MCB 150 Discussion 13 Trivia

Viruses infect only eukaryotes

• True

• False

The influenza virus is typical of many animal viruses in that is has an envelope composed of lipids and glycoproteins. Which of the following statements about the envelope is ACCURATE?

• The envelope glycoproteins are encoded by genes found in the host genome.

• The envelope is obtained from the host cell upon entry into the cell.

• The envelope is obtained from the host cell when the virus buds from the plasma membrane.

• The envelope is inside the capsid.

Answer explanation

When a virus has a broad host range

• it does not require close contact to infect a new host.

• it can infect many different cell types.

• it can infect many different species.

• it can infect many cell types or species.

Which of the following components of a virus is not encoded by its own genome?

• capsid

• lipid bilayer of viral envelope

• spike glycoproteins of viral envelope

• bacteriophage anchoring structures

Which of the following is not an emerging virus?

• HIV

• Influenza

• Zika

• Coronavirus

Answer explanation

An emerging virus is one that has arisen recently or has recently shown a greater probability of causing infection.

Example: SARS-CoV2

How do the reproduction of human immunodeficiency virus (HIV) and bacteriophage lambda differ from each other?

• HIV encodes and uses reverse transcriptase, while lambda phage does not

• HIV production requires integrase, while bacteriophage lambda does not

• HIV can reproduce in either eukaryotic or prokaryotic cells, while bacteriophage lambda can only infect bacteria

• Bacteriophage lambda attaches to specific proteins on the cell

  surface, while HIV does not

Answer explanation

Persons infected with HIV often die of opportunistic diseases because:

• HIV can transduce other viruses into virulent strains.

• HIV is a retrovirus.

• HIV mutates easily.

• HIV destroys T cells.

Answer explanation

helper T cells interact with other cells of the immune system to facilitate the production of antibodies and other molecules that target and kill foreign invaders of the body. When large numbers of helper T cells are destroyed by HIV, the function of the immune system is seriously compromised, and the individual becomes susceptible to infectious diseases called opportunistic infections that would not normally occur in a healthy person. For example, Pneumocystis jiroveci, a fungus that causes a type of pneumonia, is easily destroyed by a healthy immune system. However, in people with AIDS, Pneumocystis jiroveci pneumonia can be fatal.

Tags

NGSS.HS-LS3-2

During HIV reproduction, spike glycoproteins:

• do not enter the cell with the virus.

• are released into the cytoplasm by cellular enzymes.

• are assembled into the virus along with reverse transcriptase.

• are embedded in the viral capsid.

Answer explanation

Drugs that are HIV protease inhibitors:

• prevent HIV protease from degrading host cell proteins.

• block the translation of HIV proteases.

• prevent HIV proteases from breaking apart capsid proteins.

• bind to HIV proteases and prevent the proteases from breaking apart capsid proteins.

It has been difficult to create an effective vaccine against HIV because reverse transcriptase cannot correct its errors.

• True

• False