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Topic -Cell and its organelles
The body of an organism from the simplest to the most complex form is made of tiny microscopic units called cell. A cell is the structural and functional unit of life.
-Cell-
Structure of some cells
PROKARYOTIC CELL
EUKARYOTIC CELL
* Size is small (1-10 micrometre)
* Size is large (5-100 micrometre)
* Nucleus is absent and known as nucleoid.
* Nucleus is present &with nuclear membrane.
* Contains single chromosome.
* Contains a number of chromosomes.
* Cell division takes place by budding or fission.
*Cell division takes place by mitosis or meiosis.
ANIMAL CELL
PLANT CELL
* Generally small in size.
* Generally larger than animal cell.
* No cell wall is present.
* Cell wall in addition to the plasma membrane.
* Plastids are absent. Vacuoles are small.
* Plastids are present. Vacuoles are large.
* Nucleus is generally near the centre.
* Nucleus is present near the periphery.
Difference b/w different types of cell
*CELL WALL*CELL MEMBRANE
*NUCLEUS *GOLGI APPARATUS
*LYSOSOMES *RIBOSOMES
*MITOCHONDRIA *VACUOLES*PLASTIDS
Different types of organelles in a cell:
The organelle that i have
chosen is :Nucleus
What is nucleus?
Nucleus is the largest & the most conspicious organalle of the cell. It was discovered by robert
brown in 1831. The nucleus controls all the activities taking place inside the cell, thus
known as ‘master or director of the cell’. There are four components of the cell. A true nucleus
is present in all eukaryotic cells.
*Nuclear Membrane: It is a 2-layered envelope which is porous & semi-permeable .
*Nucleoplasm: It is transparent, semifluid, colloidal ground substance in which chromatin are present.
*Nucleolus: It is a darky stained, spherical structure.
*Nuclear Chromatin: network of long, fine threads called chromatin.
There are 4 components of nucleus :
(i) The nucleus controls cell metabolism & other activities ,hence, it is called ‘Master or Director of the cell.
(ii)Chromatin part of the nucleus contains all the genetic information required for the growth & development of an organism.
(iii) Nucleus plays a central role in cellular reproduction
(iv) It also determines the development and future form of a cell.
Functions of nucleus:
• CELL IS THE STRUCTURAL AND FUNCTIONAL UNIT OF LIFE.
• CELL WAS DISCOVERED BY ROBERT HOOKE IN 1665.
• DIFFERENT CELL ORGANELLES ARE CELL MEMBRANE, CELL WALL, NUCLEUS, GOLGI APPARATUS, LYSOSOMES, RIBOSOMES, MITOCHONDRIA, PLASTIDS & VACUOLES.
• NUCLEUS IS THE MOST CONSPICUOUS AND LARGEST ORGANELLE OF A CELL.
• IT WAS DISCOVERED BY ROBERT BROWN IN 1831.
• IT IS ALSO KNOWN AS DIRECTOR OF THE CELL AS IT CONTROLS ALL THE ACTIVITIES OF THE CELL
• NUCLEUS IS FORMED OF 4 COMPONENTS : NUCLEAR MEMBRANE , NUCLEOPLASM, NUCLEOLUS, NUCLEAR CHROMATIN.
Summary
THANK YOU !