Seed | VVI 5 Marks Question | Bihar Board 2026 | Class 12 Biology

*Hello students!* In today’s Biology lecture, we will learn the topic *Seed (Formation, Structure, Types, Functions)* in a very simple and exam-focused way. This topic is very important for the *5-marks long answer* in Bihar Board Class 12 exam. --- 🎯 *What You Will Learn in This Video* ✔ Definition of seed ✔ How seed is formed (Ovule → Mature seed) ✔ Structure of a typical seed ✔ Seed parts: Seed coat, Embryo, Endosperm ✔ Types of seeds: Monocot & Dicot ✔ Functions of a seed ✔ Conditions for germination ✔ Neat & labelled diagram ✔ Model 5-marks answer for board exam --- 📘 *SEED – Complete and Easy Explanation* ⭐ *Definition of Seed* A *seed* is a *mature ovule* formed after fertilization. It contains: an **embryo**, stored **food**, and a protective **seed coat**. A seed is the structure that grows into a *new plant* during germination. --- 🌿 *Formation of Seed* 1️⃣ *Fertilization* Male and female gametes fuse to form a **zygote**. *Endosperm* is formed to store food. 2️⃣ *Ovule transforms into Seed* *Integuments* → become *Seed coat* *Zygote* → develops into *Embryo* *Endosperm* → becomes *food reserve* The point where ovule was attached → *Hilum* 3️⃣ *Maturation of Seed* The seed becomes dry and hard. It is now ready for *germination* under suitable conditions. --- 🌱 *Structure of a Mature Seed* A typical seed has **three main parts**: --- *1️⃣ Seed Coat* Outer protective covering of the seed Made of two layers: *Testa* – outer layer *Tegmen* – inner layer --- *2️⃣ Embryo* The young plant inside the seed. It has three parts: *Radicle* → becomes the root *Plumule* → becomes the shoot *Cotyledons* → seed leaves that store food --- *3️⃣ Endosperm / Stored Food* Provides nourishment to the embryo during germination Abundant in *monocot seeds* like maize and wheat --- 🌾 *Types of Seeds* ⭐ *1. Dicot Seed* Has *two cotyledons* Example: Pea, Bean ⭐ *2. Monocot Seed* Has *one cotyledon* Example: Maize, Rice, Wheat --- 🌱 *Seed Germination – Essential Conditions* A seed requires: ✔ Water (moisture) ✔ Oxygen ✔ Suitable temperature ✔ A healthy embryo --- 📝 *Model 5-Marks Answer (Board Exam Style)* **A seed is the mature ovule formed after fertilization. It consists of a protective seed coat, an embryo, and stored food. The integuments of the ovule form the seed coat. The zygote develops into the embryo, which has radicle, plumule, and cotyledons. Endosperm or cotyledons store food for the embryo. Seeds are of two types: monocot and dicot, depending on the number of cotyledons. Under favourable conditions of water, oxygen, and temperature, the seed germinates to form a new plant!! नमस्कार विद्यार्थियों! आज के इस Biology lecture में हम *बीज (Seed)* को बहुत ही सरल और परीक्षा-उन्मुख तरीके से समझेंगे। यह टॉपिक बिहार बोर्ड कक्षा 12 में *5 अंक* के प्रश्न के रूप में आता है। *अर्थ:* बीज वह संरचना है जिसमें भविष्य का पौधा (embryo) सुरक्षित रहता है। 📝 *5 अंक का उत्तर (Bihar Board — Perfect Answer)* “निषेचन के बाद परिपक्व अंडाणु को बीज कहते हैं। बीज तीन मुख्य भागों—बीज आवरण, भ्रूण तथा भोजन—से मिलकर बना होता है। अंडाणु के आवरण बीज आवरण में बदल जाते हैं। युग्मनज (zygote) विकसित होकर भ्रूण बनता है तथा एण्डोस्पर्म भोजन संग्रह करता है। भ्रूण में रैडिकल, प्लूम्यूल तथा बीजपत्र होते हैं। बीज दो प्रकार के होते हैं—द्विबीजपत्री तथा एकबीजपत्री। अनुकूल परिस्थितियों में बीज अंकुरित होकर नया पौधा बनाता है।”* --