UPSC Prelims 2016 Q31: Science & Technology – Biotechnology & Genetics
In the context of the developments in Bioinformatics, the term 'transcriptome', sometimes
seen in the news, refers to
- (a) a range of enzymes used in genome editing
- (b) the full range of mRNA molecules expressed by an organism
- (c) the description of the mechanism of gene expression
- (d) a mechanism of genetic mutations taking place in cells
Answer: (b) the full range of mRNA molecules expressed by an organism
Explanation
Transcriptome
The transcriptome is the full range of mRNA molecules (RNA transcripts) expressed by a cell or organism at a given time.
It shows which genes are switched on.
| Term | Meaning |
|---|---|
| Genome | The complete set of DNA |
| Transcriptome | The complete set of RNA transcripts (mRNA) |
| Proteome | The complete set of proteins |
| Metabolome | The complete set of small metabolites |
The options checked:
| Option | Verdict |
|---|---|
| (a) A range of enzymes used in genome editing | Incorrect; those are tools such as Cas9 |
| (b) The full range of mRNA molecules expressed by an organism | Correct |
| (c) The description of the mechanism of gene expression | Incorrect |
| (d) A mechanism of genetic mutations taking place in cells | Incorrect |
The genome is the same in every cell, but the transcriptome differs from tissue to tissue.
Answer: (b) the full range of mRNA molecules expressed by an organism.
Why each option is right or wrong
- (a) Incorrect. Enzymes used in genome editing are tools, not the transcriptome.
- (b) CORRECT. The transcriptome is the full range of mRNA molecules expressed by an organism.
- (c) Incorrect. It is a set of molecules, not a description of the mechanism of gene expression.
- (d) Incorrect. It has nothing to do with a mechanism of genetic mutations.
Key point
Genome = all DNA; transcriptome = all mRNA expressed; proteome = all proteins. The transcriptome varies by tissue and time.
Remember
Transcriptome = all mRNA of an organism.
Common mistakes
- Confusing transcriptome (RNA) with genome (DNA).
- Reading '-ome' as a process; it means a complete set.
- Thinking the transcriptome is the same in every cell of the body.
Exam tip
The suffix '-ome' means 'the whole set of'. Transcript + ome = all transcripts.
Sources
- NCERT Class XII — Biology (Molecular Basis of Inheritance: transcription)
- National Human Genome Research Institute — Talking Glossary of Genomic and Genetic Terms: Transcriptome