Cell Organelles are like very small  parts inside a cell that do specific functions to keep the cell function. They are like workers in a factory, each with its own role to make sure the cell stays healthy and works properly. These organelles work together like a team to help the cell do all its important functions.

Also Read: Importance of Biology

Cell Organelles for Class 9

Cell organelles are small units within a cell that perform specific roles, similar to workers in industries. Single Membrane-bound organelles and double membrane-bound organelles are the two main kinds.

Single membrane-bound organelles

In this Type, organelles resemble little bags with a single layer of membrane around them. One example is the “endoplasmic reticulum,” that helps in the production of proteins and lipids. Another is the “Golgi apparatus,” which packages and delivers proteins and lipids to their destinations.

Double membrane-bound organelles

Two layers of membrane cover double membrane-bound organelles. The most well-known is the “nucleus,” that acts as the cell’s brain and stores all of its vital instructions. Then, The “mitochondria” commonly referred to as the cell’s powerhouses generate energy for the cell to function.

Consider a cell to be a busy factory with many workers carrying out their jobs. Some are in single membrane-bound organelles, such as the endoplasmic reticulum and Golgi apparatus, while others are in double membrane-bound organelles, such as the nucleus and mitochondria. Each worker has a particular duty that contributes to the cell’s existence and function.

Organelles without membrane

Cell organelles that do not have a membrane include the cell wall, ribosomes, and cytoskeleton.  You can find them in both bacterial and eukaryotic cells.

Cell Organelles Diagram.

A Cell Organelles Diagram shows the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, and other cellular components. It helps understand their roles within a cell.

How many cell organelles are there?

There are several cell organelles, but the exact number can vary depending on how specific you want to be in your categorization. In a general sense, there are about 13 major cell organelles. 

Plasma Membrane

The plasma membrane, also known as the cell membrane or the cytoplasmic membrane, is a lipid bilayer and protein-rich cell membrane that creates a selectively permeable cell membrane.

Plant and animal cells both have plasma membranes. It acts as a selectively permeable membrane, allowing specific materials to enter and exit the cell based on their needs. The cell membrane in an animal cell provides form and protects the interior contents of the cell. The fluid mosaic model is based on the structure of the plasma membrane. According to the fluid mosaic concept, subcellular structures composed of a lipid bilayer embed protein molecules in plasma membranes.

Cytoplasm

Plant and animal cells both include cytoplasm. Jelly-like substances are found between the cell membrane and the nucleus. Water, organic, and inorganic substances mostly compose them.The cell organelle are embedded in the cytoplasm, which is a necessary component of the cell. These cell organelles contain enzymes, which are primarily responsible for managing all metabolic activity within the cell and are the location of the majority of chemical interactions.

Nucleus

In all eukaryotic cells, the nucleus is a double-membraned organelle. It is the the largest cell organelle in the cell and serves as the control center for cellular activity as well as the DNA storage facility. The nucleus is spherical, and encircled by a nuclear membrane. It is a porous membrane (similar to cell membrane) that provides a barrier between the cytoplasm and the nucleus. The nucleus contains small spherical structures called nucleoli. It also contains an important component known as chromosomes.

Chromosomes are tiny, thread-like structures that contain another vital element known as a gene. Genes are a genetic unit in organisms, which aids in the transmission of features from one generation (parents) to the next (offspring). As a result, the nucleus regulates the characteristics and functions of cells in our bodies.  The nucleus’ major role is to monitor cellular functions such as metabolism and development by utilizing DNA’s genetic information. Nucleoli in the nucleus are in charge of protein and RNA production.

Endoplasmic Reticulum

The Endoplasmic Reticulum is a network of fluid-filled membranous tubes. They are the cell’s transport system, responsible for carrying resources throughout the cell. Endoplasmic Reticulum comes in two varieties:

Rough Endoplasmic Reticulum

Cisternae, tubules, and vesicles make up the Rough Endoplasmic Reticulum, which is located all around the cell and plays an important role in protein synthesis.

Smooth Endoplasmic Reticulum

The Smooth Endoplasmic Reticulum stores organelles and creates lipids and steroids while detoxifying the cell.

Mitochondria

Mitochondria earn their reputation as the cell’s powerhouses by producing energy-rich compounds. In some species, they maternally transmit the mitochondrial genome. Sausage-shaped organelles with a double membrane are present in practically all eukaryotic cells.

The double membranes divide its lumen into two different aqueous compartments. Scientists refer to the inner compartment as a ‘matrix,’ which folds into cristae, while the outside membrane forms a continuous barrier with the cytoplasm. They generally come in a variety of sizes and are round or oval in form. In the cell, mitochondria produce energy in the form of ATP and transform molecules through aerobic respiration.

Also Read: What is Mitochondria

Plastids

Plastids are pigment-containing membrane-bound organelles. They are classified into three kinds based on the pigments used:

Chloroplast

Chloroplasts are double membrane-bound organelles that can range in form from disc to spherical, discoid, oval, and ribbon. Leaf mesophyll cells contain chloroplasts and other carotenoid pigments. These pigments are in charge of capturing light energy for photosynthesis. The inner membrane encloses the stroma. Flattened disc-shaped chlorophyll-containing structures pile up like a stack of coins in thylakoids.  Each stack is called a granum (plural: grana), and stromal lamellae, which are flat membranous tubules, connect the thylakoids of distinct grana. The chloroplast stroma, like the mitochondrial matrix, includes double-stranded circular DNA, 70S ribosomes, and enzymes essential for carbohydrate synthesis.

