Life Processes CBSE Class 10 Science Revision Notes Chapter 6


Revision notes for Class 10 Science Chapter 6 Life Processes help you understand all the essential topics of the chapter with ease. The askIITians Science experts have created revision notes for this chapter based on the latest CBSE syllabus and exam pattern. These notes include detailed, pointwise explanations for all the topics of the Life Processes chapter along with important diagrams and tables. You can access these online revision notes for free from our website and study them at your pace. 


Chapter 6 Life Processes of Class 10 Science include topics like processes that are essential for maintaining life, nutrition, autotrophic nutrition, heterotrophic nutrition, nutrition in human beings, respiration, transportation in human beings, transportation in plants, excretion in human beings, and excretion in plants. Our online revision notes of this chapter can benefit you in many ways:


  • Remove your doubts regarding life processes 
  • Get a deeper understanding of different life processes in human beings
  • Get free explanations for all the topics of life processes chapter 
  • Prepare your classwork for life processes chapter 
  • Learn the topics related to the life processes chapter for exams
  • Solve NCERT exercises of the chapter 


Free Revision Notes for CBSE Class 10 Science Chapter 6 Life Processes 


All the processes such as respiration, nutrition, circulation, excretion etc. that are necessary for the survival of the living organisms are known as life processes.


Modes of Nutrition

The two most common types of nutrition are autotrophic nutrition and heterotrophic nutrition.


Autotrophic Nutrition

It is a type of nutrition in which inorganic materials such as carbon dioxide, is used up to synthesise organic food by a process known as photosynthesis. For example, green plants use an autotrophic mode of nutrition. Organisms that use the autotrophic mode of nutrition are known as autotrophs.


Now the question arises how does autotrophic nutrition occur in plants using photosynthesis?

For photosynthesis to occur, carbon dioxide, water, sunlight and chlorophyll are the required raw materials. Sunlight provides energy, chlorophyll is used to absorb the sunlight, carbon dioxide is reduced to carbohydrates and water is oxidised to release the oxygen. Water is taken up from the soil through the roots.

The site where photosynthesis occurs is known as chloroplast. They contain a green colour pigment known as chlorophyll that traps sunlight for photosynthesis.

The steps of photosynthesis are as follows-

  • Absorption of light by chlorophyll.
  • Conversion of light energy into chemical energy.
  • Splitting of water into hydrogen and oxygen.
  • Finally, reduction of carbon dioxide into carbohydrates.

Leaves contain small openings known as stomata which helps in the exchange of gases. The stomata/stoma is surrounded by a guard cell which guards the opening and closing of stomata. Guard cells also contain chloroplast.

Fig.1. Structure of Stomata


The overall equation of photosynthesis is:

Fig.2. Overall Equation of Photosynthesis


Heterotrophic Nutrition

In this mode of nutrition, an organism is unable to synthesise its food. It is of the following types-

  1. Holozoic nutrition is a type of nutrition where an organism takes in whole food and breaks it inside the body. For example, Amoeba.
  2. Saprophytic nutrition is nutrition in which organisms feed on dead and decaying matter. For example, fungi.
  3. Parasitic nutrition is nutrition in which an organism feeds on a living host. For example, Cuscuta. 


Nutrition in Human Beings

Humans consist of the alimentary canal which starts from the mouth and ends at the anus. The parts of the alimentary canal are as follows-

  1. Mouth
  2. Pharynx
  3. Oesophagus/food pipe
  4. Stomach
  5. Small intestine
  6. Large intestine
  7. Rectum
  8. Anus

Fig.3. Human Digestive System

Mouth is the first portion of the alimentary canal. The mouth consists of a muscular tongue and teeth. The cavity inside the mouth is known as the oral cavity.

Fig.4. Human Mouth Parts


Mechanism of Digestion of Food

  • Food digestion process begins in the mouth. Food is complex in nature.
  • To break down food and absorb it, we need biological catalysts known as enzymes.
  • The mouth contains salivary glands that secrete saliva. Saliva contains an important enzyme known as the salivary enzyme that breaks down starch into simple sugars.
  • The food then passes via the oesophagus into the stomach. The movement of the food inside the oesophagus occurs via rhythmic contraction of muscles, this is known as peristalsis.
  •  The stomach contains gastric glands that secrete mucus, hydrochloric acid and pepsin. Pepsin is a protein-digesting enzyme.
  • After the stomach, food then enters the small intestine. The small intestine is larger in herbivores due to cellulose digestion compared to carnivores.
  • Complete digestion of carbohydrates, proteins and fats occurs in the small intestine.
  • The small intestine receives secretions from the pancreas and bile from the liver. Bile helps in the emulsification of fats whereas the pancreas secretes enzymes such as trypsin for protein digestion. The intestinal wall also contains glands that secrete intestinal juice.
  • The small intestine has villi that increase the surface area for the absorption of food.
  • The unabsorbed food is then transferred to the large intestine where water is absorbed.
  • Undigested food is then expelled out from the anus.



  • It is a metabolic process that involves the breakdown of food to release energy is known as respiration.

