Reference no: EM1391013

1) A mutation that changes a codon sequence, and subsequently changes the amino acid that should have been placed at that point in the polypeptide chain, is called a
A. frameshift mutation.
B. missense mutation.
C. silent mutation.
D. nonsense mutation.

 

2) A mutation that changes a codon that originally coded for an amino acid into a stop codon is called a
A. frameshift mutation.
B. missense mutation.
C. silent mutation.
D. nonsense mutation.

 

3) Assume that a new low-calorie sweetener is developed. The structure is novel and is tested with the Ames test for mutagenicity. The following results are obtained:
Sample Number of his+ revertant colonies
distilled water 2
distilled water + rat liver enzymes 3
Sweetener 1
sweetener + rat liver enzymes 805

What conclusion is most consistent with this data?
A. The sweetener is not mutagenic.
B. Rat liver enzymes are highly mutagenic.
C. The sweetener is not mutagenic but can be converted into strong mutagens.
D. The sweetener is mutagenic and can be converted into strong mutagens.
E. The sweetener and its conversion products are equally mutagenic.

 

4) What protein makes Okazaki fragments?
A. primase.
B. helicase.
C. DNA polymerase III.
D. DNA polymerase I.
E. ligase.

5) In the modification of eukaryotic mRNA, a "cap" consisting of a/an _________ and a tail consisting of _______ are usually added to the transcript.
A. acetyl group; multiple cytosines
B. multiple guanines; methyl group
C. multiple thymines; acetyl group
D. methyl group; multiple adenines

6). RNA polymerase binds to a sequence called a/an ______________ before beginning transcription.
A. promoter
B. operator
C. structural gene
D. replication origin

 

7) In Sanger (enzymatic extension) sequencing, what causes DNA synthesis to terminate at a specific base?
A. chemicals that cleave DNA after particular bases
B. fluorescent chemicals
C. nucleotide triphosphates that lack a base
D. nucleotide triphosphates that lack a hydroxyl
E. nucleosides that lack a 5' phosphate

8) What are differences between chromosomes of most prokaryotes and those of eukaryotes?
A) The prokaryotic chromosome is linear, while the eukaryotic chromosome is circular.
B) The prokaryotic chromosome is circular, while the eukaryotic chromosome is linear.
C) The prokaryotic chromosome has one origin of replication, while eukaryotic chromosomes have several.
D) The prokaryotic chromosome does not have nucleosomes, while the eukaryotic chromosome does.
E) The prokaryotic chromosome is not necessary for the organism's survival, while the eukaryotic chromosome is.

9) As helicase unwinds the DNA molecule, what keeps the strands apart?
A) DNA polymerase
B) Reverse transcriptase
C) Replication fork
D) Single-strand binding proteins
E) Okazaki fragments

10) Which enzymes are responsible removal of the RNA primers and replacement with DNA nucleotides and repairing the single-stranded nick adjacent to Okazaki?
A) DNA primase
B) DNA polymerase I
C) DNA polymerase III
D) DNA ligase
E) DNA polymerase II

11) Which enzyme activity is associated with the proofreading mechanism of DNA polymerase I?
A) 5'-to-3' exonuclease activity
B) 3'-to-5' exonuclease activity
C) 5'-to-3' polymerase activity
D) 3'-to-5' polymerase activity

12) Which type of RNA is found only in eukaryotes?
A) mRNA
B) tRNA
C) rRNA
D) snRNA

13) During transcription, the synthesis of the mRNA strand proceeds in which direction?
A) 5' to 3' only
B) 3' to 5' only
C) Both 5' to 3' and 3' to 5'
D) Either 5' to 3' or 3' to 5'
E) First 5' to 3', and then 3' to 5'

 

14) Which of the following are true?
A) Prokaryotes have only one kind of RNA polymerase, but several different sigma factors
B) Prokaryotic messages are polycistronic.
C) In eukaryotes, small ribosomal subunit binds to 5%u2019 methylated cap and migrates to AUG start codon.
D) In eukaryotes, the mRNA can only be translated by one ribosome at a time.
E) Exons are spliced out of prokaryotic mRNAs
F) Initiating tRNA in prokaryotes is fMet.
G) Eukaryotes, nuclear membrane prevents coupling of transcription and translation.
H) In eukaryotes, translation continues until the ribosome encounters the poly-A tail.

 

15) Every amino acid contains
A) an amino group
B) an acetyl group.
C) a hydroxyl group
D) a carboxyl group
E) an R group

16) What is the role of tRNA in translation?
A) It brings together two subunits of a ribosome.
B) It couples an amino acid with aminoacyl-tRNA synthetase.
C) It helps fold up the finished polypeptide chain.
D) It catalyzes peptidyl transferase activity.
E) It binds to an mRNA codon and carries the corresponding amino acid

 

17) But the following steps of translation in prokaryotes in order:
_____ Termination of translation is signaled by one of three stop codons
_____ An Aminoacyl-tRNA binds to the ribosome in the A site
_____ The small subunit binds to the Shine-Dalgarno sequence
_____ The ribosome moves along the mRNA one codon toward the 3%u2019 end
_____ The small subunit of migrates to the region of the mRNA containing AUG codon
_____ The large subunit binds to the small subunit
_____ A peptide bond is formed between the amino acids in the P and A sites
_____ A special initiator tRNA binds to the AUG