Handout #3 - HIV Part 2 - Definitions

Question 1

What does HIV stand for?

Answer 1

Human Immunodeficiency Virus

Question 2

What does AIDs stand for?

Answer 2

Acquired Immune Deficiency Syndrome

Question 3

Nucleocapsid protien

Answer 3

A small but extremely important protein that stabilizes the HIV RNA in free virus particles and also plays a critical role in several steps in viral multiplication inside host cells.

Question 4

Attachment (HIV Reproduction) - Long Definition

Answer 4

The virus binds with the gp120 to the CD4 receptor. Upon binding it undergoes a shape change that allows it to bind secondarily to co-receptors. Secondary binding is required for viral entry into the host cell. Secondary binding occurs to one or the other host molecules called CXCr4 or CCr5.

Question 5

Attachment (HIV Reproduction) - Short Definition

Answer 5

Fusion of HIV to host cell’s surface.

Question 6

Entry (HIV Reproduction) - Short Definition

Answer 6

The virus gets into the cell, and the capsid stays outside.

Question 7

Entry (HIV Reproduction) - Long Definition

Answer 7

Viral membrane fuses with the host cell membrane and the nucleic acid core is released into the cell. gp41 is required for the fusion process. Capsid proteins remain affiliated with core, and appear to help protect it from host cell defence responses.

Question 8

Formation of Viral DNA (HIV Reproduction) - Short Definition

Answer 8

Viral DNA is formed by reverse transcription outside of the nucleus.

Question 9

Formation of Viral DNA (HIV Reproduction) - Long Definition

Answer 9

Once inside the host cell, reverse transcriptase converts the single stranded RNA into double stranded DNA as the nucleic acid core moves through the cytoplasm to nuclear pores.

Question 10

Integration (HIV Reproduction) - Short Definition

Answer 10

Viral DNA is transported across the nucleus and integrates into the host DNA.

Question 11

Integration (HIV Reproduction) - Long Definition

Answer 11

Viral DNA combines with integrase (which was brought into the cell with the viral core) and then integrated into the host genome.

Question 12

Translation (HIV Reproduction)

Answer 12

Viral mRNA is exported to, and translated in the cytoplasm (it’s used as genomic RNA and to make viral proteins).

Question 13

Formation of Immature Virus Particles (HIV Reproduction) - Short Definition

Answer 13

New viral RNA moves to the surface of the cell.

Question 14

Formation of Immature Virus Particles (HIV Reproduction) - Long Definition

Answer 14

New proteins and some of the mRNA moves to the host membrane where host proteins promote budding and release o the immature virus.

Question 15

Maturation (HIV Reproduction) - Short Definition

Answer 15

Virus matures.

Question 16

Maturation (HIV Reproduction) - Long Definition

Answer 16

The new viral particles mature when the viral protease enzyme cuts longer polypeptides into functional units.

Question 17

Clinical latency

Answer 17

The time between acute infection and the onset of AIDS. Viral reproduction occurs at low rates, mainly in lymph nodes. CD4+ levels are slowly depleted. Only 0.25-0.3% of infected cells release new viral particles.