Life Processes Class 10 Notes- CBSE Science Chapter 6

Life processes class 10 notes

The processes that work together to maintain ‘life’ are referred to as life processes. Essential life processes include nutrition, respiration, circulation, and excretion. All of these processes are carried out by a single cell in unicellular organisms. To carry out the processes, multicellular organisms have well-developed systems.

Nutrition & Categories based on it

Nutrition refers to the process by which an organism consumes and utilises food. Nutrition is required because organisms require energy to perform various activities. The nutrients provide energy. For growth and repair, organisms require a variety of raw materials. Nutrients provide these raw materials.
Nutrients: Nutrients are materials that provide nutrition to organisms. The main nutrients are carbohydrates, proteins, and fats, which are referred to as macronutrients. Micronutrients are minerals and vitamins that are required in small amounts.

Nutrition & Categories


Nutritional Modes are:

  1. Nutrition by Autotrophs.
  2. Nutrition in Heterotrophic Conditions

Autotrophic Nutrition

During this process, the following things happen. Light energy absorption by chlorophyll. Light energy gets transformed into chemical energy, whereas water molecules are reformed into hydrogen and oxygen atoms. Carbon dioxide is converted to carbohydrates. Green plants absorb water via their roots from the soil. In this way, water has already been absorbed and Stomata help in absorbing sunlight and is assimilated by the chlorophyll of the plant. The roots of these green plants collect water from the soil. Sunlight enters the plant through its stomata and is absorbed by chlorophyll and other green elements of the plant.

6CO2+12H2O −−−−−−> C6H12O6+6H2O+6O2 (in presence of chlorophyll and sunlight)

Heterotrophic Nutrition

Heterotrophic Nutrition - life processes class 10 notes


Heterotrophs are completely dependent on autotrophs for food. There are three types of heterotrophic nutrition:
Holozoic Nutrition entails ingesting complex foods through a specialised digestive system and breaking them down into small pieces so that they can be absorbed. Amoeba and humans, for example.

Saprophytic nutrition refers to organisms feeding on the dead organic remains of other creatures. Fungi, for example, appreciate bread moulds, yeast, and mushrooms.

Parasitic Nutrition: Parasites feed on other living beings (the host) while providing no benefit to the host. Examples include Cuscuta, ticks, lice, leeches, and tapeworms.

Holozoic Nutrition in Amoeba

Amoeba is a unicellular animal that feeds in a holozoic manner. Food digestion occurs after food ingestion in holozoic nutrition. As a result, digestion occurs within the organism’s body. The steps of the holozoic mode of nutrition include:

  • Ingestion, digestion, absorption, assimilation, and egestion are the five steps in holozoic nutrition.
  • Ingestion: The process of taking in food is referred to as ingestion.
  • Digestion is the process of breaking down complex food substances into simple molecules. The resulting simple molecules can be absorbed by the body.
  • Absorption refers to the process of digested food absorption.
  • Assimilation: Assimilation is the process of utilising digested food for energy, growth, and repair.
  • Egestion is the process of eliminating undigested food from the body.

Amoeba is a unicellular animal that feeds in a holozoic manner. The amoeba cell membrane continues to protrude into pseudopodia. Amoeba forms a food vacuole by surrounding a food particle with pseudopodia. Food particles and water are found in the food vacuole. Digestive enzymes are secreted in the food vacuole, where digestion occurs. The digested food is then absorbed from the food vacuole. Finally, the food vacuole approaches the cell membrane, where undigested food is expelled.


These are the following process that occurs during photosynthesis. Firstly Light energy is absorbed by chlorophyll. Light energy is converted into chemical energy, and water is split (broken) into hydrogen and oxygen. then CO2 reduction through carbohydrate utilisation.

Sunlight activates chlorophyll, causing the water molecule to split. The hydrogen produced by the splitting of a water molecule is used to reduce carbon dioxide and produce carbohydrates. Photosynthesis produces oxygen as a byproduct. Carbohydrate is then converted into starch and stored in leaves and other parts of the plant. The light reaction includes the splitting of water molecules.

stomata are tiny pores in the epidermis of a leaf or stem that allow for gas exchange and transpiration. Stomatal Functions are the Gaseous exchange (O2 and CO2) in and out of the chlorophyll and losing water during transpiration. The turgidity of guard cells regulates the opening and closing of stomatal pores. When guard cells absorb water from surrounding cells, they swell to form a turgid body, which expands the pore between them (Stomatal Opening).

When water is released, they become flaccid and shrink, closing the pore (Stomatal Closing).


Importance of Photosynthesis:

Photosynthesis is the primary means by which solar energy is made available to various living beings. Green plants are the primary food producers in the ecosystem. All other organisms rely on green plants for food, either directly or indirectly. Photosynthesis also contributes to the balance of carbon dioxide and oxygen in the atmosphere.

