Translation

Question 1

What is translation?

Answer 1

Process of converting mRNA codons into an amino acid sequence (protein)

Question 2

What are the main components needed for translation? (5)

Answer 2

mRNA, tRNA, ribosome, amino acids, and energy (ATP/GTP)

Question 3

What is a codon?

Answer 3

A 3-nucleotide sequence on mRNA that codes for one amino acid

Question 4

How many total codons exist?

Answer 4

64 total (61 code for amino acids, 3 are stop codons)

Question 5

What is the start codon and what amino acid does it code for?

Answer 5

AUG → Methionine

Question 6

What are the stop codons?

Answer 6

UAA, UAG, UGA

Question 7

What does “redundancy” in the genetic code mean?

Answer 7

Multiple codons can code for the same amino acid

Question 8

What are the two key regions of a tRNA molecule?

Answer 8

Amino acid attachment site (3′ end) and anticodon

Question 9

What enzyme attaches the correct amino acid to a tRNA?

Answer 9

Aminoacyl-tRNA synthetase

Question 10

What is a “charged tRNA”?

Answer 10

A tRNA molecule with its specific amino acid attached

Question 11

What is the “wobble hypothesis”?

Answer 11

Flexibility in pairing at the third base of a codon allows one tRNA to match multiple codons

Question 12

What are the two ribosomal subunits?

Answer 12

Small (reads mRNA) and large (forms peptide bonds)

Question 13

What are the three tRNA binding sites on a ribosome?

Answer 13

A (aminoacyl), P (peptidyl), and E (exit)

Question 14

What happens during initiation of translation?

Answer 14

Ribosome binds mRNA, tRNA carrying methionine binds start codon, large subunit joins

Question 15

What happens during elongation?

Answer 15

New tRNAs enter A site, peptide bonds form, ribosome shifts, and empty tRNA exits

Question 16

What catalyzes peptide bond formation?

Answer 16

rRNA in the ribosome (acts as a ribozyme)

Question 18

What happens during termination?

Answer 18

Stop codon appears, release factor binds, polypeptide and ribosome are released

Question 19

What is a polysome (polyribosome)?

Answer 19

Multiple ribosomes translating the same mRNA simultaneously

Question 20

How do prokaryotes differ from eukaryotes in translation?

Answer 20

In prokaryotes, transcription and translation occur simultaneously; in eukaryotes, they are separate

Question 21

What is an allosteric protein?

Answer 21

A protein that changes shape when bound to another molecule

Question 22

what is the difference between an inducible operon & a repressible operon?

Answer 22

inducible: typically off and are turned on by an inducer molecule
Repressible: typically on and are turned off by a co-repressor molecule