Pre AP Biology -CELLS 5.3 Viruses- MCQ Exam Style Questions -New Syllabus

Pre AP Biology -CELLS 5.3 Viruses- MCQ Exam Style Questions – New Syllabus 2025-2026

Pre AP Biology -CELLS 5.3 Viruses- MCQ Exam Style Questions – Pre AP Biology – per latest Pre AP Biology Syllabus.

Pre AP Biology – MCQ Exam Style Questions- All Topics

Question

Suppose that your friend has chickenpox. Which of the following you might conclude?

a. She was infected with Flavivirus during her recent trip to Africa.
b. She was infected with Flavivirus, which she contacted after being in contact with livestock.
c. She was infected with varicella-zoster virus, and her immune system will prevent the onset of shingles later in her life.
d. She was infected with varicella-zoster virus, which might later in her lifetime also give her shingles.

▶️ Answer/Explanation

Detailed solution

The correct answer is d.
Chickenpox is caused by the varicella-zoster virus (VZV).
After the initial infection resolves, the virus stays latent in the nerve tissues.
Later in life, the virus can reactivate due to stress or a weakened immune system.
This reactivation results in a painful skin rash known as shingles (herpes zoster).
Options a and b are incorrect as Flavivirus causes diseases like Yellow Fever or Zika.
Option c is incorrect because the primary infection does not prevent, but rather enables, future shingles.

Question

Which of these characteristics applies to both animal viruses and bacterial viruses?

a. They commonly have envelopes.
b. Only their nucleic acid enters the host cell.
c. They have a capsid divided into a head and a tail.
d. They bind to specific receptors on the host cell.

▶️ Answer/Explanation

Detailed solution

Correct Option: d
Both animal and bacterial viruses (bacteriophages) must recognize and attach to specific surface receptors on the host cell membrane to initiate infection.
Option a is incorrect because envelopes are rare in bacterial viruses but common in animal viruses.
Option b is incorrect because many animal viruses enter the host cell entirely (capsid and all) via endocytosis or fusion.
Option c is incorrect because the “head and tail” structure is a signature of many bacteriophages, whereas animal viruses are typically spherical or helical.
Host specificity is determined by the precise fit between viral attachment proteins and host cell receptors.
This mechanism ensures that a virus only infects a specific range of host species or tissue types.

Question

What happens when a bacteriophage enters the lysogenic stage?

a. The bacteriophage enters the host cell and kills it immediately.

b. The bacteriophage enters the host cell, picks up host DNA, and leaves the cell unharmed.

c. The bacteriophage merges with the host cell’s plasma membrane, forming an envelope, and then exits the cell.

d. The bacteriophage’s DNA integrates into the host cell’s genome.

▶️ Answer/Explanation

Detailed solution

Correct Option: d
In the lysogenic cycle, the viral DNA is integrated into the bacterial chromosome.
The integrated viral genome is then referred to as a prophage.
The host cell remains alive and continues to function and reproduce normally.
Every time the host bacterium undergoes binary fission, the prophage DNA is also replicated.
This allows the virus to persist in a latent state within a population of bacteria.
Under certain environmental stress, the prophage may exit the genome and initiate the lytic cycle.

Pre AP Biology -CELLS 5.3 Viruses- MCQ Exam Style Questions -New Syllabus