Question 1

Which of the following best describes the structure of most bacterial chromosomes?

Accepted Answer

Circular, double-stranded DNA compacted into a nucleoid

Question 2

A eukaryotic chromosome contains several origins of replication. Approximately how far apart are these origins typically spaced?

Accepted Answer

$$100,000 bp$$

Question 3

Which of the following is NOT a function of telomeres in eukaryotic chromosomes?

Accepted Answer

Serving as origins of replication

Question 4

What is the basic repeating structural unit of eukaryotic chromatin?

Accepted Answer

Nucleosome

Question 5

A nucleosome consists of:

Accepted Answer

DNA wrapped around 8 histone subunits (2 each of H2A, H2B, H3, H4)

Question 6

Which of the following best explains why eukaryotic DNA must be tightly compacted?

Accepted Answer

To fit the large amount of DNA into the nucleus and regulate gene expression

Question 7

Which proteins are primarily responsible for the first level of DNA compaction in eukaryotes?

Accepted Answer

Histone proteins

Question 8

What is the function of matrix-attachment regions (MARs) in eukaryotic chromosomes?

Accepted Answer

They anchor DNA to the nuclear matrix, forming radial loops

Question 9

Which of the following statements about heterochromatin is correct?

Accepted Answer

It is tightly compacted and generally transcriptionally inactive

Question 10

During which phase of the cell cycle are eukaryotic chromosomes most highly compacted?

Accepted Answer

Metaphase

Question 11

Which of the following best describes the difference between euchromatin and heterochromatin?

Accepted Answer

Euchromatin is less condensed and transcriptionally active; heterochromatin is more condensed and generally inactive

Question 12

Which of the following is a correct order of DNA compaction in eukaryotic cells, from least to most compact?

Accepted Answer

Naked DNA → nucleosome → 30-nm fiber → metaphase chromosome

Question 13

A scientist is studying a eukaryotic gene that is highly expressed. In which chromatin state is this gene most likely to be found?

Accepted Answer

Euchromatin

Question 14

Which of the following chemical modifications is NOT typically associated with histone proteins?

Accepted Answer

Glycosylation

Question 15

A viral genome is being analyzed. Which of the following statements is most accurate?

Accepted Answer

Viral genomes can be composed of either DNA or RNA

Question 16

Which of the following best explains why the genome size of some salamanders is much larger than that of humans, despite not having more genes?

Accepted Answer

Salamanders have a higher proportion of repetitive DNA sequences

Question 17

Which of the following is a key difference between prokaryotic and eukaryotic chromosomes?

Accepted Answer

Prokaryotic chromosomes are circular and lack telomeres; eukaryotic chromosomes are linear and contain telomeres

Question 18

Which of the following best describes the role of the nuclear matrix in eukaryotic cells?

Accepted Answer

It organizes chromosomes into radial loop domains for further compaction

Question 19

Which of the following abbreviations correctly matches the number of base pairs it represents?

Accepted Answer

kb = $$10^3 bp$$

Question 20

A mutation disrupts the function of histone H1 in a eukaryotic cell. Which level of chromatin structure would be most directly affected?

Accepted Answer

30-nm fiber formation

Chromosome Structure and DNA Sequence Organization

Study Guide - Practice Questions