4.1

Question 1

Properties of life that viruses lack

Answer 1

1. Not comprised of cells
2. Lack homeostasis/internal regulation
3. No growth or metabolism
   4.Do not respond to stimuli
4. Cannot reproduce as an organism/must manipulate host cell

Question 2

Virus

Answer 2

a non-living obligate intracellular parasite
*Super small and cannot see w/ microscope

Question 3

Virion

Answer 3

a virus that is extra cellular

Question 4

Genome

Answer 4

DNA or RNA, varies considerably in size and organization
*Controls the virus replication strategy
*Different types of genomes require different approaches in order to translate viral proteins

Question 5

Sense DNA (+DNA)

Answer 5

Non-template strand of DNA that is not transcribed

Question 6

Antisense DNA (-DNA)

Answer 6

Template-strand of DNA that gets transcribed

Question 7

Sense RNA (+RNA)

Answer 7

mRNA that is translated into a protein

Question 8

Antisense RNA (-RNA)

Answer 8

RNA that is a complimentary strand to translated mRNA

Question 9

Central Dogma

Answer 9

Antisense DNA is transcribed into Sense RNA
*DNA–>RNA–>Protein

Question 10

DNA Viruses

Answer 10

Type 1 (dsDNA) and Type 2 (ssDNA)

Question 11

RNA Viruses

Answer 11

Type 3 (dsRNA), Type 4 (+ssRNA), and Type 5 (-ssRNA)

Question 12

Retro Viruses

Answer 12

Type 6 (ssRNA-RT) and Type 7 (dsDNA-RT)

Question 13

Why is there a very high mutation rate?

Answer 13

Viral genomes are small and have little to no proofreading/repair mechanisms
*Fast mutation rates=new strains of same virus
*Many strains of HIV=super infections or co-infections

Question 14

Capsid

Answer 14

protein coat protecting the genome, may carry accessory proteins, composed of capsomeres which are made up of protomers

Question 15

Helical

Answer 15

repeated capsomeres that form a filamentous capsid surrounding the genomic material
Ex: Tobacco mosaic virus, Mumps virus, Ebola virus

Question 16

Polyhedral

Answer 16

capsomeres that form unique shape; may be referred to as cubic, regular, or isometric
Ex: Adenovirus, Herpesvirus

Question 17

Spherical

Answer 17

Has spherical capsid/proteins; sphere surrounding the genomic material
Ex: Influenza virus, Coronavirus

Question 18

Complex

Answer 18

“catch-all” group with no real pattern, often combination of several shapes but not classified as such
Ex: T4 Bacteriophage, Variola virus, Rabies virus

Question 19

Envelope

Answer 19

host-derived lipid membrane, contains host and viral proteins
*Not ever virus has an envelope i.e. “naked virus”
*Does not determine shape
*Can have various host proteins in its membrane and contain various capsid shapes (Enveloped virus with helical capsid)

Question 20

Attachment (Spike) Proteins

Answer 20

glycoproteins that recognize one or more specific host cell receptors
*Crucial for attachment; found on naked and enveloped viruses
*Needs host cell to attach and take over
*Controls viral tropism

Question 21

Viral Tropism

Answer 21

the spectrum of cells of a host that a virus may infect

Question 22

Human Immunodeficiency Virus

Answer 22

Glycoprotein (GP) 120: spike protein binds to CD4 and CCR5/CXCR4 found on WBC’s
*Mutations in the CCR5 receptor render the virus unable to attach the target cell; results in immunity to HIV-1 infections

Question 23

DNA Virus Types

Answer 23

Adenovirus, CMV, EBV, HPV, HSV-1, HSV-2, Parvovirus, Variola virus, VZV

Question 24

Retrovirus Types

Answer 24

HIV and HBV