Life Process Class 10 full Notes

 

🌱 Introduction

Life processes are essential biological activities that keep living organisms alive. The four major processes are:

Nutrition

Respiration

Transportation

Excretion

🍽️ Nutrition

Nutrition is the process by which organisms obtain and utilize food.

Types of Nutrition

Autotrophic Nutrition – Organisms prepare their own food.

Photoautotrophic: Plants use sunlight and chlorophyll.

Chemoautotrophic: Certain bacteria use chemical energy.

Heterotrophic Nutrition – Organisms depend on others for food.

Holozoic Nutrition: Ingestion of whole food (Humans, Amoeba).

Saprophytic Nutrition: Feeding on dead and decaying matter (Mushrooms, Bread mold).

Parasitic Nutrition: Living on or inside another organism without killing it (Tapeworm, Lice, Cuscuta).

📌 Important Example: Cuscuta – a parasitic plant.

🌞 Photosynthesis in Plants

Photosynthesis is the process by which plants prepare food using:

Sunlight

Chlorophyll

Carbon dioxide

Water

Equation: [6CO_2 + 6H_2O → C_6H_{12}O_6 + O_2]

Key Points

Oxygen is released as a by-product.

Glucose is stored as starch in plants.

In animals, glucose is stored as glycogen.

Stomata Function

Tiny pores for gas exchange and transpiration.

Opening and closing controlled by guard cells.

Desert Plants (CAM Pathway)

Stomata remain closed during the day to prevent water loss.

Open at night to absorb CO₂.

CO₂ stored as malic acid, later converted to glucose in sunlight.

🧬 Nutrition in Simple Organisms

Amoeba: Uses pseudopodia to engulf food, digests inside food vacuole.

Paramecium: Uses cilia to push food into oral groove, digests, and expels waste via anal pore.

👩‍⚕️ Human Digestive System

Steps of Digestion

Mouth – Teeth (mechanical digestion), tongue (taste), saliva (salivary amylase breaks starch).

Esophagus – Peristaltic movement pushes food.

Stomach – Gastric juice contains:

Pepsin (digests protein)

HCl (provides acidic medium, kills germs)

Mucus (protects stomach lining)

Small Intestine – Final digestion and absorption:

Liver produces bile (emulsifies fats).

Pancreas secretes enzymes (amylase, trypsin, lipase).

Intestinal juice completes digestion.

Villi absorb nutrients.

Large Intestine – Absorbs water.

Rectum & Anus – Stores and expels waste.

📌 Key Point: Digestion begins in the mouth, not the stomach.

🌬️ Breathing vs Respiration

Breathing: Physical process of inhalation and exhalation.

Respiration: Chemical process of breaking down food to release energy.

Types of Respiration

Aerobic Respiration – Uses oxygen, produces energy.

Anaerobic Respiration – Without oxygen.

Alcoholic fermentation (produces alcohol).

Lactic acid fermentation (produces lactic acid).

📌 Exam-Oriented Highlights

Photosynthesis releases oxygen due to water splitting.

Glucose stored as starch in plants, glycogen in animals.

Stomata opening/closing controlled by guard cells.

Herbivores have longer small intestines than carnivores (to digest cellulose).

Breathing ≠ Respiration.

🖼️ Suggested Images

Diagram of Photosynthesis cycle 🌞

Structure of Stomata 🌿

Human Digestive System 🧍‍♂️

Respiration cycle in cells ⚡

✅ Conclusion

Life processes are fundamental to survival. Understanding nutrition, respiration, transportation, and excretion helps us grasp how living organisms sustain themselves. For exams, focus on diagrams and key points like stomata, photosynthesis equation, and human digestion steps.

Ritt (Quick Revision):

Nutrition → Autotrophic & Heterotrophic

Photosynthesis → CO₂ + H₂O → Glucose + O₂

Stomata → Gas exchange & transpiration

Human digestion → Mouth → Stomach → Intestine → Absorption

Respiration → Aerobic vs Anaerobic