KPS/086/ STUDY MATERIAL / VIII/2017-18

1.  Have you ever seen a blacksmith beating an iron piece? Do you find a change in the shape of these pieces on beating? Would you expect a similar change in wood log on beating?

2.  Give reasons for the following:

  1. Fresh milk must be boiled before consumption but processed milk stored in packets can be consumed without boiling
  2. Raw vegetables and fruits are kept in refrigerators whereas jams and pickles can be kept outside
  3. Farmers prefer to grow beans and peas in nitrogen deficient soils
  4. Mosquitoes can be controlled by stagnation of water though they don’t live in water

3.  Draw and explain the Nitrogen cycle

4.  For the microorganism below:

  1. Name the microorganism and the group to which it belongs
  2. Name the food item on which the microorganism grows
  3. Does it grow well in dry or moist conditions
  4. Is it safe to eat the food item infected by the microorganism?

5.  Which observation will help you in identifying the slide of an onion peel and a slide of cheek cell.

6.  What changes will you observe in the dough after one hour when you put yeast in the wheat flour ?

7.  In an area with scarce supply of water, which system of irrigation would you prefer drip system or sprinkler? Give reasons for your answer.

8.  If you have a bowl of fresh curd and a stale bread slice

  1. Which microorganisms do you expect to find on these food items?
  2. Which of these can be consumed?

9.  One day Reeta went to a jeweller’s shop with her mother. Her mother gave an old gold jewellery to the goldsmith to polish. Next day when they brought the jewellery back, they found that there was a slight loss in its weight. Can you suggest a reason for the loss in weight?

10.  Complete the following reactions and tell in which the displacement reaction will take place. Give reason for your answer

  1. CuSO4 + Fe →
  2. Mg + CuSO4 →
  3. CuSO4 + Zn →
  4. ZnSO4 + Cu →

11.  Rana wants to buy shirts for summer. Should he buy cotton shirts or shirts made from synthetic material? Advise Rana giving your reasons.

12.  We can boil water in a paper cup while paper catches fire easily. Explain the process.

13.  The Earth would be a big mound of rubbish were it not for bacteria or fungi. Why?

14.  Paheli watched her grandmother pack mango pickle. Her grandmother immersed the pickle in oil. Why?

15.  List four differences between a plant cell and an animal cell

16.  Explain why chloroplast is found only in plant cells

17.  Why is cell membrane also called a semi-permeable membrane?

18.  Why are mitochondria called the power house of the cell?

19.  Why do plant cells have cell wall while animals don’t?

20.  Why are lysosomes called the suicide bags of the cell?

21.  Distinguish between metals and non-metals based on following properties:

  1. Appearance
  2. Hardness
  3. Malleability
  4. Ductility
  5. Conductivity
  6. Sonority

22.  Why does silver jewelry turn black over time?

23.  Why do we wrap food items in aluminum foils?

24.  Why does copper form a dull green coating?

25.  What is a displacement reaction? Explain with examples

26.  Complete the table:

Name of the gland / Location / Hormone secreted / Function
Pituitary Gland
Thyroid Gland
Pancreas
Adrenaline
Testes
Ovaries

27.  When Amoeba grows due to absorption and utilization of food, it undergoes cell division.

  1. Draw a labelled diagram of Binary fission in Amoeba.
  2. How many daughter cells are formed because of Binary fission?
  3. Give any two examples of organisms that reproduce by Budding.