Deck 10: Chromosome Organization and Molecular Structure

Question 1

An Alu sequence is an example of what?

A)Retroelement
B)Transposable element
C)Highly repetitive DNA
D)All of the answers are correct

Answer 1

D

Question 2

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

Answer 2

A

Question 3

Where do kinetochores attach to chromosomes?

A)Telomeres
B)Specific genes on the chromosome
C)Centromeres
D)They don't attach to DNA

Answer 3

C

Question 4

Why do amphibians have so much more DNA than humans?

A)Amphibians have more repetitive sequences than do humans
B)Amphibians are more biologically complex than mammals are
C)Amphibians have more genes than do humans
D)Amphibians are tetraploid, while humans are diploid

Question 5

Chemicals such as quinolones are anti-bacterial. How does it kill bacteria?

A)It inhibits DNA gyrase
B)It inhibits DNA compaction
C)It inhibits DNA replication
D)All of the answers are correct

Question 6

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

A)Negative super coiling
B)Positive super coiling
C)Chromatin remodeling
D)All of the answers are correct

Question 7

DNA topoisomerase I does which of the following?

A)Introduce positive super coils
B)Relieve positive super coils
C)Introduce negative super coils
D)More than one of these

Question 8

Digesting chromatin with a high concentration of DNAse I would yield fragments of what approximate size?

A)200
B)400
C)600
D)1100

Question 9

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

A)<50
B)150
C)200
D)>1,000

Question 10

How many origins of replication are there in bacteria?

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

Question 11

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 the answers are correct

Question 12

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

Question 13

How many types of histone proteins are there?

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

Question 14

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 the answers are correct

Question 15

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 16

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

A)Nucleosomes
B)Loop domains
C)30 nm fiber
D)None of the answers are correct

Question 17

Where is the bacterial chromosome located?

A)Nucleus
B)Nucleolus
C)Nucleoid
D)Nuclear envelope

Question 18

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

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

Question 19

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

A)Telomeres
B)Centromeres
C)Kinetochores
D)Origins of replication

Question 20

Which direction would you turn Z-DNA to introduce negative super coils?

A)Right
B)Left

Question 21

Over winding of the DNA decreases the number of turns in the double helix, and thus results in super coils in the DNA.

Question 22

Which of the following is correctly matched with its description?

A)Highly repetitive DNA contains transposable elements and genes that are expressed in abundance and thus have many copies.
B)Moderately repetitive DNA contains unique sequences, such as genes found in one or a few copies.
C)Non-repetitive DNA is composed of thousands of copies of many short repeats.
D)Moderately repetitive DNA contains retro elements, such as the Alu sequence.
E) Moderately repetitive DNA contains transposable elements and genes that are expressed in abundance and thus have many copies.

Question 23

The function of condensin is to

A) cause the chromosomes to uncompact following mitosis.
B) coat the chromosomes and condense them into heterochromatin through the compaction of radial loops.
C) hold the DNA to the histone proteins in the nucleosome core particle.
D) trigger DNA to be compacted in a nucleosome core particle.
E) none of these

Question 24

Each radial loop domain may contain between 10 and 100 base pairs of DNA.

Question 25

Which of the following is NOT part of the structure of the nucleosome core particle?

A) It is composed of an octamer of proteins.
B) There is a linker region between two nucleosomes of about 200 base pairs.
C) There are two copies each of H2A, H2B, H3 and H4.
D) The DNA is wrapped around the core slightly over two complete turns.
E) The DNA wrapped around the core contains 146-147 base pairs.

Question 26

The zig-zag 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 27

A nucleosome is a combination of _______ and _______.

A) histone proteins, scaffold proteins
B) RNA, transcription proteins
C) DNA, histone proteins
D) RNA, histone proteins
E) DNA, scaffold proteins

Question 28

The majority of bacterial DNA is negatively super coiled.

Question 29

The origins of replication in eukaryotic chromosomes are spaced about every _______ base pairs.

A) 100,000
B) 1000
C) 100
D) 10
E) 500

Question 30

The term genome refers to the complete complement of sequences and genes that an organism possesses.

Question 31

Which of the following represents the highest level of chromosome condensation?

A)Radial loop domain
B)30 nm fibers
C)Double helix
D)Nucleosome
E)Heterochromatin

Question 32

Areas of the chromosome that remain highly condensed are called ______.

A)Euchromatin
B)Facultative heterochromatin
C)Constitutive heterochromatin
D)Barr body

Question 33

A Barr body is an example of what?

A)Constitutive heterochromatin
B)Facultative heterochromatin
C)Constitutive euchromatin
D)Facultative euchromatin

Question 34

The 30 nm fiber is formed from arrays of nucleosomes.

Question 35

Which of the following assists the alignment of sister chromatids during metaphase?

A)Radial loop domains
B)Cohesin
C)Centromeres
D)Nucleosomes
E) Condensin

Question 36

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 37

A nucleus is 4 $\mu$ m in diameter. Its DNA is composed of a million base pairs. Approximately how much does it 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 38

Which of the following is NOT a mechanism used by bacteria to condense their DNA?

A) Super coiling
B) Packaging the DNA with histone proteins
C) Looping of the DNA
D) Increase or decrease the number of turns in the DNA
E) Anchoring the DNA loops with DNA-binding proteins

Question 39

The different DNA configurations that are generated by super coiling are called topoisomers of one another.

Question 40

Which of the following represents the lowest level of chromosome condensation?

A)Radial loop domain
B)30 nm fibers
C)Heterochromatin
D)Nucleosome
E) Euchromatin

Question 41

The DNA-protein complex in eukaryotic chromosomes is called the genome.

Question 42

Why do positively charged amino acids appear more often than usual in histone proteins?

A)Because histones have a higher molecular mass, which improves DNA compaction
B)Because histones are strongly attracted to the positively charged phosphate backbone of DNA
C)Because histones and DNA have opposite charges, which improves the compaction of DNA into nucleosomes
D)Because histones and DNA have the same charge, which improves the compaction of DNA into nucleosomes