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Organelle

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What is an Organelle?

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In this article, we are going to discuss the organelles meaning.

  • Organelles can be defined as small structures within the cytoplasm that carry out functions necessary to maintain homeostasis in the cell. 

  • Organelles are involved in many processes, for example, energy production, building proteins, secretions, destroying toxins, and are also involved in responding to external signals.

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Two Categories of Organelles

Organelles are considered either membranous or non-membranous. 

  • Membranous organelles possess their own plasma membrane which is used to create a lumen separate from the cytoplasm. 

  • Organelles may be the location of hormone synthesis or they may be the location of degradation of macromolecules. 

  • Non-membranous organelles are not surrounded by a plasma membrane and most non-membranous organelles are part of the cytoskeleton, which is the major support structure of the cell. 

  • These include filaments, microtubules, and centrioles.


Examples of Organelles

In eukaryotic organisms, nearly every cell has a nucleus though there are exceptions. The other common organelles seen are listed below-

  • Mitochondria

  • Plastids (among autotrophs) 

  • Endoplasmic reticula

  • Golgi apparatus

  • Lysosomes

  • Vacuoles.

Some special cells or organelles like neurons also contain synaptic vesicles. All of these structures are membrane-bound. Macromolecular complexes like ribosomes, spliceosomes, centrioles, as well as centrosomes are not surrounded by a membrane, but are important organelles in most cells, performing vital functions like organizing the cytoskeleton, synthesizing proteins, and processing RNA.


Functions of Organelle

  1. Nutrition - The function of the unicellular organisms ingest food as large particles from the environment and then undergo intracellular digestion. This process needs the presence of organelles such as food vacuoles or it needs the presence of phagosomes and lysosomes  which carry digestive enzymes.

  2. Transport - Intracellular transport is often managed through crisscrossing cytoskeletal filaments and these act like corridors. These filaments form a series of pathways that position organelles as well these filaments transport materials. In this activity, filaments are aided by motor proteins that usually contain two domains – one which is used to interact with the cargo and the other to navigate the cytoskeletal filament. 


Cell Organelles Meaning

Let’s know what is meant by cell organelles! The cellular components are known as cell organelles. These cell organelles include both membrane bound organelles and non-membrane bound organelles, present within the cells and are distinct in their structures and functions. These cell organelles are responsible to coordinate and function efficiently for the normal functioning of the cell. A few of them function by providing shape as well as support, whereas some are involved in the locomotion and reproduction of a cell. There are various organelles which are present within the cell . They are classified into three categories based on the presence or absence of membrane.

Organelles Without Membrane: Cell wall, Ribosomes, Cytoskeleton

Single membrane-bound organelles: Vacuole, Lysosome, Golgi Apparatus, Endoplasmic Reticulum are some single membrane-bound organelles.

Double Membrane-Bound Organelles: Nucleus, mitochondria and chloroplast. 


Difference between Organs and Organelles

Organ, as well as an organelle, are two structural units, which are specialized to perform a unique function in the body of animals. 


The Main Difference between an Organ and an Organelle is That -

  •  An organ is a large part of an organism, composed of tissues that perform similar functions.

  •  An organelle is a specialized structure found inside cells and these carry out a specific life process. 

  • Organelles from cells. 

  • Cells form tissues, and tissues form organs. Organelles occur in all eukaryotes. They are microscopic. 

  • But, organs are macroscopic and can only be found in animals and plants. Here are some organelles -Mitochondria, chloroplast, Golgi apparatus, endoplasmic reticulum, and the nucleus. 

  • The kidney, heart, liver, lungs, and brain are the organs in humans. Flower, seeds, as well as spores, are the reproductive organs in angiosperms.

Different Cell Organelles and Their Functions

Cell Organelles

Structure of Cell Organelles

Functions

How Do These Look Like?

Cell Membrane

A double membrane composed of lipids and proteins. Present both in plant and animal cells.

Cell membrane provides shape that protects the inner organelle of the cell and acts as a selectively permeable membrane.

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Centrosomes

Composed of Centrioles and found only in animal cells.

Centrosomes play a major role in organizing the microtubule and Cell division.

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Chloroplasts

Present only in plant cells and contains a green-colored pigment known as chlorophyll.

Sites of photosynthesis.

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Cytoplasm

A jelly-like substance, which consists of water, dissolved nutrients, as well as waste products of the cell.

Responsible for the cell’s metabolic activities.

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Endoplasmic Reticulum

A network of membranous tubules. It is present within the cytoplasm of a cell.

Forms the skeletal framework of the cell, and is also involved in the Detoxification, production of Lipids and proteins.

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Golgi Apparatus

Membrane-bound, sac-like organelles, and it is present within the cytoplasm of the eukaryotic cells.

It is mainly involved in secretion as well as involved in intracellular transport.

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Lysosomes

A tiny, circular-shaped, single membrane-bound organelles, which is filled with digestive enzymes.

Helps in digestion as well as is responsible for removing wastes and digests dead and damaged cells. Therefore, it is also called the “suicidal bags”.

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Mitochondria

An oval-shaped, membrane-bound organelle, also called the “Power House of The Cell”.

The mitochondria main sites of cellular respiration. They are also involved in storing energy in the form of ATP molecules.

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Nucleus

The largest, double membrane-bound organelles, which contains all the cell’s genetic information.

Controls the activity of the cell and controls the hereditary characters.

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Plastids

Double membrane-bound organelles. There are 3 types of plastids:

  1. Leucoplast –Colourless plastids.

  2. Chromoplast–Blue, Red, and Yellow colour plastids.

  3. Chloroplast – Green coloured plastids.

Helps in the process of photosynthesis and pollination, Imparts colour for leaves, flowers, and fruits, and stores starch, proteins, and fats.

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Vacuoles

A membrane-bound, fluid-filled organelle found within the cytoplasm.

Provide shape as well as rigidity to the plant cell and helps in digestion, excretion, and storage of substances.

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FAQ (Frequently Asked Questions)

Question 1) What are All of the Organelles?

Answer ) There are six Cell Organelles -

  • Nucleus - Animal cell.

  • Ribosomes - Ribosomes are known as the protein factories of the cell.

  • Endoplasmic reticulum - Ribosomes on the outer surface of the endoplasmic reticulum play a vital role in protein synthesis within cells. 

  • Golgi apparatus.  

  • Chloroplasts. 

  • Mitochondria.

Question 2) What are Organelles and Their Function?

Answer) We can define an organelle as a subcellular structure that has one or more functions to perform in the cell, just like an organ does in the body. Among the more important cell organelles are the nuclei, mitochondria, which produce chemical energy; and ribosomes, which assemble proteins.