5/15/14

Chapter 21 worksheet answers:

1. Viruses do not grow, do not maintain homeostasis,
and do not metabolize.
2. They found that infected tobacco plant sap
from which bacteria had been filtered still
caused the disease.
3. Purified tobacco mosaic virus could be crystallized,
which is a property of chemicals.
4. b
5. d
6. a
7. c
8. In the lytic cycle, the viral genes enter the cell
and use the host cell to replicate viral genes
and to make viral proteins, such as capsids.
Complete viruses are formed, and the cell is
broken open and destroyed, releasing the
viruses. In the lysogenic cycle, the viral genome
replicates without destroying the host cell.
9. A provirus is the viral gene that has been
inserted into the host chromosome during the
lysogenic cycle. A pathogen is any agent that
causes disease.
10. HIV is the name of the virus that causes
AIDS. Individuals who have AIDS are unable
to defend themselves against infections that
do not normally occur in healthy individuals.
11. T
12. F
13. F
SECTION 21-2
1. bacteria
2. bacteria
3. eukaryotes
4. eukaryotes
5. bacteria
6. bacteria
7. bacteria
8. Gram-negative
9. bacteria and eukaryotes
10. pili and flagella
11. antibiotics
12. photosynthetic
13. photosynthetic
14. chemoautotrophic
15. heterotrophic
16. Bacteria compete for the proteins, fats, carbohydrates,
minerals, and vitamins in your body.
17. Borrelia burgdorferi causes Lyme disease.
Lyme disease is transmitted by the bite of an
infected tick.
18. Dense collections of Streptococcus mutans
bacteria in the mouth cause tooth decay.
19. Bacteria harm hosts by metabolizing their
hosts or by releasing toxins that are poisonous
to eukaryotic cells.
20. penicillin
21. viruses
22. T
23. T
24. F