Why Nutrition Matters: Benefits and Functions in Living Organisms
Nutrition is defined as the process of taking in food and converting it into energy and other vital nutrients required for life. Nutrients are the kind of substances that provide the necessary energy and biomolecules for carrying out various body functions. All the organisms in the universe need nutrients for proper growth and functioning, but they show divergence in how they fulfil their demand. Some of the animals feed on inorganic compounds to meet their requirement of nutrients, while others utilize the complex compounds. The mode of nutrition changes from one species to another species.
Types of Nutrition
Generally, there are two types of nutrition among living organisms, namely:
Autotrophic mode
Heterotrophic mode
Autotrophic Nutrition
In this mode of nutrition, organisms use simple inorganic matters, such as water and carbon dioxide in the presence of light and chlorophyll to synthesize food on their own. It is also said as the process of photosynthesis, where light energy is converted into food such as glucose, this type of organisms are called autotrophs. Some of the examples where autotrophic nutrition is observed in plants, algae, and bacteria (cyanobacteria).
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During the process of photosynthesis, carbon dioxide and water is converted into carbohydrates, which are stored in the form of starch in the plants. Later when plants require energy, it will be derived from the stored starch in plants. The process of photosynthesis is mainly explained in three stages: Absorption (The chlorophyll present in leaves traps the light coming from the sun). Conversion (in this light energy is converted into chemical energy and water will split into hydrogen and oxygen molecules). Reduction (this is the final stage, where carbon dioxide is reduced to form carbohydrates ). All the three events discussed above are not a continuous process and they may or may not take place sequentially.
Heterotrophic Nutrition
All the organisms are not capable of producing food on their own, such organisms depend mainly on others for their nutrition. The organisms that are not capable of producing their own food and depend on the other organisms or sources are known as heterotrophs, and this mode of nutrition is called heterotrophic nutrition.
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All the animals and fungi are heterotrophs in nature, they can be of many varieties depending on their environment and the adaptations. Like some of them depend on plants for nutrition known as herbivores and others depend on an animal known as carnivores. Also, there are some heterotrophs that eat both plants and animals.
There are different heterotrophs based on their mode of nutrition given below:
Parasites (e.g. leeches, ticks)
Saprophytes (e.g. mushrooms)
Holozoic (e.g. humans, dogs)
Nutrition Food Values
Apple Nutrition of One Raw, Unpeeled, Medium-Sized Apple (100 grams):
Calories: 52
Water: 86%
Protein: 0.3 grams
Carbs: 13.8 grams
Sugar: 10.4 grams
Fibre: 2.4 grams
Fat: 0.2 grams
Rice Nutritional Value of Brown and White rice
Raw Peanuts Nutrition (100 grams)
Calories: 567
Water: 7%
Protein: 25.8 grams
Carbs: 16.1 grams
Sugar: 4.7 grams
Fibre: 8.5 grams
Fat: 49.2 grams
Saturated: 6.28 grams
Monounsaturated: 24.43 grams
Polyunsaturated: 15.56 grams
Omega-3: 0 grams
Omega-6: 15.56 grams
Trans: 0 grams
Milk Nutrition in 1 Cup (Around 240 ml of Milk)
Calories: 149
Water: 88%
Protein: 7.7 grams
Carbs: 11.7 grams
Sugar: 12.3 grams
Fibre: 0 grams
Fat: 8 grams
Do You Know?
Which is the best nutritious food? Some of the best nutritious foods are salmon, kale, seaweed, garlic, shellfish, potatoes, livers, sardines, blueberries, dark chocolates, and egg yolks. If a person needs lots of nutrients without calories, the most obvious strategy is to take dietary supplements.
FAQs on Nutrition: Meaning, Types & Essential Facts
1. What is nutrition as per the CBSE Class 10 syllabus for 2025-26?
Nutrition is the fundamental biological process by which an organism obtains and utilises food for its various life activities. This process is crucial for providing energy for metabolic functions, materials for growth and development, and substances to repair damaged tissues. It involves several stages, including ingestion, digestion, absorption, assimilation, and egestion.
