Question 1

Which of the following best explains why anthrax spores are particularly dangerous as a biological weapon?

Accepted Answer

They can survive for decades in harsh environments and are resistant to many disinfectants.

Question 2

Ciprofloxacin is effective against Bacillus anthracis because it inhibits which of the following enzymes, thereby halting DNA replication?

Accepted Answer

Topoisomerase IV

Question 3

Which of the following is a major difference between bacterial DNA replication and human DNA replication?

Accepted Answer

Human DNA has linear chromosomes with telomeres, while bacterial DNA is typically circular and lacks telomeres.

Question 4

A public health official is considering distributing antibiotics widely during an anthrax attack. Which of the following is a potential risk of this strategy?

Accepted Answer

It may lead to increased antibiotic resistance in the population.

Question 5

Which of the following best describes the structure of DNA?

Accepted Answer

Double helix with sugar-phosphate backbone and nitrogenous bases.

Question 6

Why are the ends of linear chromosomes (telomeres) more vulnerable to shortening during DNA replication?

Accepted Answer

DNA polymerase cannot fully replicate the 3' ends of linear DNA, leading to progressive shortening.

Question 7

Which types of cells normally have active telomerase?

Accepted Answer

Germ cells, stem cells, and cancer cells

Question 8

If Maria’s drug successfully activates telomerase in her somatic cells, what is a potential risk associated with this therapy?

Accepted Answer

Uncontrolled cell growth leading to increased cancer risk.

Question 9

A DNA sequence is located on chromosome 11. To amplify only that portion using PCR, which of the following is necessary?

Accepted Answer

Use primers that specifically bind to sequences flanking the target region.

Question 10

If you start with one DNA molecule and perform 20 cycles of PCR, how many copies will you have after 20 rounds? (Assume perfect doubling each cycle.)

Accepted Answer

$$2^{20}$$

Question 11

The restriction enzyme Mst II recognizes the sequence CCTGAGG. If a mutation changes this to CCTGTGG, what will happen during a restriction digest?

Accepted Answer

The enzyme will not cut at the mutated site, resulting in a larger DNA fragment.

Question 12

In a gel electrophoresis experiment, DNA fragments are separated based on which property?

Accepted Answer

Fragment size, with smaller fragments moving farther through the gel.

Question 13

Which of the following is a key ethical consideration when providing access to anti-aging treatments that activate telomerase?

Accepted Answer

Ensuring equitable access to all populations, regardless of socioeconomic status.

Question 14

Which of the following best describes the role of topoisomerase IV in bacterial DNA replication?

Accepted Answer

It relieves supercoiling during replication.

Question 15

A patient’s DNA is analyzed using restriction enzymes and gel electrophoresis. If the patient has a mutation that removes a restriction site, what will be observed on the gel?

Accepted Answer

Fewer, larger DNA fragments compared to the normal sample.

Question 16

Which of the following is a real-world consequence of widespread antibiotic use during a bioterrorism event?

Accepted Answer

Development of antibiotic-resistant bacterial strains.

Question 17

Which equation correctly represents the exponential amplification of DNA during PCR, where $$n is $$the number of cycles?

Accepted Answer

$$2^n$$

Question 18

Why do most somatic (body) cells lack telomerase activity, and how does this affect their lifespan?

Accepted Answer

They lack telomerase, so their telomeres shorten with each division, leading to cellular aging and limited lifespan.

Question 19

In a DNA fingerprinting scenario, why is it important that each person receives one copy of each gene from each parent?

Accepted Answer

It allows for the identification of genetic relationships through comparison of alleles.

Question 20

Which of the following is a plausible medical application of telomerase activation in human cells?

Accepted Answer

Slowing cellular aging and promoting cell renewal.

Science to Society: Anthrax, DNA Replication, Telomerase, and Genetic Analysis

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