S CIENCE 7:U NIT B Topic 2: Stems/Leaves NyOhUc

P HOTOSYNTHESIS P RE -T EST 1.Green plants make their own food in a process called ____________________. 2.What are the ingredients plants need to produce their food? 3.The plant's characteristic green color comes from the chemical _____________. 4.This chemical is found in special cells in the leaves called __________________.

5.The plant's food is a form of sugar called _________________. 6.The tiny openings on the underside of leaves are called ___________________. 7.All life on earth depends on plants. How is this possible? 8.Plants and animals have a wonderful partnership. What is it that plants need from animals and what do plants produce that is essential to animals? 9.Glucose that isn't used by the plant can be stored as _______________. 10.All forms of energy on earth such as the fuels used in our cars are traceable to plants and sunlight. Explain that statement.

S TEMS Functions 1. Transport water/nutrients between the leaves and roots 2. Support (ensures the plant receives adequate light) 3. Food storage

L AYERS OF A T REE A. Heartwood Dead wood in centre Gives the tree it strength B. Xylem Carries water/dissolved minerals from roots  leaves Why? Needed for PHOTOSYNTHESIS! C. Cambium Live part of the tree Generates new xylem/phloem each year Creates the tree cookie effect

L AYERS OF A T REE A. Phloem Carries sugar (glucose) from leaves to the rest of the tree Dead cells becomes part of the old bark B. Bark Woody skin Stops a tree from drying out Protects/insulates

T HERE ARE 6 T YPES OF M ODIFIED S TEMS 1. Tubers 2. Runners 3. Corms 4. Bulbs 5. Rhizomes 6. Flattened Stems

1. T UBERS A fleshy underground stem or root serving for reproductive and food storage Example Potatoes, sugar cane, yams, dahlias, day lilies

2. R UNNERS Horizontal stems that run at or just below the soil surface to aid in reproduction. When above ground they are called “Runners”. At various location along the stem roots begin to grow Example Strawberries, peppermint, spider plant

3. C ORMS Like a tuber Short, upright, hard Covered with thin, dry papery leaves Example Crocus, gladioli

4. B ULBS Short, upright organ used by plants for food storage/reproduction, with specialized leaves modified into thick fleshy scales Usually round/egg-shaped with a pointy end that goes up Example Tulips, lilies, onions, hyacinths, daffodils

5. R HIZOMES Fleshy horizontal stems that run underneath the soil Buds for new plants occur along the Rhizome Example Calla Lily, Canna, Lily of the Valley, Common Iris

6. F LATTENED S TEMS Helps to preserve water Example: Prickly pear cacti

L EAVES Propose! PHOTOSYNTHESIS (majority occurs in the leaves) Structure

P HOTOSYNTHESIS The process of converting light energy to chemical energy and storing it in the bonds of sugar (glucose) Plants need only light energy, CO 2, and H 2 O to make glucose The process of photosynthesis takes place in the chloroplasts, specially using chlorophyll, the green pigment in plants