Translation I

Question 1

What is the Central Dogma?

Answer 1

DNA makes RNA makes Protein

Question 2

How is information in prokaryotes organized?

Answer 2

Genes are tightly spaced, dont have exons, and genes with related functions are often coded on the same mRNA

Question 3

What performs Translation? What direction?

Answer 3

Ribosomes on mRNA and it occurs in the 5’ to 3’ direction

Question 4

What are the stop codons?

Answer 4

UAA, UGA and UAG

Question 5

What does a stop codon do?

Answer 5

Tells a ribosome where to stop making a protein at

Question 6

What is a start codon? What does it code for?

Answer 6

AUG and codes of methionine

Question 7

What does the start codon do?

Answer 7

Starting point for translation

Question 8

What is the first amino acid in prokaryotes?

Answer 8

Modified form of methionine called formyl-methionine (f-met)

Question 9

What is the rate of translation in bacteria?

Answer 9

Roughly the same as transcription (45-50 bases or 15-17 aa per second)

Question 10

What does the 5’ end correspond to?

Answer 10

The amino end of the protein

Question 11

What does the 3’ end correspond to?

Answer 11

The carboxyl end of the protein

Question 12

Polysome

Answer 12

Multiple ribosomes performing translation on a single mRNA

Question 13

Where do we see polycistronic mRNAs? What does it mean?

Answer 13

Prokaryotic mRNAS. Carry coding for more than one protein.

Question 14

What are codons?

Answer 14

Three base sequences in the mRNA

Question 15

What are anticodons?

Answer 15

Complementary three base sequences in the tRNA. When paired int he ribosome, they are antiparallel to codons.

Question 16

What is the wobble position?

Answer 16

The base at the 3’ end of the codon (5’ on the anticodon)

Question 17

On the anticodon, what can occupy the wobble position?

Answer 17

Inosine, which then pairs with A,C, or U.

Question 18

What does the inosine allow for?

Answer 18

The cell to make fewer tRNAs for the given amino acid.

Question 19

Where are Amino acids attached to on the tRNA?

Answer 19

3’ end

Question 20

What are the three sites for binding/holding/releasing tRNA’s on a ribosome?

Answer 20

A, P and E sites. They correspond in the order tRNA moves through them. (Unless it is the first one in translation initiation, then it starts at P)

Question 21

Two types of ribosomes

Answer 21

Large and small subunits

Question 22

How big is a large subunit ribosome?

Answer 22

(50s in prokaryotes and 60s in eukaryotes

Question 23

How small is a small subunit ribosome?

Answer 23

30s in prokaryotes and 40s in eukaryotes

Question 24

How do tRNA appear in 3d?

Answer 24

Bent

Question 25

How many steps are there to translation? What are they?

Answer 25

4 - Activation, Initiation, Growth, Termination

Question 26

What three steps are performed in the ribosome?

Answer 26

Initiation, growth, termination

Question 27

aminoacyl-tRNA synthetase enzymes

Answer 27

Covalently attaches proper amino acid to each tRNA for activation. Reads the anti-codon and catalyzes attachment of proper amino acid to the end of the tRNA

Question 28

How many of aminoacyl-tRNA synthetase enzymes are there?

Answer 28

20 - one for each aa

Question 29

How many classes of aminoacyl-tRNA synthetase enzymes are there? How do they differ?

Answer 29

2 - differ by the way they bind to tRNA and which hydroxyl of the ribose ring they attach the amino acid to

Question 30

Class 1 Enzymes do what

Answer 30

attach the aa to the hydroxy on carbon 2

Question 31

Class 2 Enzymes do what

Answer 31

attach the aa to the hydroxy on carbon 3

Question 32

What is the importance of aminoacyl-tRNA synthetase enzymes?

Answer 32

Provides accuracy as inaccuracy would slow translation down.

Question 33

What rRNA is contained by prokaryotes large ribosome?

Answer 33

23S and 5S

Question 34

What rRNA is contained by eukaryotes large ribosome?

Answer 34

28S, 5.8s and 5s

Question 35

What rRNA is contained by prokaryotes small ribosome?

Answer 35

16 s

Question 36

What rRNA is contained by eukaryotes small ribosome?

Answer 36

18s