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Cell
Cell  
QUESTION: Hello sir

Thanks sir I understood the concept of size of cells

Sir I have sent some attachment see and please answer my question

My question as the topic is given that what are living things made up of ,and to show that they gave an activity of mounting of an onion peel, my confusion is when onion is non living that how by that non living thing we can show that what are living organism made up of. Sir if u want to refer our text book u can refer from Google , u will get that,in PDF form,
Class 9th ncert science textbook free download

Thank u sir


















Thankyou

ANSWER: Hi Aishwarya
  I have seen your attachment and this is a common lab study that most beginning biology classes when first using the microscope. I have done this many times. It seems that your confusion involves how this observation of onion cells helps in the study of cells.
 First of all your statement that these onion cells are non living is incorrect. Remember that plants are living organisms. All of the cells in the inner layerof the onion are living cells. The dry outer layer consist of dead cells.
 When you looked at the cells under the scope did you see the flowing protoplasm and the nucleus of the cell. Sometimes you have to stain the cell with iodine to see the nucleus
  Observing living onion cells just gives an example of one kind of cell in living things. Different types of living cells appear differently

---------- FOLLOW-UP ----------

QUESTION: Hello sir

Sir I agree that plant cells are living cells but I am talking about onion, its cells would be living if was attached to plant like when its was growing its cells would me living but when we snatch the onion from plant body cells will not able to respire because when it was attached to plant body it cells were getting enough oxygen to survive but when we remove the contact the cell will die, how in onion cells are living and same in all vegetables and plants.

And sir second thing if cells are living then onion must grow ,

Sir when I observed cells in microscope I not saw flowing of protoplasm , I think the reason is we have compound microscope in our school, it is not visible clealy.Am I right

Answer
Think of it this way Aishwarya. I am sure you would agree that life comes from life. I fyou do not slice the onion and just leave it, it will eventually sprout a green shoot out of the top..  (Life comes from life) If you leave a potato it will produce buds.  An onion is made up of living storage cells which get the energy to reproduce from stored glucose and starches. The cells are anaerobic and do not require oxygen.
I do not know why you could not observe the flow in your onion cells


There is one more thing you should remember about cells There is a minimum of three things that a cell must have in order to be a cell 1. A cell membrane 2. protoplasm and 3. a nucleus. There is something in the human body that lacks one of these and is yet called a living cell. I will leave it up to you to discover what it is. If you can figure it out let me know  

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Walter Hintz

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Science teacher for over 50 years. MSc. in biology. I can answer questions in general biology, zoology, botany, anatomy and physiology and biochemistry.

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I have a MSc in biology and have been a science teacher for over 50 years. At present I am a faculty member at a college and a science consultant at seven catholic schools.

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The Ohio journal of Science
Momentum-The Journal of the Catholic Education Association

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