Chromoplasts

Chromoplasts include fat-soluble, carotenoid pigments such as xanthophylls, carotene, and others that give plants their distinctive color – yellow, orange, red, and so on.

Leucoplasts

Leucoplasts are plastids that are colorless and store nutrients. Amyloplasts store carbs, aleuroplasts store proteins, and elaioplasts store oils and fats.

Ribosomes

These non-membrane-bound cytoplasmic organelles form a tight association with the endoplasmic reticulum. Many cells contain microscopic particles composed of two-thirds RNA and one-third protein. Scientists refer to them as 70S in prokaryotes or 80S in eukaryotes, with the ‘S’ signifying density and size, also known as Svedberg’s Unit. Researchers have identified two subunits within the 70S and 80S ribosomes. Cells either encase them within the endoplasmic reticulum or let them float freely in the cytoplasm. Ribosomal RNA and ribosomal proteins constitute their two components.

Their major job in all live cells is protein synthesis, which ensures cell survival.

Golgi Apparatus

The Golgi Apparatus, also known as the Golgi Complex, comprises flattened, stacked pouches called cisternae and consists of a membrane-bound organelle. This cell organelle is largely in charge of delivering, altering, and packaging proteins and lipids to their final destinations. All cells, including plant and animal cells, contain the Golgi Apparatus in their cytoplasm.

Microbodies

Electron microscopes exclusively reveal membrane-bound vesicular organelles containing numerous enzymes and proteins in both plant and animal cells.

Cytoskeleton

It is a continuous network of filamentous proteinaceous structures that stretch from the nucleus to the plasma membrane in the cytoplasm. It is present in all living cells, particularly eukaryotes. Many types of proteins in the cytoskeleton matrix quickly divide or disassemble depending on the needs of the cells. The principal roles include supplying the cell with structure and mechanical resistance against deformation, and the contractile nature of the filaments aids in motility during cytokinesis.

Cilia and Flagella

Cilia are hair-like projections, tiny structures that exist outside the cell wall and function as oars to move the cell or extracellular fluid. Flagella are somewhat larger and are in charge of cell motility. The eukaryotic flagellum varies structurally from the bacterial equivalent. An axoneme is the core of the cilium and flagellum, consisting of nine pairs of progressively organized peripheral microtubules and a set of central microtubules running parallel to the axis. The central sheath encases the central tubules and connects them with a bridgeh. A radial spoke links the central sheath to one of the peripheral microtubular pairs. As a result, there are a total of 9 radial spokes. The cilia and flagella come from structures similar to centrioles called  basal bodies.

Centrosome and Centrioles

The centrosome organelle consists of two centrioles, which form mutually perpendicular structures. Each centriole comprises 9 evenly spaced peripheral tubulin protein fibrils, with interconnected triplets making up each fibril. Researchers refer to the proteinaceous center of the centriole as a hub. The hub joins the peripheral fibrils through a protein-based radial spoke. During cell division, centrioles from the basal bodies of the cilia and flagella generate spindle fibers.

Vacuoles

Cells commonly characterize vacuoles as irregularly shaped storage bubbles, and cells commonly recognize them as membrane-enclosed fluid-filled organelles. The vacuole stores food or other substances that a cell may require to live. It also serves as a repository for garbage. Vacuoles finally dispose of the waste materials. As a result, the rest of the cell is safe from infection. The size and quantity of vacuoles in animal and plant cells varies. Plant cells contain bigger vacuoles than animal cells.

What is cellular apparatus ?

The term “cellular apparatus” can refer to the various organelles and parts inside a cell that work to carry out their roles. The nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, and other structures are among them. They function as specialized machinery, each with a unique duty, to make sure that the cell can carry out activities such as energy production, protein synthesis, and structural maintenance.

A Human Cell Diagram

A human cell diagram depicts the structure of a cell, including its organelles, nucleus, cell membrane, and cytoplasm. It helps in explaining the complex nature of cellular biology.

Frequently Asked Questions 

Which cell organelle is known as the cell's powerhouse?

Mitochondria are cell organelles that are known as the "Powerhouse of the Cell" because they carry out cellular respiration and create energy molecules known as ATP (Adenosine Triphosphate).

What exactly is a Nucleoid?

A nucleoid is an irregular-shaped, non-membranous cell organelle found in all prokaryotic cells. They are the bearers of a cell's genetic material.

In plants, where can we locate chloroplasts and chromoplast pigments?

The plastids chloroplasts and chromoplasts are found in all plant cells. Chloroplasts contain the green pigments seen in leaves, green stems, and so on. Chromoplasts contain the colorful pigments seen in all of the plant's colorful sections, such as flowers and fruits.

What is cell organelles

Cell organelles are like tiny organs within cells, each with a specific job. For example, the nucleus controls the cell, while mitochondria produce energy. These parts help cells function properly.

List of Cell organelles

• Nucleus: Controls cell activities.
• Mitochondria: Produces energy.
• Endoplasmic Reticulum: Makes and transports proteins.
• Golgi Apparatus: Processes and packages molecules.
• Cell Membrane: Controls what enters and exits the cell.

Conclusion

In conclusion, Cell Organelles – Types, Structure, and Functions are essential for cell function. These small structures function similar to the organs of a cell, each having a different purpose. They all function together for keeping cells alive, from the energy-producing mitochondria to the recycling hub known as the lysosome. The nucleus, like the brain of the cell, contains genetic information. The endoplasmic reticulum and the Golgi apparatus aid in the production of proteins and packing. The cytoskeleton and cell membranes keep the cell shape and govern what goes in and out. At the most tiny level, these organelles enable life to exist.

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