Deck 12: Molecular Structure of Chromosomes and Transposition

Question 1

What is a mechanism of condensation shared by both prokaryotes and eukaryotes?

A) nucleosomes
B) loop domains
C) 30 nm fiber
D) None of these choices are correct.

Answer 1

B

Question 2

Where is the bacterial chromosome located?

A) nucleus
B) nucleolus
C) nucleoid
D) nuclear envelope

Answer 2

C

Question 3

How many origins of replication are there in bacteria?

A) 0
B) 1
C) 2
D) More than two

Answer 3

B

Question 4

How many types of histone proteins are there?

A) 4
B) 5
C) 7
D) 8

Question 5

Quinolones kill bacteria by what mechanism?

A) It inhibits DNA gyrase.
B) It inhibits DNA compaction.
C) It inhibits DNA replication.
D) All of these choices are correct.

Question 6

What is one reason why an amphibian,such as a salamander,might have a larger genome than a mammal,such as a chimpanzee?

A) The amphibian is more complex than the mammal.
B) The amphibian has more structural genes than the mammal.
C) The amphibian has more repetitive sequences than the mammal.
D) The amphibian has more introns than the mammal.

Question 7

Loop domains are responsible for what level of condensation of the bacterial chromosome?

A) 10-fold
B) 100-fold
C) 1000-fold
D) 10,000-fold

Question 8

A nucleus is 4 μm in diameter.Its DNA is composed of a million base pairs.Approximately how much does the DNA need to be condensed in order to fit inside the nucleus?

A) 30-fold
B) 100,000-fold
C) 1 million-fold
D) 3 million-fold

Question 9

The majority of the nonrepetitive genes in an organism are found in which of the following?

A) unique sequences
B) moderately repetitive sequences
C) highly repetitive sequences
D) None of these choices are correct.

Question 10

One would expect heterochromatic regions of DNA to be more compacted than euchromatic regions.

Question 11

An Alu sequence is an example of what?

A) moderately repetitive element
B) Unique sequences that are less frequent than moderately repetitive genes, but more frequent than other unique sequences.
C) highly repetitive DNA
D) unique sequence DNA

Question 12

DNA topoisomerase I does which of the following?

A) introduce positive supercoils
B) relieve positive supercoils
C) introduce negative supercoils
D) More than one of these choices are correct.

Question 13

Which of the following is found at the end of a eukaryotic chromosome?

A) telomeres
B) centromeres
C) kinetochores
D) origins of replication

Question 14

Unique sequences make up approximately what percent of the human genome?

A) 5%
B) 25%
C) 40%
D) 80%

Question 15

Digestion with a low concentration of DNase I results in multiple sized fragments that represent the nucleosomes spaced along chromosomal DNA at intervals of approximately how many nucleotides? 

A) 60
B) 400
C) 600
D) 1100

Question 16

Which of the following would introduce more twists into the DNA molecule of a bacterial cell?

A) negative supercoiling
B) positive supercoiling
C) chromatin remodeling
D) All of these choices are correct.

Question 17

Where do kinetochores attach to chromosomes?

A) telomeres
B) specific genes on the chromosome
C) centromeres
D) They do not attach to DNA.

Question 18

What is the purpose of MARs and SARs?

A) to bind to the nuclear matrix
B) to form loop structure
C) to condense DNA
D) All of these choices are correct.

Question 19

About how many bases of DNA wrap around a histone complex?

A) <50
B) 146
C) 200
D) >1,000

Question 20

What types of amino acids are most responsible for the binding of DNA to histones?

A) hydrophobic amino acids
B) polar amino acids
C) positively charged amino acids
D) negatively charged amino acids

Question 21

The experiment by Noll,1974,supported the observation that histones were regularly spaced on chromosomes because

A) digestion with increased amounts of DNase I resulted in one or a few bands.
B) limited digestion with DNase I resulted in DNA fragments that differed in size by approximately 200 bp.
C) digestion with low or high amounts of DNase I resulted in a fragment that was found at the bottom of the gel.
D) a digestion performed with a moderate amount of DNase I gave results that were very similar to results obtained with higher amounts of DNase I.

