Question 1

Which of the following best describes a virus?

Accepted Answer

A non-living infectious particle consisting of genes packaged in a protein coat

Question 2

Which structure is responsible for recognizing and binding to host cells in many animal viruses?

Accepted Answer

Viral envelope glycoproteins

Question 3

A bacteriophage injects its DNA into a bacterial cell. What is the next step in the lytic cycle?

Accepted Answer

The host cell's machinery is used to synthesize viral genomes and proteins

Question 4

Which of the following statements about restriction enzymes is TRUE?

Accepted Answer

They recognize and cut specific palindromic DNA sequences

Question 5

A scientist is using EcoRI to cut a DNA sequence. EcoRI recognizes the sequence $$5'–GAATTC–3'. If a $$linear DNA molecule contains 4 EcoRI sites, how many fragments will be produced?

Accepted Answer

$$5$$

Question 6

Which of the following best explains why antibiotics are ineffective against viral infections?

Accepted Answer

Viruses lack cell walls and metabolic pathways targeted by antibiotics

Question 7

Which process allows a virus to remain dormant within a host cell's genome and be passed to daughter cells during cell division?

Accepted Answer

Lysogenic cycle

Question 8

Which of the following is a key reason why RNA viruses tend to evolve more rapidly than DNA viruses?

Accepted Answer

RNA viruses have higher rates of mutation due to lack of proofreading during replication

Question 9

A patient is diagnosed with Creutzfeldt-Jakob disease. What is the causative agent?

Accepted Answer

A prion

Question 10

Which of the following best describes the function of the CRISPR-Cas system in bacteria?

Accepted Answer

It provides adaptive immunity against viral infection by recognizing and cutting foreign DNA

Question 11

Which of the following is an example of a disease caused by a retrovirus?

Accepted Answer

HIV/AIDS

Question 12

A plant virus is transmitted from parent to offspring through seeds. This is an example of:

Accepted Answer

Vertical transmission

Question 13

Which of the following is NOT a characteristic of prions?

Accepted Answer

They contain both DNA and RNA

Question 14

Which of the following best describes the difference between a prophage and a provirus?

Accepted Answer

A prophage is integrated viral DNA in a bacterial genome, while a provirus is integrated viral DNA in an animal genome

Question 15

Which of the following is a correct statement about the R-naught ($$R_0) $$value in epidemiology?

Accepted Answer

It is the average number of people one infected person will transmit the disease to

Question 16

Which of the following is a real-world example of a pandemic?

Accepted Answer

1918 Spanish flu

Question 17

A restriction enzyme recognizes the sequence $$5'-GGATCC-3'$$ and cuts between the G and G. If a circular plasmid contains this sequence three times, how many fragments will be produced after digestion?

Accepted Answer

$$1$$

Question 18

Which of the following is a plausible reason why the flu vaccine is not 100% effective each year?

Accepted Answer

Influenza viruses mutate rapidly, leading to new strains

Question 19

Which of the following best explains why restriction enzymes do not cut the host bacterium's own DNA?

Accepted Answer

The host DNA is methylated at the recognition sites

Question 20

Which of the following is a correct application of the CRISPR-Cas system in biotechnology?

Accepted Answer

Cutting specific DNA sequences to edit genes

Viruses: Structure, Replication, and Impact on Living Organisms

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