4C- Viruses and Bacteria

A student produces a labeled drawing of a virus for a presentation. The student states that the capsid has a function similar to the nuclear membrane found in animal cells. Which of these describe the similar functions of capsids and nuclear membranes?

• both transport proteins throughout the structures

• both provide energy for activities in the structures

• both protect genetic information for the structures

• both code for the proteins needed for reproduction of the structures

In the 1880's, Louis Pasteur developed a method of weakening viruses. The weakened viruses could be injected into healthy individuals. How is this method effective in fighting viral diseases?

• the immune system develops antibodies in response to the weakened viruses

• the weakened viruses attach to unaffected viruses in the host and interrupt the viral reproductive cycle

• the rate of genetic mutation in the host is decreased due to the introduction of weakened viruses

• weakened viruses are unable to enter the host organism

Which of these describes a difference between viruses and cells?

• cells contain protein, and viruses contain only carbohydrates

• viruses have flagella, and cells have only cilia

• cells reproduce independently, and viruses require a host to reproduce

• viruses have membranes made of proteins, and cells have membranes made of nucleic acid

The human immunodeficiency virus (HIV) often infects and destroys CD4 T cells. Thes CD4 T cells are one of many kinds of white blood cells that are an important part of the immune system. The most common danger related to the destruction of CD4 T cells is -

• an increase in the risk of high blood pressure

• an increase in the threat of diseases caused by microorganisms and viruses

• a decrease in the flow of blood to vital organs

• a decrease in the amount of oxygen being transported to tissues

Viruses can be transmitted through air, water, food, insect bites, and direct skin contact. Once a virus gains entry to the body, it invades a host cell in order to -

• deactivate the host cell's defenses

• synthesize antibodies for defense

• metabolize host proteins and grow

• access cellular processes for replication

The 1918 influenza epidemic killed between 50 million and 100 million people worldwide. This epidemic happened near the end of World War I. More people died from the influenza epidemic than were killed in the war. Which of the following explains why this virus was so deadly worldwide?

• infected soldiers returning from the war spread the virus when they coughed

• food was scarce because of the war, so people were undernourished, and their immune systems were weakened

• medical personnel often became ill as a result of exposure to airborne virus particles

• all of the above

A photograph of a virus is shown. The projections on the surface of this virus allow the virus to -

• move inside a host cell

• attach to a host cell

• control a host cell's DNA

• signal other viruses to infect a host cell

Cold sores are caused by the herpes simplex virus type 1. A company that wants to develop antiviral drugs would ask a research immunologist to study -

• the mechanisms used by the virus to infect cells

• how closely related the virus is to cold viruses

• the metabolism of the virus

• meiosis in the virus

Bacteria is what type of cell?

• prokaryote
• eukaryote

The genetic material of a virus is in the form of

• RNA
• DNA
• either RNA or DNA