Connect the four Core drug requirements
Combine definition, bacterial treatment, resistance and the viral contrast.
Exam scope and assessment notes
Core and Extended · Biology 0970, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked; human subject-teacher review, supervised practical competence and cumulative assessment remain pending. Cambridge states that IGCSE 0970 has the same subject content as IGCSE 0610, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
Before you begin
- Distinguish bacteria from viruses; recall enzymes, chemical reactions, pathogens and reproduction of bacteria.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which is the correct four-idea combination?
What you will learn
- Use each requirement in a complete explanation
- Correct a mixed pathogen and drug claim
Connect the four Core drug requirements
Four Core links: introduced chemical effect; appropriate antibacterial use; drug-specific bacterial resistance; no direct antibiotic action against viruses. Original teaching model.
| Feature | Meaning |
|---|---|
| Definition | Introduced substance affects body chemical reactions |
| Use | Appropriate bacterial infections |
| Resistance | Bacterial survival reduces a specified drug’s effectiveness |
| Virus contrast | No direct antibiotic action against viruses |
Use each requirement in a complete explanation
A complete Core explanation keeps four ideas connected but distinct. A drug is an introduced substance that affects chemical reactions in the body. An antibiotic is a drug used for appropriate bacterial infections. Some bacteria are resistant to particular antibiotics, reducing those drugs’ effectiveness. Antibiotics do not directly affect viruses in the antibacterial treatment account.
Consider an invented account in which substance A is introduced into the body, kills susceptible bacteria and leaves strain R surviving, while a separate virus V remains unaffected. The chemical action makes A a drug; its susceptible bacterial effect is antibacterial action. R’s survival illustrates resistance to A, and V’s lack of response is consistent with the bacteria–virus distinction.
Correct a mixed pathogen and drug claim
The same account does not prove that the patient’s body has become resistant or that every antibiotic must fail against R. Nor does it justify using A whenever symptoms are unpleasant. Use the organism and drug labels, distinguish direct pathogen effects from symptom relief and retain the need for appropriate clinical use. This prevents a correct definition being attached to an incorrect treatment inference.
When answering an unfamiliar question, first identify what was introduced and what chemical effect is supplied. Then identify the pathogen category, any susceptibility evidence and the result. Keep the conclusion within that evidence. The Supplement lessons extend the Core resistance statement by explaining selection, reproduction and why avoiding unnecessary antibiotic exposure can limit development of resistant populations.
Pause and explain
What extra explanation is added in Supplement?
Worked example
Use the four Core ideas to describe the invented A, R and V account.
Show the worked solution
- A is an introduced chemically active drug used against susceptible bacteria.
- R resists A; V is a virus and is not directly affected.
Answer A is an antibacterial drug in the model; resistant R reduces its effectiveness, while virus V is not directly affected.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
List the four Core ideas in this section.
Give me a hint
Use one clear clause for each.
Compare my reasoning
- Define an introduced substance affecting body chemistry and appropriate antibacterial use.
- State bacterial resistance and the lack of direct viral action.
Drugs affect body chemical reactions after introduction; antibiotics treat appropriate bacterial infections; some bacteria resist particular antibiotics and reduce effectiveness; antibiotics do not directly act against viruses.
Look for these in your work
- Include all four ideas
- Keep bacteria and viruses distinct
Explain the roles of A, resistant strain R and virus V in the supplied account.
Give me a hint
Separate substance category and two pathogen outcomes.
Compare my reasoning
- A is a drug with antibacterial action in the model.
- R survives A; V has no direct antibiotic response.
A is an antibacterial drug in the supplied model. R’s resistance limits A’s effectiveness; virus V is not directly affected by A.
Look for these in your work
- Identify the antibacterial drug
- Describe both target outcomes
Correct: any unpleasant symptom needs an antibiotic because the patient’s body is resistant and antibiotics kill all viruses.
Give me a hint
Restore target, resistance and use distinctions.
Compare my reasoning
- Not every symptom or bacterial infection needs antibiotics; appropriate assessment matters.
- Resistance belongs to bacteria, and antibiotics do not directly target viruses.
Appropriate assessment determines antibiotic need. Resistance belongs to bacteria, not the patient’s body, and antibiotics do not directly act against viruses.
Look for these in your work
- Correct treatment need and resistance
- Correct the viral target claim
Common mistakes
- Merging drug definition with automatic treatment need.
- Changing bacterial resistance into host-body resistance.
What can you explain now?
What extra explanation is added in Supplement?
Compare with the explanation
Selection and reproduction of resistant bacteria under antibiotic pressure
It explains population development and essential use.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Connect all four Core requirements in one explanation without inventing personal treatment or viral effects.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.