BiologyCode 9700
Protein synthesis
What this topic asks you to be able to do
- state that a gene, a stretch of nucleotides lying within a DNA molecule, directs the making of a polypeptide
- describe the principle behind the universal genetic code: each triplet of DNA bases either codes for a specific amino acid or stands for a start or stop codon
- describe how polypeptides are built from the information held in DNA through transcription and translation, including what each of these does: ribosomes, codons and anticodons, RNA polymerase, messenger RNA (mRNA), transfer RNA (tRNA)
- state that the DNA strand serving as the template in transcription is termed the transcribed or template strand, while its partner is termed the non-transcribed strand
- account for how, in eukaryotes, the primary transcript, the RNA produced after transcription, is altered: non-coding introns are cut out and coding exons are spliced together to yield mRNA
- state that a gene mutation is an alteration to the sequence of base pairs found in DNA, which may lead to a polypeptide that has changed
- explain that a gene mutation results from the insertion, deletion or substitution of nucleotides in DNA, and outline the possible effect of each type on the polypeptide that is made