2. What are the two main modes of nutrition found in living organisms?
The two primary modes of nutrition are Autotrophic and Heterotrophic nutrition.
- Autotrophic Nutrition: Organisms, like green plants and some bacteria, produce their own food from simple inorganic substances such as carbon dioxide and water, using light or chemical energy. Photosynthesis is the most common example.
- Heterotrophic Nutrition: Organisms, like animals and fungi, cannot synthesise their own food and depend on other organisms for their nutritional requirements.
3. How is autotrophic nutrition fundamentally different from heterotrophic nutrition?
The fundamental difference lies in the source of energy and carbon. Autotrophs are 'producers'; they convert inorganic materials (like CO₂ and H₂O) into complex organic food using an external energy source like sunlight. Heterotrophs are 'consumers'; they obtain their energy and carbon by ingesting and breaking down complex organic substances previously made by autotrophs or other heterotrophs. Essentially, autotrophs create their own food, while heterotrophs must eat other organisms to get theirs.
4. Can you explain the process of nutrition in a simple organism like Amoeba?
Nutrition in Amoeba is a classic example of holozoic nutrition and occurs in five steps:
- Ingestion: Amoeba engulfs a food particle using finger-like projections called pseudopodia, which fuse to form a food vacuole.
- Digestion: Digestive enzymes are secreted into the food vacuole to break down the complex food into simpler, soluble molecules.
- Absorption: The digested food diffuses from the food vacuole into the cytoplasm.
- Assimilation: The absorbed nutrients are used for energy, growth, and repair.
- Egestion: The undigested waste material is moved to the surface of the cell and thrown out.
5. What are the essential raw materials for photosynthesis and what are its end products?
Photosynthesis is the cornerstone of autotrophic nutrition in plants. The essential raw materials required for this process are:
- Sunlight: The energy source, trapped by chlorophyll.
- Chlorophyll: The green pigment in chloroplasts that absorbs light energy.
- Carbon Dioxide (CO₂): Taken from the atmosphere through stomata.
- Water (H₂O): Absorbed from the soil through the roots.
6. Why do herbivores like cows have a longer small intestine than carnivores like tigers?
This difference in digestive anatomy is directly related to their diet. Herbivores consume plant matter, which is rich in cellulose, a complex carbohydrate that is difficult to digest. A longer small intestine provides a larger surface area and a longer transit time, allowing for more complete digestion and absorption of nutrients from cellulose with the help of symbiotic bacteria. In contrast, carnivores eat meat, which is primarily protein and fat and is much easier to digest, so they do not require such a long intestine.
7. What constitutes a balanced diet and why is it important for human health?
A balanced diet is one that contains all the essential nutrients in the correct proportions to maintain good health. Its importance lies in preventing diseases, promoting proper growth, and providing adequate energy. The main components include:
- Carbohydrates: For primary energy.
- Proteins: For building and repairing tissues.
- Fats: For stored energy and insulation.
- Vitamins and Minerals: For various metabolic functions and protection against diseases.
- Water and Fibre: For hydration and proper digestion.
8. What are the broader consequences of malnutrition in humans?
Malnutrition refers to deficiencies, excesses, or imbalances in a person’s intake of energy and/or nutrients. Its consequences go beyond just body weight. Undernutrition can lead to stunting (low height for age), wasting (low weight for height), and weakened immunity, making a person highly susceptible to infections. Overnutrition, on the other hand, can lead to obesity, which increases the risk of chronic non-communicable diseases like type 2 diabetes, cardiovascular problems, and certain types of cancer.
9. How does the human digestive system ensure the complete digestion of different food components like carbohydrates, proteins, and fats?
The human digestive system uses a combination of mechanical and chemical processes. Digestion begins in the mouth, where salivary amylase starts breaking down carbohydrates. In the stomach, pepsin enzyme begins protein digestion in an acidic medium. The final and most crucial digestion occurs in the small intestine, where it receives secretions from the pancreas and liver. Pancreatic enzymes break down all three components—carbohydrates, proteins, and fats. Bile from the liver emulsifies fats, increasing the efficiency of fat-digesting enzymes (lipases).
