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Name ______________________________ Class ___________________ Date __________________
Skills Worksheet
Viruses
Use the terms from the list below to fill in the blanks in the following passage.
bacteriophages
capsid
emerging diseases
envelope
lysogenic cycle
lytic cycle
prions
prophage
provirus
temperate viruses
viroids
viruses
Segments of nucleic acids contained in a protein coat are called
(1) _______________________. The protein coat, or (2) ___________________,
may contain RNA or DNA, but not both. Many viruses have a(n)
(3) _______________________, which surrounds the capsid and helps the virus
enter cells. Viruses that infect bacteria are called (4) _______________________.
Viruses cause damage when they replicate inside cells many times. When the
viruses break out, the cell is destroyed. The cycle of infection, replication, and cell
destruction is called the (5) _______________________
_______________________.
During an infection, some viruses stay inside the cells but do not make new
viruses. Instead, the viral gene is inserted into the host chromosome and is called
a(n) (6) _______________________. Whenever the cell divides, the provirus also
divides, resulting in two infected host cells. This type of replication cycle is called
a(n) (7) _______________________ _______________________. Viruses whose
replication includes the lysogenic cycle are called (8) _______________________
_______________________. When the DNA of a temperate phage is integrated
into the host’s chromosome, the phage is known as a
(9) _______________________.
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Modern Biology
47
Viruses
Name ______________________________ Class ___________________ Date __________________
Viruses continued
Diseases that evolve in a geographically isolated area and are caused by
pathogenic viruses are called (10) _______________________
_______________________. Infectious disease agents that have a single strand of
RNA and have no capsid are called (11) _______________________. There is a
newly discovered class of infectious particles called
(12) _______________________, which are composed of protein with no nucleic
acid.
In the space provided, write the letter of the description that best matches the term
or phrase.
_____ 13. retrovirus
_____ 14. reverse transcriptase
_____ 15. virulent
_____ 16. oncogene
_____ 17. vector
_____ 18. inactivated virus
_____ 19. lysis
_____ 20. attenuated virus
_____ 21. protease inhibitor
_____ 22. proto-oncogene
a. intermediate host that transfers a
pathogen
b. gene that causes cancer
c. the bursting of a cell, releasing new
viruses
d. RNA virus that contains reverse
transcriptase
e. viruses that reproduce only by the lytic
cycle
f. weakened form of a virus
g. blocks capsid synthesis
h. gene that can be converted into a
cancer-forming gene
i. cannot replicate in a host cell
j. uses RNA as a template to make DNA
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Modern Biology
48
Viruses