RBSE Class 10 Science Life process Quick Revision Notes is an important resource for students preparing for the RBSE Class 10 Science board examination. The chapter explains the basic processes that keep living organisms alive including nutrition, respiration, transportation and excretion. These life processes help organisms obtain food, release energy, transport essential substances and remove harmful wastes from the body.

These quick revision notes are based on the NCERT Science Class 10 Syllabus followed by RBSE. These notes are useful for last minutes revision and help students clear their concepts before the examination. You can also go through Class 10 Science Solutions to improve your rank.

Life Processes Notes

Every living organism performs certain basic activities to remain alive. These activities are called life process. They are essential for maintaining life because they provide energy, help in growth and repair, transport materials throughout the body and remove waste substances.

The four main life processes are:

Nutrition
Respiration
Transportation
Excretion

If any one of these processes stops, the organisms cannot survive.

Nutrition

What is nutrition?

Nutrition is the process by which living organisms obtain food and utilize it to produce energy, grow, repair damaged tissues, and carry out all life activities.

Food supplies nutrients such as carbohydrates, proteins, fats, vitamins and minerals that are necessary for proper functioning of the body.

Nutrition is of two types on the basis of mode of taking food

Autotrophic nutrition
Heterotrophic nutrition

Autotrophic Nutrition

In this type of nutrition, organisms prepare their own food form simple inorganic substances like carbon dioxide and water using sunlight in the presence of chlorophyll. These organisms are called autotrophs. Examples – green plants, algae, some bacteria

The process by which green plants prepare food is called photosynthesis.

Photosynthesis

Photosynthesis is the process in which green plants prepare glucose from carbon dioxide and water using solar energy captured by chlorophyll. During this process, oxygen is released as a byproduct.

Chemical Equation of Photosynthesis

6CO₂ + 6H₂O →C₆H₁₂O₆ + 6O₂

Requirements for Photosynthesis

Sunlight
Chlorophyll

Carbon dioxide

Water

Photosynthesis cannot take place in the absence of any one of them.

Role of Chlorophyll

Chlorophyll is the green pigment present in the leaves of plants. It absorbs sunlight and converts light energy into chemical energy. This energy is then used to prepare food.

Role of Stomata

Leaves contains tiny pores called stomata. The stomata perform two important functions:

They allow carbon dioxide to enter the leaf for photosynthesis.
They help in the exchange of oxygen and water vapour with the atmosphere.

The opening and closing of stomata are controlled by guard cells.

How Do Plants Obtain Raw Materials?

Plants require carbon dioxide, water and sunlight for photosynthesis.

Carbon dioxide is obtained through stomata.
Water is taken from soil by roots.
Sunlight is absorbed by chlorophyll present in the chloroplast of leaf cells.

Heterotrophic Nutrition

Organisms that cannot prepare their own food depend on other organism for nutrition. This mode of nutrition is called heterotrophic nutrition and such organisms are known as heterotrophs.

Examples: Human beings, animals, fungi, most bacteria

Heterotrophic nutrition is of three main types:

Saprophytic nutrition

In this mode, organisms obtain food from dead and decaying organic matter. They release digestive enzyme on the dead material, digest it outside the body and absorb the dissolved nutrients.

Examples: mushroom, bread mould, fungi

These organisms play an important role in decomposing dead plants and animals.

Parasitic nutrition

In this mode of nutrition, one organism lives on or inside another living organism and derives food form it. The organism obtaining food is called the parasite, while the organism providing food is called the host.

Examples: Cuscuta, tapeworm, leech

Parasite often harm the host by taking away nutrients.

