On this Site:

- One Click NCERT Books download >>
- Get your CBSE related queries solved >>
- Animated Tutorials: >>
- CBSE Power point Notes: (See Sidebars)
- Previous year solved papers (See Sidebars)
- Practical based MCQs: (See Sidebars)
Help: Use the search box for better results



1. Which activity is basic to living?
A. Life processes
2. Give one term-science that deals with life processes.
A. Physiology.
3. What is the similarity between chlorophyll and haemoglobin?
A. Both are pigments. Chlorophyll is green pigment where as haemoglobin is red coloured pigment.
4. Define Chemosynthesis.
A. It is the mode of autotrophic nutrition in which external energy required for synthesis of organic food is obtained from chemical reaction.
5. What is photolysis of water? What are its products?
A. It is the photocatalytic splitting of water into its components. Products are protons, electrons and oxygen.
6. What are the important enzymes of pancreatic juice and their function?
A. (i) amylase-digests carbohydrate
(ii) lipase- digests fat
(iii) trypsin- digests protein
7. Give reasons of dental caries in people.
A. It is the tooth decay due to gradual softening of Enamel and Dentine. It take place when bacteria acting on sugar produce acids which softens the enamel.
8. With schematic diagram explain double circulation in man.
A. Refer to Text.
9. Explain mechanism of urine formation.
A. It takes place in three steps.
Blood flows into Glomerulus under pressure.
So blood is filtered under pressure called ultra filtration.
Small solutes (urea ,uric acid, amino acids, hormones, glucose, ions etc) and water are filtered out into bowman's capsule called filtrate.
Filtrate passes into nephron tubule. The tubule absorbs all useful components required for the body.
Some of the waste from blood is secreted into the tubule. 
Extra salts and ions are also secreted for proper concentration and pH of the urine.
Diagram: See Your NCERT Text book
10. Why is diffusion insufficient to meet oxygen requirement of multicellular organisms like us?
a.The body is covered by dead cells.
b.The living cells are not in contact with external environment.
c.Diffusion can't carry oxygen to each and every cell as it's a slow process.
11. Explain the role of HCl in our stomach.
a.Activation of enzyme Pepsin.
b.Acidifies food for the action of Pepsin.
c.Kills microbes present in the food.
12. What is the advantage of terrestrial organisms over aquatic organisms for obtaining oxygen for respiration?
A. Air has more percentage(21%) of oxygen than dissolved oxygen percentage of water that's why they get more oxygen than aquatic organisms.
13. How are lungs designed to maximize area for gaseous exchange?
a.Highly branched respiratory tract.
b.Thin wall alveolar membrane having balloon like structure.
c.Network of capillaries over the surface of alveoli.
14. Describe fat digestion in human body and the organ where it occurs.
a.Fat is first emulsified with the help of bile salt.
b.Emulsification converts fat into very fine droplets.
c.They are acted upon pancreatic lipase.
d.Lipase breaks fat into fatty acid and Glycerol.
e.It take place duodenum of small intestine.
15. How are water and minerals transported in plants?a.Trachieds and vessels of xylem tissue carry water from roots to leaves.
b.This tissue form a continuous system of water conducting channel reaching all plant parts.
c.Root cell which are in contact with the soil actively takes up ion which creates a difference in the concentration of ions in soil and root cells.
d.So, water moves into roots creating a column of water that is steadily pushed upward.
e.Due to transpiration there is loss of water from the cells of leaf. It creates a suction which pulls water from xylem cells of roots.
So, transpiration helps in the absorption and the upward movement of water.
16. How are food and other substances transported in plants?
a.Transport of soluble products of photosynthesis is called Translocation and it occurs in sieve tube and companion cells of phloem.
b.These substances move from leaves to storage organs, growing organs etc. both in upward and downward direction.
c.Photosynthetic product in the form of Sucrose is transferred from leaf cells to Phloem in expense of energy.
d.This increases osmotic pressure of phloem tissue, so water moves into the tissue.
e.The osmotic pressure moves the material in the phloem to tissues which is in less pressure according to the plants need.
17. Give labeled Diagrams for the following.
a.Digestive system of man.
b.Respiratory system of man.
c.Structure of Nephron.
d.Structure of Stomata.
e.Structure of Heart.
f.Parts of Brain.
g.Reflex action and reflex arc.


barku said...

pls add answers for the activities based on all chapters

Saad Amir said...

Revision in any subject has most important for the students.Because it strong the basics ideas of the student.
regards, saad from

Rajkumar Singh said...

This kind of activity is very important and very useful to students and they will have a lot practice.

Top Mat Colleges in Delhi