Deck 9: DNA And The Molecular Structure Of Chromosomes

Question 1

In Sia and Dawson's 1931 experiment:

A) Mice were required to demonstrate the transforming principle
B) Used serum to precipitate IIIS cells from a mixture of heat-killed IIIS and living IIR cells
C) They showed that mice play no direct role in the transforming principle
D) Heat-killed IIR cells mixed with living IIIS cells gave rise to IIR colonies
E) None of these

Answer 1

C

Question 2

Which large organic molecules are essential chromosome components?

A) Lipids and proteins
B) Proteins and nucleic acids
C) Nucleic acids and polysaccharides
D) Proteins and polysaccharides

Answer 2

B

Question 3

Why were some geneticists reluctant to accept the idea of nucleic acids as genetic material even after the discovery of the structure of DNA in 1953?

A) Proteins were larger than nucleic acids
B) Nucleic acids exhibit less structural variability than proteins
C) It was proven in 1871 that proteins were the source of genetic material
D) All of these
E) None of these

Answer 3

B

Question 4

After Griffiths 1928 experiments leading to the discovery of the Transforming Principle,subsequent experimentation demonstrated that:

A) The transforming principle could not be carried out in vitro
B) The conversion of Type IIIR to Type IIIS was due to mutation
C) The process of heat-killing cells was not entirely effective.
D) DNAse treatment eliminates all transforming activity
E) RNAse treatment eliminates all transforming activity

Question 5

Hershey and Chase used radiolabeled T2 phages to identify which component of the phage entered E.coli during infection.Which of the following matches the radiolabel with the appropriate phage component?

A) ³²P DNA, ³?S Protein
B) ³²P Protein, ³?S RNA
C) ³²P RNA, ³?S DNA
D) ³²P Protein, ³?S DNA
E) ³²P Protein, ³?S Protein

Question 6

RNA was first identified as the genetic material of the tobacco mosaic virus (TMV)through an experiment in which:

A) Protein and nucleic acid were radioactively labeled
B) Protein, RNA, and DNA were digested using various enzymes
C) The protein coats and RNA from two distinctive TMV strains were exchanged
D) RNA underwent CsCl density-dependent centrifugation
E) None of these

Question 7

Which of the following are essential functions that the genetic material must perform?

A) Replication, mutation, gene expression
B) Replication, adaptation, mutation
C) Transcription, translation, storage
D) Transcription, translation, replication
E) None of these

Question 8

How does mutation allow an organism to evolve? 1.Changes in the genetic material allow organisms to adapt to modifications in the environment
2)Changes in the genetic material allow organisms to survive in limited types of environment
3)Mutations do not allow an organism to evolve

A) 1
B) 2
C) 3
D) 1 and 2
E) 2 and

Question 9

Which of the following materials was used by Avery,McLeod,and McCarty in their experimentation to identify the transforming agent?

A) DNAse
B) RNAse
C) Protease
D) RNAse and Protease
E) All of these

Question 10

Which of the following is a genotypic function that the genetic material must be able to perform?

A) Replication
B) Mutation
C) Adaptation
D) Gene expression
E) Translation

Question 11

Infectious agents that contain small circular pieces of RNA that are not packaged in a protein coat are known as:

A) Prions
B) Viruses
C) Bacteria
D) Viroids
E) Protisits

Question 12

Which of the following is a phenotypic function that genetic material must be able to perform?

A) Replication
B) Mutation
C) Adaptation
D) Gene expression
E) Translation

Question 13

Infectious agents that contain only altered forms of protein and no nucleic acid are known as:

A) Prions
B) Viruses
C) Bacteria
D) Viroids
E) Protists

Question 14

The genetic information in most organisms,excluding viruses,viroids,and prions,is encoded in what molecule? A)RNA
B) Protein
C) DNA
D) Lactose
E) Lactase

Question 15

The pathogenic effects of viroids are thought to result from:

A) The ability to alter normal patterns of gene expression
B) The ability to directly mutate DNA
C) The ability to indirectly mutate RNA
D) The ability to stop gene expression
E) The ability to enhance gene expression

Question 16

The work carried out by Hershey and Chase had one flaw: a high degree of ³?S was found inside the cells.This flaw was later addressed by:

