Cell Structure and Functions Part 1



                               
                                             Chapter 8: Cell- Structure and Functions


Good morning boys! Welcome to the first class of science.
The lesson we are going to study is  - CELL-STRUCTURE AND FUNCTIONS.
You have learnt in your earlier classes that CELL is the basic structural and functional unit of life. There are many different kinds of cells and each kind of cell performs a specific function. 

In this class, we will learn more about cell, its structure and functions. So let all start the topic for today.

Important Instructions
1. Topic highlighted in red need to copied in your notebook.
2. Topic highlighted in green need to read only.
3. Topic highlighted in black need to be read in reference to your book.
4. Web links are shared where ever required for better understanding and highlighted with blue.

Important Instructions for completion of your note book.
1. Make an index. Make column and write sno, chapter name,  remark and sign.
2. On new page, write chapter name.
3. On the left hand of your note book write all the key words(terms to remember) page 126 given in the starting of your reader book.
4. Do very neat and clean work. 
5. Draw diagrams with pencil only. Labeling is very important. No coloring required.
6. On right side of your note book, start your question-answer that are given at the end of the blog.

LEARNING OUTCOMES OF THIS CLASS

By the end of this lesson you will be able to-

-Name the scientist who discovered cell.
-Distinguish between unicellular and multi-cellular organisms
-Give examples of unicellular and multi-cellular organisms
-Describe the various structure, size and shape of a cell

All livings things are made up of cells that are so tiny that they can only be seen under a microscope. Cell was discovered by ROBERT HOOKE in 1665, when he was observing thin slices of cork under a microscope.

He found that the cork is made up of box-like compartments formed a honeycomb structure. He called these compartment as cells.

Have a look on this image. No need to draw it.









A single cell is capable of performing all biological activities in any living organism. Cell forms the lowest level of organisation which has life. This level of organisation is called Cellular Level of Organisation.

The Cell: All living organisms are made up of very small compartment-like building blocks called cells.

  • A cell is the smallest unit of life.
  • A cell is capable of performing all biological activities in any living organisms.

Learners, do you know cells shows a wide variation in terms of shape, size function and other features. Let us all learn that-

DEPENDING ON THE NUMBER OF CELLS ORGANISMS CAN BE GROUPED AS FOLLOWS-

 # UNICELLULAR ORGANISMS - These are organisms that consist of only one cell . Example, amoeba. In unicellular organisms all functions of the body are carried out by a single cell.

# MULTI-CELLULAR ORGANISMS- These are organisms that consist of many cells . Examples-algae, plants,animals. In multi-cellular organisms, the various functions in the body are divided among different groups of cells.

Read Page no 127.

CELLS DIFFER IN SIZE-

The size of cell may differ in unicellular and multi-cellular organism. The size of a cell may vary from 0.1 micrometer to as large 170 mm X 130 mm.

 For example
- The egg of an ostrich is about 7 cm ( it is the largest )
-The unicellular  alga, Acetabularia, has a length of 10 cm.
- The bacterium Mycoplasma is the smallest cell of about 0.1 micrometer.

Remember ! THE SIZE OF A CELL HAS NO RELATIONSHIP WITH THE BODY SIZE OF THE ORGANISM , it is only related to its function. For example, the nerve cells, both in rat and elephant are long and branched and perform the same function.

DIFFERENT CELLS HAVE DIFFERENT SHAPES ( the shape of a cell is related to its function and location)

For example 

-AMOEBA is irregular in shape and keeps on changing its shape.
-The NERVE cell is long, branched  and has thread like projections.

Refer the diagrams given on page 128. (No need to draw)

The nerve cell is the longest cell. (Draw the diagram)

For more details, click on the link given below

https://youtu.be/vduncK7yMsQ

I hope you must have enjoyed learning today. Share your comment in the box. Meet you all in next class tomorrow.

HOMEWORK
1. Read pages 126-128 of your reader.
2. Define cell.
3. Write two difference between unicellular and multi-cellular organisms.
4. Name the cell in our body which is about a metre in length.
5. Draw well labelled diagram of a nerve cell.


Comments

  1. Good Morning Sir,
    My Name is Samrath Singh

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  3. Good morning sir I am Alan Roy

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  4. good morning sir
    i am Adhiveer Gandhi

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  5. Good Morning Sir,
    I am Uday Singh.

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  6. Good morning Sir, I am Anirudh Trivedi

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  7. Good morning sir, Manvendra Snehashish here.

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  8. Good Morning Sir. I am Avi Surana.

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  9. Good morning sir, I am Navye Malhotra

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  10. Goodmorning sir, I am Rudra sethi

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  11. good morning sir
    I am Dakshesh Pilania

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  12. Good morning sir. My name is Falit.

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  13. Good morning sir. I am chirag

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  14. Good morning Sir, I am Aditya Sagar

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  15. Good morning sir I am Alan Roy

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  16. Good morning sir Aaryan Saini here
    PRESENT

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  17. good morning sir this is Arnav Daga 8E

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  18. Good morning My name is Shaun Steni

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  19. Good morning sir I am Evaan Dayal

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  20. Good morning Sir, I am Remthanglien Aomar Varte

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  21. Good Morning Sir

    I am Vedant Kumar

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  22. Good Morning Sir,
    I am Aryan Puri

    ReplyDelete
  23. GOOD MORNING LEARNER,
    WRITE YOUR DOUBTS IN COMMENT BOX, WITH YOUR NAME.
    IT WILL MORE OF INTERACTIVE THEN. LEARNING IS ALWAYS TWO WAY
    YOUR SCIENCE TEACHER

    ReplyDelete
    Replies
    1. This comment has been removed by the author.

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  24. Sir do we have to write terns on the left page or divide a page into two?

    ReplyDelete
    Replies
    1. NO, YOU HAVE A COPY. ONE LEFT PAGE WRITE TERMS TO REMEMBER. THEN START YOUR WORK AND CARRY ON WITH IT. SIMPLE

      Delete
  25. Good morning mam, i m lakshay chandel,8E

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  26. This comment has been removed by the author.

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  27. Good Morning Sir, I am Shreyansh Agarwal.

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  28. Good morning sir
    I am Ayush Jain

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  29. respected sir, can u tell us the ans of Q4 in hw

    ReplyDelete
  30. Good Morning Sir!
    I am Maulik
    I attended your class but forgot to publish my name.

    ReplyDelete
    Replies
    1. dear maulik, you have already written your name in comment box.

      Delete
  31. Sir do we have to write the definitions of terms to remember

    ReplyDelete
  32. good morning sir
    i am pall anand

    ReplyDelete
  33. Sir,
    I just started doing my homework and noticed that the first question is define cell
    But the first thing that you made us write in the copy was the definition of a cell so what should we do?
    Should we write it again?
    Please clear my doubt, I am Aaryan Saini (8-E)

    ReplyDelete
  34. This comment has been removed by the author.

    ReplyDelete
    Replies
    1. YOU HAVE TO WRITE THE DIFFERENCE BETWEEN UNICELLULAR AND MULTI CELLULAR ORGANISMS

      Delete
    2. This comment has been removed by the author.

      Delete
  35. Good morning sir! I am Alan Roy 8-E

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  36. sir do we have to write the questions also

    ReplyDelete
  37. Good morning sir I'm Arnav Daga

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  38. Good morning sir I am allen sushil

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  39. Good morning sir , I am Naman kalra

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