Biology: Nutrition Part 2 | Carbohydrates & Fats Explained | RRB NTPC 2026

 In this second installment of our Biology: Nutrition series, Dharmendra Shukla Sir dives deep into the world of Macronutrients. If you missed Part 1, be sure to check our Biology playlist to build a strong foundation before jumping into this lecture.

This class is essential for students preparing for RRB NTPC, Group D, ALP, and other competitive exams where Science plays a key role.

📺 Watch the Full Lecture

Click here to watch Biology: Nutrition Part 2 on YouTube

🍞 1. Carbohydrates: The Fuel of the Cell

Carbohydrates are organic compounds made of Carbon, Hydrogen, and Oxygen in a 1:2:1 ratio [04:13]. They are the primary source of energy for our bodies.

• Key Functions: Provides instant energy (4.3 kcal per 1 gram). It accounts for nearly 85-90% of our daily energy needs [06:27].

• Sources: Potatoes, Rice, Bread, Bananas, and Honey.

• Types of Carbohydrates:

  • Monosaccharides: Simple sugars like Glucose (Blood Sugar), Galactose (Brain Sugar), and Fructose (Fruit Sugar - the sweetest natural sugar) [15:29].

  • Disaccharides: Formed by two monosaccharides. Examples include Sucrose (Table Sugar), Maltose (Malt Sugar), and Lactose (Milk Sugar) [20:47].

  • Polysaccharides: Complex chains like Starch (stored in plants), Glycogen (stored in the human liver), and Cellulose (found in plant cell walls) [24:10].

🥑 2. Fats (Lipids): The Energy Reserve

Fats are also composed of Carbon, Hydrogen, and Oxygen, but they contain less oxygen compared to carbohydrates [31:09].

• Key Functions: They act as energy reserves and thermal insulators (keeping the body warm). 1 gram of fat provides 9.3 kcal, which is much higher than carbohydrates [33:29].

• Composition: Fats are made of Fatty Acids and Glycerol [35:08].

• Types of Fats:

  • Saturated Fats (Animal Fats): Usually solid at room temperature (e.g., Ghee, Butter). Exception: Fish Oil [37:47].

  • Unsaturated Fats (Plant Fats): Usually liquid at room temperature (e.g., Mustard Oil, Olive Oil). Exception: Palm Oil [39:17].

• Hydrogenation: The process of converting unsaturated vegetable oils into saturated fats (like Vanaspati Ghee) using Hydrogen gas and a Nickel catalyst [39:59].

🚀 Exam-Oriented Quick Facts

• Brain Sugar: Galactose [16:55].

• Table Sugar: Sucrose (found in sugarcane and beetroot) [20:47].

• Animal Starch: Glycogen (stored in the liver via Insulin hormone) [26:17].

• Iodine Test: Used to detect the presence of Starch (turns blue-black) [25:14].

📚 What's Next?

In the upcoming lectures, we will cover Vitamins in detail, followed by Proteins and Minerals. To master these topics, we recommend practicing with the S Chand Railway Science books, which feature thousands of previous year questions (PYQs) tailored for the RRB NTPC 2026 exam.

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