MCQ’s
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Class 11th Biology Chapter 12, Nutrition, explores how organisms obtain and utilize nutrients necessary for their growth, development, and maintenance. Here’s a general overview:
- Definition of Nutrition: Nutrition refers to the process by which organisms take in and use food to support their life functions. It involves the intake, digestion, absorption, and metabolism of nutrients to produce energy and build body tissues.
- Types of Nutrition:
- Autotrophic Nutrition: Organisms like plants, algae, and some bacteria synthesize their own food using simple inorganic materials (carbon dioxide and water) through photosynthesis or chemosynthesis.
- Heterotrophic Nutrition: Animals, fungi, and non-photosynthetic bacteria rely on consuming other organisms or organic substances to meet their nutritional needs.
- Macronutrients:
- Carbohydrates: Provide the primary source of energy for organisms. They are broken down into glucose, which is used in cellular respiration to generate ATP.
- Proteins: Essential for growth and repair of tissues. They are broken down into amino acids, which are used to build proteins in the body.
- Fats (Lipids): Serve as an energy reserve and are also important for cell membrane structure. Fats are broken down into fatty acids and glycerol.
- Micronutrients:
- Vitamins: Organic compounds needed in small amounts for various metabolic processes. Examples include Vitamin C, Vitamin D, and Vitamin B complex.
- Minerals: Inorganic elements like calcium, iron, and potassium, which are crucial for bone health, oxygen transport, and nerve function.
- Modes of Heterotrophic Nutrition:
- Holozoic Nutrition: Involves the ingestion of solid food followed by digestion, absorption, and assimilation. Found in animals like humans.
- Saprotrophic Nutrition: Organisms, such as fungi, obtain nutrients by decomposing dead organic matter.
- Parasitic Nutrition: Parasites, like tapeworms, live on or inside a host organism and derive nutrients at the host’s expense.
- Human Digestive System:
- Ingestion: The process of taking in food via the mouth.
- Digestion: The breakdown of food into simpler substances. It includes mechanical digestion (chewing) and chemical digestion (enzymatic action).
- Absorption: The uptake of digested nutrients into the bloodstream, primarily in the small intestine.
- Assimilation: The incorporation of absorbed nutrients into body tissues for growth and repair.
- Egestion: The removal of undigested waste material from the body.
- Importance of Balanced Diet: A balanced diet provides the right proportions of macronutrients (carbohydrates, proteins, and fats) and micronutrients (vitamins and minerals) for maintaining health and preventing nutritional deficiencies.
This chapter focuses on the different modes of nutrition and the essential nutrients required by organisms, with an emphasis on the human digestive system and the importance of a balanced diet for maintaining health.