Deck 10: Chromosome Organization and Molecular Structure

Question 1

Where do kinetichores attach to chromosomes?

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

Answer 1

C

Question 2

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 the above

Answer 2

A

Question 3

Why do amphibians have so much more DNA than humans?

A) Repetitive sequences
B) They are more complex than mammals
C) They have more genes
D) They are tetraploid

Answer 3

A

Question 4

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 5

How many types of histone proteins are there?

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

Question 6

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

A) Right
B) Left

Question 7

Where is the bacterial chromosome located?

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

Question 8

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

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

Question 9

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 10

How many origins of replication are there in bacteria?

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

Question 11

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

Question 12

What term is used to describe highly repetitive DNA?

A) Heterochromatin
B) Homochromatin
C) Euchromatin
D) Prochromatin

Question 13

Digestion with a low concentration of DNAse I would yield fragments of what approximate size?

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

Question 14

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

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

Question 15

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 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

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 18

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

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

Question 19

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 20

An Alu sequence is an example of what?

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

Question 21

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

Question 22

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 23

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 24

The 30 nm fiber is formed from arrays of nucleosomes.

Question 25

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

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

Question 26

Areas of the chromosome that remain highly condensed are called .

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

Question 27

Which of the following is correctly matched with its description?

A) Highly repetitive DNA contains transposable elements and genes that 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 expressed in abundance and thus have many copies.

Question 28

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 29

Which of the following promote the formation of heterochromatin during metaphase?

A) Radial loop domains
B) Condensing and cohesion
C) 30 nm fibers
D) Nucleosomes

Question 30

A nucleus is 4 μm 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 31

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 32

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

Question 33

A Barr body is an example of what?

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

Question 34

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 35

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 36

Which of the following 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 37

The majority of bacterial DNA is negatively super coiled.

Question 38

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

Question 39

Bacteria are small infectious particles that require a host cell to replicate.

Question 40

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 41

What reanneals at the lowest mol x sec/L on a Cot curve?

A) Highly-repetitive DNA
B) Moderately-repetitive DNA
C) Non-repetitive DNA

Question 42

In a self assembly virus, the viral genome contains instructions for noncapsid proteins that aid in the assembly of the virus.

Question 43

Viruses are small infectious particles that require a host cell to replicate.

Question 44

Directed assembly viruses means that the subunits of the virus spontaneously bind together to produce
a new virus.

Question 45

A Cot curve can be used to determine .

A) The sequence complexity of a given organism
B) The total concentration of DNA in a cell
C) The number of origins of replication
D) The length of the chromosome in base pairs

Question 46

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

Question 47

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