Protein Synthesis And Transcription and Translation

Question 1

Transcription (where it occurs, what it is, 3 stages)

Answer 1

Occurs in nucleus, process of making mRNA

1) Initiation
- RNA polymerase binds to molecule (to promoter) , begins to unwind
- RNA polymerase adds complimentary nucleotides

2) Elongation
- complimentary strand of mRNA is produced in a 5’ to 3’

3) termination
- RNA Polymerase recognizes end sequence of gene to be transcribed and released strand

Question 2

Modifications

Answer 2

Addition of 5’ cap
-provides attachment point for ribosome 
-protects
Addition of a Poly-A Tail
-protects
Removal of introns
-nonsense coding that would interfere with functioning of THAT protein

Question 3

Codon

Answer 3

When strand of mRNA is translated, 3 bases corresponds to an amino acid

Question 4

3 major molecules in translation and structures

Answer 4

mRNA

Ribosomes: large and small subunits
A site, P site (peptide bond formed), E site

tRNA: single stranded RNA folded
Anticodon binds to mRNA
terminal arm carries corresponding amino acid

Question 5

3 stages of translation

Answer 5

1) Initiation
- small ribosomal subunit binds to 5’ cap
- moves down strand, start codon reaches P site, large subunit binds and translation begins

2) Elongation
- next tRNA molecule enters A site
- ribosome moves down strand of mRNA and tRNA moves into P and E sites
- P site makes peptide bond

3) termination
- when ribosome reaches stop codon, an enzyme (the release factor) dismantles the complex and translation ends