Infection & ResponseDefinitions

Key Definitions

Part of Plant Diseases and Defenses · GCSE GCSE Biology revision

This definitions covers Key Definitions within Plant Diseases and Defenses for GCSE Biology. Plant pathogens, defense mechanisms, disease identification, crop protection It is section 14 of 18 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.

Topic position

Section 14 of 18

Practice

22 questions

Recall

21 flashcards

Key Definitions

Pathogen A microorganism (or other agent) that causes disease in a host organism.

Cuticle A waxy, waterproof layer covering the outer surface of leaves and stems, acting as a physical barrier against pathogen entry.

Tobacco Mosaic Virus (TMV) A viral plant pathogen that causes a mosaic pattern of light and dark patches on leaves by disrupting chloroplast function, reducing photosynthesis and stunting growth.

Rose black spot A fungal disease of roses (caused by Diplocarpon rosae) that produces black/purple spots on leaves, causes yellowing (chlorosis), and leads to early leaf fall.

Chlorosis Yellowing of leaves caused by loss of chlorophyll, resulting in reduced photosynthesis. A common symptom of plant disease or nutrient deficiency.

Antimicrobial compound A chemical produced by a plant (e.g., tannins, essential oils) that kills or inhibits the growth of bacteria, fungi, or other microorganisms.

Vector An organism (e.g., aphid) that carries and transmits a pathogen from one host plant to another without being harmed itself.

Induced response A defense mechanism that is activated only when a pathogen is detected, producing antimicrobial chemicals or strengthening cell walls at the site of attack.

Keep building this topic

Read this section alongside the surrounding pages in Plant Diseases and Defenses. That gives you the full topic sequence instead of a single isolated revision point.

How It Works: Plant Defense Systems Common Misconceptions The Silent Battle in Your Garden Key Facts: Plant Diseases

Practice Questions for Plant Diseases and Defenses

What type of pathogen causes rose black spot disease?

A. Fungus
B. Virus
C. Bacterium
D. Protist

1 markfoundation

Explain how rose black spot affects the growth of infected plants.

2 marksstandard

Quick Recall Flashcards

What is a plant pathogen?

A microorganism that causes disease in plants, such as fungi, bacteria, or viruses.

What is rose black spot?

A fungal disease that affects roses, causing black or purple spots on leaves, which turn yellow and drop off, reducing photosynthesis.

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How It Works: Plant Defense Systems

Common Misconceptions