Lecture 29 - Translation and Protein synthesis

Question 1

what are the 5 key players in translation?

Answer 1

1. mRNA (messenger RNAs)
2. tRNA (transfer RNAs)
3. Ribosome
4. codons
5. anticodons

Question 2

what do transfer RNA molecules provide?

Answer 2

-the physical link that decodes the mRNA into the encoded polypeptide

Question 3

what does tRNA do?

Answer 3

-links the mRNA sequence with the amino acid sequence

Question 4

what are codons?

Answer 4

three-nucleotide long sequences

Question 5

what dictates tRNAs?

Answer 5

the mRNA template

Question 6

what does the anticodon loop recognize?

Answer 6

the 3-nt code on the mrNA template

Question 7

why have some bases on the tRNA have been post-transcriptionally modified?

Answer 7

to enhance anticodon recognition and specificity

Question 8

what does the anticodon recognqie?

Answer 8

3-nt codon on the mRNA

Question 9

what does each codon translate to?

Answer 9

one of the 20 amino acids

Question 10

what are the 3 top codons?

Answer 10

1. UAA
2. UAG
3. UGA

Question 11

what is the start codon?

Answer 11

AUG (codes Met)

Question 12

what are aminoacyl-tRNA synthesases responbile for?

Answer 12

first step in decoding

Question 13

what does Aminoacyl-tRNA synthetase do?

Answer 13

links the right amino acid to a tRNA

Question 14

how many aminoacyl-tRNA synthetase for each amino acid?

Answer 14

there is generally one for each of the standard 20 amino aicds

Question 15

how many subunits do ribosomes have?

Answer 15

two subunits

Question 16

what else does the ribosome contain?

Answer 16

proteins

Question 17

how many tRNA binding sites do ribosomes have?

Answer 17

3 binding sites

Question 18

when do polysomes form?

Answer 18

-they form when multiple ribosomes initiate + elongate multiple mRNAs from the same gene

Question 19

what are 4 things that translation involves?

Answer 19

1. initiate
2. elongation
3. termination
4. ribosome recycling

Question 20

how can bacterial translation initiation be regulated?

Answer 20

-interrupting binding of 16S rRNA to SD sequence interferes with bacterial translation

Question 21

what is the 16S rRNA?

Answer 21

-16S rRNA locates the Shine-Dalgarno sequence upstream from the AUG start codon at beginning of open reading frame (ORF)