Unit D — Viruses

1. If a person previously had cow pox and was infected with small pox, then the
effect would be severe.
person would most certainly die.
effect would be minimal if any even occurred.
person could become sick with any kind of pox, including chicken pox.

2. During the vaccination against small pox, what did Jenner inject into people?
Fluid from a cowpox blister.
Blood from an infected cow.
Pus from an infected person.
Antibiotics he developed against small pox.

3. Which of the following scientists was the first to see the tobacco mosaic virus?
Miller.
Meyer.
Beijerinick.
Iwanowski.

4. Which of the following scientists concluded that tobacco mosaic disease was caused by organisms capable of reproduction?
Miller.
Meyer.
Beijerinick.
Iwanowski.

5. Which of the following scientists demonstrated that tobacco mosaic disease could be transferred from an infected plant to a healthy plant in the juice extracted from the infected plant?
Miller.
Meyer.
Beijerinick.
Iwanowski.

6. Which of the following scientists conducted experiments that led to his belief that the cause of tobacco mosaic disease was either a very small bacterium or a toxin produced by the bacteria?
Miller.
Meyer.
Beijerinick.
Iwanowski.

7. The structure of Bacteriophage T4 is BEST described as an arrangement of
proteins surrounding a chromosome made of DNA.
proteins surrounding a chromosome made of RNA.
chromosomes made of DNA surrounding a core of proteins.
chromosomes made of RNA surrounding a core of proteins.

8. Viral specificity, the fact that a given type of virus can only affect one kind of host cell, is
because of toxins produced by non-host cells.
a result of the matching of chemical structures.
an indication of their relative strength or weakness.
nature’s way of ensuring a wide distribution of viruses.

9. A “phage” (short for bacteriophage) is a type of
bacterial cell.
virus that invades bacteria cells.
cell that is prone to bacterial infections.
bacteria that is prone to viral infections.

10. E. coli lives in
water.
bacteria.
blood cells.
intestines of mammals.

11. Which of the following sequences BEST describes the lytic cycle?
Infection — replication — self-assembly — lysis.
Replication — infection — self-assembly — lysis.
Lysis — replication — self-assembly — infection.
Lysis — self-assembly — infection — replication.

12. A lysogenic cycle differs from a lytic cycle in several ways. Which of these is NOT one of them?
The cycle includes a period of “dormancy.”
The host cell doesn’t burst open, it just eventually dies.
The viral chromosome joins the host cell’s genetic material.
The genetic material of the virus is produced by the host cell.

13. A prophage is BEST described as
active viral genetic material.
dormant viral genetic material.
active bacterial genetic material.
dormant bacterial genetic material.

14. The genetic material of a retrovirus will organize the synthesis of
DNA from its RNA structure.
DNA from its DNA structure.
RNA from its RNA structure.
RNA from its DNA structure.

15. Retroviruses are significant in studies of human diseases because they inject
cancer-causing genes.
cancer-preventing genes.
genetic material that produces cancer-causing genes.
genetic material that produces cancer-preventing genes.

16. RNA differs from DNA in all of the following EXCEPT one. Which one?
RNA contains uracil, while DNA doesn’t contain uracil.
RNA is single stranded, while DNA is double stranded.
RNA contains ribose, while DNA contains deoxyribose.
RNA is not normally found in human cells, while DNA is.

17. A pathogen is BEST described as a
toxic chemical.
virus or bacterium.
carrier of a disease.
disease-causing microbe.


18. Certain types of white blood cells release proteins that clump together foreign cells. What are these proteins called?
Antibiotics.
Antibodies.
Pathogens.
Interferons.

19. Interleukins, proteins released by certain white blood cells, function to
absorb pathogens in the blood stream.
activate other white blood cells during an infection.
deactivate the immune system after an infection has passed.
warn body cells that there are pathogens in the blood stream.

20. Which of the following is typical of passive immunity?
It is relatively short-lived.
A person makes their own antibodies.
It comes and goes depending on a person’s health.
It can be induced by injecting a weakened pathogen.