Gene transcription Flashcards
Why is mRNA synthesis and translation needed?
- It increases protein efficiency. Each cell only has 1 copy of a gene, lots of RNA molecules can be made from this 1 gene, so lots of proteins are synthesised quickly and simultaneously.
- Facilitates regulation. Regulation of RNA synthesis and function is a key point of regulation
How does mRNA transcription occur?
RNA polymerase binds to the promoter region of DNA near the gene. This catalyses the binding of complementary RNA nucleotides. Many RNA molecules made from 1 gene so lots of proteins made.
How is mRNA process and exported?
It is processed in the nucleus. Primary mRNA is converted into mature mRNA by splicing. mRNA is single stranded so it is not as stable as DNA, to make it stable a 5’ cap and poly-a-tail is added. This helps the mRNA to be exported safely. mRNA can only leave the nucleus if it is fully functional. The nuclear pores will only allow mature mRNA out if all 3 of the correct proteins are present (5’ cap, poly-a-tail and exon junction complex).
What is RNA splicing and how does alternative splicing help development?
RNA splicing is the removal of introns from primary RNA to form mature RNA. The axons are then joined up. The process is catalysed by a splicosome.
Alternative splicing can select particular axons to be expressed and recycle they others, this helps to make new proteins from the same gene. Different alternative splicing can happen at different stages of development.
