Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Seed Structure: A seed consists of an embryo (the baby plant), a food store (cotyledon), and a tough outer skin called the testa. The food store provides energy until the plant can perform photosynthesis using and .
Germination Conditions: Seeds require three specific conditions to begin growing, often remembered as 'WOW': Water (), Oxygen (), and Warmth. Light is generally not required for the initial stages of germination.
The Germination Process: The seed absorbs , swells, and the testa splits. The radicle (young root) grows downwards first to anchor the plant and absorb nutrients, followed by the plumule (young shoot) which grows upwards.
Seed Dispersal: The process of spreading seeds away from the parent plant to reduce competition for space, light, and .
Methods of Dispersal: 1. Wind (light seeds with wings or hairs), 2. Water (buoyant seeds), 3. Animal Internal (seeds eaten and excreted), 4. Animal External (hooks/burrs that stick to fur), 5. Explosion (pods that burst open).
Respiration in Seeds: During germination, seeds use the stored glucose () and oxygen () to release energy for growth, producing and as by-products.
📐Formulae
💡Examples
Problem 1:
An experiment is set up with four test tubes containing seeds. Tube A: Dry cotton wool at . Tube B: Wet cotton wool at . Tube C: Wet cotton wool at . Tube D: Boiled water covered with oil at . In which tube will germination occur?
Solution:
Tube B
Explanation:
Germination requires Water (), Oxygen (), and Warmth. Tube A lacks . Tube C lacks Warmth ( is too cold). Tube D lacks (boiling removes dissolved oxygen and oil prevents more from entering).
Problem 2:
Identify the dispersal method for a dandelion seed which has a light, fluffy 'parachute' structure.
Solution:
Wind Dispersal
Explanation:
The 'parachute' increases the surface area of the seed, allowing it to be caught by air currents and carried away from the parent plant to prevent competition for and minerals.