Sec 4 Biology Infectious Diseases topical questions

State the difference between an infectious and a non-infectious disease, giving one example of each.

Describe the structure of a virus.

Explain why a doctor does not prescribe antibiotics for influenza.

State two routes by which pathogens spread, and one measure that reduces transmission along one of them.

State three measures a school can take to reduce droplet transmission of respiratory infections among its students.

Explain how vaccination protects a person against a disease they have never had.

State two structural differences between a bacterial cell and a virus.

A town clinic vaccinates 340 of 400 residents in one week and reaches 380 of 400 the next. Calculate both coverage percentages, and explain why the higher coverage better limits the spread of droplet-borne disease.

Explain how the misuse of antibiotics leads to the spread of antibiotic-resistant bacteria.

Explain why a bacterium can reproduce outside a host cell but a virus cannot.

During an outbreak at a care home, 18 of 60 unvaccinated residents fell ill with influenza, but only 2 of 120 vaccinated residents did. Calculate the illness rate in each group and state how many times higher the risk was without vaccination.

A patient with a viral sore throat asks for antibiotics. Explain why the prescription would be useless and potentially harmful.

Describe the signs and symptoms of influenza, explain how it is transmitted, and state three measures that reduce its spread.

A single bacterial pathogen cell enters the body and divides every 30 minutes. Calculate how many cells descend from it after 4 hours, and explain two reasons why the body’s immune response is essential against such growth.

A patient is prescribed a 7-day antibiotic course but feels better on day 5 and stops. Calculate the percentage of the course completed, and explain fully why stopping early endangers both the patient and the wider community.

Compare influenza and pneumococcal disease in terms of causative agent, transmission and reduction measures, and explain why telling the two apart matters for treatment.

Plan an investigation to compare the number of bacteria on a student’s hands before and after washing. State how the bacteria are collected, the controls needed, and the expected result.

A described graph tracks a bacterial infection during a 7-day antibiotic course: the population falls from 100% to 20% in two days, to 2% by day 5, then — because the patient stops on day 5 — rebounds to 60% by day 10. Interpret each stage of the curve and explain what a completed course would have looked like.