Holozoic nutrition

Holozoic nutrition is the mode of nutrition in which food is taken inside the body and then digested. This type of nutrition involves five main steps:

Ingestion
Digestion

Absorption

Assimilation
Egestion

Examples: human beings, amoeba, cow, dog

Nutrition in Amoeba

Amoeba is unicellular organism that shows holozoic nutrition. It feeds by surrounding the food particle with temporary finger like projections called pseudopodia. The food is enclosed inside a food vacuole, where digestive enzymes break it down into simpler substance. The digested food is absorbed into the cytoplasm and used for energy, growth and repair. Finally, the undigested food is thrown out through the cell membrane.

This process is known as phagocytosis.

Nutrition in Human beings (Digestive system)

The human digestive system consists of a long tube called the alimentary canal which extends from the mouth to the anus.

Different parts of the alimentary canal perform specialized functions in the digestion and absorption of food.

1.Mouth

Food enters the body through the mouth.
Teeth break food into smaller pieces.
Saliva moistens the food and makes swallowing easier.
Saliva contains an enzyme called salivary amylase.
Salivary amylase breaks down starch into simpler sugars.
The tongue mixes food with saliva and helps in swallowing.

2.Oesophagus (Food pipe)

The oesophagus carries food from the mouth to the stomach.
Food moves through rhythmic muscular contraction called peristaltic movements.
These movements occur throughout the alimentary canal.

3.Stomach

The stomach is a muscular organ that expands when food enters it.
Its muscular walls help mix food with digestive juices.
Gastric glands present in the stomach wall release three important substances:

Hydrochloric acid :

Creates an acidic medium
Helps the enzyme pepsin function.
Helps kill harmful microorganisms.

Pepsin :

A protein digestive enzyme.
Helps break down proteins.

Mucus:

Protects the inner lining of the stomach from the action of acid.

4.Small intestine

The small intestine is the longest part of the alimentary canal.
It is highly coiled and fits into a compact space.
Complete digestion of carbohydrates, proteins and fats takes place here.
It receives bile juice from the liver and pancreatic juice from the pancreas.

Role of bile juice

Bile is produced by the liver.
It makes the acidic food coming from the stomach alkaline.
Bile salt break large fat globules into smaller droplets.
This process is called emulsification of fats.

Role of pancreatic juice

The pancreases secretes pancreatic juice containing digestive enzymes.
Trypsin helps digest proteins.
Lipase breaks down emulsified fats.

Role of intestinal juice

The gland present in the walls of the small intestine release intestinal juice.
Its enzymes complete digestion by converting:
Proteins into amino acids.
Complex carbohydrates into glucose.
Fats into fatty acids and glycerol.

6.Absorption of digested food

The inner lining of the small intestine contains numerous finger like projections called villi.

Functions of villi:

Increase the surface area for absorption.
Absorb digested nutrients.
Contains of rich network of blood vessels.
Help transport absorbed food to different body cells.
The absorbed nutrients are used for obtaining energy, building new tissue and repairing old tissues

7.Large intestine

The unabsorbed food enters the large intestine.
Its wall absorbs additional water from the remaining material.
The remaining undigested material is removed through the anus

8.Anus

The undigested waste material leaves the body through the anus. Its exit is regulated by the anal sphincter.

Respiration

Respiration is the process by which food material, particularly glucose are broken down inside the cells to release energy.
This energy is used for carrying out different life activities.

Breakdown of glucose

The first step of glucose breakdown takes place in the cytoplasm.
Glucose, a six-carbon molecule, is broken down into a three-carbon molecule called pyruvate.
Pyruvate can then follow three different pathways depending on the availability of oxygen.

Aerobic respiration

Aerobic respiration takes place in the presence of oxygen
Pyruvate is broken down in mitochondria.
It produces carbon dioxide and water.
A large amount of energy is released.

Equation

Glucose + Oxygen→ Carbon dioxide + water + energy

Anaerobic respiration in Yeast

Anaerobic respiration takes place in the absence of oxygen
Pyruvate is converted into ethanol and carbon dioxide.
This process takes place in yeast during fermentation.
It releases less energy than aerobic respiration.

