Cell

Cell

• Cell is the basic structure and functional unit  of living beings.

• Study of cell = Cytology.

• Robert Hooke is considered the father of cell science because he was the first to discover cells in 1665 AD, but he discovered dead cells, which he had seen in the bark of a tree.

• The first living cell was discovered by Antonie Van Leeuwenhoek, who had seen the living cell in a pond with his telescope.

• The Smallest cell - Mycoplasma

• The biggest cell - Ostrich Egg

• The Smallest cell in human body - Sperm

• The biggest cell in human body - Ovum

• The longest cell in human body - Neuron

Cell Theory

German a botanist and a zoologist M.J Schleiden and T. Schwann gave cell theory, In this theory, they sad that:-

• Every organism originates from a single cell.

• The body of every organism is made of one or more cells.

• In the process of origin of a cell, Nucleus plays the role of the main worker or creator.

Cell Structure

Remember the Cell Structure from this figure, you will remember it quickly and for a long time.

Human Cell Structure Image.

Cell Membrane

The Cell membrane has a boundary that controls the substance that enters the cell, which allows only that thing to enter inside it which is useful; whatever is not useful is not allowed to enter inside, that is why it is called Semipermeable.

Lysosome

• The enzymes present in lysosome  are acidic, which helps in digestion.

• Enzymes present in lysosome:- Protease, Ribonuclease, Deoxyribonuclease & Phosphatase.

• In the year 1964 two scientists Hirsch and Cohen explained that lysosomes help in destroying dead, diseased and damaged cells, so It is called "Suicide Bag Of Cell".

• Lysosomes present in the liver and  pancreas cells of some birds are more developed and active, which helps in the synthesis of protein.

Mitochondria

• Discovered by Richard Altmann in 1890, found in the cytoplasm.

• Altman named it Bioplast and Carl Benda named it Mitochondria. 

•  it is called Power House.

Plastid

• It is found only in Plant Cells and is of three types

(a). Chloroplast

(b). Chromoplast 

(c). Leucoplast.

(a). Chloroplast :- A pigment called chlorophyll is found in these plastid, with the help of which the process of photosynthesis take place which produces food. Hence, it is called the kitchen of the plant cell.

(b) Chromoplast :- These are coloured plastids, these plastids provide colour to flower, seeds etc.

(c). Leucoplast :- it is a colourless  plastid. it is found in those parts of the plant where sunlight does not reach, for example:- roots and underground stem. it is a plastid that stores food materials, it mainly converts amino acids into fatty acids.

Difference between Plant Cell and Human Cell

Difference between Plant Cell and Human Cell, Image