Life Processes Class 10 Notes | Nutrition & Photosynthesis Explained (Part 1)

Introduction

In our daily life, we observe two types of matter around us — living and non-living. Although both are made up of the same basic elements such as carbon, hydrogen, oxygen, and nitrogen, living organisms possess unique characteristics that distinguish them from non-living things.

Living organisms continuously perform certain essential functions to sustain life. These functions are collectively known as life processes. Understanding these processes is crucial for Class 10 students as it forms the foundation for advanced Biology concepts and helps in exam preparation.

In this part, we will focus on nutrition and photosynthesis, which are fundamental to the survival of all living organisms.

🎥 Watch Video Explanation

https://www.youtube.com/watch?v=2MDJSX0nQKc

What are Life Processes?

Life processes are the basic activities that are necessary to maintain life in an organism. These processes ensure that the body remains functional, organized, and alive.

Some of the important life processes include:

• Nutrition

• Respiration

• Transportation (Circulation)

• Excretion

• Growth and development

• Reproduction

• Response to stimuli

👉 These processes occur in both plants and animals, though the mechanisms may differ.

Characteristics of Living Organisms

Living organisms exhibit certain characteristics that help us identify them. However, no single characteristic alone is sufficient to define life.

Some common characteristics include:

• Movement – Ability to move or show internal movement

• Growth – Increase in size and development over time

• Structure – Organized cellular structure

👉 These features together help distinguish living organisms from non-living matter.

Nutrition

Nutrition is one of the most important life processes. It refers to the process by which organisms obtain food and utilize it to produce energy.

Even when we are resting or sleeping, our body requires energy to maintain internal functions such as breathing, digestion, and circulation.

Importance of Nutrition:

• Provides energy for daily activities

• Helps in growth and repair of tissues

• Supports synthesis of important substances like proteins

• Maintains overall body functioning

Types of Nutrition

Organisms obtain food in different ways depending on their nature. There are two main types of nutrition:

🔹 1. Autotrophic Nutrition

Autotrophic organisms prepare their own food using simple inorganic substances.

• These organisms are called autotrophs

• They use sunlight, carbon dioxide, and water to produce food

👉 Examples:

• Green plants

• Blue-green algae

• Some bacteria

🔹 2. Heterotrophic Nutrition

Heterotrophic organisms depend on other organisms for food.

• They cannot synthesize their own food

• They obtain nutrients from plants or other animals

👉 Examples:

• Humans

• Animals

Photosynthesis

Photosynthesis is the process by which green plants prepare their own food using sunlight.

👉 This process is based on the Photosynthesis

Raw Materials Required:

• Carbon dioxide (from air)

• Water (from soil)

• Sunlight

• Chlorophyll (green pigment in leaves)

Energy Storage:

• Plants store energy in the form of starch

• Animals store energy in the form of glycogen

Events in Photosynthesis

Photosynthesis occurs in a series of steps:

• Absorption of light energy by chlorophyll

• Conversion of light energy into chemical energy

• Splitting of water molecules into hydrogen and oxygen

• Reduction of carbon dioxide to form carbohydrates

👉 This entire process mainly takes place in the leaves of plants.

Stomata and Their Functions

Stomata are tiny pores present on the surface of leaves.

Functions of Stomata:

• Exchange of gases (oxygen and carbon dioxide)

• Loss of water through transpiration

Role of Guard Cells

Guard cells are specialized cells that control the opening and closing of stomata.

• When guard cells absorb water, they swell and the stomata open

• When guard cells lose water, they shrink and the stomata close

👉 This mechanism helps regulate gas exchange and water loss in plants.

Role of Guard Cells

Guard cells are specialized cells that control the opening and closing of stomata.

• When guard cells absorb water, they swell and the stomata open

• When guard cells lose water, they shrink and the stomata close

👉 This mechanism helps regulate gas exchange and water loss in plants.

Important Exam Questions

1. What is nutrition?

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

2. Why is nutrition necessary? Is nutrition a necessary for an organism. discuss

Nutrition is essential because it:

• Provides energy

• Helps in growth and repair

• Maintains body functions

3. How do guard cells regulate stomata?

Guard cells control stomata by swelling (opening) and shrinking (closing).

4. What is photosynthesis?

Photosynthesis is the process of converting light energy into chemical energy in plants.

5. What is the site of photosynthesis?

Photosynthesis occurs in the leaves of plants.

6. Name the part labelled A and B in the given diagram below and write their function

A----GAURD CELL - helps in opening and closing of stomatal pore

B-- STOMATAL PORE-- exchange of gas and transpiration