Biology (NTSE/Olympiad)  

1. The cell

Nucleus, Structure & Working

Nucleus :
• It is the most important part of cell which control all the activities of cell.
Structure of Nucleus :
• The nucleus has a double layered covering called nuclear membrane.
• The nuclear membrane has pores inside the nucleus to its outside, that is, to the cytoplasm.
• The nucleus contains chromosomes, which are visible as rod-shaped structures only when the cell is about to divide.
• Chromosomes are composed of DNA and protein.
• Functional segments of DNA are called genes.
• In a cell which is not dividing, this DNA is present as part of chromatin material.
Function of nucleus :
• It play a important role in cellular reproduction.
• DNA contain the information necessary for constructing & organizing cells.
• Nucleoid - In some organisms nuclear region of cell may be poorly defined due to the absence of nuclear membrane. Such an undefined nuclear region called nucleoid.
Note :
Prokaryotic cell- Cell which do not have well defined nuclear region . called prokaryotic cells. Pro - Primitive
Karyon - nucleus
Eukaryotic cells - Cells which have well defined nuclear region, called eukaryotic cells.
• Along with nucleus membrane, prokaryotic cells lack most of cell organells.

If you want to give information about online courses to other students, then share it with more and more on Facebook, Twitter, Google Plus. The more the shares will be, the more students will benefit. The share buttons are given below for your convenience.

NTSE Biology (Class X)

NTSE Biology (Class IX)


NTSE Physics Course (Class 9 & 10)

NTSE Chemistry Course (Class 9 & 10)

NTSE Geography Course (Class 9 & 10)

NTSE Biology Course (Class 9 & 10)

NTSE Democratic Politics Course (Class 9 & 10)

NTSE Economics Course (Class 9 & 10)

NTSE History Course (Class 9 & 10)

NTSE Mathematics Course (Class 9 & 10)