D1.2 Protein Synthesis Flashcards
transcription definition
synthesis of messenger RNA using a DNA template
what is rna polymerase
enzyme that catalyses the synthesis of RNA molecules from a DNA template
where does transcription occur
cytoplasm for prokaryotes
nucleus in eukaryotes
process of transcription simple
part of dna unwinds because hydrogen bonds between complementary base pairs break
complementary copy of code from gene is made by building mRNA
RNA nucleotides pair up with complementary bases on unzipped DNA molecule
double stranded dna re-formed when hydrogen bonds between mRNA and DNA strands break
coding strand `
strand of dna that carries the genetic code
not used as template during replication
template strand
opposite dna strand which doesnt carry genetic code
used during transcription to produce mRNA
complementary to coding strand of DNA
role of hydrogen bonds in transcription
broken in dna to unzip it
formed between mRNA strand and DNA strand for complementary base pairing
which strand is transcribed to form MRNA molecule
template strand
to get an rna transcript of coding strand
why is dna is a very stable molecule
due to hydrogen bonding between the DNA bases of the 2 strands and the strong phosphodiester bonds between adjacent nucleotides in each strand
what does sugar phosphate backbone ensure
ensures stability of base sequence
why is stability important
so that genetic code is not prone to spontaneously breaking or changing
allows dna to act as reliable templates for transcription
gene expression
the process by which the information encoded in a gene is used to direct the synthesis of a protein molecule
what to specialised cells do to match requirements of cell
switch them on or off
which genes get switched on
genes that are expressed and undergo transcription and translation
which genes get switched off or silenced
genes that are not expressed and do not go through transcription or translation
translation definition
the information. of mRNA is decoded into proteins
involves taking the genetic code from the mRNA and synthesising a polypeptide
where does translation occur
in the cytoplasm
when does translation occur
after transcription as the mRNA template comes from transcription
what are the parts of a ribosome
2 - big and small
what are ribosomes made of
protein and rRNA
ribosomal rna