Feb Flashcards
(34 cards)
What is the function of the upper epidermis?
It protects the leaf and is transparent to allow light to pass through.
Why does the upper epidermis not contain chloroplasts?
To allow sunlight to pass through to the palisade layer, where photosynthesis occurs.
What is the function of the lower epidermis?
It contains stomata for gas exchange and helps regulate water loss.
What are stomata, and where are they found?
Small pores in the lower epidermis that allow gases to move in and out.
What is the main function of the palisade layer?
It is the main site of photosynthesis, as it contains many chloroplasts.
How is the palisade layer adapted for photosynthesis?
• Tightly packed cells to capture more light.
• Contains many chloroplasts.
• Elongated vertically to absorb more light.
What is the function of the spongy mesophyll?
• Main site of gas exchange.
• Loosely packed cells allow gases to move.
• Contains some chloroplasts for photosynthesis.
What is the function of the xylem?
It transports water and minerals from the roots to the leaf.
What is the function of the phloem?
It transports dissolved sugars (glucose) from the leaf to the rest of the plant.
What is the function of guard cells?
They control the opening and closing of stomata to regulate gas exchange and water loss.
When do stomata close?
When guard cells become flaccid (limp) due to water loss, preventing excessive evaporation.
How do you test for starch?
Add iodine solution → Turns blue-black if starch is present.
How do you test for glucose?
Add Benedict’s solution and heat → Green, yellow, or brick-red if glucose is present.
How do you test for proteins?
Add Biuret solution → Turns purple if protein is present.
How do you test for lipids (fats and oils)?
- Add ethanol and shake.
- Add water.
- A cloudy white emulsion indicates lipids.
What is the word equation for photosynthesis?
Carbon dioxide + Water → Glucose + Oxygen
(In the presence of light and chlorophyll).
What is the symbol equation for photosynthesis?
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
In the presence of light and chlorophyll.
What are the three limiting factors of photosynthesis?
- Light intensity
- Carbon dioxide concentration
- Temperature
How does temperature affect photosynthesis?
• Too low → Enzymes work slowly, slowing down photosynthesis.
• Too high → Enzymes denature, stopping photosynthesis.
How does light intensity affect photosynthesis?
More light → Faster photosynthesis, up to a certain point.
How does carbon dioxide concentration affect photosynthesis?
More CO₂ → Faster photosynthesis, but only until another factor becomes limiting.
What role do enzymes play in photosynthesis?
They speed up the chemical reactions in photosynthesis.
What happens to enzymes at high temperatures?
They denature, stopping photosynthesis.
Why do plants stop photosynthesis at very low temperatures?
Enzymes work too slowly in cold conditions.
