Specific Diseases

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CognitoSpecific diseases — bacteria, viruses, fungi, protists

Key facts & methods

Measles: virus. Spread by droplets (coughs/sneezes). Symptoms: fever, red rash. Complications: pneumonia, brain damage. Prevented by MMR vaccination.
HIV: virus. Spread by sexual contact or exchange of body fluids (e.g. sharing needles). Attacks immune cells (T-lymphocytes). Late stage = AIDS (immune system fails). Antiretroviral drugs slow progression. No cure.
TMV (Tobacco Mosaic Virus): infects plant cells. Spread by contact/vectors. Causes mosaic discolouration of leaves. Reduces photosynthesis → stunted growth. No cure — infected plants removed.

Salmonella: bacteria. Spread by contaminated food (especially poultry). Symptoms: fever, abdominal cramps, vomiting, diarrhoea. Prevented by food hygiene, cooking thoroughly, vaccinating poultry.
Gonorrhoea: bacteria (Neisseria gonorrhoeae). STI — spread by sexual contact. Symptoms: thick yellow/green discharge, pain urinating. Treated with antibiotics — but antibiotic resistance increasing. Prevented by barrier contraception (condoms).

Rose black spot: fungus (Diplocarpon rosae). Black/purple spots on rose leaves → leaves turn yellow and drop. Spread by water/wind. Treated with fungicides; affected leaves removed and destroyed.
Malaria: protist (Plasmodium). Spread by female Anopheles mosquito (vector). Symptoms: fever, sweating, vomiting — recurring. Prevented by: mosquito nets, insect repellent, draining stagnant water, antimalarial drugs.

Vaccination: measles (MMR), salmonella in poultry.
Antibiotics: gonorrhoea (bacterial), but antibiotic resistance is a growing problem.
Antiretroviral drugs: HIV — slow replication but do not cure.
Barrier methods: condoms reduce sexually transmitted infections.
Vectors: controlling mosquito populations reduces malaria.
Hygiene: hand washing, food preparation, isolating infected individuals.

Exam questions — 5 questions · 11 marks · AQA 8461 style

1 markHIV transmissionAQA 8461 style

HIV is transmitted by:

A Droplets from coughs and sneezes

B Contact with infected water supplies

C Sexual contact or exchange of body fluids such as blood

D Insect vectors

1 markRose black spotAQA 8461 style

Rose black spot affects roses by:

A Causing brown rot in the roots, preventing water uptake

B Producing black/purple spots on leaves which turn yellow and fall off, reducing photosynthesis

C Blocking xylem vessels so water cannot reach the leaves

D Producing toxins that kill leaf cells directly

4 marksCompare disease preventionAQA 8461 style

Compare the methods used to prevent malaria with those used to prevent measles. (4 marks)

Hint: Measles = vaccination. Malaria = vector control. Compare the approaches and explain why they differ.

+40 XP

3 marksAntibiotic resistance concernAQA 8461 style

Gonorrhoea is now much harder to treat than in the past. Explain why, in terms of antibiotic resistance. (3 marks)

Hint: Natural selection: mutation → resistant bacteria survive → reproduce → resistance spreads. This is an evolution question.

+30 XP

1 markHIV treatmentAQA 8461 style

What type of drug is used to treat HIV, and what does it do?

A Antibiotics — kill the HIV virus directly

B Antiretroviral drugs — slow the rate at which HIV replicates, delaying progression to AIDS

C Vaccines — prevent HIV infection after exposure

D Fungicides — target the protein coat of the virus