Cell The Unit o...

Different parts of human body perform different function. Human body has heart to pump blood, stomach to digest food, skeletal muscles to perform movement and locomotion and so on. Heart has a special type of muscle cells called cardiac muscles which contract rapidly, rhythmically and tirelessly; they never get fatigue during life time of an organism. Stomach has special cells such as mucous cells to secrete mucus for lubricating the food, zymogen cells (or Chief cells) to secrete a proenzyme of protein digestive enzyme, the pepsin, called pepsiogen, parietal cells or oxyntic cells to secrete hydrochloric acid (CHl) activating pepsinogen into functional pepsin and also for killing germs of food. Skeletal muscles are striated and voluntary muscles, i.e., their contraction depends on your will or control. Due to this property of skeletal muscle cells, you are able to move your hands and ten fingers in the desired ways.
Like the human body, the cell has got division of labour. In fact, each cell has got certain specific components within it known as cell organelles. Each kind of cell organelle performs a special function, e.g., making of new material in the cell such as protein synthesis by ribosomes, food (glucose/ starch) synthesized by chloroplasts, clearing up the waste substances from the cell by the lysosomes, etc. Thus, a cell is able to live and perform its functions because of these organelles. These organelles together constitute the basic building blocks called the cells. Quite interestingly all cells are organised to have the same basic structure, no matter what their function is or what organism they are found in.