Unit 9C and 9D Lesson 1 Photosynthesis Objectives: to learn the different parts of the plant, to learn that light is the energy source for photosynthesis, and to learn the word equation for photosynthesis. Targets: 1-7

Work to Do Read pages 82 and 83 Complete questions 1-8. Homework –Complete Activity Sheet C7S1 –Define the following keywords: Stomata, chlorophyll, flower, glucose, photosynthesis, biomass, chloroplasts

Parts of a Flowering Plant The flower is the reproductive part of the plant. It produces seeds which will grow into adult plants. The stem gives the plant support and it helps to position the plant in the sun. The stem also carries water from the roots to the leaves. The roots take water and minerals. They also attach the plant to the ground and make sure it doesn’t blow away. Leaves are where photosynthesis take place. This is where you find most of the chlorophyll in the plant.

Photosynthesis Photosynthesis is a chemical reaction. It is the way that plants convert energy from the sun into food. Four things are needed for photosynthesis: In photosynthesis plants use sunlight to join molecules of water and carbon dioxide to form glucose. The plants then use glucose as food. If the plant doesn’t need to use the glucose straight away it converts it to starch so that it can be stored. One of the products of photosynthesis is oxygen which we use to breath. –Sunlight –Water –Carbon Dioxide –Chlorophyll: This is the stuff which makes plants green. It is found in structures called chloroplasts.

Photosynthesis Formula The word equation for photosynthesis is: Water + carbon dioxide glucose + oxygen Sunlight Chlorophyll

Where Does the Carbon Dioxide and Water Come From? The plant gets its carbon dioxide from the air. The carbon dioxide enters the plants leaf through tiny holes called stomata. (One hole is called a stoma.) The oxygen which is produced by plants leaves the leaf through the stomata. The water comes from the soil and is absorbed by the roots. Stoma Stomata Animation

Biomass Biomass is a measure of how much mass a plant has. In other words how much of the plant there is. The glucose which is created along with minerals absorbed by the roots are turned into several different chemicals. These chemicals help the plant to grow and add to its biomass.

Factors Which Affect Photosynthesis An increase in the amount of light will increase the rate of photosynthesis. An increase in the amount of carbon dioxide will increase the rate of photosynthesis. An increase in temperature will increase the rate of photosynthesis. (This is until it gets too hot then there will be a sharp decrease in the rate of photosynthesis.)