RETROVIRIDAE , HIV , AIDS - MMRS

Question 1

Inactive oncogenes in animals and humans are called?

Answer 1

Proto-oncogenes

Question 2

Genes in humans and animals that can cause the malignant transformation of normall cells into cancer cells?

Answer 2

Oncogenes

Question 3

This enzyme is an RNA-dependent DNA polymerase that converts the viral RNA into DNA.

Answer 3

Reverse Transcriptase

Question 4

When normal cells grow on a plate of nutrient media, they form a single layer and stop dividing when they touch each other. This is called?

Answer 4

Contact Inhibition

Question 5

These are normal cells that has receptor proteins in the cell membrane that regulate cell growth which binds to receptors to regulate growth.

Answer 5

Mitogens/ Growth Factors

Question 6

This acts as an intracellular growth messenger after being phosphorylated?

Answer 6

Phosphotyrosine

Question 7

Oncogene that encodes a transmembrane protein that also phosphorylates tyrosine but at ten times the normal rate?

Answer 7

Rous Sarcoma Virus Oncogene ( scr)

Question 8

Virus linked to a paralytic disease that occurs in the tropics ( Caribbean Islands) called tropical spastic paraparesis?

Answer 8

HTLV-I

Question 9

What human retrovirus was isolated from T-cells of patients with a T-cell variant of hairy cell leukemia and this virus has no known role in producing disease?

Answer 9

HTLV-II

Question 10

Are sequences that code for the proteins inside the envelope thus code for the virion’s major structural proteins that are antigenic?

Answer 10

gag ( Group antigen) : CA (p24), MA, NC

Question 11

What are the viral core proteins? (3)

Answer 11

1. CA ( capsid -p24)
2. MA ( matrix)
3. NC ( nucleocapsid)

Question 12

This flank the whole viral genome and serve 2 important functions such as promoter / enhancing function and involves in the insertion of virus into the host DNA.

Answer 12

LTRs - Long terminal repeat sequence)

Question 13

This encodes the vital protease, integrase and reverse transcriptase enzymes.

Answer 13

pol

Question 14

Is a vital HIV enzyme that cleaves gag and pol proteins from their larger precursor molecules ( post translational modification).

Answer 14

Protease

Question 15

This codes for the envelope proteins that, once glycosylated from glycoprotein , form the glycoprotein spikes gp120 & gp41.

Answer 15

env

Question 16

Regulatory and accessory proteins termed as early proteins due to their activities in HIV early life cycle? (3)

Answer 16

1. tat
2. rev
3. nef

( Ta ReNe! para Early )

Question 17

Regulatory and accessory proteins termed as late proteins due to their activities in the late stage of HIV replication? (3)

Answer 17

1. vif
2. vpr
3. upu

(Very Very late, Upu )

Question 18

This protein encodes the viral transactivator protein. It binds to the viral genome and activates transcription. This is a potent promoter of viral activity.

Answer 18

tat

TransAcTivator protein

Question 19

Is another promoter that revs up viral activity by achieving a unique mechanism where it binds to the env gene to decease splicing and revs up the reading of gag, pol, and env to produce virions.

Answer 19

rev

Question 20

Is crucial to the HIV virulence and evasion of the host immune system. It down regulates expression of both CD4 and MHC Class I on the infected CD4 cell, thereby helping it escape the hosts cytotoxic T cell mediated killing.

Answer 20

nef

Question 21

Is required for double-stranded DNA to be produced from the HIV RNA genome and has also been found to block the effects of APOBEC3 enzyme.

Answer 21

vif

Question 22

Is an exciting family of enzymes that can breakdown newly synthesized viral DNA. And appears to represent an innate antiviral defense.

Answer 22

APOBEC

Question 23

Plays an important role in regulating nuclear import of HIV-1 and is required for virus replication on non-dividing cells, such as macrophages.

Answer 23

vpr ( viral protein r )

Question 24

Is able to down regulate CD4 and MHC I expression on cell surfaces and it facilitates HIV virion release from infected cells.

Answer 24

upu

Question 25

Three essential retroviral enzymes & are parts of Pol proteins ?

Answer 25

1. **Protease** - is a vital HIV enzyme that cleaves gag and pol proteins from their larger precursor molecules. Protease deficiency HIV virions can not form their viral core and are non-infectious. 2. **Reverse Transcriptase** - converts viral RNA to DNA. 3. **Integrase** - facillitates integration into host DNA causing malignant transformation.

Question 26

Envelope proteins that once glycosylated, form the glycoprotein spikes? (2)

Answer 26

1. **gp 120** : head 2. **gp 41** : stalk Together they are called as gp160 and bind to CD4 receptors on T-cells

Question 27

Patients who **fail to produce normal levels of this protein appear to be resistant to HIV infection?**

Answer 27

CCR5

Question 28

Lymphocytes derived proteins that binds to CCR5 that appears to **inhibit HIV infection?** (3)

Answer 28

1. RANTES 2. MIP1-a 3. MIP1-beta