Question 1

Which of the following is NOT an essential characteristic of hereditary material as described in the study materials?

Accepted Answer

It must be able to catalyze metabolic reactions.

Question 2

Which scientist first isolated DNA, and from what source did he extract it?

Accepted Answer

Friedrich Miescher; nuclei of white blood cells

Question 3

Which of the following best describes the directionality of a DNA strand?

Accepted Answer

It is based on the carbons of the deoxyribose sugar, with a 5’ phosphate end and a 3’ hydroxyl end.

Question 4

Which of the following statements about complementary base pairing in DNA is correct?

Accepted Answer

Adenine pairs with thymine via two hydrogen bonds, and guanine pairs with cytosine via three hydrogen bonds.

Question 5

Which of the following is a key difference between DNA and RNA nucleotides?

Accepted Answer

DNA contains deoxyribose, while RNA contains ribose.

Question 6

What is the primary force that stabilizes the double helix structure of DNA?

Accepted Answer

Hydrogen bonds between complementary bases and base-stacking interactions

Question 7

Which form of DNA is most common in living cells and what are its key features?

Accepted Answer

B-DNA; right-handed twist, 10.4 bp per turn, 2 nm diameter

Question 8

Which of the following best explains why genome size does not always correlate with organismal complexity in eukaryotes?

Accepted Answer

Most of the genome in complex organisms is made up of repetitive and non-coding DNA.

Question 9

Which of the following statements about viral genomes is TRUE?

Accepted Answer

Viral genomes can be composed of either DNA or RNA, and can be single- or double-stranded.

Question 10

Which enzyme is responsible for introducing negative supercoils into bacterial DNA?

Accepted Answer

DNA gyrase (topoisomerase II)

Question 11

What is the function of histone proteins in eukaryotic cells?

Accepted Answer

They package and condense DNA into nucleosomes, aiding in chromosome structure and gene regulation.

Question 12

Which of the following best describes the difference between LINEs and SINEs in the human genome?

Accepted Answer

LINEs code for reverse transcriptase, while SINEs do not.

Question 13

A researcher is studying a segment of DNA that consists of the sequence TTAGGG repeated thousands of times at the end of a chromosome. What is this region called, and what is its primary function?

Accepted Answer

Telomere; protection of chromosome ends from degradation

Question 14

Which of the following best describes the packaging of bacterial chromosomes?

Accepted Answer

They are circular, supercoiled, and anchored by proteins in the nucleoid region.

Question 15

Which of the following is a feature of facultative heterochromatin?

Accepted Answer

It has variable levels of condensation and is related to gene transcription.

Question 16

Which of the following is TRUE about retrotransposons?

Accepted Answer

They use an RNA intermediate and encode reverse transcriptase for copying themselves into new locations.

Question 17

A scientist is using fluorescence in situ hybridization (FISH) to visualize chromosomes. What is the main advantage of this technique?

Accepted Answer

It enables the identification of specific chromosome locations within the nucleus using fluorescent probes.

Question 18

Which of the following statements about archaeal chromosomes is correct?

Accepted Answer

They are usually circular and may contain plasmids, with histone-like proteins present.

Question 19

Which of the following best describes the role of condensin proteins during mitosis?

Accepted Answer

They regulate the coiling of chromatin into tightly compacted mitotic chromosomes.

Question 20

A DNA sample is found to contain 30% adenine. According to Chargaff’s rules, what percentage of guanine would you expect to find in this sample?

Accepted Answer

$$20\%$$

DNA and Chromosome Structure: Organization, Packaging, and Genome Complexity

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