Effects of Viruses on Host Cell

Question 1

What are 3 effects of viruses on host cells?

Answer 1

1. Cytocidal
2. Non-cytocidal
3. Cell transformation

Question 2

Cytocidal effects on host cells lead to cell death via ____________ or _____________

Answer 2

1. Lysis

2. Apoptosis

Question 3

Non-cytocidal effects of viruses on host cell lead to what kind of infections?

Answer 3

Persistent infections

Question 4

Cell transformation effects of viruses on host cells lead to __________ cells

Answer 4

Tumor

Question 5

What is a cytopathic or cytopathogenic effect?

Answer 5

Damaged or morphological changes to host cells during virus invasion

Question 6

Cell fusion involves the fusion of _____________ membrane of 4 or more cells to produce enlarged cell with 4 or more nuclei

Answer 6

Plasma

Question 7

Cell fusion results from fusion of an ______________ cell w/neighboring _______________ or _______________ cells

Answer 7

1. Infected
2. Infected
3. Uninfected

Question 8

T/F: Inclusion bodies in host cell during viral replication help ID certain viral infections

Answer 8

TRUE

Question 9

Inclusion bodies are abnormal structures in cell __________ or ____________ or both, having characteristic staining properties

Answer 9

1. Nucleus

2. Cytoplasm

Question 10

Inclusion bodies can be what 3 things?

Answer 10

1. Accumulation of viral components
2. Result from degenerative charges in cell
3. Crystalline aggregates of virions

Question 11

Acidophilic staining recognizes for ______ dyes and appear the color _________

Answer 11

1. Acid

2. Pink

Question 12

Baso Philip staining recognizes ________ dyes and appears a ______/_______ color

Answer 12

1. Basic

2. Purple/blue

Question 13

What are 5 types of mechanisms of virus-induced cell injury and death?

Answer 13

1. Inhibition of host-cell nucleic acid synthesis
2. Inhibition of host-cell RNA transcription
3. Inhibition of host-cell protein synthesis
4. Lysosomes release hydrolytic enzymes, which destroys cell
5. Interfere with cell membrane function

Question 14

Apoptosis is ___________ cell death

Answer 14

Programmed

Question 15

What mediates cell death?

Answer 15

Activation of host-cell caspase enzymes

Question 16

_____________ are responsible for degradation of cell’s own DNA and proteins

Answer 16

Caspases

Question 17

What is the intrinsic (mitochondrial) pathway?

Answer 17

Activated as result of increased permeability of mitochondrial membrane subsequent to cell injury

Question 18

How is the extrinsic (death receptor) pathway activated?

Answer 18

Activated by engagement of specific cell-membrane receptors, which are members of TNF receptor family

Question 19

Cytotoxic T lymphocytes and NK cells can initiate apoptosis, using preformed mediators such as ___________ and ____________ that directly activate caspases in target cell

Answer 19

1. Perforin

2. Granzyme

Question 20

Antibody-dependent cell mediated cytotoxicity results from what?

Answer 20

Surface membrane fusion of enveloped viruses

Question 21

What is cell transformation?

Answer 21

Change of normal cell to cancer cell

Question 22

What is neoplasia?

Answer 22

Abnormal tissue overgrowth that may be localized or disseminated

Question 23

What is a benign neoplasm?

Answer 23

Growth produced by abnormal cell proliferation that remains localized and does not invade adjacent tissue

Question 24

What is a malignant neoplasm?

Answer 24

Locally invasive and may also spread to other parts of body

Question 25

What is metastasis?

Answer 25

Spread of cancer cells from the part of the body where it started to other parts of body

Question 26

What are two important tumor suppressor genes?

Answer 26

Rb and p53

Question 27

What are tumor suppressing genes?

Answer 27

Plays role in keeping cell division in check and encodes proteins that regulate and inhibit uncontrolled growth

Question 28

What are proto-oncogenes?

Answer 28

Encode proteins that function in normal cellular growth an differentiation

Question 29

What are oncogenes?

Answer 29

Mutated forms of proto-oncogenes or aberrantly expressed proto-oncogenes

Question 30

What is Rb: retinoblastoma protein?

Answer 30

Important tumor suppression gene/protein that blocks E2F and keeps cell division in check

Question 31

What is p53 protiein?

Answer 31

Important tumor suppression gene/protein that prevents cells w/damaged DNA from entering cell division; if no repair can happen, mediated apoptosis

Question 32

Oncogenic viruses generally have a _________ genome

Answer 32

DNA

Question 33

What are oncogenic DNA viruses?

Answer 33

Have viral oncogenes in viral DNA

Question 34

What happens when oncogenic DNA viruses infect permissive cells?

Answer 34

They can replicate successfully and results in no cancer/cell lysis

Question 35

What happens when oncogenic DNA viruses infect non-permissive cells?

Answer 35

Cannot replicate and results in cancer or replication

Question 36

What are acutely transforming retroviruses?

Answer 36

Steal proto-oncogene from infected host cell DNA and the virus converts the proto-oncogene into oncogene (cancer causing gene)

Question 37

What is a slow/chronic transforming retrovirus?

Answer 37

Virus genome gets inserted into regulatory gene of host cell DNA and regulatory cannot function properly , resulting in excessive cell division or cancer

Question 38

What are tumor antigens?

Answer 38

New antigens appear on surface of tumor cells that may provoke immune response

Question 39

How are tumor antigens expressed?

Answer 39

FOCMA