Parts of the cell

• The basic components of a cell are cell membrane, cytoplasm and nucleus.

Cell Membrane:

• The cytoplasm and nucleus are enclosed within the cell membrane, also called the plasma membrane.
• It is made of proteins and lipids.
• It is porous and allows the movement of substances or materials both inward and outward.
• The boundary of the plant cell is the cell membrane covered by another thick covering called the cell wall.

Cell Wall:

• There is an outer thick layer in cells of plants called cell wall. Cell wall is an additional covering over the cell membrane in plant cells.
• It gives shape and rigidity to the cells. Bacterial cell also has a cell wall.
• This additional layer surrounding the cell membrane is required by the plants for protection against variations in temperature, high wind speed, atmospheric moisture, etc.

Cytoplasm:

• It is the jelly-like substance present between the cell membrane and the nucleus.
• Various other components, or organelles, of cells are present in the cytoplasm.

Nucleus:

• Nucleus is an important component of the cell.
• It acts as control centre of the activities of the cell hence it is also known as Brain of the Cell.
• Nucleus is separated from the cytoplasm by a membrane called the nuclear membrane.
• Nuclear membrane is discontinuous due to which pores are formed in between and these pores are known as nucleopore.
• A smaller spherical body in the nucleus is called the nucleolus.
• The jelly like substance filled in nucleus is known as nucleoplasm.
• Nucleus contains thread-like structures called chromosomes which carry genes and help in inheritance or transfer of characters from the parents to the offspring.
• Gene is a unit of inheritance in living organisms which is made up of DNA (Deoxyribo Nucleic Acid).
• Genes controls the transfer of hereditary characteristic from parents to offspring.

• Entire content of a living cell is known as protoplasm.
• It includes the cytoplasm and the nucleoplasm.
• Protoplasm is called the living substance of the cell.
• In some unicellular organisms, nucleus is not well developed and nuclear material is present in the form of entangled mass of thread known as chromosome.
• There is no nuclear membrane.
• Hence nuleoplasm and cytoplasm are intermixed.
• The cells having nuclear material without nuclear membrane are termed prokaryotic cells.
• Organisms with these kinds of cells are called prokaryotes (pro: primitive; karyon: nucleus).
• All other organisms (unicellular and multicellular) contain cells having well organised nucleus with a nuclear membrane are designated as eukaryotic cells.
• Such organisms with well developed nucleus are termed as eukaryotes (eu: true; karyon: nucleus).

Vacuoles:

• Round dark sac like structures found in the cytoplasm are called vacuole.
• Large vacuoles are common in plant cells.
• Vacuoles in animal cells are much smaller and large in number.
• Their function is to store various components of the cell.
• It also provides rigidity and turgidity to the cell.

Plastid:

• Several small coloured bodies in the cytoplasm of the cells of Tradescantia leaf scattered in the cytoplasm of the leaf cells. These are called plastids.
• They can be coloured or colourless.
• The colour is because is of the presence of some pigments. Such plastids are called as chromoplast.
• “Chromo” means colour and “plast” means “plastid”
• Some of them contain green pigment called chlorophyll leaf cells.
• Green coloured plastids are called chloroplasts essential for photosynthesis.

• Other colourless platids are known a leucoplast.
• “Leuco” means colourless or white and “plast” means “plastid”.

Other Organelles: