Molecular Biology Test Bank Chapter 5

1- During SDS PAGE, which of the following does not directly affect the migration of the polypeptides through the gel?

A) The size of the polypeptide
B) The strength of the electric field
C) The molecular mass of the protein
D) The native charge on the polypeptides
E) The SDS

... Answer is D)

2- A technique is needed to rapidly separate positively charged histone proteins from a crude cell extract. Which of the following should be chosen?

A) SDS-PAGE
B) Phosphocellulose cation-exchange chromatography
C) Pulse-field gel electrophoresis
D) Gel filtration chromatography
E) DEAE-Sephadex chromatography

... Answer is B)

3- Rapid purification of proteins based on size can best be done using

A) Gel filtration.
B) Ion-exchange chromatography.
C) Native gel electrophoresis.
D) 2-D gel electrophoresis.
E) Cation-exchange chromatography.

... Answer is A)

4- In molecular biology all of the following methods can detect small traces of radioactivity except

A) Liquid scintillation counting.
B) Autoradiography.
C) X-ray film.
D) Phosphorimaging.
E) Spectrophotometry.

... Answer is E)

5- A DNA fragment was treated with EcoRI restriction enzyme. The restriction pattern is shown below. How many fragments should be visible on a Southern blot if radioactively labeled probe "1" was used?

A) 0
B) 1
C) 2
D) 3
E) 4

... Answer is D)

6- Which of the following techniques is not used to quantify the level of gene expression?

A) Southern blotting
B) Northern blotting
C) S1 mapping
D) RNase protection
E) Nuclear run-off

... Answer is A)

7- Which of the following is used to study the interaction of proteins with DNA?

A) S1 nuclease protection
B) DNase-1 footprinting
C) DNA fingerprinting
D) Southern analysis
E) Northern blotting

... Answer is B)

8- A major function of reporter gene assays is to

A) Measure mutation rates of a gene.
B) Measure transcriptional levels.
C) Measure replication.
D) Monitor luciferase activity.
E) Monitor CAT activity.

... Answer is B)

9- A new insulin gene was isolated and a study was planned to look at the function of the promoter region. Which of the following would be the best choice for this study?

A) Southern analysis
B) Immunoblotting
C) Reporter gene assay
D) PCR
E) Immunoprecipitation

... Answer is C)

10- Which of the following is not true about run-on transcription assay?

A) Isolated nuclei are used in the assay.
B) Cytoplasmic RNA is included in the assay.
C) The reaction is done in the presence of labeled nucleotide.
D) The assay can reveal the transcription rates of genes
E) Genes being transcribed can be identified.

... Answer is B)

11- Which of the following is a substrate for -galactosidase?

A) lacZ
B) Chloramphenicol
C) X-gal
D) Acetyl-CoA
E) Both lacZ and acetyl-CoA

... Answer is C)

12- The SELEX method is used for which of the following

A) Discover short RNA sequence that interact with other molecules
B) Assay transcriptional levels abundant aptamers
C) Evaluate transcribed regions of DNA
D) Discover new mutations in rRNA sequences
E) None of the choices are correct.

... Answer is A)

13- A 3000 bp circular DNA was treated with both HindIII and EcoRI restriction enzymes. EcoRI cuts at position 100.HindIII cuts at positions 500 and 2000.Which of the following represents the fragment that would be observed if the restricted DNA were analzyed using agarose gel electrophoresis?

A) 400, 100, 1000, 1500
B) 400, 500, 1500
C) 400, 100, 1600
D) 500, 100, 500, 900
E) 500, 1000, 600

... Answer is A)

14- Which of the following isotopes would be the most appropriate for the end-labeling of a DNA strand with a radioactive phosphate?

A) alpha-32P
B) 35S
C) beta -32P
D) gamma -32P
E) 14C

... Answer is C)

15- Which of the following can be used to establish relatedness between individuals?

A) DNA fingerprinting
B) DNA typing
C) RFLP analysis
D) DNAse footprinting
E) DNA fingerprinting, DNA typing, and RFLP analysis are correct.

... Answer is E)

16- Site-directed mutagenesis is used for which of the following purposes?

A) To insert fragments of more than 100 pairs into a specific DNA site
B) To induced site-specific recombination
C) To make changes to specific bases in DNA
D) To remove large segments of a DNA sequence
E) Both to induced site-specific recombination and to make changes to specific bases in DNA are correct.

... Answer is B)

17- A circular 3000 bp UC18 plasmid DNA sample was treated with BamHI restriction enzyme. The plasmid has restriction sites at position 100 and position 2000.Which of the following choices represents the size fragments that would be observed on an agarose gel?

A) 2900, 100
B) 1900, 100, 1000
C) 1900, 1100
D) 2900, 50, 50
E) 1900, 50, 50, 1000

... Answer is B)

18- It is suspected that a novel histone protein only interacts with the promoter region of -globin genes. Which of the following techniques should be used to confirm this suspicion?

A) EMSA
B) DNase footprinting
C) Filter binding
D) Gel mobility shift assay
E) All of the choices are correct.

... Answer is E)

19- Which of the following is not used in a Sanger chain termination reaction?

A) ddATP
B) ddUTP
C) ddCTP
D) ddGTP
E) ddTTP

... Answer is B)

20- A set of six probes was used to compare a DNA sample taken from a crime scene to the DNA of an arrested suspect. Each probe can detect one in every one hundred persons. Results showed that all six probes detected identical patterns in both DNA specimens. What is the chance for a match using all six probes?

A) 1 in 106
B) 1 in 1010
C) 1 in 1011
D) 1 in 1012
E) 1 in 108

... Answer is D)

21- A study was conducted to identify a liver cell gene (zed) that has a length of 3000 bp. A southern blot was prepared using DNA from the liver cell and a probe made to region 1600-2000 of zed. Analysis of the blot revealed that there are two spots present, one at 3000 and another at 2000.A plausible explanation for this observation is:

A) There is an identical copy of this gene on another chromosome.
B) The gene was cut in two equal portions by a restriction enzyme.
C) There is a another gene with sequence similar to gene zed.
D) Both there is an identical copy of this gene on another chromosome and there is a another gene with sequence similar to gene zed are correct.
E) No explanation can be given using the available data.

... Answer is C)

22- The best method for separating large DNA fragments greater that 1Mb is by electrophoresis in 1% agarose gels.

A) True
B) False

... Answer is B)

23- During the first phase of two-dimensional gel electrophoresis, each polypeptide migrated based on its molecular mass.

A) True
B) False

... Answer is B)

24- Fluorescence in situ hybridization can be used to locate genes on individual chromosomes.

A) True
B) False

... Answer is A)

25- The G-less cassette assay is conducted using a promoter fused to a short DNA sequence and can be used to measure the transcription activity in a cell.

A) True
B) False

... Answer is A)

26- Primer extension can be used to locate the exons in a transcript..

A) True
B) False

... Answer is B)

27- __________ is a means of detecting radioactive compounds with photographic emulsion.

28- ____________ is a method used to detect DNA-protein interactions.

29- A ________________ map is used to indicate the positions on genes on a chromosome.

30- _____________ ________________ can be used to produce disrupted genes in several organisms.

1-26 : MCQ questions
27-30 : Fill Blank questions

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