HIV and Viruses 2C

Question 1

Define HIV

Answer 1

A virus which affects the immune system and eventually leads to aids

Question 2

What is AIDS

Answer 2

A condition where the immune system deteriorates and eventually fails this makes someone with AIDS more vulnerable to diseases. Initial symptoms include, minor infections of mucus membranes an recurring respiratory infections
As AIDS progresses patients are more prone to more serious infections and its these infections that kill the patient not HIV itself

Question 3

How does HIV affect the immune system

Answer 3

It infects and eventually kills T Helper cells and without T helper cells the immune system is unable to produce an effective response

Question 4

How do people develop AIDS

Answer 4

People develop AIDS when their T helper cell numbers are critically low

Question 5

Describe HIV structure

Answer 5

A core that contains genetic material (RNA) and some proteins including the enzyme reverse transcriptase which is needed for virus replication

A capsid

Extra outer layer called an envelope made up of a membrane from a previous host cell

Lots of attachment proteins

Question 6

How does HIV replicate

Answer 6

1. Attachment protein attaches to membrane of host cell
2. Capsid released into cell and it uncoats and releases RNA into the the cells cytoplasm
3. Inside the cell reverse transcriptase is used to make the complementary strand of DNA from the viral RNA template
4. Double stranded DNA is made and inserted into the human DNA
5. Host cell enzymes are used to make viral proteins from the viral DNA found within the human DNA
6. Viral proteins are assembled into new viruses which bud from the cell and go on to infect other cells

Question 7

Why do antibiotics not kill viruses

Answer 7

Antibiotics kill bacteria by interfering with their metabolic reactions

Bacterial enzymes and ribosomes are different from human enzymes and ribosomes. Antibiotics only target bacterial ones so that they don’t damage human cells

Viruses don’t have their own enzymes and ribosomes they use the ones in host cells so because they don’t have their own antibiotics can’t inhibit them as they don’t target human processes

Question 8

HIV treatment

Answer 8

Antiviral drugs these are designed to target the few virus- specific enzymes in HIV this is reverse transcriptase these are called reverse transcriptase inhibitors and they slow down the progression of HIV and AIDS

No cure best way is to control spread

Spread by unprotected sexual intercourse