Nutrition in Humans

Humans are omnivores, meaning they can eat both plant-based and animal-based foods. Humans, being more complex, have a more complicated nutrition system. The digestive system conceptualised for life processes consists of an alimentary canal and associated digestive glands that work together to nourish the body. Human nutrition is divided into five stages: ingestion, digestion, absorption, assimilation, and egestion. These steps occur inside the alimentary canal, four stages occur: ingestion, digestion, absorption, and egestion, while food assimilation occurs throughout the body.

Digestive Canal

Digestion In humans follows a path starting from the digestive canal. Starting with the alimentary canal is a long tube with varying diameters. It begins with the mouth and concludes with the anus. The alimentary canal is made up of the oesophagus, stomach, small intestine, and large intestine.


  • It is the opening of the alimentary canal and aids in food digestion.
  • The buccal cavity located behind the mouth is also referred to as the mouth.
  • The buccal cavity contains teeth and the tongue.
  • The set of teeth aids in food mastication.
  • The tongue contains taste buds, which aid in the tasting of food.
  • The salivary glands open in the buccal cavity and release saliva, which starts the digestion process.


  • Teeth are hard structures that exist in the buccal cavity which assist us in cutting, shearing, and masticating the food we consume.
  • A tooth’s vertical section reveals four layers: enamel, dentine, cement, and dental pulp.
  • Enamel is the hardest and most mineralized part of the human body.
  • Dentine constitutes the majority of the tooth and is composed of 70% inorganic salts.
  • The lining of a tooth and bony socket contains cement.
  • The dental pulp is the soft centre of the tooth that contains nerve endings, blood and lymph vessels, and connective tissue.
  • Human teeth are classified into four types: incisors, canines, molars, and premolars, each with a distinct function. The dental formula is 2:1:2:3 for humans.


  • The stomach is a bag-shaped organ. The stomach’s highly muscular walls aid in the churning of food.
  • The stomach walls secrete hydrochloric acid. Germs found in food are killed by hydrochloric acid.
  • Furthermore, it makes the stomach medium acidic. The acidic medium is required for gastric enzymes to function.
  • Protein is partially digested by the enzyme pepsin, which is secreted in the stomach.
  • The mucus that is secreted by the stomach walls protects the stomach’s inner lining from damage caused by hydrochloric acid.

The pancreas is located beneath the stomach. It produces pancreatic juice, which contains numerous digestive enzymes. It is not the main point of the digestive tract but plays a very crucial role in digestion.

Also Check – Light Class 10 Notes

The Small Intestine

The small intestine is the longest part of the alimentary canal, measuring approximately 20 feet in length in humans.
It is divided into three sections: the duodenum, which follows the stomach, the jejunum, which is in the middle, and the ileum, which is further into the large intestine. The small intestine’s internal surface is folded into finger-like projections called villi.
The pancreas and liver share a common pancreatic duct that enters the duodenum. The small intestine is responsible for the majority of chemical digestion and absorption.

The Large Intestine

The human large intestine is about 5 feet long.
It is divided into two sections: the colon (about 1.5 m) and the rectum (10 cm).

  • The human large intestine is about 5 feet long.
  • It is divided into two sections: the colon (about 1.5 m) and the rectum (10 cm in length in the adult).
  • The region of the large intestine following the ileum is known as the colon, while the final section is known as the rectum.
  • The colon is divided into three sections: ascending colon, transverse colon, and descending colon.
  • An appendix is a small finger-like outgrowth seen at the base of the ascending colon.
  • It is home to many beneficial bacteria that aid in food digestion.
  • Anus connects the rectum to the outside world.
  • Internal and external anal sphincters exist in the anus.

Respiration – Life Processes Class 10 Notes

Types of respiration, aerobic and anaerobic respiration, the human respiratory system, and plant respiration

Respiration refers to the process by which a living being uses food to obtain energy. Respiration is an oxidation reaction that produces energy by oxidising carbohydrates. Mitochondria are the sites of respiration, and the energy released is stored as ATP (adenosine triphosphate). ATP is stored in the mitochondria and released as needed.

Respiratory steps: The cytoplasm is where the glucose is broken down into pyruvate. Pyruvic acid is formed by the breakdown of the glucose molecule. The glucose molecule contains six carbon atoms, whereas pyruvic acid contains three carbon atoms.
Pyruvic Acid’s Fate: Pyruvic acid is further broken down in mitochondria, and the molecules formed depend on the type of respiratory paths taken up in an organism. Aerobic respiration and anaerobic respiration are the two pathways of the respiratory process.

