8.4 - Polypeptide Synhesis - Transcription And Splicing Flashcards
(16 cards)
What is transcription?
The process of making pre - mRNA using part of the DNA as a template
What enzyme acts on a specific region of DNA casing the two strands to separate?
DNA helicase
Why do you want to separate the two DNA strands
To expose the nucleotide bases in that region
What is the nucleotide bases on the DNA strand that are being copied called?
Template strand
What pairs with the DNA template strand?
Their complementary nucleotides
What enzyme moves along the strand and joins the nucleotides together to form a pre mRNA molecule?
RNA polymerase
Where do the complementary nucleotides come from?
The pool which is present in the nucleus
What does Adenine (A) join to when making pre mRNA?
Uracil (U)
What happens when the RNA reaches a particular sequence of bases on the DNA called a “stop” triplet code?
It detaches and the production of pre mRNA is then complete
Does slicing happen in both eukaryotic and prokaryotic cells?
No, only in eukaryotic cells
What is pre mRNA spliced into
MRNA
Do exons or introns code for a protein
Only exons
Why do we get rid of introns that dont code for a protein?
Would prevent the synthesis of a polypeptide
Why cant mRNA diffuse out of the nucleus?
To big
If mRNA cant diffuse out of the nucleus how does it get out?
Leaves via a nuclear pore
What happens to the mRNA once it is out the nucleus?
It is attracted to a ribosome which it then attaches to ready for the next stage of the process: translation
