Life Processes | Class 10 Life Process notes | Life processes class 10 Notes | Chapter 6 Science Class 10 Notes

 Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

Overview:   (Life Processes  | Class 10 Life Process notes)

This chapter delves into the essential life processes in living organisms, focusing on how they obtain and utilize nutrition. The topic also explores different modes of nutrition and the processes involved in obtaining energy and nutrients.

 Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

Nutrition  

Nutrition refers to the process by which living organisms take in and use food for growth, energy, and development. Organisms can have different modes of nutrition based on how they acquire food.

Types of Nutrition

1. Autotrophic Nutrition

Autotrophic nutrition is the process where organisms, like plants, produce their own food. This happens primarily through photosynthesis.

• Raw Materials for Photosynthesis: The essential components required for photosynthesis are carbon dioxide, water, and sunlight. Plants use these to create glucose and oxygen.

• Site of Photosynthesis: Photosynthesis occurs mainly in the leaves of plants, specifically within the chloroplasts, which contain chlorophyll to absorb light energy.

• Key Events of Photosynthesis: The process involves converting light energy into chemical energy. Plants use sunlight to convert carbon dioxide and water into glucose and oxygen, which is vital for their survival and growth.

Stomata

Functions of Stomata: Stomata are tiny pores found on the surface of leaves that allow gases like oxygen and carbon dioxide to enter and exit. They also facilitate the loss of excess water in the form of vapor.

2. Heterotrophic Nutrition

Heterotrophic nutrition is when organisms obtain their food from other living organisms. This can include animals, fungi, and some bacteria. These organisms cannot make their own food, so they rely on consuming plants or other animals for nutrition.

Nutrition in Humans

• Human Digestive System: The human digestive system plays a crucial role in breaking down food into simpler substances that can be absorbed into the bloodstream. This process involves several organs such as the mouth, stomach, small intestine, and large intestine, each contributing to the digestion and absorption of nutrients.

Introduction

• Every living organism carries out specific life processes such as growth, excretion, breathing, and circulation, among others.

• Life processes are the vital functions like respiration, digestion, and other activities that sustain life and help in the maintenance of the body.

Types of Nutrition

Nutrition in Plants

• Plants are known as autotrophs.
• They produce their own food through processes like photosynthesis.
• Plants do not consume other organisms for food; instead, they manufacture it using sunlight, carbon dioxide, and water.

Nutrition in Animals

• Animals are classified as heterotrophs.
• They rely on plants or other organisms for their food sources.

Autotrophic Nutrition

• Autotrophic nutrition is a process where organisms use inorganic substances, such as carbon dioxide and water, to produce organic food through photosynthesis.
  Example: Green plants.

• Organisms that perform autotrophic nutrition are referred to as autotrophs, such as green plants.

• Autotrophs take simple inorganic substances and convert them into complex, high-energy compounds like carbohydrates.

• This type of nutrition is accomplished through photosynthesis, where autotrophs absorb carbon dioxide (CO2) and water (H2O), using sunlight and chlorophyll to produce carbohydrates.

Photosynthesis Equation:

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Raw Materials for Photosynthesis

• Sunlight: This is a vital energy source required for the process of photosynthesis.

• Chlorophyll: The green pigment in plants that captures sunlight for the photosynthesis process.

• Carbon Dioxide (CO2): CO2 enters the plant through tiny openings on the leaves called stomata. Oxygen (O2) is released as a by-product through the same stomata.

• Water: Water, along with essential minerals like nitrogen and phosphorus, is absorbed by the plant roots from the soil.

Location of Photosynthesis

Certain plant cells contain specialized structures known as chloroplasts, which house the green pigment chlorophyll. These organelles are where photosynthesis takes place.

Key Steps in Photosynthesis

• Light Absorption: Chlorophyll absorbs light energy from the sun.

• Conversion and Water Splitting: The absorbed light energy is transformed into chemical energy, and water is broken down into hydrogen and oxygen.

• Carbon Dioxide Reduction: Carbon dioxide is converted into carbohydrates during the process.

