Cell division is a process of multiplying or replicating cells.
Mitochondria
Francis Crick and James Watson.
Deoxyribose Nucleic Acid.
Genes are the basic unit of inheritance.
Amelia noticed a unfertilized egg of an ostrich while she didn't notice the smallest one because the size of the smallest cell is about 0.01 mm-0.10 mm which can’t be observed with naked eye. We can observe the small cells under a microscope. On the other hand, the size of a unfertilized egg of an ostrich is big and weighs 2.25 Kg.
Cell membrane is known as the boundary of the cell, which is semi-permeable in nature, decides the movement of the components inside or outside the cell.
Cytoplasm is a jelly-like substance present inside the cell that contains the cell organelles like nucleus, mitochondria and endoplasmic reticulum etc. The function of the cytoplasm is to store and release energy and it is also a site of all metabolic activities.
The following postulates of the cell theory are as follows: -
(a)The cell is considered as the basic structural and functional unit of life.
(b)All living organisms are made up of cells or cell.
(c)New cells develop from existing cells.
The differences between unicellular and multicellular organisms are given below in a table: -
The differences between animal and plant cell are given below: -
Nucleus
Nucleus is the most important organelle of a cell. It is a spherical-shaped surrounded by a nuclear membrane in eukaryotic cells. It is a site of chromosomes which contains the genetic information which describes all the features of the human body. Protein Synthesis process is also started here.
Endoplasmic Reticulum
Endoplasmic reticulum is a network of membranous tubes near the nucleus. It is responsible for the transportation of substances in or out and protein synthesis.
Cytoplasm
Cytoplasm is a jelly-like substance present inside the cell that contains the cell organelles. It is a site of all metabolic activities and store or release energy.
Cell membrane
The outer covering of the cell that is responsible for the transportation of the components inside or outside the cell. It is semi-permeable in nature.
Lysosomes
Lysosomes are small and rounded sacs present inside the cell. They are responsible for the digestion of foreign bodies. Therefore, they are also called suicidal bags.
This Cell structure and functions Class 8 Extra Questions and asnwers is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.
