The Fundamental Unit of Life Blog 3

CLASS 9 CHAPTER 5 

THE FUNDAMENTAL UNIT OF LIFE

Day 3

" Whenever you feel sad, just remember that there are trillions of cells in your body & all they care about is you!!"

Dear Students, 

Welcome Back!😊

I hope you have completed your yesterday's assignment.

This is our third lecture for this chapter. After this class, you will be able to:

• Explain that the Nucleus is considered as the brain of the cell.
• List and explain various parts of the nucleus.
• Define genes and chromosomes.

Note: Content written in blue should be recorded as notes in the Biology Notebook.

Happy Learning!😊

Next component that is present in every cell is:

Nucleus

1. It is considered as the Brain of the cell.
2. It is a membrane-bound cell organelle.
3. It is generally spherical and is located in the center of the cell.
4. .It acts as a control center for all the activities of a cell as it controls cellular reproduction, by which a single cell divides and forms two new cells.
5. Along with the environment, the nucleus plays an important role in determining the way the cell will develop and what form it will exhibit at the time of maturity.

(To be drawn in bio notebook)

Structure of the Nucleus:

1. Nuclear Membrane:

• The nucleus is separated from the cytoplasm by a membrane called Nuclear Membrane.
• It is a double Layered covering.
• It is porous in nature and allows movement of materials between cytoplasm and inside of the nucleus.

2. Nucleolus:

• It is round granule inside the Nucleus.
• It assists in making proteins in the cell.

3. Nucleoplasm:

• It is a semi-solid substance that fills up the nucleus.

4. Chromosomes:

• They are rod-shaped structures and are visible only when a cell is about to divide.
• They contain information for the inheritance of features from one generation to another in the form of DNA (deoxyribonucleic acid).
• Functional segments of DNA are called Genes, which is a unit of inheritance in living organisms.
• when a cell is not dividing, DNA is present as part of chromatin material. chromatin material is visible as an enlarged mass of thread-like structures. Whenever a cell is about to divide chromatin material gets organized to chromosomes.

Note: In some organisms like bacteria, the nuclear region of the cell may be poorly defined due to the absence of a nuclear membrane. Such an undefined nuclear region containing only Nucleic acids is called Nucleoid. 

https://youtu.be/fV-sG3od1k0 (Check this video on Structure of Nucleus)

The third component present in general is:

Cytoplasm

• It is the fluid content inside the plasma membrane. It contains many specialized cell Organelles that are capable of performing a specific function in the cell.

Cell Organelles

the specific component which performs a special function such as making new material in the cell, cleaning up waste material from the cell, etc. 

Assignment

• Read from Pg. no. 61-62 of the N.C.E.R.T Textbook.
• https://youtu.be/NkC9AiJf7gI?t=10 (Parts of a cell)

I hope it helped!

See you for the Next Class!

Take care.😊😊😊