A small organ-like structure present inside the cell is called a cell organelle. It has a particular structural makeup and performs a specific function. Depending upon the presence or absence of membrane, cell organelles can be classified into three categories, namely:
Without membrane: Some cell organelles like ribosomes are not bounded by any membrane. They are present in prokaryotic as well as eukaryotic organisms.
Single membrane-bound: Some organelles are bounded by a single membrane. For example, vacuole, lysosome, Golgi Apparatus, Endoplasmic Reticulum etc. They are present only in a eukaryotic cell.
Double membrane-bound: Cell organelles like mitochondria and chloroplast are double membrane-bound organelles. They are present only in a eukaryotic cell.
Structure and Functions of Cells
Structure and functions of different cell inclusions are as follows-
Occurrence/ Characteristic & Structure
Cell Membrane/ Plasma Membrane
Present in both plant cell and animal cell.
Selectively Permeable: Allows the materials in and out of the cell according to the requirement of the cell.
Encloses the contents of the cell.
Provides shape: animal cell.
Allows transport: by Diffusion and Osmosis.
Present only in a plant cell.
Hard and rigid.
Made up of cellulose in plant
Gives shape and turgidity.
Contains 80-90% water and many organic and inorganic compounds.
Colloidal, viscous, jelly like fluid inside the cell.
Contains enzymes responsible for all the metabolic activity taking place inside the cell.
(Director/ Brain of the Cell)
Covered by a double membranous nuclear membrane in a Eukaryotic Cell.
Contains DNA, RNA, Protein, nucleolus, and Chromatin network.
Controls the activity of the cell.
Starts cell division.
It has the chromosomes or DNA which controls the hereditary characters
Mitochondria (The Power House of The Cell / Storage Batteries)
Double membranous structure.
Autonomous body as contains its own DNA.
The main seat of respiration.
Stores energy in the form of ATP molecules.
(Shipping Department of Cell)
Discovered by Camillo Golgi in 1898.
Originates from RER.
Contains Sac like Cisternae and Vesicles.
Has two faces – cis face or receiving face and trans face or supplying face.
Modification, Packaging, and transport of materials
Synthesis of lysosomes, plasma membrane
(Framework of Cell)
A network of membranes.
RER bears ribosomes and appears rough
SER does not have ribosomes
Forms the skeletal framework of the cell.
Transport of materials from one cell to other.
Provides a surface for the synthesis of material – Proteins in RER and Lipids in SER.
Formation of lysosomes, Golgi bodies andvacuoles
Detoxification of harmful substances in the liver.
Arise from ER and GB
Surrounded by tonoplast and filled with cell sap
Store cell sap which may be liquid or solid food, toxic byproduct.
Provide rigidity and turgidity to plant cell
Lysosomes (Suicidal bags of Cell, natural scavenger, cellular housekeeper)
Present in all animal cells and few plant cells
Tiny circular single membrane-bound structures filled with digestive enzymes
Intracellular digestion of food in unicellular organisms.
Ribosomes (Protein Factories)
Without a membrane
Consist of two subunits – 60S and 40S in eukaryote both made up of RNA
Synthesis of Proteins
Leucoplast –Colourless plastid;
Chromoplast –Coloured Plastid – blue, red, yellow
Chloroplast – Green plastid
Autonomous self-duplicating body
Chloroplast – Perform Photosynthesis – Helps in the release of oxygen
Chromoplast – impart colour to flowers which help in pollination
Leucoplast – Storage
Amyloplast –Store starch
Aleuroplast – Store Protein
Elaioplast – Store fat
Question 1: Write the name of different plant parts in which chromoplast, chloroplast and leucoplast are present.
Chloroplast are present in green parts of the plant like leaves, the stem of cactus, raw mango fruit etc
Chromoplast are present in colourful parts of the plant like flowers, fruits etc
Leucoplast is present in parts not exposed to sunlight like roots, potato etc.
Question 2: Name the organelles which show the analogy written as under
Transporting channels of the cell- Endoplasmic Reticulum
Powerhouse of the cell- Mitochondria
Packaging and dispatching unit of the cell- Golgi Body