2.4: HIV

Virus recap:

Acellular and nonliving

Have a coat around the core (capsid)

Attachment proteins help virus attach to host cell

Core of genetic material (DNA or RNA)

Have no cytoplasm or ribosomes

What is transcription?

An RNA molecule is made from a DNA template by RNA polymerase

What is translation?

Polypeptide is made from RNA template by ribosomes

What is reverse transcription?

DNA molecules are made from an RNA template using reverse transcriptase

What is step one of the life cycle of HIV?

Binding: Protein on HIV readily binds to a protein called CD4. HIV most frequently targets helper T cells.

What is step two of the life cycle of HIV?

Fusion: protein capsid fuses with cell-surface membrane. RNA and enzymes of HIV enter helper T cell.

What is step three of the life cycle of HIV?

Reverse transcription: HIV reverse transcriptase converts virus’s RNA into DNA

What is step four of the life cycle of HIV?

Integration: Newly made DNA is moved into the helper T cell’s nucleus where it is integrated into the cell’s DNA

What is step five of the life cycle of HIV?

Replication: HIV DNA in nucleus creates mRNA using cell’s enzyme’s. the mRNA holds instructions for new RNA to go into the new HIV.

What is step six of the life cycle of HIV?

Assembley: mRNA passes out of the nucleus through a nuclear pore and uses cell’s protein synthesis mechanisms to make more HIV

What is step seven of the life cycle of HIV?

Budding: HIV particles break away from the helper T cell with a piece of its cell-surface membrane to form the lipid envelope in virus particles.

Order these stages of the HIV life cycle:

Fusion

Assembley

Budding

Binding

Reverse transcription

Replication

Integration

Binding

Fusion

Reverse transcription

Integration

Replication

Assembley

Budding

How does HIV cause AIDS?

Infection of HIV leads to death of T helper cells

Less T helper cells = less activation of B lymphocytes, less phagocytes, and less cytotoxic T cells

If untreated, patients can die from other infections such as pneumonia, TB, or cancer.

How do antibiotics work?

1. Disrupting the cell wall of the bacteria

2. Disrupting the proces of cell division

3. Disrupting another aspect of their metabolism

Why will antibiotics not work with viruses?

Viruses do not have a cell wall

Viruses do not carry out cell division

Virsues don’t have a metabolism