Controlling Communicable Diseases | OCR A-Level Biology B (Advancing Biology) (H422)
Controlling Communicable Diseases
- 51 questions
- 4 subtopics
- Biology content, examined on all three papers
- Component 01, Component 02 and Component 03
Controlling Communicable Diseases is examined in all three written papers — the specification states that Components 01, 02 and 03 can each assess content from any of the five modules, so nothing is confined to one paper.
It covers vaccination and vaccination programmes, problems and ethics of vaccine development and use, antibiotics and antibiotic resistance and investigating antibiotics, disinfectants and hygiene.
Sample questions from Controlling Communicable Diseases
Answer each one closed book first, then open the answer.
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Vaccination and vaccination programmes
Why does a live vaccine usually give stronger and longer-lasting protection than a killed one?
Show the answer
The attenuated pathogen reproduces inside the body, so its antigens are presented in increasing amounts over a much longer period and a far larger clone of memory cells is produced. -
Vaccination and vaccination programmes
What is herd immunity?
Show the answer
Herd immunity is the protection of a whole population, including unvaccinated individuals, that arises when so many people are immune that the pathogen cannot find enough susceptible hosts to spread between. -
Problems and ethics of vaccine development and use
Give two reasons, other than its mutation rate, why no effective HIV vaccine has been produced.
Show the answer
The virus integrates into the host cell's own DNA where it can remain hidden, and it destroys the T helper cells that would otherwise coordinate a response against it. -
Problems and ethics of vaccine development and use
Why is a vaccination programme less effective in a population that is short of dietary protein?
Show the answer
Antibodies and lymphocytes are made of protein, so people who are protein deficient cannot mount a full response to the vaccine and gain much less protection from it. -
Antibiotics and antibiotic resistance
Name an antibiotic that inhibits nucleic acid synthesis and state how it works.
Show the answer
Ciprofloxacin inhibits DNA gyrase, the enzyme that unwinds bacterial DNA, so the DNA cannot be replicated. -
Antibiotics and antibiotic resistance
Describe two ways in which a resistant bacterium can survive an antibiotic.
Show the answer
It may produce an enzyme such as penicillinase that breaks the antibiotic molecule down, or its target protein may be altered so that the antibiotic can no longer bind to it. -
Investigating antibiotics, disinfectants and hygiene
State three variables that must be kept the same when the effects of two antibiotics are compared on one plate.
Show the answer
The volume and concentration of antibiotic soaked into each disc, the depth of the agar in the plate, and the age and density of the bacterial culture used to make the lawn. -
Investigating antibiotics, disinfectants and hygiene
Distinguish between a bacteriostatic and a bactericidal antibiotic.
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A bacteriostatic antibiotic stops the bacteria reproducing without killing them, leaving the immune system to clear them, whereas a bactericidal antibiotic kills the bacteria outright.
The 4 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Vaccination and vaccination programmes | Recall questions on how vaccines produce memory cells, live attenuated vaccines for measles and tuberculosis and their drawbacks, vaccines of killed pathogens and fragments, booster doses, herd immunity, who depends on it, and what happens when coverage falls. | 13 |
| Problems and ethics of vaccine development and use | Recall questions on antigenic variability and the yearly influenza vaccine, antigenic shift and pandemics, why no HIV vaccine exists, live vaccines reverting to virulence, the cold chain and rural distribution, protein deficiency, and the HPV vaccine and the ethical objections to it. | 13 |
| Antibiotics and antibiotic resistance | Recall questions on how different antibiotics attack a bacterium, why viruses are unaffected, the cell differences that make selective toxicity possible, how resistance spreads, and the hospital-acquired strains. | 13 |
| Investigating antibiotics, disinfectants and hygiene | Recall questions on testing antibiotics with discs on a bacterial lawn, measuring zones of inhibition and calculating their area, controls and control variables, penicillin against Gram-positive and Gram-negative bacteria, bacteriostatic and bactericidal antibiotics, disinfectants and antiseptics, and handwashing with soap. | 12 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
OCR A-Level Biology B (Advancing Biology) Active Recall Guide
Every topic, not just this one. 2,895 questions with their answers.