Transcription
Definition
Transcription is the first step of gene expression, where a segment of DNA is copied into RNA (specifically mRNA) by the enzyme RNA polymerase. This process occurs in the nucleus in eukaryotes and transfers genetic information from DNA to messenger RNA, which then carries the code to ribosomes for protein synthesis.
Key Points for NEET
- 1RNA polymerase synthesizes RNA in 5' to 3' direction
- 2Template strand of DNA is read 3' to 5'
- 3mRNA undergoes processing: capping, splicing, polyadenylation
- 4Occurs in nucleus (eukaryotes) or cytoplasm (prokaryotes)
- 5No primer required unlike DNA replication
Example
The insulin gene being transcribed into mRNA in pancreatic beta cells
Asked in NEET
Related Terms
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More Genetics Definitions
DNA Replication
DNA replication is the biological process by which a DNA molecule makes an identical copy of itself. This semiconservative process ensures that genetic information is accurately transmitted from parent to daughter cells during cell division. Key enzymes include DNA polymerase, helicase, and ligase.
Translation
Translation is the process by which ribosomes decode the mRNA sequence into a polypeptide chain (protein). It involves transfer RNA (tRNA) molecules that bring specific amino acids to the ribosome, where they are joined together in the order specified by the mRNA codons. This occurs in the cytoplasm.
Chromosome
A chromosome is a thread-like structure of DNA and protein found in the nucleus of cells that carries genetic information. Humans have 46 chromosomes (23 pairs). During cell division, chromosomes condense and become visible under a microscope. They contain genes that determine an organism's traits.