Deck 39: The Genetic Code

Question 1

The error frequency of protein synthesis is approximately __________________.

Answer 1

10−4

Question 2

A genetic code which reads 5`CCCACUGUA3` codes for what amino acid sequence?

Answer 2

Pro-Thr-Val

Question 3

The 3` CCA terminal region of tRNA contains the __________________.

Answer 3

acceptor stem

Question 4

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) CCA 3`
b) polysome
c) PPi hydrolysis
d) transcription
e) translation
f) phosphorylated
g) pG
h) two
i) wobble
j) three
k) charged tRNA
l) 30S
m) 20S
In prokaryotic gene expression, _______________ and translation are closely coupled in time and space.

Question 5

Class I aminoacyl-tRNA synthetases acylate the __________________ or 3` hydroxyl group of the terminal adenosine of tRNA.

Question 6

Proteins constitute only __________________ of the mass of ribosomes.

Question 7

The genetic code is __________________, in that some amino acids are coded for by more than one codon .

Question 8

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) CCA 3`
b) polysome
c) PPi hydrolysis
d) transcription
e) translation
f) phosphorylated
g) pG
h) two
i) wobble
j) three
k) charged tRNA
l) 30S
m) 20S
The amino acid is attached to the tRNA molecule at _______________.

Question 9

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) CCA 3`
b) polysome
c) PPi hydrolysis
d) transcription
e) translation
f) phosphorylated
g) pG
h) two
i) wobble
j) three
k) charged tRNA
l) 30S
m) 20S
Hydrolysis of _______________ drives the charging of tRNA with amino acids.

Question 10

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) CCA 3`
b) polysome
c) PPi hydrolysis
d) transcription
e) translation
f) phosphorylated
g) pG
h) two
i) wobble
j) three
k) charged tRNA
l) 30S
m) 20S
Another name for an amino acid ester of tRNA is _______________.

Question 11

Precision of tRNA-mRNA recognition takes place at the first __________________ base pairs of the codon.

Question 12

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) CCA 3`
b) polysome
c) PPi hydrolysis
d) transcription
e) translation
f) phosphorylated
g) pG
h) two
i) wobble
j) three
k) charged tRNA
l) 30S
m) 20S
An I in the first position of the anticodon indicates that _______________ codons can be read by that tRNA.

Question 13

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) CCA 3`
b) polysome
c) PPi hydrolysis
d) transcription
e) translation
f) phosphorylated
g) pG
h) two
i) wobble
j) three
k) charged tRNA
l) 30S
m) 20S
The small subunit of the ribosome is _______________.

Question 14

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) CCA 3`
b) polysome
c) PPi hydrolysis
d) transcription
e) translation
f) phosphorylated
g) pG
h) two
i) wobble
j) three
k) charged tRNA
l) 30S
m) 20S
The term applied to the process of protein synthesis is _______________.

Question 15

Aminoacyl-tRNA synthetases contain both an activation site and an __________________ site.

Question 16

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) CCA 3`
b) polysome
c) PPi hydrolysis
d) transcription
e) translation
f) phosphorylated
g) pG
h) two
i) wobble
j) three
k) charged tRNA
l) 30S
m) 20S
The 5` end of tRNA is _______________.

Question 17

The synthesis of __________________ is the crucial step in protein synthesis.

Question 18

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) CCA 3`
b) polysome
c) PPi hydrolysis
d) transcription
e) translation
f) phosphorylated
g) pG
h) two
i) wobble
j) three
k) charged tRNA
l) 30S
m) 20S
The _______________ hypothesis explains why some tRNA molecules can bind to more than one codon.

Question 19

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) CCA 3`
b) polysome
c) PPi hydrolysis
d) transcription
e) translation
f) phosphorylated
g) pG
h) two
i) wobble
j) three
k) charged tRNA
l) 30S
m) 20S
_______________ is a group of ribosomes bound to a single mRNA.

Question 20

The activation of a tRNA involves the formation of an __________________ intermediate.

Question 21

How is a high level of fidelity maintained in attaching the amino acids to the tRNA structure?

Question 22

Why is it important that transcription and translation are tightly coupled?

Question 23

How much energy is used to attach the amino acid to the tRNA?

Question 24

What is significant about yeast alanyl-tRNA?

Question 25

How does the size of an amino acid influence accurate attachment of the amino acid to the tRNA in aminoacyl-tRNA synthetase reactions?

Question 26

Describe the subunits of E. coli ribosomes.

Question 27

Explain why some bases in RNA cannot be involved in base pairs.

Question 28

What is significant about the direction of transcription and translation?

Question 29

What are some of the features common to tRNA molecules?

A) Each is a single chain with between 73 and 93 ribonucleotides.
B) They contain many unusual bases.
C) About half the nucleotides in tRNA are base-paired.
D) They usually have a pG at the 5′ terminal.
E) All of the above.

Question 30

In preparation for attachment to the tRNA, amino acids are activated by:

A) methylation.
B) adenylation.
C) dimethylation.
D) All of the above.
E) None of the above.

Question 31

Where is the attachment site and where is the anticodon loop with respect to the nucleotide sequence and with respect to the L-shaped structure of tRNA?

Question 32

The rate of translation in E. coli is ________ amino acids per second.

A) 5
B) 20
C) 40
D) 120
E) None of the above.

Question 33

Which of the following components of the tRNA is/are important for the binding specificity of the tRNA synthetase?

A) acceptor stem
B) anticodon loop
C) TΨC loop
D) A and B
E) A, B, and C

Question 34

Which amino acid has only one codon triplet?

A) phenylalanine
B) alanine
C) methionine
D) aspartate
E) None of the above.

Question 35

Accuracy during translation occurs because of:

A) codon degeneracy.
B) wobble at the third site.
C) tRNA specificity in binding the mRNA.
D) aminoacyl tRNA charging.
E) the structure of mRNA and the stability of that molecule.

Question 36

Protein synthesis takes place on:

A) lysozomes.
B) nuclear pores.
C) vacuoles.
D) ribosomes
E) None of the above.

Question 37

The actual three-dimensional structure of tRNA is a(n):

A) L-shape.
B) cloverleaf.
C) twisted triple helix.
D) All of the above.
E) None of the above.

Question 38

What is the amino acid error rate in protein synthesis? Is this rate logical in evolutionary terms of function?

Question 39

The start signal for most organisms is:

A) ATG.
B) AUG.
C) AAA.
D) UAA.
E) AGG.

Question 40

The ribosome is thought to be:

A) an example of a catalyst that has survived from the RNA world.
B) unique to eukaryotes.
C) a ribozyme.
D) A and C.
E) A, B, and C.

Question 41

What role does the ribosomal RNA play in the 70S ribosome structure?

Question 42

What is the theory about how palindromic RNA polymerase transcription termination signals function?

Question 43

What is meant by the statement "Degeneracy minimizes the deleterious effects of mutation"?

Question 44

Give an example of how the treatment of diabetes has benefited from the near universality of the genetic code.