Class 8 CBSE Important Questions of BIOLOGY

      Cell Structure and Functions

1.  Mention the layer outside the plasma membrane of a plant cell.
2. Name the outermost layer of an animal cell.
3. Name the cells having branching structure.
4. Why cells could not be observed before seventeenth century?
5. What is the basic structural and functional unit of all living organisms?
6. Which organism has the smallest cell?
7. Which is the largest cell visible by unaided eye?
8. Name the four elements, which form major part of protoplasm.
9. Give two examples of unicellular organisms.
10. Name the jelly like substance present between the nucleus and the cell membrane.
11. Name the living substance of the cell.
12. Which organelle is called control centre of the activities of the cell?
13. Give two examples of prokaryotes.
14. Name the largest organelle present in a cell.
15. Name the green plastids present in cell. 
16. Write a brief note on mitochondria.
17. Why do we stain the small components of section, before seeing under the microscope? Name a stain.
18. Name any four cell organelles found in the cell cytoplasm?
19. Why is the cell called basic unit of living organism?
20. What is the function of cell membrane?
21. What is the function of nerve cell?
22. What are the basic components of cell?
23. Why plant cell have cell wall?
24.  Describe the variations in shape and size of cells.
25. Explain why chloroplasts are found only in plant cells?
26. Write the functions of the following             a) Mitochondria b) Chromosomes c) Plastids
27. Write three differences between prokaryotic and eukaryotic cells.
28. Where are chromosomes found in a cell? State their function.
29. Draw the diagram of plant and animal cell.
30. Make a sketch of the human nerve cell. What function do nerve cells perform
31. Write short notes on the following: a)Cytoplasm b) Nucleus
32. Differentiate between plant and animal cell.

. Conservation of Plants and Animals

1. What is deforestation?
2. What do you understand by biodiversity?
3. What is the difference between flora and fauna?
4. What is species?
5. Name the first Reserve Forest of India.
6. What was the objective of Project Tiger?
7. Name the book that keeps a record of the endangered animals and plants.
8. What are migratory birds?
9. What is the difference between deforestation and reforestation?
10. Give one plant and one animal species which are the endemic species of Panchmarhi Biosphere Reserve.
11. Name two natural causes of deforestation.
12. What is a biosphere?
13. Who lays down rules and policies to protect and conserve forests?
14. What activities are strictly prohibited in a wildlife sanctuary?
15. What is an ecosystem?
16. What will happen to a deforested area if it is left undisturbed?
17. What is desertification?
18. Name any four biosphere reserves present in India?
19. What are endemic species? Give one example.
20. What is the difference between a zoo and a wildlife sanctuary?
21. What are endangered species? Give one example.
22. Why do birds fly to far away areas?
23. Name the national park and sanctuaries that constitute Panchmarhi Biosphere Reserve.
24. Give two reasons which endanger the existence of endemic species.
25. What are the objectives of Forest Act?
26. How floods are caused due to deforestation?
27. Why do we need the forests? Give three reasons.
28. Why conservation of forests and wildlife sanctuary is necessary?
29. What are the various purposes for which trees are cut?
30. Name the protected areas meant for protection of flora and fauna.
31. Why do we need to save paper? Give three reasons.
32. Suggest three steps that can be taken to conserve forests?
33. Deforestation is a harmful activity. Give reasons for the given statement.
34. How does deforestation cause droughts?
35. How does deforestation cause desertification?

