4.3.2Unit 4: Energy, Environment, Microbiology and Immunity
Plant Products with Antimicrobial Properties — IAL Edexcel Linear Revision Notes & Topical Questions
5 min read 4 parts Lesson 18 of 28 Unit quiz
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Section 1 of 4Plant Defences
Plants are attacked by microorganisms, so they have evolved chemical defences.
Plant Defences
The threat
- The threat Bacteria and fungi can damage a plant and may even kill it.
Chemical defences
- Chemical defences Plants make antiseptic compounds and antibiotics that kill microbes or stop their growth.
Exploiting them
- Exploiting them Humans can use these chemicals as the basis for drugs to treat bacterial and fungal diseases.
Plant extracts
- Plant extracts An extract containing antimicrobial chemicals can be prepared and tested on bacteria in the laboratory.
Section 2 of 4Drugs from Plants
Many modern medicines were first discovered in plants.
Willow bark
- Willow bark Used for pain relief for centuries, its active ingredient was extracted and led to the development of modern aspirin.
Quinine
- Quinine A drug obtained from the cinchona tree that is used to treat and prevent malaria.
Other uses
- Other uses Plant compounds also provide medicines ranging from painkillers to cancer drugs.
Known dose
- Known dose Purifying the active compound allows medicines with a precise concentration, which gives a reliable dose.
Section 3 of 4Advantages of Isolating Compounds
Extracting and analysing the active ingredient brings several benefits.
1
The chemical structure of the active compound can be analysed to find out exactly what produces the effect.
2
Scientists can then make a synthetic version in the laboratory, so fewer plants need to be removed from the environment.
3
The molecule can be modified in the laboratory to make it more effective or to reduce side effects.
4
These developments have improved our ability to treat disease.
Section 4 of 4Exam Checklist & Tips
4.3.2 – Key Points for the Exam
- Antimicrobial A substance that kills microorganisms or prevents their growth.
- Antiseptic A chemical used to kill microbes on living tissue or surfaces.
- Active ingredient The chemical in a medicine that produces its effect.
- Synthetic Made artificially in a laboratory rather than extracted from a living organism.
Common Mistakes
- Saying plants make antibiotics for human use; they make them to defend themselves against microbes.
- Stating that quinine is used to treat bacterial infections, when it is an anti-malarial drug.
- Assuming that a plant extract has a standard dose, when the amount of active ingredient varies with the plant.
- Forgetting that synthetic copies reduce the need to harvest wild plants.
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