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 botany option b: biotechnology and bioinformatics biotechnology in agriculture gm crops transgenic organisms

Which of the following is correctly matched?

  1. Agrobacterium tumefaciens- Tumour

  2. pBR 322- Enzyme

  3. Thermus aquaticus- Bt gene

  4. Ligase- Molecular scissors

  5. Hind II- Plasmid vector
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Agrobacterium tumefaciens contains a Ti plasmid that causes crown gall disease (tumors) in plants. Other options are incorrectly matched; for example, Hind II is a restriction enzyme, not a vector.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Which one of the following hydrolyze internal phosphodiester bonds in a polynucleotide chain?

  1. Lipase

  2. Protease

  3. Exonuclease

  4. Endonuclease
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Endonucleases hydrolyse internal phosphodiester bonds in a polynucleotide chain. Function of nucleases is to break phosphodiester bond. A nuclease is an enzyme capable of cleaving the phosphodiester bonds between the nucleotide subunits of nucleic acids. Nucleases are usually further divided into endonucleases and exonucleases, although some of the enzymes may fall in both categories. 

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Which enzyme act as chromosomal breaks?

  1. DNA polymerase

  2. DNase

  3. DNA ligase

  4. DNA polymerase II
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The enzyme that cause chromosomal breaks are DNase. A deoxyribonuclease or DNase, is any enzyme that catalyzes the hydrolytic cleavage of phosphodiester linkages in the DNA backbone, thus degrading DNA. Deoxyribonucleases are one type of nuclease, a generic term for enzymes capable of hydrolising phosphodiester bonds that link nucleotides.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Molecular scissors which cut DNA at specific site is known as

  1. Pectinase

  2. Polymerase

  3. Restriction endonuclease

  4. Ligase
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A restriction enzyme or restriction endonuclease or molecular scissors is an enzyme used in genetic engineering that splices DNA at or near specific recognition nucleotide sequences, known as restriction sites. Thus, the correct answer is option C.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Match List I with List II and select the correct answer.

List-I(Enzymes) List-II(Characteristic Activity)
a. Terminal transferees $1$. Stable above $90$ degrees C
b. Polynucleotide kinesis $2$. Cleave the ends of linear DNA
c. Taq DNA polymerases $3$ Adds phosphate to $5$ OH end of DNA or RNA
d. Exonucleases $4$. Adds a number of nucleotides to $3'$ end of DNA or RNA
$5$. Regulate the level of super coiling of DNA molecule
  1. A-$5$, B-$4$, C-$1$, D-$2$
  2. A-$4$, B-$3$, C-$1$, D-$2$
  3. A-$3$, B-$4$, C-$5$, D-$1$
  4. A-$4$, B-$3$, C-$2$, D-$1$
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

One of the following enzyme is used to cut genes at specific sites, therefore, useful in recombinant technology

  1. Ligase

  2. Topoisomerase

  3. Pepsin

  4. Restriction endonuclease
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Restriction endonuclease are a part of cellular defense system in bacteria. These enzymes cleave or restrict external or exogenous DNA. A type of these enzymes act on specific palindromic sequences which they recognize.

Multiple choice

What is the last step for gene transfer?

  1. Digestion of gene and vector (by restriction endonuclease)

  2. Isolation of gene and vector (by PCR)

  3. Selection and expression of transgenic construct

  4. Ligation of gene and vector (by DNA ligase)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In gene transfer, the final step is the selection and expression of the transgenic construct to ensure the host organism has successfully incorporated and is expressing the desired gene.