Q.The stain used to visualise motochondria is

Learning cell biology can feel like walking into a busy workshop where every tool has a job — and the skill you are really building is matching each organelle to the task it performs. Once you can pair a structure with its function on sight, the whole cell stops being a jumble of names and starts making sense as an organised, cooperating team.

Here is a practical set of pairings that come up again and again:

• Nucleus — control and heredity. It directs the activities of the other organelles and holds the chromatin (DNA), the cell's hereditary information.
• Mitochondria — energy. Aerobic respiration happens here, generating ATP, which is why they are called the power houses of the cell.
• Chloroplast — capturing light. Found in plant cells, it holds chlorophyll and traps light energy for photosynthesis.
• Ribosome — protein synthesis. The site where proteins are assembled; it has no membrane and can sit free in the cytoplasm or on the rough ER.
• Rough endoplasmic reticulum — protein-making highway. ER studded with ribosomes; abundant in cells that actively make and export proteins.
• Smooth endoplasmic reticulum — lipid factory. The main site for making lipids, and in animal cells, steroid hormones.
• Golgi apparatus — packaging and dispatch. It modifies, packages and sends materials to targets inside or outside the cell.
• Lysosome — the cell's stomach. Filled with hydrolytic enzymes that digest carbohydrates, proteins, lipids and nucleic acids.
• Vacuole — storage. A membrane-bound pocket (bounded by the tonoplast) that stores water, sap and waste; very large in plant cells.
• Cell wall — rigid support. A non-living outer layer in plants and fungi that gives shape and protection. …