Question 1

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 C

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

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 B

Question 4

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 5

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 6

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 7

Which of the following pieces of information has been determined about the human genome?

Accepted Answer

A)   Chromosome 13 has the most genes per bp.
B)   The size of the human genome is 3 Gbp.
C)   The average gene size is 45 kbp.
D)   Chromosome X has the fewest genes.

Question 8

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 9

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

Question 10

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 11

A segment of DNA has been sequenced and noted as the following: AYKWHT. Which of the following is the correct interpretation of this notation?

Accepted Answer

A)   A, T/C, G/T, A/T, A/C/T, T
B)   A, G/T, A/G, C/G, G/T, A/C/T
C)   A, A/C/G, A/T, C/T, T, U
D)   A, A/G, C/T, A/C, G/T, C/G, T

Question 12

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 13

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 14

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 15

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

Accepted Answer

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

Question 16

In Maxam-Gilbert sequencing, co-migrating bands that are present in lanes from the tube treated with hydrazine (T or C) and the tube treated with hydrazine plus salt (T) are read as which of the following nucleotides?

Accepted Answer

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

Question 17

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 18

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 19

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 20

What part of the human genome accounts for encoded proteins?

Accepted Answer

A)   75%
B)   50%
C)   10%
D)   2%

Exam 10: DNA Sequencing