protein synthesis Flashcards
how are genes expressed?
proteins
what is a gene
a section of a dna which codes for a protein .
made up of nucleotides
what does RNA do in the process of protein synthesis?
transports messages from DNA to ribosomes.
helps produce proteins (t-RNA)
what happens if a gene is faulty?
regular protein is not produced.
functions of proteins
structural regulatory transport defense catalytic contractile
what is each code consisting of?
codon - three nucleotide
characteristics of a dna triplet code are?
redundant/degenerate(more than one can code for a protein)
unambiguous(code for only one aminoacid)
non overlapping(read in groups of three)
universal
the two stages of protein synthesis
- transciption
2. translation
what is transcription ?
base sequences in DNA are copied onto m-rna as codons
what is translation?
codons of m-rna are used to produce proteins
steps of the process of transcription.
- Helicase (an enzyme) attaches to a region of DNA in the template strand.
- the exposed base sequences are bound to complementary nitrogenous bases to form pre-mRNA by the movement of RNA polymerase along the template dna strand.
- pre-mrna is modified.
what is post-transcription modification?
when pre mrna is modified to mrna.
- introns are cut out.
- extrons are bonded to form a shorter mrna .
- mrna is chemicaaly capped (methyl cap)
- poly-A-tail is added
what does t-rna do?
when codons are “read out” from the mrna , trna with the matching anticodon brings the respective amino acid to the site of protein synthesis.
What happens in transcription ?
Sections of DNA are unwound using RNA polymerase, exposing a group of nucleotides.
Complementary bases assemble opposite to the temple strand
Pre mRNA is synthesised
Introns are spliced off from the final mRNA which travels to the ribosome
Where does transcription happen?
5’end -3’ end
