Cell Membrane: Separates the cell from its external environment and protects it from injury.

Plasma Membrane: A flexible and selectively permeable barrier that encloses the cell, regulating the movement of substances in and out. It ensures the cell maintains homeostasis by allowing essential nutrients to enter while expelling waste products and harmful substances. It also plays a role in cell signaling and communication.

Cytoplasm: A gel-like substance that fills the cell and surrounds the organelles. It acts as a medium for chemical reactions, providing the necessary environment for metabolic processes and organelle activities. It also helps in the movement of materials within the cell.

Nucleus: The control center of the cell, housing the genetic material (DNA) that dictates all cellular functions, including growth, reproduction, and protein synthesis. It also regulates gene expression, determining which proteins the cell produces.

Nucleolus: Located within the nucleus, it is the site where ribosomal RNA (rRNA) is synthesized and combined with proteins to form ribosomal subunits, which are later transported out to the cytoplasm for protein synthesis.

Chromatin: A complex of DNA and proteins found within the nucleus, it stores genetic information and is responsible for regulating gene activity. During cell division, chromatin condenses into chromosomes to ensure proper DNA distribution.

Mitochondria: Known as the powerhouses of the cell, these organelles generate energy in the form of ATP through cellular respiration. They also play a role in regulating the cell cycle and apoptosis (programmed cell death).

Rough Endoplasmic Reticulum (RER): A network of membranes studded with ribosomes, giving it a rough appearance. It is primarily involved in the synthesis and folding of proteins, which are then transported to the Golgi apparatus for further processing.

Smooth Endoplasmic Reticulum (SER): Lacks ribosomes and is involved in the synthesis of lipids, including oils, phospholipids, and steroids. It also detoxifies drugs and poisons and stores calcium ions, which are crucial for muscle contraction and other cellular activities.

Ribosomes: Small, spherical structures found either floating freely in the cytoplasm or attached to the RER. They are the sites of protein synthesis, where messenger RNA (mRNA) is translated into polypeptide chains.

Golgi Apparatus: A stack of flattened membrane-bound sacs that modify, package, and sort proteins and lipids received from the endoplasmic reticulum. It prepares these molecules for transport to their final destinations, either inside or outside the cell.

Golgi Vesicle: Small membrane-bound sacs that bud off from the Golgi apparatus. They transport proteins and lipids to their target locations, including the plasma membrane or other organelles, and are essential for secretion processes.

Lysosome: A spherical organelle containing digestive enzymes. It breaks down macromolecules, cellular debris, and invading pathogens. Lysosomes also play a role in autophagy, where the cell recycles its own damaged components.

Peroxisome: A small, membrane-bound organelle that contains enzymes for breaking down long-chain fatty acids and toxic substances like hydrogen peroxide. It is crucial for lipid metabolism and maintaining cellular health.

Vacuole: A storage organelle that varies in size depending on the cell type. It stores water, nutrients, and waste products, helping to maintain osmotic balance and providing structural support in plant cells.

Centrosome: A region near the nucleus that organizes microtubules and is critical for cell division. It contains a pair of centrioles in animal cells, which help form the spindle fibers necessary for chromosome separation during mitosis.

Microtubule: Hollow, cylindrical structures made of tubulin proteins. They provide structural support, form the cytoskeleton, and act as tracks for the movement of organelles and vesicles. They are also involved in the separation of chromosomes during cell division.

Microfilament: Thin, thread-like structures composed of actin proteins. They support the cell’s shape, enable cellular movements like crawling or contraction, and are involved in processes such as cytokinesis during cell division.

Intermediate Filament: Rope-like fibers that provide mechanical support to the cell, helping it withstand stress and maintain its structural integrity. They also anchor organelles in place.

Secretory Vesicle: Small sacs that transport molecules, such as proteins and hormones, from the Golgi apparatus to the plasma membrane. These vesicles fuse with the membrane to release their contents outside the cell in processes like exocytosis.