Equation

Glucose → ethanol + carbon dioxide + water

Anaerobic breakdown in muscle cells

Sometimes muscle cells do not receive sufficient oxygen during sudden physical activity. In this situation
Pyruvate is converted into lactic acid
Lactic acid accumulation in muscles causes cramps.

Difference Between Aerobic and Anaerobic Respiration

Aerobic respiration	Anaerobic respiration
Takes place in the presence of oxygen	Takes place in the absence of oxygen
Glucose is completely broken down	Glucose is incompletely broken down.
Produces carbon dioxide and water	Produces ethanol and carbon dioxide in yeast or lactic acid in muscles.
Releases more energy	Releases less energy
Involves mitochondria for the breakdown of pyruvate	Takes place in the cytomplasm

ATP- Energy Currency of the Cell

ATP stands for Adenosine Triphosphate
It is called the energy currency of the cell because it provides energy for various cellular activities.
Energy released during respiration is used to synthesis ATP from ADP and inorganic phosphate.
When ATP breaks down, energy is released.
This energy is used for muscle contraction, protein synthesis and conduction of nervous impulses.
The text book states that breaking the terminal phosphate linkage in ATP releases approximately 30.5kJ/mol o energy.

Respiration in Plants

Plants exchange gases through stomata and other sufaces.
Carbon dioxide and oxygen move through diffusion.
Large intercellular spaces help gases reach different cells.
At night photosynthesis does not occur, so carbon dioxide produced during respiration is released.
At night, photosynthesis does not occur so carbon dioxide produced during respiration is released.
During the day, carbon dioxide produced during respiration is used in photosynthesis and oxygen release is the major gas exchange activity.

Respiration in Aquatic Organisms

Aquatic organisms use oxygen dissolved in water.
The amount of dissolved oxygen in water is lower than the oxygen available in air.
Therefore, aquatic organisms breathe faster than terrestrial organisms.
Fish take water through their mouth.
Water passes over the gills.
Dissolved oxygen is absorbed by the blood.

Human Respiratory System

Human beings use lungs for respiration.

The pathway of air is:

Nostrils →Nasal passage →Throat→ Trachea→ Bronchi Bronchioles →Alveoli

Nostrils: allow air to enter the body. Fine hairs filter inhaled air.

Mucus: helps trap dust particles and microorganism.

Trachea: provides an air passage. Rings of cartilage prevent it from collapsing.

Bronchi: Two main branches of the trachea that enter the lungs.

Bronchioles: smaller branches inside the lungs.

Alveoli: Balloon-like structure where exchange of gases takes place.

Alveoli and Exchange of Gases

Alveoli provide a large surface area for the exchange of gases.
Their walls are thin.
They are surrounded by an extensive network of blood vessels.
Oxygen diffuse from alveolar air into the blood.
Carbon dioxide diffuses from the blood into the alveoli.
Carbon dioxide is removed during exhalation.
The large surface area of alveoli makes gas exchange efficient.

Mechanism of Breathing

Inhalation:

Ribs move upward and outwards.
The diaphragm flattens.
The chest cavity becomes larger.
Air enters the lungs.

Exhalation:

Ribs move downward and inwards.
The diaphragm relaxes and becomes dome shaped.
The chest cavity becomes smaller.
Air moves out the lungs.

Transport of Respiratory Gases

Oxygen is transported by red blood corpuscles with the help of hemoglobin.
Haemoglobin has a high affinity for oxygen.
Carbon dioxide is more soluble in water than oxygen and is mostly transported in dissolved form in blood.

Transpiration

Transportation is the process of carrying essential materials such as food, oxygen, water and minerals from one part of an organism to another.
Transportation occurs differently in plants and animals.

Transportation in Human Beings (Circulatory system)

The human transport system consists of:

Blood
Heart
Blood vessels

Blood

Blood is fluid connective tissue.
It consists of a fluid medium called plasma in which blood cells are suspended.

