MakingFood

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3

Leave in direct sunlight for a few hours

Result?

A bubble of oxygen gas should form at the top of the test tube as it photosynthesises

Slide 18

Summary of Photosynthesis

Plants’ waste product- oxygen- is essential for animal life.

Slide 19

Quick Quiz 1

1. What does a plant need for photosynthesis?

2. What does a leaf produce during photosynthesis?

3. What is chlorophyll?

4. How do the leaves obtain water?

5. How does the plant obtain carbon dioxide?

6. List 3 uses of the glucose produced by photosynthesis?

7. Name the storage form of carbohydrate in a leaf.

Carbon dioxide, water, chlorophyll, light.

Oxygen, glucose

A green pigment which absorbs the sun’s energy

Through the roots (and xylem tubes by osmosis

From the air (through stomata)

Cellulose (structural), starch (storage), energy

Starch.

Slide 20

A leaf in time Library activity

Source: http://www.life.uiuc.edu/plantbio/102/links.html

Read through the file and take some short notes to summarise the life of a leaf

http://www.portlandpress.com/pp/books/online/leaf/alit_eng.pdf

Slide 21

Leaves…

Leaves are the organs of photosynthesis and make all the food for a plant.

We will look at:

Outer layers (top & bottom)

Inner structure including veins (its transport system)

Slide 22

Internal structure

Collect the handout ‘Leaf structure’ and add labels/notes.

mesophyll

waxy cuticle

Slide 23

Outer layer- upper surface

1. The waxy cuticle is a waterproof layer which cuts down water loss by evaporation.

2. The upper cells of the leaf make up the epidermis.

They are transparent so light passes straight through them into the next layer of cells…

Slide 24

The palisade layer contains cells with lots of chloroplasts.

The spongy layer (spongy mesophyll) contains rounded cells with many air spaces allowing CO2 to circulate and reach the palisade cells, while O2 leaves.

Hence this is where most photosynthesis occurs.

Chloroplasts contain chlorophyll which is the chemical which absorbs the sun’s light energy.

mesophyll

Slide 25

Workbook Activities

p 66-67 Leaf surface and thickness

p67 Leaf layer cards- matching