    REPRODUCTION IN ANIMAL

1. What are the types of reproduction?
2. Why reproduction is an essential process?
3. What are male reproductive parts?
4. Name the reproductive parts of females.
5. What are the different parts of a sperm?
6. Name the organism which produces the largest eggs.
7. Define foetus.
8. What is metamorphosis?
9. Define sexual reproduction.
10. What is reproduction?
11. (a) Define fertilisation(b) Expand IVF
12. Name the organs that produce sperms and ova in males and females, respectively.
13. Why does a hen sit on its eggs?
14. How much time is needed for development of a chick from embryo?
15. What do you mean by fertilisation? What is the result of fertilisation?
16. What are viviparous animals? Give examples.
17. What are the different stages in the life cycle of a frog?
18. What are gametes?
19. Name the various methods of asexual reproduction with an example of each.
20. (a) Define sexual reproduction.(b) Why an individual has some characteristics of father and some of mother?
21. What are gametes? Differentiate between sperms and ova.
22. Differentiate between internal and external fertilisation.
23. Write down the type of fertilisation in (a) Frogs (b) Hens (c) Humans (d) Fish.
24. What is the difference between the eggs of a hen and of a frog?
25. Why frogs and fish produce a large number of gametes?
26. What is an embryo? Where does the development of a human embryo take place?
27. Describe the female reproductive organs in brief?
28. Describe the male reproductive organs in brief?
29. Discuss the steps that occur during sexual reproduction.
30. Differentiate between oviparous and viviparous animals. Give one example of each.
31. What are the differences between development of young ones in frogs and in humans?
32. Differentiate between asexual and sexual reproduction.
33. MWhat is binary fission? Name the organism in which the binary fission is a method of reproduction.
34. Answer the following in one word:             (a) Process of production of exact copies of an organism(b) First cloned mammal(c) First person to perform cloning of an animal successfully (d) Babies born through in vitro fertilisation(e)Type of reproduction in amoeba
35. Explain the process of budding. Name two organisms in which budding takes place

Reaching the Age of Adolescence

1. Why should teenagers take a bath at least once everyday?
2. What are chromosomes?
3. What is the period of adolescence?
4. What do you understand by the term adolescence?
5. When does the puberty end?
6. What causes increase in height of the person during puberty?
7. Why is it necessary to eat right kind of food during the growing years?
8. What is the other name for voice box in males?
9. Why does the voice of boys become hoarse during the age of adolescence?
10. How many pairs of chromosomes are there in the cells of human beings?
11. What determines the sex of an unborn baby?
12. Why is iron necessary for the body?
13. Name the male and female hormones that are secreted at the onset of puberty
14. What is the function of mammary glands?
15. Name the gland whose secretion control the secretion of sex hormones.
16. Name the hormone that causes metamorphosis in frogs.
17. What will be the sex of the individual with sex chromosomes as XY?
18. What is the period of reproductive phase in females?
19. What are the differences between menarche and menopause?
20. What is menstruation?
21. Why endocrine glands are called ductless glands? Give two examples.
22. A girl is 13 years old and 135 cm tall. At the end of growth period how much tall will she be?
23. What is the difference between the voice of a girl and a boy? Why this happens?
24. What is the importance of adrenal glands in humans?
25. Write the causes of: (a)Diabetes(B)Goiter
26. What mental changes occur during puberty?
27. Why a girl should not become pregnant during teenage?
28. Why young people get acne and pimples during puberty?
29. How do hormones act to bring about onset of puberty?
30. List three secondary sexual characters of boys and girls? 