Plasma:

Transport food, carbon dioxide and nitrogenous wastes in dissolved form.
Also carries salts and other substances.

Red Blood Corpuscles

Carry oxygen
Contain haemoglobin which combines with oxygen.

Platelets

Help in blood clotting.
Prevent excessive loss of blood from damaged blood vessels.

Human Heart

The human heart is a muscular organ approximately the size of a fist. It has four chambers:

Right atrium
Right ventricle
Left atrium
Left ventricle

The heart pumps blood throughout the body.

The right and left sides of the heart are separated to prevent the mixing of oxygenated and deoxygenated blood.

Functions of the Four chambers

Right atrium : receives deoxygenated blood from the body.

Right ventricle: pumps deoxygenated blood to the lungs.

Left atrium : receives oxygenated blood form the lungs.

Left ventricle: pumps oxygenated blood to the entire body.

The ventricles have thicker walls than the atria because they pump blot out the heart. Valves prevent the backward flow of blood.

Path of Blood Circulation

Deoxygenated blood:

Body →Vena cava→ Right atrium →Right ventricle →Pulmonary artery→ Lungs

Oxygenated blood

Lungs →Pulmonary Veins →Left atrium →Left ventricle →Aorta→ Body

Double Circulation

Double circulation is the process in which blood passes through the heart twice during one complete cycle of circulation.

It consists of two types :

1.Pulmonary Circulation

Right ventricle →Lungs →Left atrium

It carries deoxygenated blood from the heart to the lungs and brings oxygenated blood back to the heart.

2.Systemic circulation

Left ventricle →Body tissues →Right atrium

It carries oxygenated blood from the heart to the body and returns deoxygenated blood to the heart.

Importance of Double Circulation

Prevents mixing of oxygenated and deoxygenated blood.
Ensure an efficient supply of oxygen to the body.
Supports the high energy requirement of birds and mammals.
Helps maintain constant body temperature.
Heart Structures in different Animals

Animal group	Number of heart chambers
Fishes	Two
Amphibians	Three
Reptiles	Three
Birds	Four
Mammals	Four

Blood vessels

There are three main types of blood vessels

Arteries

Carry blood away from the heart.
Have thick and elastic walls.
Carry blood under high pressure.

Veins

Carry blood toward the heart.
Have comparatively thin walls.
Contain valves to prevent backward flow to blood.

Capillaries

Are the smallest blood vessels.
Have walls only one cell thick.
Allow exchange of materials between blood and surroundings cells.

Difference Between Arteries, Veins and Capillaries

Arteries	Veins	Capillaries
Carry blood away from the heart.	Carry blood towards the heart.	Connect arteries and veins
Thick elastic walls.	Thins walls	One cell thick wall
Blood flows under high pressure	Blood flows under lower pressure	Exchange materials with tissues
Do not h ave valves	Have valves	Vary narrow vessels

Blood Pressure

Blood pressure is the force exerted by blood against the walls of blood vessels. There are two types of blood pressure:

Systolic Pressure: Pressure in the arteries during ventricular contraction.
Diastolic Pressure: Pressure in the arteries during ventricular relaxation.

The normal blood pressure is approximately 120/80 mm of Hg. Blood pressure is measured using an instrument called sphygmomanometer. High blood pressure is called hypertension.

Maintenance by platelets

Platelets help clot blood at the points of injury. This reduces blood loss and prevents a fall in blood pressure.

Lymph

Lymph is also known as tissue fluid.
It is a colourless fluid.
It contains less protein than blood plasma.
It is formed when some plasms, proteins and blood cells escape through capillary walls into tissue spaces.
It drains excess tissue fluid back into the blood.
It carries digested and absorbed fats from the intestine.

Transportation in Plants

Plants need to transport water, mineral and food from one part of the body to another.

The plant transport system consists of two main vascular tissues:

1.Xylem

Transports water and minerals from roots to other parts of the plant.
Consists of vessels and tracheids
Transport generally takes place in the upward direction.

