Chap#3|Vacuole and centrioles|Class 11 biology|New Edition Book скачать в хорошем качестве

Chap#3|Vacuole and centrioles|Class 11 biology|New Edition Book

Here’s a Class 11 Biology “Chapter 3”–style explanation of Vacuole and Centrioles (based on standard Class 11 cell structure content similar to your New Edition Book syllabus): ⸻ 📘 Vacuole — Class 11 Biology 🧬 What is a Vacuole? • A vacuole is a membrane-bound, fluid-filled sac found in the cytoplasm of many eukaryotic cells.  • The membrane around it is called the tonoplast.  Plant cells usually have a large central vacuole, while animal cells (if present) have small temporary vacuoles.  ⸻ 🧠 Structure • Bounded by a single membrane (tonoplast).  • Inside it contains cell sap — water plus dissolved substances like salts, sugars, and wastes.  ⸻ 📌 Functions of Vacuoles 1. Storage: Stores water, nutrients, pigments, and waste products.  2. Osmosis & Turgor: By regulating water, vacuoles help maintain turgor pressure, which keeps plant cells rigid.  3. Support: Helps give shape and structural support to the plant body.  4. Digestion (in some cells): In protozoa or white blood cells, vacuoles help digest food or expel excess water (e.g., contractile vacuole).  ⸻ 🔬 Centrioles — Class 11 Biology 🧬 What are Centrioles? • Centrioles are small cylindrical structures found in the cytoplasm of animal cells (and some lower eukaryotes).  • A pair of centrioles forms the centrosome, usually located near the nucleus.  ⸻ 🧱 Structure • Each centriole is made of nine triplets of microtubules arranged in a ring (a “9-triplet” pattern).  • The two centrioles are perpendicular to each other.  ⸻ 📌 Functions of Centrioles 1. Cell Division: Help organize the spindle fibers that pull chromosomes apart during mitosis and meiosis.  2. Formation of Cilia & Flagella: Act as basal bodies to form cilia and flagella.  3. Microtubule Organization: Help in arranging microtubules within the cell.  ⸻