Biology STAAR Review: Viruses

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

• the mechanism used the virus to infect cells

• how closely related the virus is to cold viruses

• the metabolism of the virus

• meiosis in the virus

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

• move inside a host cell

• attach to the host cell

• control a host cell's DNA

• signal other viruses to infect a host cell

The picture shows a 3-D model of a virus called a bacteriophage. Bacteriophages can infect bacteria such as E. coli. In what way are the bacteriophage and E. Coli alike?

• They contain antibodies

• They reproduce by mitosis

• They have identical genomes

• They lack membrane-bound organelles

A student states that the capsid has a similar function to the nuclear membrane found in animal cells. Which of these describes 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

In 1898 Friedrich Loeffler and Paul Frosch found evidence that the cause of the highly contagious hoof-and-mouth disease in livestock was a microscopic infectious particle. It was discovered that this particle requires a host cell to reproduce. Which pathogen is most likely responsible for causing hoof-and-mouth disease in livestock?

• A bacterium, because it is contagious

• A fungus, because it infects livestock

• A protist, because it is microscopic

• A virus, because it require a host cell to reproduce

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

• The immune system develops antibodies in response 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 the 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. These 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 though 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

True or false: viruses do NOT contain genetic material

• True

• False