Photosynthesis Light make Clickview How a plant works











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Photosynthesis Light make Clickview - How a plant works, In focus- Plants/ light and water Interactive http: //www. pbs. org/wgbh/nova/methuselah/photosynthesis. html Pearsoned- http: //wps. pearsoned. com. au/sa 2/53/13780/3527772. cw/index. html Brainpop - http: //www. brainpop. com/search. weml? keyword=Photosynthesis

Like animals, plants need food and oxygen for growth Unlike animals, some plants make their own food from very simple substances: carbon dioxide gas from the air, sunlight, and water from the soil.

This food making process is called photosynthesis. The green colour in leaves is due to a substance called chlorophyll which can absorb energy from sunlight. Chlorophyll is contained within Chloroplasts

Photosynthesis Because sunlight is needed for this process to occur, plants can only photosynthesise in the daytime. The sugars (glucose) that are formed during photosynthesis may be stored in the plant in the form of starch.

This is shown in the following word equation Reaction takes place in the chloroplasts sunlight Carbon dioxide + water Sugar + oxygen Chlorophyll glucose The complete chemical equation is This is here to Balance the equation sunlight 6 CO 2 + 12 H 2 O chlorophyll C 6 H 12 O 6 + 6 H 2 O + 6 O 2

In complex plants (most of the ones you’re familiar with) photosynthesis occurs in one specialised “organ”, the leaf. A typical leaf consists of a broad, flat part called the lamina, which is joined to the rest of the plant by a stalk or petiole

Running through the petiole are vascular bundles containing the xylem and phloem (water and sugar conducting tissue) The top and bottom of the leaf are covered by a layer of close fitting, flat cells: the epidermis. The epidermis cells often secrete a waxy cuticle which reduces water loss



On the lower epidermis, there are usually small holes called stomata. Each stoma is surrounded by a pair of guard cells which can open or close the space between them. This is where gas exchange occurs (ie. CO 2 in, O 2 out)
