Chapter 17: Gene Expression From Gene to Protein Flashcards
What is transcription?
Conversion of DNA to RNA
What is translation?
Conversion of RNA to Protein
How does DNA encode information for a protein?
Uses nonoverlapping nucleotide words (3 letters each)
What is a template strand?
The strand that is looked at when making an RNA match
What is a codon?
A sequence of 3 DNA or RNA nucleotides
In what direction is DNA read?
3’ —-> 5’
In what direction is mRNA made?
5’ —-> 3’
In what direction is mRNA read?
5’ —-> 3’
What is the start codon?
Where you start reading from
- AUG
What is the stop codon?
Where you stop reading from
- UAA
- UAG
- UGA
What are the 3 stages of transcription and what happens in each one?
- Initiation
- RNA polymerase binds to the promoter on the DNA
- the double helix opens so that the template strand can be read to make mRNA
- Elongation
- mRNA is made in the 5’ to 3’ direction
- Termination
- after the polyadenylation signal (AAUAA) is reached, RNA polymerase detaches
- complete mRNA transcript is released
What are the two things required for mRNA to complete translation in eukaryotes?
A 5’ cap and a Poly-A Tail
What is a 5’ cap?
- extra nucleotides that consist of phosphates
- It is attached to the 5’ end of mRNA
What is a Poly-A Tail?
- a long chain of A nucleotides
- AAAAAAAAA
- It is attached to the 3’ end of mRNA
What’s a secondary purpose of the 5’ cap and the Poly-A Tail?
To protect the protein content within the mRNA strand from degradation