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Life Processes - NUTRITION5.2 NUTRITION5.2 NUTRITION5.2 NUTRITION5.2 NUTRITION

Grade 10CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Life processes are the basic functions performed by living organisms to maintain their life on earth, including nutrition, respiration, transport, and excretion.

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Nutrition is the process of intake of nutrients (like carbohydrates, fats, proteins, minerals, vitamins, and water) and their utilization by an organism.

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Autotrophic Nutrition: Organisms like green plants use simple inorganic materials (CO2CO_2 and H2OH_2O) to prepare organic food in the presence of sunlight and chlorophyll through the process of photosynthesis.

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Photosynthesis steps: (i) Absorption of light energy by chlorophyll, (ii) Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen, (iii) Reduction of carbon dioxide to carbohydrates.

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Heterotrophic Nutrition: Organisms depend on other organisms for food. Types include Saprophytic (feeding on dead matter), Parasitic (deriving nutrition from a host), and Holozoic (ingestion of solid organic material).

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Nutrition in Amoeba: A holozoic process involving ingestion via pseudopodia, digestion in a food vacuole, absorption, assimilation, and egestion.

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Human Alimentary Canal: A long tube extending from the mouth to the anus, including the esophagus, stomach, small intestine, and large intestine.

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Enzymatic Digestion: Specific biocatalysts called enzymes break down complex food. For example, Salivary amylase breaks starch into sugar, Pepsin digests proteins in the stomach, and Lipase breaks down fats.

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Small Intestine: The site of complete digestion of carbohydrates, proteins, and fats. It receives secretions from the liver (bile) and pancreas (pancreatic juice).

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Absorption: The inner lining of the small intestine has numerous finger-like projections called villi, which increase the surface area for the absorption of digested food into the blood.

📐Formulae

6CO2+12H2O→ChlorophyllSunlightC6H12O6+6H2O+6O26CO_2 + 12H_2O \xrightarrow[\text{Chlorophyll}]{\text{Sunlight}} C_6H_{12}O_6 + 6H_2O + 6O_2

Starch→pH 6.8Salivary AmylaseMaltose\text{Starch} \xrightarrow[\text{pH } 6.8]{\text{Salivary Amylase}} \text{Maltose}

Proteins→Acidic mediumPepsinPeptones + Proteoses\text{Proteins} \xrightarrow[\text{Acidic medium}]{\text{Pepsin}} \text{Peptones + Proteoses}

Fats→Bile Salts (Emulsification)Emulsified Fats\text{Fats} \xrightarrow{\text{Bile Salts (Emulsification)}} \text{Emulsified Fats}

Emulsified Fats→LipaseFatty acids+Glycerol\text{Emulsified Fats} \xrightarrow{\text{Lipase}} \text{Fatty acids} + \text{Glycerol}

Proteins→TrypsinPeptides\text{Proteins} \xrightarrow{\text{Trypsin}} \text{Peptides}

💡Examples

Problem 1:

Explain the role of HClHCl and Mucus in the human stomach.

Solution:

HClHCl creates an acidic medium (pH≈1.8pH \approx 1.8) which facilitates the action of the enzyme pepsin and kills bacteria. Mucus protects the inner lining of the stomach from the action of the acid under normal conditions.

Explanation:

The gastric glands in the stomach wall release Gastric juice containing Hydrochloric acid (HClHCl), Pepsin, and Mucus.

Problem 2:

How is the small intestine designed to maximize the absorption of digested food?

Solution:

The inner lining of the small intestine has millions of tiny finger-like projections called villi. These villi increase the surface area for absorption. Each villus is richly supplied with blood vessels to carry the absorbed food to every cell of the body.

Explanation:

Increased surface area via villi ensures that the maximum amount of nutrients from the C6H12O6C_6H_{12}O_6 and amino acids enter the bloodstream efficiently.

Problem 3:

What is the function of Bile juice in the digestion of fats?

Solution:

Bile juice performs two functions: (i) It makes the acidic food coming from the stomach alkaline so that pancreatic enzymes can act, and (ii) Bile salts break down large fat globules into smaller globules (emulsification).

Explanation:

Emulsification increases the efficiency of the enzyme lipase, which acts on fats to convert them into fatty acids and glycerol.