Chapter 21

Question 1

Structure of Virus

Answer 1

Non Cellular
Tiny infectious particles
1. Nucleic acids
2. Enclosed in Protein Coat (Capsid)
3. Membranous Envelope

Question 2

Capsid

Answer 2

Protein Shell that encloses viral genome.
Built from capsomeres (protein subunits)

Question 3

Membranous Envelope

Answer 3

Surrounds the capsid
Derived from host cell membrane
contains viral and host cell molecules

Question 4

Baltimore Classification

Answer 4

Virus classification on how mRNA is produced
Group 1,2, 3, 4, 5, 6, and 7

Question 5

Group. 1

Answer 5

dsDNA
mRNA transcribed directly from DNA template

Herpes Simpelx

Question 6

Group 2

Answer 6

SsDNA
DNA converted to DsDNA before RNa transcribed

Question 7

Group 3

Answer 7

DsDNA
mRNA transcribed from the RNA genome

childhood gastroenteritis

Question 8

Group 4

Answer 8

SsRNA
+
Genome functions as mRNA

Question 9

Group 5

Answer 9

mRNA transcribed from RNA genome
Rabies

Question 10

Group 6

Answer 10

SsRNA
viruses with reverse transcriptase

HIv

Question 11

Reverse transcriptase

Answer 11

Makes DNA from RNA genome.

The DNA is then incorporated in host genome

Then the mRNA is transcribed from incorporated DNA

Question 12

Group 7

Answer 12

DsDNA
Reverse transcriptase

Viral genome is DsDNA but viral DNA is replicated through RNA intermediate

The RNA may serve directly as mRNA or template to make mRNA

Hep B

Question 13

Virus Evolution Hypothesis
(3)

Answer 13

1. Devolution (Regressive Hypothesis)
2. Escapist (Progressive Hypothesis)
3. Self Replicating Hypothesis

Question 14

Devolution Hypothesis

Answer 14

Regressive Hypothesis

Virus started as more complicated organisms that has been evolutionary reduced

Question 15

Escapist Hypothesis

Answer 15

Progressive Hypothesis
Virus started from RNa and DNA molecules that escaped from host cell

Question 16

Self Replicating hypothesis

Answer 16

Virus originate from self relocating entities similar to transposing or other mobile genetic elements

Question 17

Lytic Cycle

Answer 17

Death of host cell
Produces new phase and breaks open the host cell wall to release progeny viruses

Question 18

Lysogenic Cycle

Answer 18

Replicates phage genome without host destroyed
Viral DNA incorporated into host cell chromosome

Question 19

Prophage

Answer 19

The integrated viral DNA
(Lysogenic Cycle)

Question 20

Retroviruses

Answer 20

uses enzyme reverse transcriptase to copy their RNA genome into DNA

HIV

Question 21

HIV

Answer 21

Human immunodeficiency virus

Causes AIDS (Acquired immunodeficiency syndrome)
Causes progressive failure of immune system.
Which allows infection or cancer to thrive

Question 22

The HIV life Cycle

Answer 22

1. virus fuses with host cell
2. Capsid with genome and protein enter
3. Viral reverse transcriptase transcribes viral RNA to DNA.
4. DNA enters the nucleus and viral integrate combines with host DNA
5. The new viral RNA is produced and creates viral proteins that combine to form new virions

Question 23

Vaccine

Answer 23

weakens solutions of virus components
Stimulates immune system to mount defense against pathogen

Question 24

AntiViral Drug

Answer 24

help to treat (not cure) viral infections

(Hard to develop as viruses use hosts replication machinery and drugs used to block virus development may harm host)

Question 25

Provirus

Answer 25

The viral DNA that is integrated into the host genome

Question 26

Acute Diseases

Answer 26

Symptoms worsen for short period time Followed by elimination of virus from the body by immune system or recovery

Question 27

Chronic Diseases

Answer 27

Virus persists in body for a long time

Question 28

chronic disease examples

Answer 28

Low Level Symptoms Intermittent Symptoms Asymptomatic

Question 29

Low Level Symptoms

Answer 29

Acute Disease Damage slowly EXA Hepatitus C and liver

Question 30

Intermittent Symptoms

Answer 30

Acute Disease Ex. Herpes

Question 31

Asymptomatic

Answer 31

No symptoms Ex Herpes 6 and 7

Question 32

Oncogenic Viruses

Answer 32

Ability to cause cancer DNA or RNA viruses Ex. Hepatitus C

Question 33

Animal Viruses

Answer 33

can insuce host cell to cooperate in process 1. Nonenveloped 2. Enveloped

Question 34

Receptor mediated endocytosis

Answer 34

form of endocytosis in which receptor proteins on the cell surface are used to capture a specific target molecule.

Question 35

Plant Viruses

Answer 35

Need mechanical damage to occur

Question 36

How do Plant get viruses

Answer 36

1. Horizontal transmission One plant to another (Via sap) 2. Vertical transmission Inherit virus from parent

Question 37

Hyperplasia

Answer 37

Abnormal proliferation of cells cause appearance of plant tumors known as Galls

Question 38

Hypoplasia

Answer 38

Decrease cell growth, thin yellow areas

Question 39

Cell necrosis

Answer 39

Directly killing plant cells

Question 40

The steps of Virus

Answer 40

1. Attachment 2. Entry 3. Replication/ Assembly 4. Egress Release new virions produced in host cell by budding or lysis

Question 41

Budding

Answer 41

Virions leave cell individually

Question 42

Lysis

Answer 42

Burst

Question 43

Apoptosis

Answer 43

cell suicide

Question 44

DNA Viruses

Answer 44

Viral DNA directs host cell replication proteins to synthesize new copies of viral genome to transcribe/translate the genome into viral proteins

Question 45

RNA Viruses

Answer 45

Encodes own enzyme that can replicate RNA into RNA RNA polymerase makes mistakes during transcription causing mutations to occur

Question 46

EXAMPLES of DNA virus

Answer 46

Chicken pox Hepatitus B Adenoviruses Herpes HIV

Question 47

EXAMPLES of RNA viruses

Answer 47

Influenza Hepatitus C Measles Rabies HIV

Question 48

Adenovirus

Answer 48

Non Enveloped Animal Virus Causes respiratory illness Uses glycoprotein spikes to attach to host

Question 49

Influenza

Answer 49

Nucleic acid and capsid protein in phospholipid bilayer Glycoprotein in envelope used to attach to host

Question 50

T4 Bacteriophage

Answer 50

Infects Escherichia coil Tail structure attacks to host Head houses DNA

Question 51

The Capsid Shapes

Answer 51

1. Helical 2. Icosahedral 3. Enveloped 4. Head & Tail

Question 52

How does HIV infect?

Answer 52

Uses CD4 molecules on T lymphocytes as one of its receptors

Question 53

CD4

Answer 53

Adhesion molecule which functions to keel diff types of immune cells in close proximity to each other during gen of T lymphocytes immune response.

Question 54

Tobacco mosaic disease

Answer 54

Transfer from plant to plant via plant extract Stunts growth and leaf color change