Question 1

In Maxam-Gilbert sequencing, a band that is present in the lane from the tube treated with formic acid (G or A) but not the tube treated with dimethyl sulfate (G) is read as which of the following nucleotides?

Accepted Answer

A)   A
B)   T
C)   C
D)   G A

Question 2

Dye terminator sequencing has been performed using capillary electrophoresis to separate the fragments. ddATP has been labeled with a "green" fluor, ddTTP with "red," ddCTP with "blue," and ddGTP with "black." The colors are detected in the following order: red, green, black, red, green, blue, red, black, black, green, blue. What is the sequence of this fragment?

Accepted Answer

A)   TCGTCATGGAC
B)   GCTACGTAATG
C)   CAGGTCATGAT
D)   TAGTACTGGAC D

Question 3

Incomplete cleaning of the fluorescently labeled sequencing ladder will result in what effect?

Accepted Answer

A)   Dim bands or peaks
B)   Unequal signal from lane to lane
C)   Dye blobs
D)   Equally spaced bands in every lane C

Question 4

The ddNTP:dNTP ratio is too high (too much ddNTP). How will this affect sequencing results?

Accepted Answer

A)   No effect
B)   A sequencing ladder of only short fragments
C)   A sequencing ladder of only long fragments
D)   Equally spaced bands in every lane

Question 5

Which is the output from capillary electrophoresis of a fluorescent product?

Accepted Answer

A)   Autoradiogram
B)   Electropherogram
C)   Pictogram
D)   Nomogram

Question 6

When two sequences are found to be exactly the same, they have which of the following?

Accepted Answer

A)   Heterology
B)   Identity
C)   Alignment
D)   Motif

Question 7

In bioinformatics, when a sequence is entered and compared with all other sequences in a database, which of the following is being performed?

Accepted Answer

A)   Algorithm
B)   Query
C)   Motif
D)   Annotation

Question 8

An analysis that takes place in silico is happening in which of the following places?

Accepted Answer

A)   Computer
B)   Laboratory
C)   Biological organism
D)   Tissue

Question 9

A Sanger sequencing procedure has been performed on a 300-bp piece of DNA. When the fragments were resolved on the gel, there were bands distributed throughout the T, C and A lanes, but in the G lane, there was one thick band at the bottom of the gel. What is the likely cause of these results?

Accepted Answer

A)   No dGTP was added to the G reaction mix.
B)   No ddGTP was added to the G reaction mix.
C)   There was only one G in the whole 300-bp piece of DNA.
D)   The 300-bp piece of DNA contained Gs only.

Question 10

Which end of the sequenced DNA is found at the bottom of a sequencing gel?

Accepted Answer

A)   5
B)   3
C)   2
D)   1

Question 11

Which of the following is the most widely used method of DNA sequencing in clinical laboratories today?

Accepted Answer

A)   Pyrosequencing
B)   Maxam-Gilbert sequencing
C)   Sanger sequencing
D)   Array sequencing

Question 12

A portion of a sequencing gel is described as follows: the first band at the bottom of the gel was in the ddATP lane; the next band going up the gel was in the ddTTP lane, then the ddCTP lane, the ddGTP lane, the ddATP lane, the ddTTP lane, the ddCTP lane, the ddCTP lane, the ddATP lane, and the ddGTP lane. Which of the following is the correct sequence as determined on this gel?

Accepted Answer

A)   5GACCTAGCTA3
B)   3ATCGATCCAG5
C)   5ATCGATCCAG3
D)   3TCAGTCAGC5

Question 13

Dideoxycytidine is added to one of four sequencing reactions. All of the DNA fragments produced in that reaction end with which of the following nucleotides?

Accepted Answer

A)   dG
B)   ddC
C)   dC
D)   ddG

Question 14

Which of the following is a genetic sequence database that is sponsored by the National Institutes of Health?

Accepted Answer

A)   PubMed
B)   Swiss-Prot
C)   GenBank
D)   Interface

Question 15

Sequencing ladders resolved by gel electrophoresis are read in which of the following directions?

Accepted Answer

A)   Top to bottom
B)   Bottom to top
C)   Across lanes
D)   Diagonally

Question 16

Which of the following are included in sequencing reactions to deter secondary structure in the template and synthesized fragments?

Accepted Answer

A)   Deaza-GTP
B)   Manganese
C)   Magnesium
D)   Extra dNTPs

Question 17

Ten equivalents of a genome were cut into small pieces and sequenced. Computers were then used to put the sequences of the pieces together to determine the sequence of the intact genome. The method described is which of the following?

Accepted Answer

A)   Basic Local Alignment Search Tool
B)   Hierarchal Genome Sequencing
C)   Whole Genome Shotgun Sequencing
D)   Gene Recognition and Assembly

Question 18

In the Sanger sequencing method, which of the following when incorporated into the growing strand are used to determine the identity of the base at a particular position in a piece of DNA?

Accepted Answer

A)   ribonucleotides
B)   deoxyribonucleotides
C)   dideoxyribonucleotides
D)   amino acids

Question 19

Cycle sequencing was made possible through the development of what reagents?

Accepted Answer

A)   Fluorescent dyes
B)   dITP
C)   Labeled primers
D)   Heat-stable polymerases

Question 20

A pyrosequencer detects visible light, making it which type of instrument?

Accepted Answer

A)   Luminometer
B)   UV spectrotometer
C)   Mass spectrometer
D)   Fluorometer

Exam 10: DNA Sequencing