Photosynthesis and Leaf Structure Flashcards
What is the chemical equation for photosynthesis?
6CO2 + 6H2O -> (light on arrow) C6H12O6 + 6O2
What is the word equation for photosynthesis?
Carbon dioxide + water -> (light on arrow) glucose + oxygen
What is an autotroph?
An organism capable of synthesising (creating) its own glucose, using light or chemical energy
Why are leaves thin?
- short distance for CO2 to diffuse into leaf cells
How is the leaf adapted for photosynthesis?
- Large surface area: absorbs more light
- Thin: short distance for CO2 to diffuse
- Chlorophyll (in chloroplasts): site of photosynthesis
Name the structures in the leaf
- waxy cuticle
- upper epidermis
- palisade mesophyll
- spongy mesophyll
- lower epidermis with stomata
- vein
What is the role of the waxy cuticle
- thin waterproof layer of lipids
- prevents water loss
What is the role of the palisade mesophyll
- contains palisade cells → rectangular (↑S.A.), lots of chloroplasts (+chlorophyll (site of photosynthesis), near top of leaf (↑light absorption for photosynthesis)
What is the role of the spongy mesophyll
- has air spaces for gas exchange
What is the role of the upper epidermis
Secretes the waxy cuticle
What is the role of the lower epidermis
Has pores called stomata
What is the role of the vein
- has the xylem (transports water from soil)
- has the phloem (converts glucose into sucrose and transports to other cells)
How are leaves adapted to GAS EXCHANGE
- broad with a large surface area
- thin → short diffusion distance
- air spaces inside leaf → increased surface area
- have stomata for gases to diffuse in and out
What happens to the guard cells during the day?
They become turgid, due to the water supplied from the roots to the cells (for photosynthesis), and open the stoma
What happens to the guard cells during the night?
They become flaccid, due to the lack of water in the cells (as the cells are only respiring (not photosynthesising)), and close the stoma