A) Protease treatment
B) Shearing for longer periods of time
C) Transfection of protoplasts with pure phage DNA
D) Using alternative isotopes.
E) This flaw was never addressed

Question 17

Before direct proof of DNA being the genetic material,indirect evidence suggesting DNA as the appropriate macromolecule,included

A) Gametes have 1/2 the amount of DNA as somatic cells
B) Molecular composition of DNA is the same in different cells of an organism, whereas RNA and protein contents vary
C) A correlation between DNA content and the number of chromosome sets per cell
D) DNA is more stable than RNA or protein
E) All of these

Question 18

Which of the following is a type of nucleic acid?

A) DNA
B) RNA
C) DNAse
D) RNAse
E) DNA and RNA

Question 19

The first direct evidence indicating that DNA,rather than RNA or protein,is the genetic material in bacteriophages was performed by:

A) Griffith
B) Avery, McLeod, and McCarty
C) Hershey and Chase
D) Watson and Crick
E) Sia and Dawson

Question 20

The first direct evidence indicating that DNA,rather than RNA or protein,is the genetic material in bacteria was gathered by:

A) Griffith
B) Avery, McLeod, and McCarty
C) Hershey and Chase
D) Watson and Crick
E) Sia and Dawson

Question 21

Underwound DNA is said to exhibit:

A) Positive supercoiling
B) Negative supercoiling
C) Positive relaxation
D) Negative relaxation
E) None of these

Question 22

Which of the following statements concerning DNA structure is incorrect?

A) The two strands of a double helix are complementary and anti-parallel
B) he structure was first predicted by Watson and Crick in 1953 to be arranged as a double-stranded helix.
C) The final structure disproved the work leading to Chargaff's rule.
D) X-ray diffraction patterns indicated a double-stranded structure with repeating substructure every 0.34 nm
E) None of these

Question 23

A structure known as _________________ is the functional state of a bacterial chromosome.

A) Folded genome
B) Haploid genome
C) Diploid genome
D) Circular genome
E) Linear genome

Question 24

Functional DNA molecules in cells typically exhibit:

A) Positive supercoiling
B) Negative supercoiling
C) Positive relaxation
D) Negative relaxation
E) None of these

Question 25

What kind of data on DNA structure was gathered by Rosalind Franklin and Maurice Wilkins?

A) 3D model
B) Base composition data
C) X-ray diffraction pattern data
D) All of these
E) None of these

Question 26

Which of the following is true regarding the structure of DNA?

A) Double stranded molecule
B) Single stranded molecule
C) Composed of nucleotides
D) Double stranded molecule and Composed of nucleotides
E) Single stranded molecule and Composed of nucleotides

Question 27

Which class of proteins is associated with DNA in chromatin?

A) Histones
B) Non-histone chromosomal proteins
C) Enzymes
D) Histones and Non-histone chromosomal proteins
E) All of these

Question 28

Which type of chemical bond attaches deoxyribose molecules together to form the backbone of a DNA molecule?

A) Hydrogen
B) Phosphodiester
C) Peptide
D) Ionic
E) Covalent

Question 29

Which of the following is not accurate according to Chargaff's rules?

A) A = T
B) C = G
C) A+T = C+ G
D) A+G = C + T
E) Purines = Pyrimidines

Question 30

Prokaryotic chromosome structure:

A) Is in a loosely condensed state in vivo called the "folded genome"
B) Has 50 to 100 domains or loops, each of which is independently negatively supercoiled
C) Consists only of DNA and protein
D) Is unaffected by RNAse treatment
E) Is unorganized as a "naked molecule of DNA"

Question 31

In a certain DNA molecule one strand is cleaved and when the complementary strand is rotated at one end.This configuration is called:

A) Relaxation
B) Supercoiling
C) Splicing
D) All of these
E) None of these

Question 32

Which of the following statements concerning the various forms of DNA is incorrect?

A) B-DNA is the conformation under physiological conditions.
B) A-DNA occurs in a partially dehydrated environment.
C) DNA-RNA duplexes exist in an A-form.
D) B and Z are right handed helices, while A is left handed.
E) All of these are incorrect

Question 33

DNA migrates toward which pole during gel electrophoresis?

