Question 1

What is the name of the nucleotide sequence that helps the 30S ribosomal subunit find the initiation codon on bacterial mRNAs?

Accepted Answer

A) the Watson-Crick sequence 
B) the Hershey-Chase sequence 
C) the Hatch-Slack sequence 
D) the Shine-Dalgarno sequence 
E) the Franklin sequence

Question 2

The surfaces of the two ribosomal subunits that face one another contain the binding sites for the mRNA and incoming tRNAs and are thus of key importance for the function of the ribosomes.The fact that these surfaces consist largely of RNA supports what proposal?

Accepted Answer

A) the proposal that primordial ribosomes were composed solely of proteins 
B) the proposal that primordial ribosomes were composed exclusively of RNA 
C) the proposal that primordial ribosomes were composed exclusively of DNA 
D) the proposal that prokaryotes gave rise to eukaryotes 
E) the proposal that endosymbiosis gave rise to eukaryotes

Question 3

Cells from a tremendously weakened embryo are examined and found to have seriously depleted levels of a number of tRNAs.If the defect resides in an RNA polymerase,which polymerase is most likely to be affected?

Accepted Answer

The answer of Cells from a tremendously weakened embryo are...

Question 4

Beadle and Tatum's research suggested that __________.

Accepted Answer

A) a gene carries the information to build lipids 
B) a gene carries the information to build carbohydrates 
C) a gene carries the information for the construction of a particular enzyme 
D) a gene is made of RNA 
E) a gene is made of DNA

Question 5

What appears to be the original form of most cellular mRNAs?

Accepted Answer

The answer of What appears to be the original form...

Question 6

Modifications to the nucleotides of pre-rRNAs are made _________?

Accepted Answer

A) posttranslationally 
B) pretranscriptionally 
C) posttranscriptionally 
D) postmitotically 
E) premitotically

Question 7

What is responsible for synthesizing hnRNAs?

Accepted Answer

A) RNA polymerase I 
B) RNA polymerase II 
C) RNA polymerase III 
D) reverse transcriptase 
E) general transcription factors

Question 8

Which enzyme,also responsible for siRNA formation,carves miRNAs from their double-stranded,fold-back RNA precursor (pre-miRNA)?

Accepted Answer

A) RNA polymerase 
B) reverse transcriptase 
C) Dicer ribonuclease 
D) DNA polymerase 
E) Mincer ribonuclease

Question 9

Where is the RNA polymerase II phosphorylated during its activation?

Accepted Answer

A) on the N-terminal end of the largest RNA polymerase II subunit 
B) on the central 20 amino acids of the largest RNA polymerase II subunit 
C) on the 3' end of the largest RNA polymerase II subunit 
D) on the 5' end of the largest RNA polymerase II subunit 
E) in the carboxyl-terminal domain (CT
D) of the largest RNA polymerase II subunit

Question 10

Which of the following is not a potential application of the CRISPR-cas9 system?

Accepted Answer

A) DNA insertions 
B) DNA deletions 
C) chromosome rearrangements 
D) RNA interference 
E) genome editing

Question 11

The intermediate stage that the group II introns pass through while undergoing self-splicing is called the _____.

Accepted Answer

A) langolier 
B) lanyard 
C) lariat 
D) lasso 
E) elsesser

Question 12

What appears to be the role of siRNA in destroying the target mRNA upon which it and its associated proteins act?

Accepted Answer

A) It cleaves the target mRNA. 
B) It stabilizes the target mRNA. 
C) It destabilizes the target mRNA's binding to its associated proteins. 
D) It guides the RISC that cleaves the target mRNA to that target mRNA due to its complementarity to that molecule. 
E) It activates the RISC complex ribonuclease.

Question 13

What is the maximum number of tRNAs that a cell would be likely to have?

Accepted Answer

A) 20 
B) 3 
C) 64 
D) 61 
E) 21

Question 14

What was the new name of Beadle and Tatum's hypothesis after it was discovered that some enzymes were composed of more than one polypeptide chain?

Accepted Answer

A) the One Gene - One Enzyme hypothesis 
B) the One Gene - One Polypeptide hypothesis 
C) the One Polypeptide - One Enzyme hypothesis 
D) the One Polypeptide - One Gene hypothesis 
E) the One Gene - Two Gene hypothesis

Question 15

What are the differences between piRNAs on the one hand and si/miRNAs on the other hand?

Accepted Answer

A) piRNAs are longer than si/miRNAs. 
B) The majority of mammalian piRNAs can be mapped to a small number of huge genomic loci,unlike si/mi RNAs. 
C) The formation of piRNAs does not involve the formation of dsRNA precursors,unlike si/mi RNAs. 
D) Formation of piRNAs does not involve cleavage by Dicer ribonuclease,but instead it depends on the endonuclease activity of the PIWI protein acting on a long,single stranded primary transcript. 
E) All of these are correct.

Question 16

How is the RISC directed to the target mRNA that it is destined to destroy?

Accepted Answer

A) The ribonuclease slicer directs the RISC to the cleavage site. 
B) The single-stranded siRNA is complementary to the target mRNA and directs the RISC to it. 
C) The passenger strand acts like a guide to direct the RISC to the target. 
D) The siRNA is complementary to the slicer ribonuclease. 
E) The siRNA is magnetically attracted to the target mRNA.

Question 17

You travel to another planet and discover that its genetic system is based on DNA,but it has 6 bases instead of 4 as happens on Earth.The proteins on the planet have 30 amino acids.What would be the likely number of letters in each codon on this planet?

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 4 
E) 6

Question 18

What is meant by referring to the genetic code as universal?

Accepted Answer

A) The genetic code is the same everywhere in the Universe. 
B) All of the organisms on Earth use the same genetic code with only minor variations. 
C) The genetic code is found in all organisms but varies extensively. 
D) The genetic code is minimal. 
E) The genetic code is multiphasic.

Question 19

What kind of DNA is the DNA that codes for rRNA?

Accepted Answer

A) highly repetitive DNA 
B) moderately repetitive DNA 
C) unique sequence DNA 
D) single copy DNA 
E) single-stranded DNA

Question 20

You have set up a cell-free transcription system in a test tube.By mixing DNA,RNA polymerase,sigma factors,ribonucleotides and other essential substances,you are able to make mRNAs identical to those made under a variety of conditions in the cells from which these components were isolated.What would happen if you were able to remove the sigma factor first added to the tube and replace it with another sigma factor?

Accepted Answer

The answer of You have set up a cell-free transcription...

Exam 11: Gene Expression: From Transcription to Translation