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If we put a cell under a microscope , there are three features that you could observe clearly in nearly every cell

  • These are : Plasma Membrane , a Nucleus , and Cytoplasm
  • Cell organelles are also present in nearly every cell ( except prokaryotes ).
  • These vary from cell to cell
  • In plant cells you can also observe an extra covering called the Cell wall .

Let us learn about the basic parts of a cell first:

 

Cell Membrane / Plasma Membrane

Every cell has a membrane around it to keep its contents separate from the external environment .

  •  The cell membrane is the outermost covering of an animal cell. 
  • It encloses the other components of the cell , such as the nucleus and the organelles.
  • It is also known as the Plasma membrane .
  • The cell membrane is flexible and its shape can be changed as needed. 
  • The plasma membrane is made of substances called lipids and proteins which lend it flexibility .

The functions of the Cell membrane are as follows:

  • Protecting the integrity of the interior cell.
  • Providing support and maintaining the shape of the cell.
  • It acts as a semi - permeable membrane that allows the entry of only selected substances into the cell.
  • Helps cells to catch/absorb food by changing its shape .

For Example - An amoeba catches its food by changing its shape and using pseudopodia to capture food.

 

Nucleus

  • The Nucleus can be described as the brain of the cell
  • It is a membrane-bound (covered by a sheath ) structure.
  • It contains the cell’s hereditary information (characteristics/genes obtained from parents)  and controls the cell’s growth, reproduction and other essential functions.
  • The membrane covering the nucleus is called the Nuclear membrane .
  • The nuclear membrane separates the cytoplasm from the contents of the nucleus .

 

Cytoplasm 

The cytoplasm is the fluid content inside the plasma membrane

  • It is a semi-liquid jelly-like material , between the nucleus and the cell membrane. 
  • All cell organelles such as endoplasmic reticulum, mitochondria, ribosomes, vacuoles, etc. float within the cytoplasm .

Cell Wall 

It is the outermost covering of a plant cell

  • It separates the interior contents of the cell from the exterior environment
  • The cell wall is permeable in nature which means it allows the passage of most materials through it .
  • The cell wall is made up of a substance called Cellulose .
  • Cellulose gives it strength and rigidity .

Here are a few functions of the cell wall:

  • It provides shape, strength and rigidity to the cell.

(The absence of the cell wall is the reason why animal cells are irregularly shaped . They have no support ).

  • It provides protection from any physical stress as well as from the external environment .
  • Controls the swelling of the cell during water intake . Without it, the cell would burst .
  • Prevents water loss from cell by trapping in the water.
  • It transports substances across different cells.

Apart from these 4 parts that are present in every cell,  a cell may also contain cell organelles

Each organelle has a separate function that it performs for the cell.

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CA Maninder Singh is a Chartered Accountant for the past 12 years and a teacher from the past 16 years. He teaches Science, Economics, Accounting and English at Teachoo