HYS CH7.3 Translation

Question 1

translation

Answer 1

RNA –> protein

Question 1

types of RNA

Answer 1

mRNA - messenger mRNA created in transcription carries a message to create a protein
- every 3 letters is a codon used to decode amino acids
- has U instead of T

tRNA brings an amino acid corresponding to the mRNA codon
- portion of tRNA that binds is anticodon sequence
- first amino acid for eukaryotes is methionine (AUG)
- first amino acid for prokaryotes is N-formylmethionine, f-Met

rRNA composes structural units of ribosome large and small sub units
- dont code

Question 2

first amino acid in prokaryotes and eukaryotes

Answer 2

• first amino acid for eukaryotes is methionine (me)
• first amino acid for prokaryotes is N-formylmethionine, f-Met

Question 3

ribsome sites

Answer 3

E, P, A

A - new tRNA enters carriing amino acid
A is first letter

P - amimo acid on strand is added to growing peptide chain

E - exit, last tRNA dissociates from ribosome

Question 4

ribosome structure and subunits

Answer 4

rRNAs and proteins
large - containes E, P, A sites
sub - under mRNA and binds first

Question 5

What are the stages of translation?

Answer 5

1. initiation
   small subunit binds to mRNA sequence (under)

in prokaryotes to shine-dalgarno sequence, in eurkaryotes to 5’ cap from posttranscriptional modification

binding signals start of translation
AUG must bind to met, locks large subunit and sites

2. elongation

elongating the peptide chain
aminoacyl-tRNA binds to A site, moved to P via peptidyltransferase

3. termination

3 stop codons (tert-3-termination)
UAA, UGA, UAG

when any one is read a release factor binds to A site to release ribosome

Question 6

what happens to polypeptide chain when its done from translation

Answer 6

now its in the cytosol
chaperone proteins condense it into 3D shape