Cell
Cell
There is large variety of living organisms around us. Each organism starts its life as a single cell. Cells have many functions which keep an organism alive. The cells is the basic structural and functional unit of all living organisms. It is the smallest unit of life and thus it is known as building blocks or basic structural unit of life. Every cell have a limited life span. Old and weak cells in the body continually die and are replaced by new cells.
Every organ in our body - the skin, the brain, the muscle or even the bone - is composed of hundreds of thousands of such cells. Similarly, every part of a plant - the leaf, the flower, the root and even the wood - is composed of an exceedingly large number of cells.As the blocks can be joined in many ways to make the building of different shapes and sizes. In the same way all , living organisms are made differently of different shapes, sizes and by different number of cells.
Cells are so small that they cannot be seen with naked eyes. So to see a cell we use a device called as microscope.
Microscope: An instrument used to see cells. Simple microscope helps to see small things but not microscopic objects. As cells are microscopic structures, are only visible under a powerful microscope like a compound microscope.
Every cell have a limited life span. Old and weak cells in the body continually die and are replaced by new cells.
The life span of different cells of the body vary differently as shown in the table.
| Cell Type | Life Span |
| Red blood cells | less than 120 days |
| White blood cells | 13 to 20 days |
| Liver cell | 200 to 300 days |
| Skin epidermal cells | 2 to 4 weeks |
| Cardiac cell | Long lived |
| Nerve cell | Long lived |
| Epithelia of small intestine | 1 week or less |
Branch of science dealing with study of structure and functioning of cells is known as ________________ | |||
| Right Option : D | |||
| View Explanation | |||
Who suggested that cell arises from pre-existing cells? | |||
| Right Option : B | |||
| View Explanation | |||
______________ proposed the cell theory. | |||
| Right Option : A | |||
| View Explanation | |||
Students / Parents Reviews [10]
My experience with Abhyas is very good. I have learnt many things here like vedic maths and reasoning also. Teachers here first take our doubts and then there are assignments to verify our weak points.
Shivam Rana
7thI have spent a wonderful time in Abhyas academy. It has made my reasoning more apt, English more stronger and Maths an interesting subject for me. It has given me a habbit of self studying
Yatharthi Sharma
10thAbhyas Methodology is very good. It is based on according to student and each child manages accordingly to its properly. Methodology has improved the abilities of students to shine them in future.
Manish Kumar
10thMy experience was very good with Abhyas academy. I am studying here from 6th class and I am satisfied by its results in my life. I improved a lot here ahead of school syllabus.
Ayan Ghosh
8thIt was a good experience with Abhyas Academy. I even faced problems in starting but slowly and steadily overcomed. Especially reasoning classes helped me a lot.
Cheshta
10thIt was good as the experience because as we had come here we had been improved in a such envirnment created here.Extra is taught which is beneficial for future.
Eshan Arora
8thMy experience with Abhyas academy is very good. I did not think that my every subject coming here will be so strong. The main thing is that the online tests had made me learn here more things.
Hiya Gupta
8thOne of the best institutes to develope a child interest in studies.Provides SST and English knowledge also unlike other institutes. Teachers are co operative and friendly online tests andPPT develope practical knowledge also.
Aman Kumar Shrivastava
10thIt has a great methodology. Students here can get analysis to their test quickly.We can learn easily through PPTs and the testing methods are good. We know that where we have to practice
Barkha Arora
10thA marvelous experience with Abhyas. I am glad to share that my ward has achieved more than enough at the Ambala ABHYAS centre. Years have passed on and more and more he has gained. May the centre flourish and develop day by day by the grace of God.