    
    MICROORGANISMS 

1. What do you understand by microorganisms? 
2. Write the name of two groups of microorganisms which live in colonies.
3. Who discovered the vaccine for small pox?
4. Name any two food items that are prepared using yeast.
5. Name the bacteria which is involved in the fixation of nitrogen in leguminous plants.
6. What do you understand by the term "Pseudopodia"? Give one function
7.  Explain how does blue-green algae help in increasing the fertility of soil.
8. Name the insects, which carry the parasite of malaria and dengue.
9. Why generally dry fruits and even vegetables are sold in sealed air tight packets?
10. What are the causes of food poisoning?
11. What are communicable and non communicable diseases? Name few of them.
12. Mention the causative organism and mode of transmission of the following diseases: (i) Tuberculosis (ii) Polio(iii) Malaria(iv) Typhoid(v) Hepatitis B(vi) Chicken Pox
13. (i) What are antibiotics?(ii) How are they manufactured?(iii) How are they useful to mankind?
14. (i) What is nitrogen fixation?(ii) Which organisms are able to fix atmospheric nitrogen?(iii) What is the need of converting atmospheric nitrogen into compounds of nitrogen?
15. Draw a diagram of (i) Amoeba (ii) Paramecium
16. (i) What are pathogens ?(ii) How can they enter in our body?
17. Describe the role of salt, sugar, oil and vinegar in preservation of food?
18. (i) What are the affects caused by disease causing microorganisms?(ii) What measures can be taken to control them?(iii) Name some plant diseases with their causative organism.
19. How can high and low temperature affects the growth of microorganisms?
20. Describe the useful and harmful effects of microorganisms.
21. (i) What are communicable diseases? (ii) With help of examples explain the spread of diseases through carriers.(iii) How can we prevent the spread of malaria and dengue?(i) What do you understand by the term vaccine?(ii) Which diseases can be prevented by vaccination?(iii) How coined the term vaccine?
22. Draw a well labelled diagram of nitrogen cycle?
23. Name any three habitats of microorganisms. 
24. Can we find a place without microbes in nature. 
25. Which microorganism is used in the production of alcohol? 
26. Name the bacteria which is responsible for the formation of curd.
27. In which form microorganisms are used in vaccine?
28. Who discovered the vaccine for small pox?
29. Who discovered the process of fermentation?
30. Mention two important uses of fungi.
31. “Virus are living or non-living.” Comment with reasons.
32. What do you mean by fermentation?
33. What are preservatives?
34. Define pasteurization.
35. Why generally dry fruits and vegetables are sold in sealed air tight packets?
36. Explain antibiotics in brief with the help of examples.
37. Describe the role of sugar, oil and vinegar in preservation of food?
38. What do you understand by vaccine? Explain in detail.
39. Mention some useful effects of microorganisms.
40. Which bacteria are responsible for Anthrax disease?
41. Name the bacteria which is involved in the fixation of nitrogen in leguminous plants.
42. Explain how do blue-green algae help in increasing the fertility of soil?
43. Name the insects which carry the parasite of malaria and dengue.
44. Mention the causative organism and mode of transmission of these organism in following diseases. (i) Tuberculosis(ii) Polio(iii) Malaria(iv) Typhoid(v) Hepatitis B (vi)Chicken Pox
45. What is nitrogen fixation? Which organisms are able to fix atmospheric nitrogen?
46. What are the effects caused by disease causing microorganisms? How can they be controlled and name some plant diseases with their causative organism?
47. What are the harmful effects of microorganisms?
48. What are pathogens?
49. What are the different ways through which pathogens enter in our body?
50. What is a carrier?
51. What preventive measures should be taken to avoid common diseases?
52. Why nitrogen fixation is necessary?
53. Draw a well labeled diagram of nitrogen cycle.
54. Name two diseases that are caused by virus. Write one important characteristics of virus.
55. Write category of the following microorganisms from which they belong. Lactobacillus, Amoeba, Chlamydomonas, Penicillium.
56. How do vaccines work?
57. Polio drops are not given to the children suffering from diarrhoea. Why?
58. Why should we avoid standing close to a tuberculosis patient while he/she is coughing?
59. Classify  the following into friendly and harmful microorganisms. Yeast, malaria parasite, Lactobacillus, bread mould, Rhizobium, Bacillus anthracis.

CROP PRODUCTION AND ITS MANAGEMENT 

1. Define pisciculture.

2. What are (a) weeds (b) threshing (c) crop
(d) sowing (e) preparation of soil ?

3. What are kharif crops? Name two kharip crops.

4. What are summer crops? Name two summer crops.

5. What are Rabi crops? Name two Rabi crops.

6. Why paddy cannot be grown in the summer season?

7. What is meant by agricultural practices?

8. How soil is prepared? What name is given to the loosening and turning of soil?

9. Name the tool used for tilling of soil, used for removing weeds and used for ploughing?

10. What are crumbs and how are crumbs broken?

11. What is a plough? Why it is necessary?  Give two advantages of ploughing the field before sowing.

12. What is meant by sowing? What are the two ways of sowing the seeds?

13. What is meant by good quality of seeds? What is the advantage of sowing seeds with a seed drill?

14. What are manure and fertilizer? Name two important fertilizer. What is organic manure? Give two advantages of using fertilizers excessively.

