1. LIFE AND LIVING and Processing
TERM 1
LIFE AND LIVING and Processing

3. Plants and food
The word photosynthesis is derived (comes from) from different words. The word ‘photo’ is the Greek word for light and ‘synthesis’ is the Greek word for putting together. Photosynthesis is the use of light to put things together.
The process by which plants make food is called photosynthesis. You say it like this: fo-toe-sin-the- sis. Photosynthesis takes place mainly in the leaves of green plants. All green plants contain a substance called chlorophyll. Chlorophyll gives the leaves and other parts of the plant their green colour. Chlorophyll, in the leaves, absorbs energy from sunlight. The leaves are thin and flat, so the plant can easily absorb the sunlight.

4. continued
Plants also need other substances to make their food. Plants absorb a gas called carbon dioxide, from the air, through their leaves. Plants absorb water through their roots.
During photosynthesis, plants use the energy from the sunlight, carbon dioxide gas from the air and water to make glucose sugar. Plants also produce oxygen during photosynthesis. Oxygen is a very important gas which living things need to stay alive.

5. How does photosynthesis occur?
Chlorophyll captures the sunlight energy.
This energy split the water into hydrogen and oxygen.
The oxygen is released into the air.
The hydrogen is used with the carbon dioxide to make glucose (sugars).
The sugars are moved from the leaves to other parts of the plants where they are stored.
The water in the plant veins carries the sugars. When the sugars reach the storage parts they are changed into starch.
Video link:

6. Plants store food as starch
Plants make more glucose than they can immediately use. Plants change some of the glucose sugar they make in their leaves into starch. The starch is the food that the plant keeps in reserve. Plants store the starch in their leaves, stems, roots, flowers, fruits and seeds. There is a lot of starch in potatoes, maize and grains like wheat.

7. roots: carrots beetroot
Plants can
store starch
in…
fruit: apples, peaches
stems: sugar cane
seeds: wheat, mealies
Flowers: broccoli, cauliflower
roots: carrots beetroot
leaves:
cabbage
Spinach
leaves
Learners drew these in their books, homework added two of their own.

8. Before we do some experiments lets recap
Plants make glucose sugar, mainly in their leaves, through a process called
photosynthesis. Plants use sunlight, carbon dioxide and water to make their food. Plants change glucose to starch and store it in different parts of the plant. Starch changes iodine solution from brown-yellow to blue-black.
We will use iodine to test for starch in leaves. Collect some leaves (just two) for your experiment.
Do not forget to complete the experiment page. You will find this page in a box as you enter the lab.

9. I for Iodine! Testing foods for starch Experiment 2:
We will experiment to find out which foods contain starch. Iodine solution can be used to test for starch.
Starch turns yellow/brown iodine solution to a blue /black colour.
Aim: To test different foods for starch.
If the food contains starch, the yellow/brown iodine will turn blue /black.

10. Materials and method Materials You will need: Iodine solution
Plastic droppers
A small amount of cooked rice, flour, a potato, a slice of bread, some cooking oil, a boiled egg, a piece of cheese and an apple
Method
Steps 1 – Put a few drops of iodine on each piece of food
Step 2 – Check the colour of the iodine solution after 1 to 2 minutes. 
Question – State which foods contain starch. 
Draw the following table to record your results in your workbook,
Don’t forget your experiment page. Complete this page and paste in your workbook before you create the table of results.

11. Is there starch in sunflower seeds?
Sunflower seeds are considered a protein food, according to MyPyramid.gov, along with other nuts and seeds, eggs, fish, poultry, meats and beans. However, like many foods, they contain a combination of protein, carbohydrate and fat. If you are counting carbohydrates, you will want to take the carbohydrate content of these seeds into account. During our next lesson we will crush some sunflower seeds and test for starch!
Homework: Find a nutrious recipe where sunflower seeds are used  Paste it in your books.
I will bring along some sunflower seeds.

12. Sunflowers!
Watch this video clip of sunflower seeds germination over lapsed time.
Now what this clip to see the structure of the sunflower and how it gracefully moves with the sun.
Here is a video to remind us how photosynthesis takes place.
You will now draw a sunflower in your books. Try and use most of the page. Include the following labels: Add the following labels to your drawing:
Roots, water, stem, leaves, flower, sunlight, carbon dioxide, oxygen.
Draw arrows to show where the water, carbon dioxide and oxygen enter the plant. Explain how a plant makes food, using your drawing as a guide.
Hint – Start your explanation at the roots Vocabulary Photosynthesis a process through which plants make.

13. Make sure your drawing is neat and colourful!
Use this to guide you in drawing.

14. Case study 1 Case Study 1 The mystery of the holes in the leaves
Many Delicious Monster leaves have holes in them.
These holes form as the leaf develops.
The leaves can then withstand strong winds without getting damaged.
(Think about banners and flags that sometimes have slits in them which allow the wind to pass through the material without ripping it.)
Another reason is so that the sunlight can pass through the leaves. This means that the big leaves at the top of the plant do not block out the sunlight for the leaves underneath

15. Case study 2 Why do plants need fertiliser?
If plants make their own food, then why do they need plant food or fertiliser? Plants need some nutrients that they cannot make themselves. The most important of these are nitrogen, potassium and phosphorus. Plants get these nutrients from the soil.
The nutrients dissolve in the water and plants absorb the water and the nutrients through their roots.
In you books: explain, using your own words, why Delicious Monster plants have holes in their leaves.
List 3 important nutrients plants cannot make themselves.

16. Plants and air
Discussion and allow the learners to draw the diagram on page 8 in their textbooks.
Add this note below the diagram drawn.
Do plants need oxygen?
What about plants? Do they breathe? Yes, they do. The correct term for this breathing is ‘respiration’. In darkness, plants only respire. In light (such as sunlight), plants respire and they carry out photosynthesis.
Activity 6, discussion.

17. Copy this table as well Respiration Photosynthesis
It takes place in all living plant cells.
It only takes place in cells that have chlorophyll.
Chlorophyll gives the cells a green colour.
It occurs in light and dark conditions.
It only occurs in light.
Oxygen is used and carbon dioxide and water are
Carbon Dioxide and water are used and Oxygen
released.
is released.
Topic revision page 10 of textbook.