Plant Structures and their functions topic 6 Flashcards
Card 1: Photosynthetic Organisms (6.1)
Key Concept: Photosynthetic organisms like plants and algae are the main producers of food and biomass on Earth.
Fact: They convert light energy into chemical energy through photosynthesis, forming the base of most food chains.
Card 2: Photosynthesis as an Endothermic Reaction (6.2)
Key Concept: Photosynthesis is an endothermic reaction, meaning it absorbs energy.
Equation: Carbon dioxide + Water → Glucose + Oxygen (in the presence of light and chlorophyll).
Fact: Light energy is essential to drive this reaction.
Card 3: Factors Affecting Photosynthesis (6.3)
Key Factors:
Temperature: Enzymes work best at an optimum temperature.
Light intensity: More light increases photosynthesis up to a point.
CO₂ concentration: Higher levels of CO₂ increase the rate until saturation.
Card 4: Limiting Factors in Photosynthesis (6.4)
Interaction of Factors: Photosynthesis can be limited by temperature, light intensity, or CO₂ concentration. If one factor is less than ideal, it becomes the limiting factor.
Card 5: Core Practical - Light Intensity and Photosynthesis (6.5)
Experiment Setup: Use pondweed and vary the distance of the light source to observe the effect on the rate of photosynthesis (measured by oxygen bubbles).
Conclusion: The rate increases as light intensity increases.
Card 6: Light Intensity and the Inverse Square Law (6.6)
Inverse Square Law: The rate of photosynthesis is inversely proportional to the square of the distance from a light source.
Formula: Intensity = 1 / (distance²).
Card 7: Root Hair Cells (6.7)
Adaptation: Root hair cells have a large surface area to absorb water and minerals efficiently.
Fact: They use active transport to take in mineral ions from the soil.
Card 8: Xylem and Phloem (6.8)
Xylem: Lignified dead cells that transport water and minerals upwards through the plant.
Phloem: Living cells that transport sucrose and other nutrients around the plant using energy (translocation).
Card 9: Transpiration and Stomata (6.9)
Process: Water moves from roots to leaves via xylem, evaporating from stomata.
Stomata Function: Control water loss and gas exchange by opening and closing.
Card 10: Translocation (6.10)
Process: Sucrose is transported through phloem from sources (leaves) to sinks (roots, fruits).
Energy Use: Active process requiring energy.
Card 11: Leaf Adaptations for Photosynthesis and Gas Exchange (6.11B)
Structure: Thin, large surface area, chlorophyll in palisade cells, stomata for gas exchange.
Function: Maximizes light absorption and gas exchange for efficient photosynthesis.
Card 12: Water Uptake and Environmental Factors (6.12)
Factors:
Light intensity: Increases transpiration.
Air movement: Faster air increases water loss.
Temperature: Higher temperatures increase transpiration rate.
Card 13: Rate Calculations for Transpiration (6.13)
Formula: Rate of transpiration = (Volume of water lost) / (Time).
Measurement: Use a potometer to measure water uptake.
Card 14: Plant Adaptations in Extreme Environments (6.14B)
Adaptations:
Smaller leaves or spines to reduce water loss.
Thick waxy cuticle to minimize water evaporation.
Sunken stomata to reduce transpiration.
Card 15: Plant Hormones and Growth (6.15)
Hormones:
Auxins: Control phototropism (response to light) and gravitropism (response to gravity).
Gibberellins: Stimulate growth and seed germination.