2.Phloem

Transport products of photosynthesis from leaves to other parts of the plant.
Transport amino acids and other substances.
Transport occurs in both upward and downward directions.
Uses energy from ATP

Difference between Xylem and Phloem

Xylem	Phloem
Transport water and minerals	Transports food and other substances
Transport is mainly upward.	Transport occurs in both directions
Movement is largely driven by physical forces	Transport requires energy
Consists of vessels and tracheids	Used sieve tube and companion cells

Transport of Water

Water is absorbed form the soil by roots.
Root cells actively absorb mineral ions
This creates a difference in ion concentration between the root and soil.
Water enters the root to eliminate this difference.
Water moves into xylem and forms a continuous column.

Root Pressure

Root pressure is the pressure developed in roots due the movement of water into the root xylem after the absorption of minerals ions. It helps push water upward through the plant.

Transpiration

Transpiration is the loss of water in the form of water vapour from the aerial parts of the plants. Water vapour mainly escapes through stomata.

Transpiration Pull

Evaporation of water from leaf cells creates a suction force that pills water upwards through xylem form the roots.

Importance of Transpiration

Helps in the absorption and upward movement of water.
Helps transport dissolved minerals from roots to leaves.
Helps regulate plant temperature.

Roots pressure is more important during the night, while transpiration pull is the major driving force during the day when stomata are open.

Transport of Food- Translocation

Translocation is the transportation of soluble substance such as sucrose.
Phloem also transports amino acids and other substances.
Food reaches storage organs such as roots, fruits and seeds.
Food is transported to growing organs.
Translocation occurs in both upward and downward directions.
ATP energy is required for translocation.

When sucrose is loaded into phloem tissue using energy from ATP, osmotic pressure increases. Water enters the phloem and creates pressure that moves food towards tissues having lower pressure.

Excretion

Excretion is the biological process of removing harmful metabolic waste products form the body.
During various metabolic activities, organisms produce waste materials such as carbon dioxide, urea and uric acid.
These wastes must be removed because their accumulation can harm the body.
Unicellular organisms generally remove wastes through simple diffusion, whereas multicellular organisms use specialized excretory organs.

Excretion in Human Beings

The human excretory system consists of :

A pair of kidneys
A pair of ureters
A urinary bladder
A urethra

Functions of Different Parts

Kidneys

Two bean shaped organs situated in the abdomen, one on either side of the backbone.
Filter blood.
Remove nitrogenous wastes such as urea and uric acid.
Produce urine.

Ureters

Two tubes connecting kidneys to the urinary bladder.
Carry urine from kidneys to the urinary bladder.

Urinary Bladder

Stores urine temporarily
Its muscular walls expand as urine accumulates.

Urethra

Carries urine from the urinary bladder to the outside of the body.

Nephron – Functional Unit of Kidney

A nephron is the basic structural and functional unit of the kidney. Each kidney contains a large number of nephrons.

Structure of Nephron

Important parts of a nephron include:

Glomerulus
Bowman’s capsule
Ranal tubule
Blood capillaries surroundings the tubule.

The glomerulus is a cluster of thin-walled blood capillaries associated with Bowman’s capsule.

Formation of Urine

Urine formation takes place through the following processes:

1.Filtration

Blood enters the glomerulus.
Water and small dissolved substances are filtered from the blood.
The filtrate is collected in Bowman’s capsule.

2.Selective reabsorption

Useful substances are reabsorbed into the blood as the filtrate passes through the renal tubule. Mainly following substances are reabsorbed:

Glucose
Amino acids
Salts
A major amount of water

3.Urine collection

The remaining waste materials ands excess water from urine. Urine passes from kidneys through the ureters into the urinary bladder, where it is stored until released through the urethra.

Regulation of Urine Production

The amount of water reabsorbed depends on:

The amount of excess water present in the body.
The amount of dissolved waste that needs to be excreted.

