3.10 Protein Synthesis
First review @November 6, 2023
Practise Q's Done
amino acid sequence of a protein is coded for by codons
a section of DNA that contains the complete sequence of codons to code for a whole
protein is called a gene
Transcription
in eukaryotic cells, DNA is contained within double membrane called nuclear envelope
chromosomal DNA is too large to leave the nucleus so it is transcribed to RNA so that
protein synthesis can occur at ribosomes— this process is called transcription
DNA is unwound by DNA helicase enzyme
only one of the two DNA strands contains the gene— this is the sense strand and runs in
the 5’ to 3’ direction
the other strand is complementary to the sense strand and doesn’t code for a protein
— this is the antisense strand and acts as the template strand
the non-coding section of DNA is transcribed to complementary RNA, which is then
a replica of the coding section of DNA (sense strand)
process of transcription:
free RNA nucleotides form hydrogen bonds with complementary bases on the
antisense strand
phosphodiester bonds are formed between the RNA nucleotides by RNA
polymerase
transcription stops at the end of the gene and the completed short strand of RNA is
called messenger RNA (mRNA)— contains the same bases as the sequence of bases
making up the gene however the base uracil on mRNA replaces thymine
mRNA molecule detaches from DNA template strand and leaves the nucleus through
a nuclear pore to travel to a ribosome so that translation can occur and the DNA
double helix reforms
3.10 Protein Synthesis 1
First review @November 6, 2023
Practise Q's Done
amino acid sequence of a protein is coded for by codons
a section of DNA that contains the complete sequence of codons to code for a whole
protein is called a gene
Transcription
in eukaryotic cells, DNA is contained within double membrane called nuclear envelope
chromosomal DNA is too large to leave the nucleus so it is transcribed to RNA so that
protein synthesis can occur at ribosomes— this process is called transcription
DNA is unwound by DNA helicase enzyme
only one of the two DNA strands contains the gene— this is the sense strand and runs in
the 5’ to 3’ direction
the other strand is complementary to the sense strand and doesn’t code for a protein
— this is the antisense strand and acts as the template strand
the non-coding section of DNA is transcribed to complementary RNA, which is then
a replica of the coding section of DNA (sense strand)
process of transcription:
free RNA nucleotides form hydrogen bonds with complementary bases on the
antisense strand
phosphodiester bonds are formed between the RNA nucleotides by RNA
polymerase
transcription stops at the end of the gene and the completed short strand of RNA is
called messenger RNA (mRNA)— contains the same bases as the sequence of bases
making up the gene however the base uracil on mRNA replaces thymine
mRNA molecule detaches from DNA template strand and leaves the nucleus through
a nuclear pore to travel to a ribosome so that translation can occur and the DNA
double helix reforms
3.10 Protein Synthesis 1
