sci_bio
Protein Synthesis: Transcription & Translation
Chapter summary, hard words and model exam answers for ICSE Class 10 Hindi.
Free online summary and notes (ICSE Class 10 Hindi). Read it here, no PDF download needed.
About the author
Biology · CBSE 10 · ICSE 10 · GCSE (AQA, Edexcel, OCR)
Summary
Proteins are the cell's workers: enzymes, antibodies, haemoglobin, hormones like insulin. Each protein is a chain of amino acids, and the order of those amino acids is written in DNA.
In the nucleus, the enzyme RNA polymerase unzips a gene and reads one DNA strand. It builds a matching mRNA copy, pairing A–U, T–A, G–C, C–G. The mRNA then leaves through a nuclear pore.
The mRNA threads through a ribosome, which reads it three bases (one codon) at a time. tRNA molecules bring the matching amino acids, joining them into a chain until a stop codon ends it.
Four bases in triplets give 64 codons for just 20 amino acids, so most amino acids have more than one codon (the code is degenerate). The same codons mean the same amino acid in nearly all life - the code is universal.
Hard words & meanings
| transcription | the copying of a gene's DNA into messenger RNA in the nucleus |
| translation | the building of a protein from the mRNA codons at the ribosome |
| mRNA | messenger RNA - the copy of a gene that carries the code to the ribosome |
| codon | a group of three mRNA bases that codes for one amino acid or a stop signal |
| tRNA | transfer RNA - brings an amino acid and matches its anticodon to a codon |
| anticodon | three bases on a tRNA that are complementary to an mRNA codon |
| ribosome | the cell structure that reads mRNA and joins amino acids into a protein |
| degenerate code | the feature that most amino acids are coded by more than one codon |
Model exam answers, grammar & audio
You have read the summary. The board-ready model answers, grammar notes, one-touch audio and writing practice for this chapter are part of Lipi©.
Sign in to unlockSee it, understand it, hear it read aloud, then write the exam answer with confidence, for a fraction of a tutor cost.