Molecular Biology Test Bank Chapter 2

1- Experiments conducted by Frederick Griffith laid the foundation for

A) Elucidation of mRNA structure.
B) DNA as the genetic material.
C) The virulence of S.pneumoniae.
D) The discovery of the capsule on S.pneumoniae.
E) Elucidation of tRNA structure.

... Answer is B)

2- In experiments conducted by Griffith, the inability of the avirulent strain to produce a lethal infection was due to

A) The presence of a protective coat.
B) Destruction by the host's white blood cells.
C) The presence of a gene for a polysaccharide coat.
D) The high body temperature of the host.
E) None of the choices are correct.

... Answer is B)

3- The analytic tools used to show that DNA was the transforming substance include all of the following except

A) Ultracentrifugation.
B) Electrophoresis.
C) UV absorption spectrophotometry.
D) Heat inactivation.
E) Chemical analysis.

... Answer is D)

4- Which of the following would be the substance of choice to destroy the DNA in a solution?

A) Ribonuclease
B) Trypsin
C) Chymotrypsin
D) Deoxyribonuclease
E) None of the choices are correct.

... Answer is D)

5- All of the following are found in RNA except

A) Adenine.
B) Deoxyribose.
C) Cytosine.
D) Guanine.
E) Uracil.

... Answer is B)

6- The structure in the figure below is an example of

A) A pyrimidine.
B) A purine.
C) Guanine.
D) Adenine.
E) Ribose.

... Answer is A)

7- The following structure is an example of

A) Deoxyribose.
B) Ribose.
C) Adenine.
D) Guanine.
E) Thymine.

... Answer is A)

8- The bonds that connect adenine to thymine in a DNA double helix are

A) Ionic.
B) Hydrophobic.
C) Hydrogen.
D) Covalent.
E) None of the choices are correct.

... Answer is C)

9- n experiment was conducted to determine the base content of DNA. Results are shown in the table below .Determine which sample of DNA is the most stable.

A) DNA1
B) DNA2
C) DNA3
D) DNA4
E) DNA5

... Answer is C)

10- The C-value paradox can be explained by

A) The number of cytosine and guanine in DNA.
B) The number of mutations in each gene.
C) The amount of noncoding DNA in an organism.
D) The number of extra genes in the genome.
E) Hyperchromic shift.

... Answer is C)

11- Rapid cooling of DNA following heating at high temperature will cause

A) The strands to break.
B) Rapid renaturation of the strands.
C) The strands to remain separated.
D) The double helix to form rapidly.
E) Mismatching between the strands.

... Answer is C)

12- The overall length of one full turn of the B-DNA helix is

A) 33.32 angstroms.
B) 33.20 angstroms.
C) 3.32 nanometers.
D) 0.332 nanometers.
E) 0.032 nanometers.

... Answer is C)

13- Phosphodiester bonds are examples of

A) Hydrophobic interactions.
B) Hydrogen bonds.
C) Covalent bonds.
D) Noncovalent bonds.
E) Ionic bonds.

... Answer is C)

14- All of the following conditions promote the denaturation of DNA except

A) Low ionic strength solutions.
B) High pH.
C) Organic solvents.
D) High temperature.
E) Extremely low temperature.

... Answer is E)

15- Which of the following is the best way to determine the base content of DNA?

A) Density gradient centrifugation
B) Gel electrophoresis
C) Spectrophotometry
D) X-ray diffraction
E) Deoxyribonuclease treatment

... Answer is A)

16- Which of the following is not found in RNA?

A) Nitrogen
B) Oxygen
C) Carbon
D) Sulfur
E) Hydrogen

... Answer is D)

17- The ability of two polynucleotide strands to hybridize is based on which of the following principles?

A) Double helical nature of DNA
B) The presence of phosphodiester bond
C) Complementary base pairing
D) The presence of 3' and 5' ends
E) The presence of covalent bonds

... Answer is C)

18- An ideal way to visualize the shape of DNA is by

A) Light microscopy.
B) Electron microscopy.
C) Centrifugation.
D) Spectrophotometry.
E) Deoxyribonuclease digestion.

... Answer is B)

19- Which of the following would prevent the formation of a phosphodiester bond in DNA?

A) Removal of a nitrogen from one of the bases
B) Removal of oxygen from carbon 2 of the sugar
C) Removal of an oxygen from carbon 3 of the sugar
D) Removal of the phosphate from the alpha position of the nucleoside triphosphat
E) Removal of the phosphate at the beta position of the nucleoside triphosphate

... Answer is C)

20- Wild Streptoccocus pneumoniae is virulent because of the absence of a capsule.

A) True
B) False

... Answer is B)

21- The phosphodiester bond in DNA is an example of a hydrogen bond.

A) True
B) False

... Answer is B)

22- In a DNA synthesis reaction the use of the following dATP molecule labeled with phosphorous-32 at the gamma position would result in a radioactively labeled DNA strand.

A) True
B) False

... Answer is B)

23- DNA strands absorb more light when the strands are separated by heat,high pH,or organic solvents.

A) True
B) False

... Answer is A)

24- The A- and B-forms of DNA structures are right-handed.

A) True
B) False

... Answer is A)

25- The melting temperature of DNA is the point at which 50% of the strands are denatured.

A) True
B) False

... Answer is A)

26- The Hershey-Chase experiments depended on two types of radioactive labels- ______________ for DNA and __________________for proteins.

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2-

27- The bases and sugars in DNA and RNA are joined together to form units called_____________.

28- One of Chargaff's rules states that the amount of cytosine is equal to the amount of _________________in DNA.

29- The annealing of two different polynucleotide strands is called _________.

30- The double helical model of DNA was described by __________ and _________ in 1953.

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1-25 : MCQ questions
26-30 : Fill Blank questions

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