DNA and protein synthesis Flashcards
(7 cards)
What is the genome
The complete set of genes in a cell
What is a proteome ?
The full range of proteins that a cell is able to produce
Where does transcription and translation happen ?
Transcription- nucleus
Translation- ribosomes
The process of polypeptide synthesis
The sequence of nucleotides on a gene on DNA acts as a template
A complimentary copy is transcribed onto mRNA acts as a template that is translated into a chain of amino acids using complimentary tRNA which carry specific amino acids which are linked together by in order peptide bonds by condensation reactions ( ATP )
Transcription
The function of transcription is copying the genetic code from DNA to mRNA
Hydrogen bonds between complimentary base pairs of gene to be transcribed are broken the DNA nucleotide bases are now exposed
One strand acts as a template to make an mRNA copy
Free rna nucleotides alongside their complimentary base pair on the template strand of DNA. Uracil replaces thymine on the mRNA
RNA polymerase joins the adjacent nucleotides together with a phosphodiester bond
RNA polymerase continues until it reaches a stop signal and then it detaches
Pre mRNA and splicing
In eukaryotic cells mRNA produced during transcription contains both introns and exons - pre mRNA
Non coding regions (introns) need to be removed because they don’t contain any genetic information that can be translated into an amino acid sequence
The introns are spliced out of the mRNA sequence by an enzyme
This produces a strand of mRNA that contains only exons (the coding regions) this is known as mature mRNA
Translation
mrna attaches to a ribosome
trna anticodons bind to complimentary codons on mrna
trna brungs specific amino acid
two trna can bind simultaneously
adjacent amino acids undergo a condensation reactionand form a peptide bond
first trna detaches and the ribosome moves to the next codon
this continues forming a polypeptide until a STOP codon is reached and the ribosome detaches