15 .What is meant by crop rotation, irrigation and system of irrigation?

16. Why should be remove the weeds?
Name the process of removal of weeds?

17. What are pesticides and weedicides?
How can we control weeds?

18 .Name the farm machine used for harvesting and threshing both?

19. What is meant by winnowing?

20 .How are food stored and why should grains be dried before storage?

21. What is meant by animal husbandry? Name some animals from whom milk can be obtained and which are reared for their meat.

22. What is broadcasting in agricultural practices? Enumerate two methods by which harvesting of crops can be done?

23. How are poultry shed maintain?

24. How do the soil and the crops benefit by proper tilling of the soil?

25. Give one word for the following statements
(a)One crop which is dependent on western monsoon.
(b) Type of crop that requires more water for irrigation?

26. Define transplantation.
How is transplantation useful to the farmer?
Explain how soil gets affected by the continuous plantation of crops In a field?

27 .Explain why most crops have a particular season in which they grow? If wheat is sown in the kharip season, what  would happen?

28. Give two reasons why seeds should be sown at correct distance?

29. Give two methods by which threshing can be done.

30. Differentiate between logging and lodging. Why does loosening of soil allow roots to breath easily?

31. How do earthworms and microbes present in the soil help the growth of crops?

32. What is meant by field fallow? A farmer never leaves field fallow ,will get a good crop?

33. Why heavy soil is considered the best soil for the growing plants? How is soil a resources for all living organisms?Give any two points.

34. Why crop rotation is useful for farmers? Name three types of crops in our country and give two examples of each.

35. What are organic food ? How is organic manure obtained?
36. The rabi crops are known as wintercrops. Give reasons.
37. Paddy can not be grown in winter season.  If yes, why?
38. Some grass is grown in a wheat field .What will it be known as?
39. During which months do farmer grow mustard in India?
40. Fishes are considered good for health. Give reason.
41. What are milch animals ?
42. Which activity of the farmer can promote growth of earthworms and microbes in the field?
43. Name two weeds that are commonly found in rice and wheat fields.
44. Terms related to agriculture practices are given below. Rearrange them in the correct sequence.
Harvesting , sowing , maturing,  rolling and ploughing , irrigation , weeding.
45. Leguminous plants do not require intravenous fertiliser. Why is it so ?
46. Name the practice followed for large scale rearing of farm animals. What facilities are provided to farm animals ?
47. Classify the following crops into kharif and Rabi crops and write in the tabular column given below: Maize, paddy, mustered, pea, gram, wheat, groundout, cotton.
48. Despite favourable climate conditions , a farmer's CROP failed to give good yield. Give the possible reasons for this.
49. Paddy is a major cereal CROP in our country.
(a) In which season is paddy cultivated?
(b) Discuss the method of sowing.
(c) What measures must be taken to prevent spoilage and insect attack of harvested grains?
50. What do you mean by drip system?

Multiple choice questions
 1.Sunflower seeds provide us mainly with :-
a. fats
b. carbohydrates
c. proteins
d. vitamins

2.Most commonly grown cereal crop is:-
a. rice
b. maize
c. wheat
d. all the above

3. Crops sown during winters are :-
a. rabi crops
b. kharif crops
c. mixed crops
d. cereal crops

4. The method of scattering seeds in the field by hand is :-
a. hand picking
b. transplantation
c. broadcasting
d. leveling


6.The disadvantage of broadcasting is :-
a. seeds are evenly distributed
b. seeds get damaged
c. seeds are unevenly distributed
d. seeds get infected

7. The disadvantage of broadcasting is :-
a. seeds are evenly distributed
b. seeds get damaged
c. seeds are unevenly distributed
d. seeds get infected

