Cells are the basic Building Blocks of all living things. The human body composed of trillion of cells. They provide structure for the body, take it nutrients from food and convert those nutrients into energy, and carry out specialized functions. Cells were discovered by Robert Hook in 1665.
Many years ago scientists believe that the first known cell originated on Earth. These were all single-celled organisms (prokaryotes) and they do not have a nucleus and internal structures called Organelles. Bacteria are prokaryotes while human cells are eukaryotes.
Types of cells:
1: Bone cells
2: Blood cells
3: Muscle cells
4: Fat cells
5: Skin cells
6: Nerve cells
7: Sex cells etc.
Difference between prokaryotes and eukaryotes
1: Single-celled organisms like bacteria. 1: Composed of many cells like humans.
2: No membrane-bound nucleus. 2: Membrane-bound nucleus.
3: Cell size range from 0.5-100um. 3: Cell size ranges from 10-150um.
4: Lack of internal structure called organelles 4: These cells contain membrane-bound
5: Cell defined by the process of Binary fission. 5: Cell divided by the Miosis.
6: Examples are bacteria and archer. 6: Examples are plants and animals.
The basics functions of the cells are:
1: Each human cell contain organelles, each organelle carry its special function such as:
And remove waste or reacting to external changes.
Its structures are permeable to some substances But not to others. It, therefore, controls the movement of substances in and out of the cell.
The nucleus is a spherical body which contains many organelles including the nucleolus. It controls the function of proteins synthesis in the human body and contains DNA and chromosomes which contain heredity material.
Its basic function is to produce the energy of cell in the form of ATP through respiration and to regulate the metabolism functions in humans.
It is the site where proteins synthesized. Proteins are required to the human body for repairing or for damaging of cells. These are the floating bodies in the cytoplasm.
Jelly-like fluid made up of mostly salt and water. It contains all the cell bodies called organelles and provides the site for the cell to perform functions within a cell.