Biology

DNA and Genetics

1,095 Questions

DNA and genetics questions explore molecular biology, DNA replication, and genetic engineering techniques. These topics are essential for various competitive exams requiring a strong foundation in life sciences. Practice these questions to understand complex biological processes thoroughly.

DNA replication mechanismsGenetic engineering techniquesGene editing toolsPolymerase chain reactionDNA sequencing methods

DNA and Genetics Questions

Multiple choice

The vector for transfer of DNA to plants is

  1. T1 plasmid

  2. pBR322

  3. YAC

  4. M13
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Correct. T1 plasmid is used as cloning vector,it is used to deliver to genes of interest into plants. IT is produced by Agrobacterium Tumifaciens.

Multiple choice

If the gene encoding the trp repressor is mutated, such that it can no longer bind tryptophan, then will the transcription of the trp operon occur?

  1. Yes, because the trp repressor can only bind the trp operon and block transcriptional initiation when it is bound to tryptophan.

  2. No, because this mutation does not affect the part of the repressor that can bind the operator.

  3. No, because the trp operon is repressed only when tryptophan levels are high.

  4. Yes, because the trp operon can allosterically regulate the enzymes needed to synthesize the amino acid tryptophan.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

If the repressor can no longer bind tryptophan, then it cannot bind the operator and transcription of the trp operon will always be on, whether tryptophan levels in the cell are high or low.

Multiple choice

Agrobacterium tumefaciens is a serious pathogen that causes crown gall disease. To initiate an infection, it needs to transfer t-DNA into the plant cell. Which of the following secretion mechanisms is used by it to transfer t-DNA?

  1. Type IV secretion mechanism

  2. Type III secretion mechanism

  3. Type II secretion mechanism

  4. Type I secretion mechanism
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

To transfer t-DNA into the plant cell, A. tumefaciens uses a type IV secretion mechanism that involves the production of a T-pilus.

Multiple choice

Which of the following is called hybridisation probe?

  1. Any heavy ds/ss DNA fragment

  2. Any heavy ds/ss RNA fragment

  3. Radioactively labelled DNA/RNA fragment

  4. Heavy element labelled lipid fragment

  5. Heavy isotope labelled protein
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Correct answer. Radioactive DNA/RNA is used to detect desired genes.