1977-11-09

其四第張七第日八十月九年巳丁

育教僑華

સર્જક.

生物

1978

「中學會考試題預習專欄

BIOLOGY (6)

明徳社主鶇

梁永華

Unit 3: Water and Organisms -

II Conventional questions:

1. The following diagram shows

the egg of a bird.

What type of food is stored in 1) Y and 2) 02

Name the following structures and explain why they are in- portant for the egg to adapt the terrestrial habitat. 1) M 2) N 3) 0 What is X2 Describe the changes of X which would be observed during incubation?

Ans.

PP: Protein and fat.

2) D: Protein and water.

Kame Hshell:

shell

mem - brane

Adaptation.

Reduce water loss. Irovides protect- ion.

Vascularized and closely attached to the shell for gaseous exchange.

|0 albumin Provides food and

sufficient water c. Germinal disc, the develop-

ing embryo.

During incubation the embryo develops a network of capil- laries which spread over the structure and extend onto the structure

2. The following diagram shows a physiological activity carried out by amoeba.

nucleua

a. Name this process.

b. What are the functions of

structure

Explain why structure X.

is commonly found in pro-

tozoa living in fresh water.

d. Explain why structure or

structures of similar func- tions are not found în plants living in fresh water.

Ans.

Excretion.

b. structure X is a contractile

vacuole. It collects excess water and waste products from the cytoplasm, It final-

ly moves to the cell membrane

and contracts, forcing its

報日僑

WAH KIU YAT PO

contents out through a tem- porary openning. The concentration of the dissolved substances in the cytoplasm of the protozoa is higher than that in the surrounding fresh water. By Osmosis, there is an inward movement of water through the semipermeable membrane into the cytoplasm. The pre- sence of contractile vacuole in fresh water protozoa is an adaptation to the sur- rounding environment..

Plants living in fresh water also have the problem deal- ing with the osmotic inflow of excess water. They have not evolved contractile va- cuole because their firm cellulose cell wall genor- ates a turgor pressure as water enters and thus pre- vent undue avelling of the. protoplasm.

water

3. The following apparatus was

set up. tightly. tied Visking tubing

a mixture of starch and

glucose solutions

After several hours it was found that glucose was pre- cent in the water in the beaker. a.What process has occured

to ensure the glucose to pass out of the tubing" b. Explain why the starch.

remains in the tubing.

6. Suggest the reagents you

should use and indicate the result you would expect for testing the presence of

Aris:

1) starch inside the tubing. 2) glucose in the water in the beaker after the experiment

a. Osmosis.

b. The starch molécules are

too large to pass through the selective Visking tubing.

1) Add 1-2 drops of iodine

solution to the fluid;

a deep blue colour is expected.

2) Add a few drops of

Fehling's A and B solu-

tions to the test solu- tion and boil; a brick/

red precipitate is ex- pected.

地理(六)

(LGILAI IY (6)

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