Plant Structure & Function Qs Flashcards
What is photosynthesis?
When PLANTS use LIGHT ENERGY to produce GLUCOSE and OXYGEN from CO2 and WATER reacting in the CHLOROPLAST
Write the word equation for photosynthesis
Carbon Dioxide + Water —> Glucose + Oxygen
Write the symbol equation for photosynthesis
CO2 + H2O → C6H12O6 + O2
What type of reaction is photosynthesis?
Endothermic (takes in light energy)
What factors affect the rate of photosynthesis?
Temperature; light intensity; carbon dioxide concentration
What is glucose used for?
Respiration, to make protein, to convert into starch and be stored
Why do plants only store glucose in the form of starch?
- Starch is large and insoluble
- Can be stored
- Will not diffuse out of chloroplast
Explain how light intensity affects the rate of photosynthesis
- Higher light intensity
- Higher/faster rate of photosynthesis
- Light energy is needed/used in photosynthesis
Explain how CO2 concentration affects the rate of photosynthesis
- Carbon dioxide is a reactant
- It is needed/used in photosynthesis
Explain how temperature affects the rate of photosynthesis
- Increase in temperature = more kinetic energy
- Enzyme and substrate collide more = more enzyme substrate complexes
- Decrease on graph = enzyme/active site denatures
- Active site changes shape
- No enzyme substrate complexes form
Describe light intensity as a limiting factor
- Light intensity is a limiting factor
- As LI increases, rate of photosynthesis increases
- To a certain point
- Beyond, the rate of P. slows down
- Temp. and conc. of CO2 are limiting factors
Describe concentration of CO2 as a limiting factor
- Conc. of CO2 is a limiting factor
- As C increases, rate of photosynthesis increases
- To a certain point
- Beyond, the rate of P. slows down
- Temp. and LI are limiting factors
Describe temperature as a limiting factor
- As temp. increases, rate of P increases
- Up to a certain point
- Beyond, rate of P decreases and stops
Describe how water enters the root hair cells
- High conc. = soil
- Low conc. = root hair cell
- Water moves from soil to cell via osmosis
Describe the structure of a leaf
Waxy Cuticle Epidermal Cells Palisade Cells Spongy Mesophyll Layer Xylem and Phloem Tubes Guard Cells Stomata
How do mineral ions enter root hair cells?
- Area of high conc. = root hair cell
- Area of low conc. = soil
- Mineral ions move from soil to cell
- via active transport (energy needed)
What are adaptations of root hair cells?
- Are many of them and long = more water and mineral ions absorbed
- Thin walls = large surface area + short diffusion distance
- Mitochondria= provides energy (active transport)
What conditions speed up the rate of transpiration?
- Hot day
- Dry day
- Windy day
- Sunny day
What conditions slows down the rate of transpiration?
- Cold day
- Humid day
- Still day
- Dull day
What is translocation?
- Movement of sugar
- In the form of sucrose
- Through the phloem tube
- In both directions
- Phloem tube has sieve plates
Describe the function of the stomata?
- Gas exchange
- Allows water vapour to leave/evaporate (via diffusion)
What is transpiration?
- Movement/loss of water vapour from leaves
- Water vapour evaporates and diffuses out of the stomata
Why is there more stomata at the bottom pf a leaf compared to the top?
- Prevents evaporation of water vapour from the leaf
- Decreases transpiration (water loss)
How is transpiration measured?
- Using a potometer
What is the role of companion cells?
Controls movement of sucrose (has nucleus unlike phloem tube)
