Lesson 10: Viruses and Viral Molecular Biology

Question 1

What type of virus is Covid?

Answer 1

Coronaviridae: Single strand RNA Genome virus

Question 2

• Circular ssRNA
• does not encode gene products or protein products
• does not have capsid or envelope
• only targets eukaryotic cells
• associated with plant disease

Answer 2

Viroids

Question 3

Normal variant is alpha helix and mutant is beta-pleated sheets

Answer 3

Prions

Question 4

Disease is caused by prions

Answer 4

Kuru, Gerstmann-straussler-syndrome, scrapie, bovine spongyform encephalopathy

Question 5

Virulent phages exhibit the lytic cycle only intemperate features have what you reproductive options?

Answer 5

many of these integrate their genome them into the host becoming a prophage

• lytic cycle
• Lysogenic cycle( May change the phenotype of the host)

Question 6

Three forms of defense against bacteriophages

Answer 6

• genetic resistance, may alter receptor proteins to prevent binding
• restriction endonucleases, cut an palindromic sequence, viral DNA will be broken down
• crisper integration of phage DNA sequence

Question 7

Three mechanisms of animal virus entry

Answer 7

• Direct penetration, viruses buying to host cell receptors
• membrane fusion
• endocytosis

Question 8

DNA viruses replicate in the?

RNA Viruses replicate in the?

Answer 8

Nucleus

Cytoplasm

Question 9

The induction of defects during embryonic development leading to congenital defects that are present at birth and not genetic

Answer 9

Taratogens 
Ex:cytomegalovirus (herpes) 
HSV 1&2
Rubella can leave to deafness in damage to sense organs
HIV

Question 10

Occurs when the sale will reverse back to a more primitive or less definitive state

Answer 10

Anaplasia

Question 11

The five viruses that account for more than 15% of all the worlds cancer

Answer 11

HBV, HCV, HPV, EPV, and HTLV-I

Question 12

• largest group of known Viruses
• most bacteriophages
• important vertebrae Viruses (herpes, Poxviruses, Pappovirsies, and adenovirises

Answer 12

Group 1 double-stranded DNA Viruses

Question 13

Chicken pox virus

Answer 13

HHV-3

Question 14

Epstein bar virus

Answer 14

HHV-4

Question 15

Most common congenital infection in US can infect any solve the body, 50 to 80% of adults will be infected by the age 40

Answer 15

HHV-5 cytomegalovirus

Question 16

Double stranded DNA virus that causes 90% of cervical cancer‘s

Answer 16

Papovavirsus

Question 17

The only human single-stranded DNA disease

Answer 17

Erythrovirus, B19, fifth disease

Parvoviridase in dogs

Question 18

• RNA genomes cannot rely on host cell enzymes for GENOME and replication or mRNA synthesis
• RNA dependent RNA polymerase completes lifecycle
• rotavirus and coltivirus

Answer 18

Group 3 double-stranded RNA viruses

Question 19

Replicates in cytoplasm and synthesizes are in a dependent RNA polymerase

Answer 19

Group 4 (+) sense single-stranded RNA virus

Ex: positive non-enveloped strand RNA virus

Question 20

• enveloped virons , peolomorphic shape with segmented and nonsegmented genomes
• cannot serve as mRNA to form viral proteins
• must bring into cell preformed RNA dependent RNA polymerase

Answer 20

Group for negative sense single-stranded RNA virus

Ex: orthomyxoviridae-influenza viruses

Question 21

What are the influenza types?

Answer 21

A-infect humans and animals, associated with the pandemics and epidemics throughout history (pigs and birds are big reservoirs)
B- infects mammals only not as severe and do not have distinguishable stereotypes
C- only mammals, not often infectious disease, distinct from type A And B

Hemagglutinin (HA) 16 types
Neuraminindase (NA) more than 9 types

Question 22

Acts to attach the virus to the host cells, allows for fusion with host cell membrane

Answer 22

Hemagglutinin

Question 23

What influenza type undergoes both types of changes?

Answer 23

Type A

Antigenic drift happens all the time
Antigenic shift only happens occasionally

Question 24

Convert single-stranded RNA into double-stranded RNA using reverse transcriptase then integrates into host cells Genome to serve as a template for mRNA synthesis in genome synthesis

Answer 24

Group 6 retroviruses (reverse transcribing Viruses)

HIV-1 (and enveloped virus with two copies of RNA)

Question 25

Genetic information transitions through a RNA strand as part of their life cycle
Includes hepatitis B virus (only DNA virus to cause hepatitis)

Answer 25

Group 7 pararetrovirsus

Question 26

A system that classifies viruses mainly on their means of mRNA synthesis

Answer 26

The Baltimore system