Stomata

Stomata are small openings found on the surface of leaves.

                                 

 Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

Functions of Stomata

• Gas Exchange: Stomata allow the exchange of gases, such as oxygen (O2) and carbon dioxide (CO2).

• Water Loss: They are responsible for the loss of a significant amount of water in the form of water vapor during transpiration.

Heterotrophic Nutrition

• Heterotrophic nutrition refers to the type of nutrition where organisms cannot produce their own food and depend on autotrophs, either directly or indirectly, for their food.
  Examples: Animals, fungi.

• Holozoic Nutrition: In this mode, organisms ingest solid food and digest it within their bodies.
  Examples: Amoeba, animals.

• Saprophytic Nutrition: Organisms in this category feed on dead or decaying organic matter.
  Example: Fungi.

• Parasitic Nutrition: Parasites obtain nourishment from a host organism by living either inside or outside the host.
  Examples: Cuscuta (a plant parasite), ticks.

How Organisms Obtain Food

• Unicellular Organisms: In single-celled organisms, food is absorbed across the entire surface of the cell.
  Examples: Amoeba, Paramecium. 

 Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

Food Intake Process in Amoeba

Amoeba feeds by engulfing its food through a process called phagocytosis. It extends its cell membrane to surround the food particle, forming a temporary pocket known as a food vacuole. Once the food is enclosed, digestive enzymes are released into the vacuole, breaking down the food into simpler substances. The absorbed nutrients are then transported to the rest of the cell, and any undigested material is expelled.

Paramecium

• Cilia: Paramecium has cilia all over its surface, which help in directing food towards a specific area.

• Food Intake: The cilia move the food particles toward a designated region where ingestion occurs.

Nutrition

Different organisms employ various methods of nutrition, depending on the source of carbon from which they obtain their food.

 Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

Nutrition in Humans

• The digestive tract in humans is essentially a continuous tube that runs from the mouth to the anus, with distinct sections that are specialized to carry out specific functions.

Human Digestive System

 Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

(i) Mouth: The mouth is responsible for the initial intake of food.

(ii) Teeth: The teeth function to break down and grind food into smaller pieces.

(iii) Tongue: The tongue helps in rolling the food, tasting it, and pushing it down the throat for swallowing.

(iv) Salivary Glands: These glands produce saliva and mucus (a sticky, gelatinous substance that lines areas like the mouth, nose, throat, and lungs). Saliva contains an enzyme called salivary amylase, which converts starch into glucose.

(v) Esophagus: The esophagus moves food from the mouth to the stomach through a series of muscle contractions and relaxations known as peristalsis.

(vi) Stomach: The stomach contains gastric glands that release gastric juices to aid in digestion.

 Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

(vii) Small Intestine: The small intestine is where the final breakdown of carbohydrates, proteins, and fats occurs.

(a) The lining of the small intestine releases digestive enzymes that transform carbohydrates into glucose, fats into fatty acids and glycerol, and proteins into amino acids.

(b) The small intestine contains villi, tiny finger-like projections that aid in the absorption of nutrients into the bloodstream.

(c) It also receives digestive secretions from the liver and pancreas.

• The food entering the small intestine is acidic, but it is neutralized to make it suitable for the action of pancreatic enzymes. The pancreas releases pancreatic juice, which contains enzymes like trypsin for protein digestion and lipase for breaking down fats.

• Fats in the intestine are initially in large globules, which makes it difficult for enzymes to act on them. Bile salts break these globules into smaller droplets, enhancing the effectiveness of the enzymes.

(viii) Large Intestine:

(a) It absorbs excess water from the remaining food matter.

(b) The undigested material is eventually eliminated from the body through the anus.

Respiration in Humans

Respiration consists of two main components:

1. Gas Exchange (Breathing): The process of absorbing oxygen from the air and releasing carbon dioxide.

2. Cellular Respiration: The breakdown of simple food molecules to release energy within the cells.

Breakdown of Glucose Through Different Pathways

• The first stage of glucose breakdown involves converting glucose (a six-carbon molecule) into a three-carbon molecule called pyruvate. This occurs in the cytoplasm.

