Exam 3 Concepts

Question 1

Characteristics of viruses

Answer 1

Obligate intracellular parasites of bacteria, protozoa, fungi algae, plants, and animals
Ultramicroscopic size, ranging from 20 nm up to 450 nm (diameter)
Not cellular in nature; structure is very compact and economical
Do not independently fulfill the characteristics of life
Inactive macromolecules outside the host cell and active only inside host cells
Basic structure consists of protein shell (capsid) surrounding nucleic acid core
Nucleic acid of the viral genome is either DNA or RNA but not both
Nucleic acid can be double-stranded DNA, single-stranded DNA, single-stranded RNA, or double-stranded RNA
Molecules on virus surface impart high specificity for attachment to host cell
Multiply by taking control of host cell’s genetic material and regulating the synthesis and assembly of new viruses
Lack enzymes for most metabolic processes
Lack machinery for synthesizing proteins

Question 2

What are used in descriptions of viruses ?

Answer 2

o

Question 3

What does replication viruses include?

Answer 3

HIV replicates in cells with CD4

Influenza virus attacks epithelial cells that have specific cell surface