Nucleus,It’s
Structure,Function !!
NUCLEUS
Cell is a fundamental component of life containing different
organelles.
Nucleus is a cell organelle. It is known as nerve center or
control canter of cell. It is also known as ‘the head of the
cell’.
From Latin nucleus, meaning ‘kernel’
The nucleus was the first organelle to be discovered by the
scientist A.V.Leeuwenhoek. He observed a ‘lumen’, the nucleus,
in the red blood cell of ‘salmon’.
Unlike mammalian red blood cell those of other vertebrates
still contains nuclei (pl. of nucleus).
DEFINITION OF NUCLEUS
The nucleus is a membrane enclosed organelle found in
eukaryotic cell (plant, animal, fungal and protista).
It is the control center of the cell.
The nucleus is a large organelle and contains most of a cell’s
genetic material.
Only eukaryotic cells have nucleus. Prokaryotic cells do not
contain a cell nucleus of membrane bound organelles.
SIZE AND SHAPE OF NUCLEUS
1. It is a spherical organelle.
2. Accounts 10 of cell’s volume.
3. It ranges from 2-5 micron meter in diameter.
STRUCTURE OF NUCLEUS
There are some parts, which are presents in nucleus.
1. Nuclear membrane.
Outer membrane: Outer membrane is one of the two
membranes that are facing the cytoplasm.
Inner membrane: Inner membrane is also one of the two
membranes which separate the nuclear matrix from the
inter membrane space.
2. Nucleoplasm: Neucleoplasm is one of the types of
protoplasm. It is covered by the nuclear membrane. The
part is liquid that surrounds the chromosomes and
nucleoli.
3. Nucleolus: Nucleolus is usually is the center of the
nucleus .it is composed of protein and nucleic acid. It
synthesized rRNA and assemble ribosomes.nucleolus
disappears when cell divided.
4. Chromosomes: The cell nucleus contains the majority of
the cell’s genetic material in the form of multiple
linear DNA molecules organized into structures called
chromosomes. During cell cycle these are organized in a
DNA-protein complex known as chromatin, and cell
division the chromatin can be seen to form the well
defined chromosomes. A small fraction of the cell’s
genes are located instead in the mitochondria.
5. Chromatin: Chromatin is composed of long thing stands of
DNA, and it contains instructions that control cell
metabolism and heredity e mitochondria.
2. Nuclear envelop: Nuclear envelop is the double membrane
that is surrounding the nucleus.
2. Nuclear pore: Nuclear pore is the huge complexes of
protein that across the nuclear envelop. It is 100 nm in
diameter. Human cell have 1000-4000 nuclear pores. It
mainly helps in nuclear transport.
FUNCTION OF NUCLEUS
1. Storage of hereditary material.
2. Storage of proteins and RNA.
3. The nucleus is the site of transcription. It contains a
variety of protein that either directly mediates
transcription or are involved in regulating the process.
4. Production of ribosome.
5. Transport of hereditary material to the rest of cells.
6. Helps in prevention.
7. The nuclear envelop allows the nucleus to control its
content and separate them from the rest of the cytoplasm
where necessary.
This is the general notes on Nucleus, It’s Structure &
Function.
Thank You.