Fig.5. Breakdown of glucose by different pathways

  • The breakdown of pyruvate into ethanol and carbon dioxide in absence of oxygen is known as fermentation. As this process occurs in absence of oxygen, it is known as anaerobic respiration. When the pyruvate is broken down into carbon dioxide and water in presence of oxygen it is known as aerobic respiration.
  • The energy released during the process is used up to synthesise the ATP (adenosine triphosphate).
  • Compared to animals, plants used stomata to exchange carbon dioxide and oxygen. This exchange occurs through diffusion.


Respiration in Human Beings

Human respiratory system starts with the nostrils, nasal cavity, pharynx, trachea, bronchi, bronchioles and then lungs. In the lungs, alveoli are present, where an exchange between oxygen and carbon dioxide takes place.

Fig.6. Passage of air in Humans

Humans have a respiratory pigment known as haemoglobin to carry the oxygen to different parts of the body and to remove carbon dioxide from the body. Compared to oxygen, carbon dioxide is more soluble in water, so it is usually transported in dissolved form.


Transportation in Human Beings

Blood is a fluid connective tissue that transports food, oxygen, carbon dioxide, nitrogenous waste etc. Blood contains plasma and blood cells. Red blood cells carry oxygen throughout the body. The heart is the pumping organ in the body.

  • The human heart is 4 chambered, with two atriums and two ventricles.
  • The left atrium receives the oxygen-rich blood from the lungs. While receiving the blood it relaxes.
  • The left ventricle pumps oxygen-rich blood throughout the body.
  • Deoxygenated blood comes from the body to the upper right atrium. It contracts to pump the blood to the right ventricle.
  • The right ventricle pumps the blood to the lungs for oxygenation.

Fig.7. Structure of Human Heart

Note: Fishes have a two-chambered heart, amphibians and reptiles have a three-chambered heart except crocodiles which possess a 4 chambered heart. Birds and mammals also have 4 chambered hearts.


Double Circulation

The right side and left side of the heart are separated to prevent the mixing of oxygenated and deoxygenated blood. In vertebrates, blood goes through the heart twice during each cycle. This is defined as double circulation.  (NTSE)

Fig.8. Double Circulation

Note: The force that the blood exerts against the wall of the vessel is known as blood pressure. The pressure of blood inside the artery during ventricular contraction is known as systolic pressure whereas the pressure in the artery during ventricular relaxation is known as diastolic pressure. The normal blood pressure is 120/80 mm of Hg.




They carry blood away from the heart

One cell thick smallest vessels

They carry blood towards the heart

They carry oxygenated blood except for the pulmonary artery.

Help in the exchange of the material between the blood and surrounding cells.

They carry deoxygenated blood except for the pulmonary vein.

They have thick walls and do not have valves.

They do not have valves

They have thin walls and also possess valves.


  • Platelets are blood cells that help in blood clotting.
  • Lymph is also known as interstitial fluid is a fluid that leaks out from the pores of the capillaries.


Transport in Plants

  • Plants have the xylem tissue for the transportation of water. Xylem transports water from the roots to different parts of the plants. Xylem tissue consists of vessels and tracheids.
  • Loss of water in the form of water vapour from the aerial parts of the plants is known as transpiration. The transpiration creates a suction that pulls the water up to the higher plants.
  •  Similarly, the transport of food in plants occurs via the phloem. It transports food from the leaves to different parts of the plants.

Fig.9. Transport in Plants



  • The process involved in the removal of nitrogenous waste from the body is known as excretion.
  • The excretory system of humans consists of a pair of kidneys, a pair of ureters, urinary bladder and urethra.
  • The basic filtration unit of the kidneys is known as nephrons.
  • The nephron is the structural and functional unit of the kidneys.
  • They consist of a bowman's capsule and a renal tubule.
  • For the formation of urine, some substances such as glucose and amino acids are selectively reabsorbed.
  • The amount of water reabsorbed depends on how much water is there in the body.
  • The urinary bladder is a muscular structure and it is under nervous control

Fig.10. Human Excretory System

Note: Plants excrete their waste through transpiration. Plants also produce other excretory waste in the form of gums, resins etc.


Online Revision Notes for CBSE Class 10 Science Chapter 6 Life Processes FAQs


  1. Why should I use revision notes for Class 10 Chapter 6 Life Processes? 

Referring to the NCERT textbook every time you study/revise a chapter is difficult. Many students get overwhelmed because they have to read the whole chapter again before exams. Revision notes can be a great option to revise the chapter easily and quickly. They include all the important definitions and diagrams that help students in understanding the concepts of the chapter. 


  1. How to study CBSE Class 10 Science Chapter 10 Life Processes? 

You must read the chapter first from the NCERT textbook and make some notes. These notes will help you revise the chapter concepts easily. Make sure that you use simple language in your notes so that revising a topic does not confuse you. Once you have understood the concepts, start solving the NCERT questions of the chapter. You can also check NCERT Exemplar problems for the chapter to test how well you understand the concepts. 


  1. What is included in the online revision notes for Chapter 10 Life Processes?

The online revision notes for Life Processes by askIITians include all the topics of this chapter like autotrophic nutrition, heterotrophic nutrition, nutrition in human beings, respiration, transportation in human beings, transportation in plants, excretion in human beings, and excretion in plants.


  1. How can askIITians help me in scoring full marks in CBSE Class 10 Science exam? 

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