CUET UG Biotechnology and its Applications MCQ Practice

This question is based on NCERT Class 12 Biology – Chapter: Microbes in Human Welfare.

A. Citric Acid → Aspergillus niger
Aspergillus niger is a fungus used commercially to produce citric acid, an important organic acid used in the food and pharmaceutical industries.
B. Ethanol → Saccharomyces cerevisiae
Saccharomyces cerevisiae, commonly known as baker's yeast, ferments sugars to produce ethanol and carbon dioxide.
It is widely used in brewing and baking industries.
C. Statins → Monascus purpureus
Monascus purpureus produces statins, which inhibit the enzyme HMG-CoA reductase.
Statins are used to lower blood cholesterol levels.
D. Cyclosporin A → Trichoderma polysporum
Trichoderma polysporum produces Cyclosporin A, an immunosuppressive drug.
It is commonly used to prevent organ transplant rejection.

EcoRI is a restriction endonuclease (restriction enzyme) widely used in recombinant DNA (rDNA) technology.
It recognizes a specific palindromic DNA sequence:
5′GAATTC3′ ​
and cuts the DNA between G and A, producing sticky ends that facilitate the insertion of foreign DNA into vectors.
Recognition and Cleavage Site
5'— G↓AATTC — 3'
3'— CTTAA↑G — 5'
The sticky ends produced by EcoRI are essential for forming recombinant DNA molecules.
Therefore, EcoRI is an enzyme, making Option 3 the correct answer.

Transcription is the process of synthesizing RNA from a DNA template. In bacteria, transcription involves:

DNA-dependent RNA polymerase – synthesizes RNA.
Sigma (σ) factor – recognizes the promoter and initiates transcription.
Rho (ρ) factor – helps terminate transcription in rho-dependent termination.

However, methyl guanosine triphosphate (7-methyl guanosine cap) is not involved in bacterial transcription.

It is added as a 5′ cap to eukaryotic mRNA after transcription (post-transcriptional modification). Bacterial mRNA does not possess a 5′ methyl guanosine cap.