– Dr. Sayan Bhattacharyya
Biology is the study of living organisms..
Living organisms can be macroorganims, or those who can be seen in naked eye, and microorganisms.
Our body is composed of cells. Many cells form a tissue. Many tissues form together a organ for one particular function. Many organ systems form our body.
The organ systems are skeletal, Muscular, nervous, excretory, pulmonary, gastrointestinal , circulatory or cardiovascular and reproductive systems.
They are similar in humans and other mammals.
All cells are not complete cells but kack some cellular components. They are called corpuscles, like Red blood corpuscles ..
The basic structure of cell are cell wall, cell membrane, cytoplasm, cytoplasmic organelles and nucleus containing Chromosome.
The Chromosome is loosely organized in bacteria but well defined in Eukaryotic cells.