Plant structures and their functions
- Created by: Former Member
- Created on: 29-05-19 15:58
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- Section 6 - Plant structures and their functions
- Photosynthesis
- Plants use energy from the sun to produce glucose which helps grow more complex structures and adds to the biomass of the plant.
- Occurs within the chloroplasts
- Endothermic reaction
- Limiting factors in photosynthesis
- Not enough light slows down the rate
- rate is directly proportional to light intensity until a certain point where temperature or carbon dioxide is the limiting factor
- Too little Carbon Dioxide also slows it down
- If there is enough light and Carbon Dioxide then temperature must be the limiting factor
- Temperature has to be just right
- Enzymes work too slowly at lower temperatures
- If the temperature is too high the enzymes denature
- Not enough light slows down the rate
- Transport in plants
- Root hairs take in minerals and water
- Each branch of roots is covered with millions of microscopic hairs
- Increased surface area for absorbing minerals from the soil
- Mineral ions are absorbed by active transport and water is absorbed by osmosis
- Each branch of roots is covered with millions of microscopic hairs
- Pholem tubes transport food
- translocation process requires energy from respiration and goes both ways
- Xylem tubes take water up
- transpiration stream,through tubes of dead cells joined end to end
- Transpiration is the loss of water from the plant
- Constant transpiration through the plant
- Caused by the diffusion and evaporation of water from a plant's surface
- Root hairs take in minerals and water
- Stomata and transpiration
- Stomata are needed for gas exchange
- Tiny pores on the surface of plants that allow gas exchange
- Guard cells change shape to control the size of the pore
- Transpiration rate is affected by environmental factors
- Brighter light increases transpiration rate, stomata begin to close as it gets darker
- Light intensity
- Warmer temperatures increases rate
- Temperature
- In stronger winds the diffusion process is quicker
- Air flow
- Brighter light increases transpiration rate, stomata begin to close as it gets darker
- You can estimate a transpiration rate
- Use a potometer
- Stomata are needed for gas exchange
- Photosynthesis
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