8. Seeds being used for sowing must be :-
a. inferior quality
b. disease free
c. hollow and light
d. all the above

9. Seed drill sows the seeds at :-
a. equal distances
b. proper depth
c. both a & b are correct
d. unequal distances

10. Two or more crops grown together in the same field is called :-
a. crop rotation
b. mixed farming
c. field fallow
d. mixed cropping

11. A bacterial disease of plants is:-
a. rust
b. wilt
c. blight
d. smut

12. Which of the following is used as a biofuel:-
a. Ethanol
b. Gammaxene
c. Manure
d. Amaranthus

13. Rearing of honeybees for products like honey and wax is called:-
a. Sericulture
b. Aquaculture
c. Pisciculture
d. Apiculture

14. Which of the following is a milch animal:-
a. Camel
b. Sheep
c. Honeybee
d. Silkworm

15.Cod liver oil from fish is found to be rich in :-
a. Vitamin A
b. Vitamin D
c. Vitamin C
d. Vitamin B

16. Conversion of ammonia into nitrates is called:-
a. nitrification
b. denitrification
c. ammonification
d. deammonification

17. Which of the following are harmful for crop plants:-
a. too little water
b. too much of water
c. both a & b
d. too much light

18. The irrigation method in which water enters the field through channels made between
two rows of crop plants is:-
a. Sprinkler irrigation method
b. Basin irrigation method
c. Furrow irrigation method
d. Drip irrigation method

6. Fill in the blanks :-
a. ______ is large scale cultivation of vegetable, fruits & flower plants.
b. ______ is the process of loosening and turning up of the soil.
c. ______ is the process of supplying water to crops at different intervals.
d. ______ is result of too much water given to the soil.
e. ______ is the science dealing with growth of plants and animals for human use
f. ______ were the first crop known to be cultivated.
g. ______ provide the staple food for people in every part of world.
h. ______ is the most important cereal in the world.
i. Better varieties of crops can be developed by plant ______.
j. ______ means producing offsprings under controlled conditions.
k. ______ is a technique used for developing new crop varieties by cross breeding.
d. In the breeding experiments anthers of plants are removed by process called ______ l. ______ farming technique of crop cultivation employs biological methods.
m. Grains are rich in ______.
n. If there is a shortfall in production, grains are made available from ______ stock

1. Match the column :-
a. Compost        i) fertilizer
b. Rodents        ii) insecticide
c. BHC               iii) pest
d. NPK              iv) weedicide
e. Metachlor    v) manure

2. Match the column :-
a. horticultural crop  i) potato
b. kharif crop              ii) crotons
c. rabi crop                  iii) agricultural waste
d. compost manure   iv) groundnut
e. green manure        v) dry leaves

3. Match the column :-
a. sowing                      i) sprinklers
b. irrigation                ii) trowel
c. weeding                  iii) sickle
d. harvesting              iv) seed drills
e. manuring                 v) manually

4.Match the column :-
a. legume crop               i) jute
b. root crop                   ii) coffee
c. cereal crop               iii) sweet potato
d. plantation crop       iv) groundnut
e. fibre crop                  v) wheat

5. Match the column :-
a. Compost                      i) fertilizer
b. Rodents                      ii) insecticide
c. BHC                            iii) pest
d. NPK                            iv) weedicide
e. Metachlor                   v) manure

6.Cod liver oil from fish is found to be rich in :-
a. Vitamin A
b. Vitamin D
c. Vitamin C
d. Vitamin B

7. Conversion of ammonia into nitrates is called:-
a. nitrification
b. denitrification
c. ammonification
d. deammonification

8. Which of the following are harmful for crop plants:-
a. too little water
b. too much of water
c. both a & b
d. too much light

9. The irrigation method in which water enters the field through channels made between two rows of crop plants is:-
a. Sprinkler irrigation method
b. Basin irrigation method
c. Furrow irrigation method

d. Drip irrigation method