules
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A precise evidence, which states that in particular cases, RNA produces genetic hereditary material comes from the fact that RNA codes for DNA, which then produces protein molecules

Multiple choice

RNA directed DNA polymerase is the other name for

  1. RNA polymerase

  2. reverse transcriptase

  3. ribozymes

  4. DNA polymerase

  5. integrase
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Reverse transcriptase, also referred to as RNA-directed DNA polymerase, is an enzyme encoded from the genetic material of retroviruses. It catalyzes the transcription of retrovirus RNA (ribonucleic acid) into DNA (deoxyribonucleic acid). This catalyzed transcription is the reverse process of normal cellular transcription of DNA into RNA, that is why it is called the reverse transcriptase.

Multiple choice

Match the following:

 
RNA polymerase type Responsible for transcription
A. RNA polymerase I 1. hnRNA
B. RNA polymerase II 2. rRNA
C. RNA polymerase III 3. snRNA

  1. A - 1, B - 2, C - 3

  2. A - 2, B - 1, C - 3

  3. A - 2, B - 3, C - 1

  4. A - 3, B - 2, C - 1

  5. A - 3, B - 1, C - 2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct because all are correctly matched. RNA polymerase I transcribes rRNAs (28S, 18S and 5.8S). RNA polymerase II transcribes precursor of mRNA, the heterogeneous nuclear RNA (hnRNA). RNA polymerase III is responsible for transcription of tRNA, 5srRNA and snRNAs (small nuclear RNAs).

Multiple choice

Assertion: In capping, methyl guanosine triphosphate is added to the 3'-end of hnRNA. Reason: In tailing, adenylate residues are added at 5'-end in a template independent manner.

Directions: In the following question, there are two statements, Assertion (A) and Reason (R). Consider both the statements independently and mark your answer as under:

1. A and R both are correct and R is the correct explanation of A.
2. A and R both are correct and R is not the correct explanation of A.
3. A is correct and R is incorrect.
4. A is incorrect and R is correct.
5. A and R both are incorrect.

  1. (1)

  2. (2)

  3. (3)

  4. (4)

  5. (5)
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because in capping, methyl guanosine triphosphate is added to the 5'-end of hnRNA. In tailing, adenylate residues are added at 3'-end in a template independent manner. It is the fully processed hnRNA, now called mRNA, that is transported out of the nucleus for translation.

Multiple choice

r RNA is formed by __________.

  1. DNA

  2. ATP

  3. t RNA

  4. Gene

  5. Nucleolus
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

DNA forms all types of RNA including ribosomal RNA{r RNA}, transfer RNA and m RNA , by the process called as transcription.

Multiple choice

Which of the following PCR formats is/are used in the detection of both DNA and RNA viruses? P. RT-PCR Q. IC-PCR R. IC-RT-PCR

  1. Only P

  2. Only Q

  3. Only R

  4. P and Q

  5. Q and R
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Nucleic acid based detection systems were greatly improved following the development of the polymerase improved following the development of the polymerase chain reaction (PCR). PCR is able to detect pathogens by targeting their genetic material (RNA/DNA). Real time PCR (RT-PCR) is used to combine amplification, detection and quantification in a single step for RNA as target. Immunocapture PCR (IC-PCR) is used to combine the advantages of serology and is a very sensitive method of detection the diseases by targeting both DNA and RNA as genetic material. Multiplex PCR (IC-RT-PCR) allows for simultaneous and sensitive detection of different DNA and RNA as genetic material in the detection of plant diseases in a single reaction.