Question 22

Which of the following is technically NOT part of the genetic information of a transposable element?

A) insertion elements
B) inverted repeats
C) direct repeats
D) transposase

Question 23

What is a nucleosome composed of?

A) It is composed of 2 copies each of H2A, H2B, H3, and H4 and 1 copy of H1.
B) DNA wrapped twice around a histone octet and includes approximately 200 bases that are not associated with the histones.
C) Two copies each of H2A, H2B, H3, and H4.
D) Two turns of DNA wrapped around an octet core of histone proteins.

Question 24

Long-terminal repeats are unique to which group of transposons?

A) integrase
B) simple transposons
C) LTR retrotransposons
D) non-LTR retrotransposons

Question 25

The individual who first proposed the existence of transposable elements was ________.

A) Sturtevant
B) Morgan
C) McClintock
D) Franklin
E) Watson

Question 26

What feature(s)may be found in insertion elements?

A) inverted repeats
B) transposase gene
C) reverse transcriptase gene
D) antibiotic resistance gene
E) integrase gene

Question 27

Which statement is true concerning chromosome compaction during cell division?

A) Radial loops are not anchored to the scaffolding proteins.
B) Overall chromosomal length is shortened.
C) Compaction results in increased transcriptional rates.
D) The 30 nm fibers are altered to 60  nm fibers.

Question 28

To date,there are no indications that transposable elements offer a selective advantage to a species.

Question 29

Overwinding of the DNA decreases the number of turns in the double helix,and thus results in supercoils in the DNA.

Question 30

LINEs and SINEs together constitute over 30% of the human genome.

Question 31

Areas of the chromosome that are highly condensed and transcriptionally inactive are called

A) euchromatin.
B) superchromatin.
C) heterochromatin.
D) MAR.

Question 32

A chromosome territory is defined as

A) a region in the nucelus that is occupied by a single chromosome.
B) a region on a chromosome that is devoid of nucleosomes.
C) a region on a chromosome that has no protein encoding genes.
D) a region in the nucleus that may have several chromosomes.

Question 33

Which enzyme is unique to the retrotransposons?

A) reverse transcriptase
B) reverse resolvase
C) transposase
D) integrase
E) reverse integrase

Question 34

The DNA of a bacterial cell must be compacted about ________ fold to fit within the confines of the cell.

A) 10
B) 100
C) 150
D) 1000
E) 1,000,000

Question 35

What is the highest level of chromosome condensation?

A) radial loop domain
B) 30 nm fibers
C) double helix
D) nucleosome
E) heterochromatin

Question 36

The zigzag and solenoid models are associated with the ________ level of DNA organization.

A) histone
B) 11nm fiber
C) beads-on-a-string
D) 30 nm fiber
E) scaffold protein

Question 37

Transposons that use an RNA intermediate for transposition are called ________.

A) R elements
B) RNAi transposons
C) retrotransposons
D) reverse transposons

Question 38

What is the lowest level of chromosome condensation?

A) radial loop domain
B) 30 nm fibers
C) double helix
D) nucleosome

Question 39

The correct order of compaction from least compacted to most compacted would be

A) naked DNA, 30 nm fiber, nucleosome, radial loop, metaphase chromosome.
B) naked DNA, radial loop, 30 nm fiber, nucleosome, metaphase chromosome.
C) naked DNA, nucleosome, 30 nm fiber, radial loop, metaphase chromosome.
D) naked DNA, metaphase chromosome, radial loop, 30 nm fiber, nucleosome.

Question 40

Which of the following enzymes is required for a transposon to move?

A) promotes strand invasion and formation of the D loop
B) jumpase
C) splicase
D) transposase