A) Positive because DNA is negatively charged
B) Negative because DNA is positively charged
C) Positive because DNA is positively charged
D) Negative because DNA is negatively charged
E) Neither positive and negative because DNA is neutral in charge

Question 34

The technique for visualizing large chromosomes using [³H] thymidine-labeled DNA on protein coated glass slides is called:

A) Pulse-field gel electrophoresis
B) Autoradiography
C) Viscoelastometry
D) DNA sequencing
E) RFLP

Question 35

Which of the following is true regarding the structure of RNA?

A) Double stranded molecule
B) Single stranded molecule
C) Composed of nucleotides
D) Double stranded molecule and Composed of nucleotides
E) Single stranded molecule and Composed of nucleotides

Question 36

Which type of chemical bond connects nitrogenous bases to each other in the center of a DNA molecule?

A) Hydrogen
B) Phosphodiester
C) Peptide
D) Ionic
E) Covalent

Question 37

DNA extracted from a bacterium was identified as having a guanine content of 14%.From this information determine the percentage of A.

A) 14%
B) 28%
C) 36%
D) 78%
E) There is not enough information to determine this.

Question 38

A single strand of a double-stranded helix has the sequence 5'-GTTTAACGTAT-3'.If the helix was in B-form,how many turns (360 degrees)would the helix make?

A) 1
B) 1.1
C) 1.5
D) 2
E) 2.1

Question 39

According to the unineme model of chromosomal structure,how many double stranded DNA molecules run parallel throughout a eukaryotic chromosome?

A) One
B) Two
C) Three
D) Four
E) Five

Question 40

The pathogenic effects of prions are thought to result from:

A) Viroids acting as a template for the synthesis of the prion proteins
B) Aberrant forms of mammalian cellular proteins that convert more mammalian cellular proteins to aberrant forms, leading to a clumping of the proteins, eventually killing the cell.
C) Prions converting viroids into abberant proteins that kill the cell
D) All of these
E) None of these

Question 41

Satellite DNA is

A) Repetitive
B) Randomly located throughout the genome
C) Prokaryotic
D) Expressed
E) None of these

Question 42

While discussing the structure of DNA with your classmates you notice that your study partner has drawn a DNA molecule that looks like the following.
3'-ATCGGUTCCAAA-5'
3'-TAACCAAGGTTG-5'
What is incorrect about this drawing of the DNA molecule?

Question 43

For dispersed moderately repetitive DNA in the human genome,which of the following is incorrect?

A) LINEs are the longest and L1 is the only functional element in the genome
B) SINEs are typically 100-400 bp in length and the most abundant
C) Transposable elements with LTRs are rarely observed
D) DNA transposons comprise about 3% of the genome
E) None of these

Question 44

How does pulsed field gel electrophoresis differ from standard gel electrophoresis?

Question 45

Which of the following characteristics or functions is not believed to be exhibited by highly repetitive DNA?

A) Structural or organizational roles for the chromosome.
B) Transposable elements
C) Heterochromatin
D) Influencing regions of chromosome pairing
E) Junk

Question 46

Compare the structure of DNA to the structure of RNA.Include at least three differences.

Question 47

What were the two major pieces of evidence that led to the deduction of DNA structure by Watson and Crick and who supplied this information?

Question 48

Three levels of condensation are required to package metaphase chromosomes.In order of complexity,lowest to highest,they are:

A) Supercoiling into nucleosomes, chromatin fiber condensation, scaffold formation
B) Chromatin fiber condensation, supercoiling into nucleosomes, scaffold formation
C) Scaffold formation, supercoiling into nucleosomes, chromatin fiber condensation
D) Supercoiling into nucleosomes, scaffold formation, chromatin fiber condensation
E) Scaffold formation, chromatin fiber condensation, supercoiling into nucleosomes

Question 49

The functions associated with telomeres are to:

A) Prevent ribonucleases from degrading the ends of linear RNA primer molecules
B) Allow the fusion of broken chromosomal ends
C) Facilitate replication of chromosomes without the loss of termini
D) Ensure the appropriate segregation of chromosomes
E) Provide chromosomal anchorage to spindle-fibers

Question 50

What are the three major forms of DNA? Identify a major context in which they are found,and what the requirements are for each.