Stuff don't know

Question 1

How does HIV evade detection?

Answer 1

1. Kills immune system that it infects which reduces the chance of HIV being detected.
2. Antigenic variation as memory cells produced from one strain wont recognise the other strains.
3. HIV disrupts antigen presentation so it cannot be detected.

Question 2

How does TB evade detection?

Answer 2

1. When engulfed by phagocytes they produce substances that prevent the lysosome fusing with the phagocytotic vacuole. So bacteria aren’t broken down and can multiply undetected.
2. Disrupts APC

Question 3

What is biodiversity?

Answer 3

Variety of living organisms in an area

Question 4

What are the two types of biodiversity and define them?

Answer 4

Species diversity- number of different species and the abundance of each species

Genetic diversity- the variation of alleles within a species.

Question 5

What is endemism?

Answer 5

When a species is unique to a single place.

Question 6

Compare bacteria and viruses?

Answer 6

1. Viruses are not cells they’re just nucleic acids surrounded by protein.
2. They’re smaller than bacteria
3. They have no plasma membrane, no cytoplasm and no ribosomes.
4. But they do have nucleic acids like bacteria

Question 7

How does HIV replicate?

Answer 7

1. Attachment protein attaches to a receptor molecule of host T helper cell.
2. Capsid released into cell where it uncoats and releases genetic material (RNA) into cell cytoplasm.
3. reverse transcriptase is used to make a complimentary strand of DNA from the viral RNA.
4. Double stranded DNA is make and inserted into human DNA.
5. Host cells enzymes are used to make viral proteins from the viral DNA.
6. Viral proteins are assembled into new viruses which bud and go infect other cells.

Question 8

What are opportunistic infections?

Answer 8

Infections that otherwise wouldn’t cause serious problems in people with healthy immune system.

Question 9

Explain the symptoms of TB

Answer 9

1. Coughing, fever and general weakness.
2. Damages the lungs and can cause respiratory failure.
3. Spread to other organs and cause organ failure

Question 10

Explain the symptoms and progression of HIV

Answer 10

1. Initial infection- severe flu like symptoms while HIV replicates rapidly.
2. Then replication drops to lower level in latency and wont experience symptoms.
3. A person is classed as having AIDs when their Thelper cell count drops below 200.
4. Initial symptoms of AIDS progresses the number of Thelper cell count drops further and patient becomes more susceptible to infection including chronic diarrhoea.
5. Later stages suffer from severe infections that could kill them.

Question 11

What are the 4 main ways bacteria enters the body?

Answer 11

1. Cuts in the skin
2. Digestive system
3. Respiratory system
4. Mucosal surfaces

Question 12

How does CF cause the production of thick sticky mucus?

Answer 12

mutation in CFTR channel protein makes it much less efficient at transporting chloride ions out of the cell and into the mucus so less water moves out by osmosis.

Question 13

Ecosystem?

Answer 13

All the organisms living in a particular area and all the non living abiotic factors.

Question 14

Habitat?

Answer 14

Place where an organism lives.

Question 15

Population?

Answer 15

All the organisms of one species in a habitat.

Question 16

Community?

Answer 16

All the organisms of difference species that live in the same habitat and interact with each other.