B4c Flashcards
What do chlorophyll pigments in chloroplasts do?
Absorb light energy for photosynthesis.
Name the parts of a leave.
Cuticle, upper and lower epidermis, palisade and spongy mesophyll layers, stomata, guard cells, and vascular bundle.
How is the cellular structure of a leaf adapted for efficient photosynthesis?
Epidermis is transparent so that light can pass through to the palisade layer.
Palisade layer at the top containing most of the chloroplasts where they can get most light.
Air spaces in the spongy mesophyll layer allow diffusion between stomata and photosynthesising cells.
Internal surface area to volume ratio is very large for diffusion.
What are the entry points of materials required for photosynthesis?
Water through root hairs and carbon dioxide through stomata.
What is the exit point of materials produced for photosynthesis?
Oxygen through stomata.
How are leaves adapted for efficient photosynthesis?
Broad so large surface area for gases to diffuse.
Thin so short distance for gases to diffuse.
Contain chlorophyll and other pigments and other pigments to absorb light from different parts of the spectrum.
How are leaves adapted for efficient photosynthesis?
Broad so large surface area for gases to diffuse.
Thin so short distance for gases to diffuse.
Contain chlorophyll and other pigments and other pigments to absorb light from different parts of the spectrum.
Have a network of vascular bundles for support and transport.
Guard cells which open and close the stomata. This allows the guard cells to control gas exchange.
What do the different pigments do?
Absorb different wavelengths of light, so plant cells can make the most of the sun’s energy by absorbing as much of it as possible.
Chlorophyll a 400 - 450 nm and 650 - 700 nm wavelength
Chlorophyll b 450 - 500 nm and 600 - 650 nm
Carotene 400 - 500 nm wavelength
Xanthophyll 400 - 530 nm wavelength
nm =nanometre
Why do broader leaves enable more sunlight to be absorbed?
So there is a large surface area exposed to light.
