Grade 8 Unit L.4 - Photosynthesis

[Pages:16]Grade 8 Unit L.4 - Photosynthesis - 1-

Grade 8 Unit L.4 - Photosynthesis

Curriculum Standards: 8.10.1, 8.10.2, 8.10.3, 8.10.4, 8.10.1

Objectives:

Describe the structure and function of each plant cell

Key Words Photosynthesis

Plant cell

Chloroplast Cell membrane Cell wall Vacuole Nucleus Absorb

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Grade 8 Unit L.4 - Photosynthesis

Different parts of animals and plants are a collection of a large number of tiny units packed together. Each of the tiny unit is a CELL.. .

A plant cell has a special structure that is used in the photosynthesis process. Look at Figure 1 of a plant cell. It has a large number of chloroplasts.

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This is a simple picture that shows the structure of plant cell.

Cell Membrane: It protects the cell and holds the content.

Cell Wall: It supports and protects the cell. .

Nucleus: It controls the development and activities of the cell.

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Cytoplasm: It contains water and protein and protects the cell organelles.

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Vacuole: It stores food and water for the cell. .

Chloroplast: Contain chlorophyll pigment which absorb the light and give plants their green color.

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Figure 1

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Grade 8 Unit L.4 - Photosynthesis

Objectives Describe the structure and function of plant cells involved in photosynthesis.

Key words

Epidermis Cuticle Palisade Stomata

phloem Xylem Leaf Guard cell Vein

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Grade 8 Unit L.4 - Photosynthesis

Leaf Structure

Figure 2

A leaf is an organ made of several different kinds of cells. Inside the leaf is a factory for making food.

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The top layer of cells, the epidermis is transparent. It has a waxy water proof layer over it that stops the leaf from drying out .Light passes through the epidermis to the next layer of cells, the palisade layer.

. . .

Palisade cells are specialized for photosynthesis. They are provided with water by the veins in the leaf. Below the palisade is a layer of cells called the spongy mesophyll.

. . .

On the lower surface of the leaf there is another layer of epidermis. Throughout this layer there are many tiny opening s called stomata. Two guard cells control the size of each stomata. They open and close the stomata. They control the exchange of oxygen and carbon dioxide between the leaf and the surrounding air.

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Grade 8 Unit L.4 - Photosynthesis

. . .

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Inside the leaf most cells are green. They contain chloroplasts where food is made.

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? Is the place from where carbondioxide Stoma enters and oxygen leaves the leaf

? The place where photosyntheis takes Palisade cell place within the leaf

? Is the vessel that transports water and

Xylem

mineral to the leaf from the roots

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Grade 8 Unit L.4 - Photosynthesis

Challenge: Research on the Internet to find out about the other parts of a leaf that are labeled in Figure 2 above.

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Grade 8 Unit L.4 - Photosynthesis

Objectives Understand that green plants make their own food by photosynthesis and that water and carbon dioxide are required. Oxygen and glucose are the products.

Key Words

Photosynthesis Chemical reaction

Product Reactant Glucose Starch Roots Energy

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