Introduction Flashcards

1
Q

What does HIV do and What is the results?

A

preferentially infects and kills helper (CD4) T lymphocytes, resulting in the loss of cell-mediated immunity.

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2
Q

Does it only kils s helper (CD4) T lymphocytes?

A

No it also kill Other cells ( macrophages and monocytes) that have CD4 proteins on their surfaces

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3
Q

Describe it’s shape?

A

(Envolped) clylinder shape

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4
Q

What are the components of its genome?

A

2 identical molecules of single Strand postive polarity RNA(diploid

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5
Q

What are the typical retroviral genes?

A

gag, pol, and env.

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6
Q

What does typical retroviral genes encode?

A

structural proteins.

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7
Q

the genome RNA has six regulatory genes name them and specify their functions?

A

Two of these regulatory genes, tat and rev, are required for replication, and the other four, nef, vif, vpr, and vpu, are not required for replication and are termed “accessory” genes.

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8
Q

What does The gag gene encodes?

A

It encodes the internal “core” proteins

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9
Q

What is the most important protein of internal “core” proteins and Why?

A

p24 protein, It is important medically as it is the antigen in the initial serological test.

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10
Q

What does the pol gene encodes?

A

s several proteins, including the virion “reverse transcriptase,” an integrase and a protease.

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11
Q

What does the env gene encodes?

A

The env gene encodes gp160, a precursor glycoprotein that cleaved to form the two envelope (surface) glycoproteins, gp120 and gp41.

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12
Q

What is the use of Differences in the base sequence of the gp120 gene?

A

To subdivide HIV into subtypes called clades.

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13
Q

Which cells are attacked by Subtype B?

A

Subtype B preferentially infects mononuclear cells and appears to be passed readily during anal sex,

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14
Q

whereas subtype E infects?

A

subtype E preferentially infects female genital tract cells and appears to be passed readily during vaginal sex.

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15
Q

What are the Three enzymes are located within the nucleocapsid of the virion ?

A

reverse transcriptase, integrase, and protease.

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16
Q

The Tat protein and another HIV-encoded regulatory protein called Nef repress the synthesis of aprotein What is it?

A

class I major histocompatibility complex (MHC) proteins.

17
Q

What is the role of the other essential regulatory gene, rev?

A

To controls the passage of late mRNA from the nucleus into the cytoplasm.

18
Q

The accessory protein Vif (viral infectivity) enhances HIV infectivity How?

A

by inhibiting the action of APOBEC3G, an enzyme that causes hypermutation in retroviral DNA

19
Q

What is APOBEC3G?

A

It is “apolipoprotein B RNA-editing enzyme” that deaminates cytosines in both mRNA and retroviral DNA, thereby inactivating these molecules and reducing infectivity