Life Processes Class 10 Notes on Respiration

Respiration entails the following points:
1. Exchange of gases: Breathing causes the intake of oxygen from the atmosphere and the release of CO2.
2. Cellular respiration is the breakdown of simple food to release energy within the cell.

Types of Respiration

There two types of respiration techniques involved in the human body which are also practised by the various organisms present in the environment.

Aerobic respiration: This type of respiration occurs when there is oxygen present. Pyruvic acid is broken down into carbon dioxide. At the end of this process, energy is released and a water molecule is formed.
Anaerobic respiration: This type of respiration occurs when there is no oxygen present. Pyruvic acid either gets converted into lactic acid or ethyl alcohol. Ethyl alcohol is typically formed during anaerobic respiration in microbes such as yeast or bacteria. Lactic acid is produced by microbes as well as muscle cells.

Leg muscle pain while running: When a person runs too fast, he may feel a throbbing pain in his leg muscles. This occurs as a result of anaerobic respiration in the muscles. The energy demand of the muscle cells increases while running. This is compensated for by anaerobic respiration, which produces lactic acid. Lactic acid deposition causes pain in the leg muscles. After resting for a while, the pain goes away.

Gaseous exchange: Aerobic respiration requires a constant supply of oxygen, as well as the removal of carbon dioxide produced during the process. Different organisms use different methods for oxygen intake and carbon dioxide expulsion. Diffusion is the method that is used by carbon dioxide expulsion. Diffusion is the method used by unicellular organisms and some simple organisms for this purpose. Diffusion is also used in plants to exchange gases. The respiratory system in complex animals is in charge of gas exchange.

Gaseous exchange

System of Human Respiration

The nose, nasal cavities, pharynx, larynx, trachea/windpipe, bronchi, bronchioles, and alveoli comprise the human respiratory system. A pair of lungs contain bronchioles and alveoli. The rib cage, rib cage muscles, and diaphragm all aid in the inhalation and exhalation of gases. Gas exchange occurs between the alveolar surface and the surrounding blood vessels. Alveoli provide a larger surface area needed for gaseous exchange.

Respiratory Physiology

Human breathing is aided by the action of internal and external intercostal muscles attached to the ribs and diaphragm.
When the dome-shaped diaphragm contracts and flattens, and the rib cage expands due to intercostal muscle action, the

Human breathing is aided by the action of internal and external intercostal muscles attached to the ribs and diaphragm. When the dome-shaped diaphragm contracts and flattens, and the rib cage expands due to intercostal muscle action, the volume of the lungs increases, pressure drops, and air from outside gushes in. This is called inhalation. To exhale, the diaphragm relaxes and returns to its dome shape, the chest cavity contracts due to intercostal muscle action, the volume inside the lungs decreases, pressure rises, and the air is forced out of the lungs.

Because inhaling air raises the concentration of oxygen in the alveoli, oxygen simply diffuses into the surrounding blood vessels.
Blood from cells contains a higher concentration of carbon dioxide than outside air, hence carbon dioxide is just excreted out of blood vessels into alveoli. Thus, breathing occurs as a result of the joint action of the intercostal muscles and diaphragm, while gas exchange occurs as a result of simple diffusion.


Human circulatory system, transportation in plants Humans, like other multicellular organisms, require a steady supply of food, oxygen, and so on. A circulatory or transport system performs this function. The circulatory system is in charge of transporting various substances in humans. The circulatory system comprises the following units in the order: heart, arteries, veins, and capillaries. Blood serves as a transporter of substances.


The heart is made up of cardiac muscles and is a complete muscular organ. It is so small that it can fit inside the wrist of an adult. The heart is a pumping organ that circulates blood. The human heart is divided into four chambers: the right atrium, the right ventricle, the left ventricle, and the left atrium. Systole is the contraction of the cardiac muscles. Diastole is the relaxation of the cardiac muscles.


These are blood vessels with thick walls that transport oxygenated blood from the heart to various organs.
The pulmonary arteries are an exception because they transport deoxygenated blood from the heart to the lungs, where it is oxygenated.


Pulmonary veins are thin-walled blood vessels that transport deoxygenated blood from various organs to the heart. These are thin-walled blood vessels that carry deoxygenated blood from various organs to the heart, with the exception of pulmonary veins, which carry oxygenated blood from the lungs to the heart. Veins have valves to prevent blood from flowing backwards.


It is a connective tissue that serves as a carrier for various substances in the body. Plasma is the first component of blood. 2. Red blood cells Platelets. Blood plasma is a pale-coloured liquid that is mostly made up of water. The matrix of blood is made up of blood plasma.
Blood cells are classified into two types: red blood cells (RBCs) and white blood cells (WBCs) (WBCs).
(a) Red Blood Corpuscles (RBCs): These are red due to the presence of haemoglobin, a pigment. Haemoglobin combines easily with oxygen and carbon dioxide. Haemoglobin is responsible for oxygen transport. Some carbon dioxide is also transported by haemoglobin.

