WS 7.4 answer

7.4       How do green plants obtain energy?

i      Words to know:

	English term	Write the words again	Chinese term
1	Photosynthesis	Photosynthesis	光合作用
2	Raw material	Raw material	原料
3	Starch	Starch	澱粉
4	Chlorophyll	Chlorophyll	葉綠素
5	Iodine solution	Iodine solution	碘液

i      Fill in the blanks:

1        Green plants can make their own food by photosynthesis. The raw materials are
carbon dioxide obtained from the air and water obtained from the soil.

2        Light energy is required in photosynthesis. It is absorbed by Chlorophyll in green leaves and other green parts of the plants.

3        The food produced is usually stored in the form of starch. And oxygen is produced as a by-product that released into the air.

4        Write down the word equation of photosynthesis.

                                                             Light energy

Carbon dioxide  + water   ---------------------------------------à food   +    oxygen

                                                      Chlorophyll                         (starch)

5        Label the picture to show the process of photosynthesis. (Hints: Fig.7.12)

6        The test for starch using iodine solution is called iodine test.
A colour change from brown to dark blue shows the presence of starch.