Artificial Kidney- Haemodialysis

When kidneys fail to function properly, harmful nitrogenous wastes accumulate in the body. An artificial kidney is used to remove these wastes through a process called dialysis.

The patient’s blood passes through tubes having a semipermeable lining.
These tubes are suspended in dialysis fluid.
Nitrogenous wastes diffuse from the blood into the dialysis fluid.
The purified blood is returned to the patient’s body.

Dialysis is similar to kidney filtration, but it does not involve selective reabsorption.

Note: In a healthy adult, the initial filtrate produced by the kidneys is about 180 litres per day. However, only about 1-2 litres of urine are actually excreted because most of the filtrate is reabsorbed.

Excretion in Plants

Plants do not have specialized excretory organs like animals. They use different method to remove or store waste materials. These methods are:

Oxygen produced during photosynthesis is released into the atmosphere.
Carbon dioxide produced during respiration is removed by diffusion.
Excess water is removed through transpiration.
Some waste products are stored in cellular vacuoles.
Waste products may be stored in leaves that later fall off.
Some wastes are stored as resins and gums.
Some waste substances are released into surroundings soil.
Dead cells and plant parts can also help in the removal of wastes.

Important Diagrams of Chapter 5- Life Processes

Students should practice the following diagrams with correct labelling:

Very important diagrams

Human digestive system
Human respiratory system
Human heart
Human excretory system
Structure of nephron
Double circulation of blood

Important Differences from Chapter Life Processes

Students should go through following comparisons:

Autotrophic and heterotrophic nutrition
Aerobic respiration and anaerobic respiration
Arteries and veins
Xylem and phloem

Quick Revision – Important Terms and Their Meanings

Term	Meaning
Nutrition	Obtaining and utilizing food
Photosynthesis	Preparation of carbohydrates by green plants by using light
Stomata	Tiny pores on the surface of leaves.
Guard cells	Cells controlling the opening and closing of stomata
Pseudopodia	Temporary finger like projections of amoeba
Cilia	Hair like structures helping paramecium obtain food
Peristalsis	Rhythmic muscular movements pushing food through the alimentary canal
Emulsification	Breaking large fat globules into smaller droplets
Villi	Finger like projections increasing the surface area for absorption
Respiration	Breakdown of food to release energy
ATP	Energy currency of the cell
Alveoli	Ballon like structures where gas exchange occurs
Haemoglobin	Respiratory pigment carrying oxygen in blood
Double circulation	Blood passes through the heart twice in one complete cycle
Systolic pressure	Arterial pressure during ventricular contraction
Diastolic pressure	Arterial pressure during ventricular relaxation
Lymph	Colourless tissue fluid involved in transpiration
Xylem	Vascular tissue transporting water and minerals
Phloem	Vascular tissue transporting food
Transpiration	Loss of water vapour from aerial parts of plants
Translocation	Transport of soluble food through phloem
Nephron	Structural and functional unit of kidney
Dialysis	Removal of nitrogenous wastes from blood using an artificial process

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RBSE Class 10 Science Model Papers 2027

Frequently Asked Questions

1.What are life processes?

Life processes are the basic maintenance activities performed by living organism to keep themselves alive. The major life processes are nutrition, respiration, transportation and excretion.

2.Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms?

In multicellular organisms, all cells are not directly in contact with the environment. Diffusion is too slow to transport sufficient oxygen to all the cells. Therefore specialized respiratory systems are required.

3.What is photosynthesis?

Photosynthesis is the process by which green plants prepare carbohydrate form carbon dioxide and water in the presence of sunlight and chlorophyll.

4.Why is chlorophyll necessary for photosynthesis?

Chlorophyll absorbs light energy from the sun, which is required to carry out photosynthesis.

5.What is the function of stomata?

Stomata allow the exchange of gases and help in the loss of water vapour from leaves. Their opening and closing are controlled by guard cells.

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