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Life Processes - Nutrition

Grade 10CBSE

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

🔑Concepts

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Nutrition is the process of intake of nutrients like CarbohydratesCarbohydrates, ProteinsProteins, and FatsFats and their utilization by the body.

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Autotrophic Nutrition: Organisms like green plants synthesize their own food using CO2CO_2 and H2OH_2O in the presence of SunlightSunlight and ChlorophyllChlorophyll.

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Photosynthesis involves three steps: Absorption of light energy by ChlorophyllChlorophyll, conversion of light energy to chemical energy and splitting of H2OH_2O molecules, and reduction of CO2CO_2 to C6H12O6C_6H_{12}O_6.

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Heterotrophic Nutrition: Organisms depend on others for food. Types include Holozoic (Amoeba, Humans), Saprophytic (Fungi), and Parasitic (Cuscuta, Ticks).

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Holozoic Nutrition in Amoeba involves PhagocytosisPhagocytosis where food is engulfed using PseudopodiaPseudopodia and digested in a food vacuole.

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Human Digestive System: Involves the Alimentary Canal starting from the MouthMouth to the AnusAnus.

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Saliva contains SalivaryAmylaseSalivary Amylase which breaks down complex StarchStarch into simple sugar (MaltoseMaltose).

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The Stomach releases HClHCl, MucusMucus, and PepsinPepsin. HClHCl creates an acidic medium (pH≈1.5−3.5pH \approx 1.5 - 3.5) for PepsinPepsin to act.

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Small Intestine: Site of complete digestion. It receives secretions from the LiverLiver (Bile) and PancreasPancreas (Trypsin, Lipase).

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Villi: Finger-like projections in the small intestine that increase the surface area for the absorption of digested food.

📐Formulae

6CO2+12H2O→ChlorophyllSunlightC6H12O6+6O2+6H2O6CO_2 + 12H_2O \xrightarrow[Chlorophyll]{Sunlight} C_6H_{12}O_6 + 6O_2 + 6H_2O

Starch→Salivary AmylaseMaltose\text{Starch} \xrightarrow{\text{Salivary Amylase}} \text{Maltose}

Proteins→Pepsin/TrypsinAmino Acids\text{Proteins} \xrightarrow{\text{Pepsin/Trypsin}} \text{Amino Acids}

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

Emulsification: Large Fat Globules→Bile SaltsSmall Fat Globules\text{Emulsification: Large Fat Globules} \xrightarrow{\text{Bile Salts}} \text{Small Fat Globules}

💡Examples

Problem 1:

What is the role of HClHCl in the human stomach during the process of nutrition?

Solution:

HClHCl creates an acidic medium which activates the enzyme PepsinPepsin for protein digestion and kills harmful bacteria.

Explanation:

PepsinogenPepsinogen is an inactive proenzyme. In the presence of HClHCl, it is converted into active PepsinPepsin, which breaks down proteins into PeptonesPeptones and ProteosesProteoses.

Problem 2:

How does AmoebaAmoeba obtain its nutrition?

Solution:

AmoebaAmoeba uses PseudopodiaPseudopodia to surround food particles, forming a food vacuole.

Explanation:

This process is called PhagocytosisPhagocytosis. Inside the vacuole, enzymes break down the food into simpler molecules which diffuse into the CytoplasmCytoplasm.