Protein synthesis Flashcards
What are the 2 steps involved in protein synthesis
- Transcription
- Translation
Define transcription
Where one gene of the DNA is copied into mRNA
Define translation
Where the mRNA joins with a ribosome, and corresponding tRNA molecules brings the specific amino acid the codon codes for
Where does transcription happen within the cell
Inside the nucleus
Why do we have the create a copy of the gene of interest on the DNA for protein synthesis (2 reasons)
- Because DNA is too big to leave the nucleus
- There are enzymes in the cytoplasm that could damage the DNA
How come mRNA is small enough to leave the nucleus but DNA isn’t
Because mRNA carries the code for one gene whereas DNA carries the code for all the genes
What is the first step in transcription, and name the enzyme
The DNA HELIX UNWINDS to expose the bases to act as a template - unwinding is catalysed by DNA HELICASE
During transcription, how many chains of DNA act as a template, and why is this
Only one because mRNA is single stranded
What type of bonds does DNA helicase break between the bases
Hydrogen bonds
Once DNA helicase has unzipped the DNA strand, what do the free mRNA nucleotides do
They align opposite exposed complementary DNA bases
What is the name of the enzyme that bonds together RNA nucleotides to create a new RNA polymer chain
RNA polymerase
What bonds form between the RNA nucleotides uses the enzyme RNA polymerase
Phosphodiester bonds
What process occurs to change pre-mRNA to mRNA
Splicing
What happens during splicing
The introns are removed
What are introns
The sequences of bases in the DNA which don’t code for amino acids