(b) White Blood Corpuscles (WBCs): These are pale in colour. They play a critical role in immunity.
(c) Platelets: Platelets are in charge of blood coagulation. Blood coagulation is a defence mechanism that prevents excessive blood loss in the event of an injury.

Double circulation

Double circulation

Double Circulation is very important from exam points of view in life processes class 10 notes. In the human heart, blood circulates twice in one cardiac cycle. Double circulation is the name given to this type of circulation. The cardiac cycle refers to a single complete heartbeat in which all of the chambers of the heart contract and relax at the same time. A normal adult’s heart beats about 72 times per minute. The heart pumps out 70 mL of blood per cardiac cycle or approximately 4900 mL of blood per minute. For an optimum level of energy to be produced warm blooded animals, double circulation is the technique to help segregate the oxygenated and deoxygenated blood.

Transportation in Plants

Plant transport systems will transport raw materials from the roots as well as energy stores from the leaves. These two paths are made up of separate sets of conducting tubes. For example, the xylem transports water and minerals from the soil. In contrast, the phloem transports photosynthetic products from the leaves to other parts of the plant.

The xylem tissue (tracheids and vessels) of the plant’s roots, stems, and leaves are interwoven to form a continuous system of water-transmitting channels that reaches all parts of the plant. Suction pressure created by transpiration drives water into the xylem cells of the roots. The water then flows steadily from the root xylem to all parts of the plant via the interconnected water-carrying channels.


Transpiration is the loss of water in the form of vapour from the plant’s aerial parts. As a result, it promotes the absorption and upward transfer of dissolved minerals in water from roots to leaves. It also regulates the temperature.

Another topic in life processes class 10 notes is Translocation. It is the movement of soluble photosynthetic products in the phloem. It transports amino acids and other chemicals. Food and other substances are transported in the sieve tubes in both the ascending and descending directions by nearby partner cells. Energy is used to facilitate phloem translocation. Sucrose is transported into phloem tissue using ATP energy. This raises the osmotic pressure of the tissue, allowing water to enter. This is the stress. This enables the phloem to transfer material based on the needs of the plant. In the spring, for example, sugar stored in the root or stem tissue would be transported to buds that require energy to grow.

Excretion Process

Excretion Process

Excretion which means the removal of any toxic metabolic nitrogenous wastes produced by the body. The excretory system in humans is made up of kidneys (two in numbers), the urine bladder, a pair of ureters, and the urethra. There are two kidneys in the abdomen, one on each side of the backbone. Urine is transported from the kidneys to the urinary bladder, where it is stored until it is expelled through the urethra.

Nephrons are basic filtration units that are abundant in each kidney. Several substances in the initial filtrate, such as glucose, amino acids, salts, and a significant amount of water, are selectively reabsorbed as the urine passes through the tube. The amount of water reabsorbed is determined by the body’s excess water.

In addition to the amount of dissolved waste to be expelled, Each kidney’s urine eventually enters the ureter, a long tube that connects the kidneys to the urinary bladder until the inflated bladder causes the urge to pass it through the urethra. The neurological system controls the bladder because it is muscular. As a result, we can control our urge to urinate.

Urine is created in three stages:

Glomerular filtration: Nitrogenous wastes, glucose, water, and amino acids filter from the blood into the nephron’s bowman’s capsule.
Tubular reabsorption occurs when beneficial chemicals in the filtrate are reabsorbed by the capillaries that surround the nephron.
Secretion Extra water and salts are secreted into the tubule, which then opens up into the collecting duct and into the ureter.

Plant excretory system:
Plants lack an excretory system and excrete via a variety of mechanisms such as transpiration, waste release into the surrounding soil, leaf loss, and waste storage in cell vacuoles. Other waste materials, such as resins and gums, are retained in ancient xylem.


Chapter 6 that is Life Processes Class 10 notes cover all the important processes of living organisms necessary for their existence on the planet earth like Nutrition, Respiration, Circulation, sexual reproduction etc. Understanding the basic life processes not only aware you of your bodily functions but also impart you knowledge that you can carry lifelong and acts responsibly for your own health.

Therefore, it is a must that students pay diligent attention to the life processes class 10 notes.

Tagged with: cbse class 10 notes | class 10 notes | class 10 science chapter 6 notes | life processes | Life Processes Class 10 Notes

Class: Subject: ,

Have any doubt

Your email address will not be published. Required fields are marked *