Photosynthesis Slide

7/29/2019 Photosynthesis Slide

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PHOTOSYNTHESIS
http://e/Photosynthesis%20in%20plants%20-%20Lesson%20Animation%20%20for%20Kids.mp4


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Photosynthesis

The first observation regarding plant nutrition

was probably made by Aristotle

After a series of experiment done by

scientists, a conclusion can be made

light

6CO2 +6H2O C6H12O6 + 6O2

chlorophyll
http://e/Photosynthesis%20in%20plants%20-%20Lesson%20Animation%20%20for%20Kids.mp4


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Photosynthesis

Substances required for photosynthesis

i. Carbon dioxide

ii. Water

iii. Light energy

Substances produced from photosynthesis

i. Glucose

ii. Oxygen


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Photosynthesis

Where does photosynthesis happens?????


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Leaf structure and function

Leaves are the main photosynthetic organs of

a plant.

Young stems and other green parts may also

carry out photosynthesis.

Arrangement of leaves ????????

Why leaves have this arrangement ???????


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Cross section of leaf


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Part of a leaf Functions

Lamina Trap sunlight for photosynthesis to

occur

Petiole Holds the leafin the best position to

receive the maximum amount of

light

Vein Main vein leads down the leaf and

branches out into side veins to

support lamina


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Part of a leaf Functions

Cuticle Reduces the loss of water by evaporation

through the epidermis

Upper and lowerepidermis

Maintain the shape of the leafProtects the cells of the leaf from

bacterial and fungi infections and from

injuries

Pallisade mesophyll Carry out photosynthesis

Spongy mesophyll Carry out photosynthesis

Involved in the exchange of the gases

between leaf and the atmosphere


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Part of a leaf FunctionsXylem Transport of water and minerals salts

Give support to the leaf

Phloem Transport of sugar which is the product of

photosynthesis from leaf to other parts ofthe plants

Guard cells Involved in the control of the size of

stomata

Controls transpiration through thestomata

Stomata Allow exchange of gases between the

internal parts of the leaf and the

atmosphere


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Adaptation of leaf

Adaptation ImportanceLeaves are thin and flat This exposes large surface area of

leaves to sunlight and air, carbon

dioxide diffuses in and oxygen diffuses

out efficientlyLeaves are arranged

alternately

This maximizes exposure of surfaces

of leaves to sunlight

Arrangement of cells of

the spongy mesophyll isloose

This makes diffusion of gases occur

efficiently

Layer of cuticle and

epithelial cells are

transparent

This ensures that sunlight can

penetrate to the mesophyll layer


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Adaptation of leaf

Adaptation ImportanceNumber of stomata on

lower surface of leaves is

large

Avoid excessive loss of water to

surrounding

To allow exchange of gases to

occurThe cells of pallisade

mesophyll have chloroplast

and arranged close to

upper epidermis

Chloroplast are exposed to sunlight

and absorb energy for

photosynthesis

Network of veins are

widely distributed on the

lamina

Enables transport of water,

minerals salts and product of

photosynthesis to be carried out

efficiently


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Leaf structure and function??????

Lamina

Cuticle

Epidermis

Palisade mesophyll

Spongy mesophyll

Guard cell

Stoma

Xylem

Phloem


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Thank you


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Adaptation of plants from different

habitats

Plants need to have a method for gaseous

exchange and an efficient means of absorbing

light energy

Land plants eg hibiscus

Aquatic plants eg water lilies

Desert plants eg cactus


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habitats

Land plants

- Large number of stomata on the lower

surfaces of leaves

- To allow maximum absorption of carbon

dioxide

- Most chloroplasts are found in palisade cells

and spongy mesophyll cells.


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habitats

Aquatic plants

- Have large, round and flat leaves

- Stomata are mostly distributed in the uppersurface of the leaves

- Aquatic plants submerged in the water do not

have stomata

- Chloroplast are found in leaves and stems of

these plants


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habitats

Desert plants

- Have reduced leaves

- Have sunken stomata

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