lecture #5 protein synthesis Flashcards
what does DNA look like
coiled
what is a gene
segment of DNA
Explain transcription
1) RNA polymerase (enzyme) bind to the gene
2) Rna polymerase copies the information of the gene to make a copy (mRNA)
mRNA IS COMPLEMENTARY TO DNA
3)mRNA (polymerase) detaches from the template strand = becomes a different strand
how is the mRNA compared to DNA
it is complementary, 1 stranded
what is a codon
Series of 3 nucleotides
what is start and stop codon
start codon codes for amino acid, not stop codon
stop codon tells when to stop
start codon = AUG
What is translation
1) mRNA and ribosome bind together
2) anti-codones is brought to the mRNA strand by tRNA (anti-codon bottom amino acid top) codes for the amino acid
3) when 2 amino acids are coded for, ribosome joins them together and moves down
4) the tRNA can then detach to repeat the process but leaves the amino acid behind
5) does this until ribosome gets to the stop codon
how does the polypeptide detach
when stop codon arrives at A site, protein called release factor binds to A site, causes water molecule to be added to hydrolyse chain from tRNA in P site
where are ribosomes made?
Nucleolus
then, ribosomes go to the cytoplasme
what is the difference between proteins synthesised in the cytoplasm vs in the rough ER
In the cytoplasm : protein might end up in the nucleus, mitochondria, peroxisome or stay in cytoplasm
- in rough ER: might be secreted, become integral proteins, remain in the ER golgy apparatus or lysosome
what is the secretory pathway
ER rough —— golgy apparatus (sorts protein) —– lysosome or cell membrane
where does protein synthesis occur (ribosomes)
In the cytoplasm
what is elongation
succession of tRNA and their amino acids as the mRNA is moved through the ribosome one codon at a time
what binds to the gene and copied it
RNA polymerase: enzyme
