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Photosynthesis - Coggle Diagram
Photosynthesis
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Photosynthetic pigment
besides chlorophyll, the leaf has other pigments such as yellow, orange, red and purple.
chlorophyll breaks down which causes the green colour to fade and carotene [orange pigment] and xanthophyll [yellow pigment] to appear.
carotene and xanthophyll are secondary pigments that support photosynthetic process.
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green leaves contain the highest % of chlorophyll compared to other leaves
red/yellow/purple leaves contain lower % of chlorophyll so they trap sunlight less effectively
Leaf structure
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exterior leaf structure adaptations:
- broad >> larger sa allows more light to be absorbed
- thin >> increased sa to vol. ratio, allows rapid diffusion of carbon dioxide
- network of veins >> veins consist of vascular bundle which transports water, mineral salts and manufactured food
internal leaf structure
transparent cover for whole leaf >> allows light to enter
impermeable to water >> reduces evaporation through leaf, prevents excessive water loss
uppermost single layer of closely-packed cells [few gaps] >> provides mechanical strength, protects inner layers of sells
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- palisade mesophyll tissue
cells arranged closely-packed vertically >> more cells exposed to sunlight
highest distribution of chloroplasts >> highest rate of photosynthesis
loosely arranged cells w numerous intercellular air spaces >> diffusion of carbon dioxide and oxygen in and out of mesophyll cells
contains some chloroplasts
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lowest part
covered by waxy cuticle
gaurd cells surround stomata and are the only epidermal cells containing chloroplasts
Absorption of light
chlorophyll does not absorb all colours of light equally, it absorbs red and blue light best as green light is reflected [ROYGBIV]
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Stomata
allows gaseous exchange between leaf and surroundings
- intake of carbon dioxide, release of oxygen for photosynthesis
- intake of oxygen, release of carbon dioxide for respiration
gaurd cells control rate of diffusion of gases by controlling size of stomata
also can control water balance in plant by controlling water loss during diffusion
What is photosynthesis?
Differenciates organisms that can produce their own food[plants — autotrophic] with organisms that cannot[animals — hetrotrophic]
It is a process which plants, algae and a few bacteria capture light energy to convert carbon dioxide and water into glucose in the presence of chlorophyll and oxygen gas is released in the process
factors affecting rate of photosynthesis:
- carbon dioxide conc. >> higher conc of CO2, higher rate of photosynthesis
- light intensity >> higher light intensity, higher rate of photosynthesis
- temperature >> closer to optimum temp, higher rate of photosynthesis
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