Mitochondria, plastids, lysosomes and other organelles of the cytoplasm
Mitochondria are present in all eukaryotic cells; they have two membranes: the outer is smooth and the inner is folded into cristae, which carry the enzymes of energy metabolism. In the inner space (the matrix) there is the mitochondrion’s own circular DNA, RNA and ribosomes, so it is semi-autonomous and multiplies by division; its main function is ATP synthesis. Plastids are specific to plant cells: photosynthesis takes place in chloroplasts (green chlorophyll), chromoplasts contain carotenoids that colour flowers and fruits, and leucoplasts (colourless) store starch; plastids can change from one kind to another. A lysosome is a single-membrane vesicle containing hydrolytic enzymes that break down proteins, carbohydrates and fats; it digests food material and removes worn-out parts. The plant vacuole contains cell sap (salts, organic substances), which allows water to enter and keeps the cell firm (turgor). The cell centre consists of centrioles and forms the division spindle during cell division.
“Organelle business card”. Each group picks one organelle and prepares its “business card” (name, structure, function, which cells have many) and presents it briefly.