Translation

Question 1

What are codons

Answer 1

triplets of nucleotides
genetic code using codons is redundant
one codon = one protein

Question 2

When do prokaryotes and euk translate

Answer 2

Pro = before transcription
Euk = transcriptio in nucleus, translation in cytoplasm

Question 3

How is the order of amino acids during translation chosen

Answer 3

mRNA codons decide the order
tRNA anticodon matches mRNA codons with the comp amino acids

Question 4

what is the tRNA called that attached specific amino acids to their tRNAs

Answer 4

aminoacyl-tRNA synthetases (enzymes)

Question 5

How is tRNA charged for translation use (aminoacylation) process

Activation, binding of tRNA, Transfer, Release

Answer 5

Activation
1) Specific amino acid bind aminoacyl-tRNA synthetase
2) ATP activates amino -> aminoacyl-AMP
3) Pyrophosphte byproduct released

Binding of tRNA
4) tRNA enters active site of aminoacyl-tRNA synthetase
5) Matches anticodon and amino acid (codon) of tRNA

Tranfer
6) enzyme transfers activated amino acid to 3’ end of tRNA
7) AMP released as byproduct

Release
8) tRNA charged and released, ready for translation

Question 6

what sites does the ribosome have that mRNA meets charged tRNA at

Answer 6

Aminoacyl-tRNA (A)
peptidyl-tRNA (P)
exit (E)

Question 7

translation three phases

Answer 7

initiation
elongation
termination

Question 8

Initiation process

Answer 8

Methionine charged tRNA binds to mRNA (ribosomal subunit)

Question 9

Elongation

Answer 9

-Ribosome moves along one codon at a time in 5’ to 3’ direction
-Polypeptides grow from N terminus to C terminus
-Charged tRNA’s bring amino acids to ribosome

Question 10

How is specificity provided during elongation

Answer 10

anticodon (tRNA) - codon (mRNA) interaction
accuracy of aminoacyl-tRNA synthetases

Question 11

what are polysomes

Answer 11

clusters of multiple ribosomes attached to single mRNA strand, simultaneously translating it into protein