• In yeast, during fermentation, the pyruvate is transformed into ethanol and carbon dioxide. As this process occurs in the absence of oxygen, it is termed anaerobic respiration.

• In the presence of oxygen, pyruvate is further broken down in the mitochondria into carbon dioxide and water, a process called aerobic respiration.

• When oxygen supply is limited, such as during intense physical activity, pyruvate is converted into lactic acid within muscle cells. This accumulation of lactic acid can lead to muscle cramps.

 Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

• The energy produced during cellular respiration is quickly used to create a molecule known as ATP, which powers all other cellular functions. During these processes, ATP is broken down, releasing a specific amount of energy that drives the endothermic reactions occurring in the cell.

• Aquatic organisms breathe at a much faster rate than terrestrial organisms because the oxygen dissolved in water is much lower compared to the oxygen available in the air.

Types of Respiration

Aerobic Respiration:

Aerobic Respiration occurs when oxygen is available. It takes place within the mitochondria of the cell. The process produces carbon dioxide and water as by-products and generates a larger amount of energy compared to other types of respiration.

Anaerobic Respiration

Anaerobic Respiration occurs when oxygen is not present. It takes place in the cytoplasm of the cell. The end products are either alcohol or lactic acid, and less energy is released compared to aerobic respiration.

Respiratory System in Humans

The human respiratory system is responsible for the exchange of gases between the body and the environment. It includes the organs that facilitate the intake of oxygen and the removal of carbon dioxide from the body. This system involves structures like the lungs, airways, and diaphragm, which work together to ensure proper breathing and gas exchange.

 Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

Passage of Air Through the Respiratory System:

• Nostrils: Air enters the body through the nostrils.

• Nasal Passage: This is the airway that directs the airflow from the nose.

• Nasal Cavity: Lined with hair and mucus membranes, the nasal cavity warms, moistens, and filters the air before it reaches the lungs.

• Pharynx: This passage contains cartilage rings that prevent it from collapsing, allowing air to flow smoothly.

• Larynx: Known as the voice box, it contains the vocal cords, which control the pitch and volume of sound, essential for speaking.

• Trachea: The trachea is the continuation of the pharynx that divides into the bronchi and esophagus. It transports air between the larynx and the lungs for breathing.

• Bronchi: These are the primary pathways that lead air into the lungs. They are branches of the windpipe, directing air into the lungs, while also carrying carbon dioxide out.

• Bronchioles: The bronchi divide into smaller tubes called bronchioles, which carry air from the trachea to the alveoli in the lungs.

• Alveoli: These tiny, balloon-like structures at the end of the bronchioles are where oxygen and carbon dioxide are exchanged between the lungs and the bloodstream.

• Blood Capillaries: These tiny blood vessels are where the transfer of oxygen and nutrients occurs from the blood to the tissues, while carbon dioxide and waste products are returned to the bloodstream.

Breathing Mechanism

Inhalation

During inhalation, the chest cavity (thoracic cavity) expands. The ribs move upward, and the diaphragm flattens. As a result, the lung volume increases, allowing air to flow into the lungs.

Exhalation

During exhalation, the chest cavity contracts. The ribs move downward, and the diaphragm takes on a dome-like shape. This reduces the lung volume, causing air to be expelled from the lungs.

 Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

Gas Exchange Between Alveoli, Blood, and Tissues

1. Oxygen-rich air enters the bloodstream, where it binds with hemoglobin in red blood cells. Oxygen is then released into the tissues via blood vessels.

2. Carbon dioxide is released into the blood, where it dissolves and is transported through the blood vessels. The carbon dioxide is then transferred to the alveoli and expelled through the nostrils.

• Terrestrial organisms: Rely on atmospheric oxygen for respiration.

• Aquatic organisms: Utilize dissolved oxygen in water for respiration.

Respiration in Plants

Plant respiration is simpler than in animals. Gas exchange occurs through: (a) Stomata in the leaves
(b) Lenticels in the stems
(c) General surface area of the roots

Circulatory System in Humans

Like all multicellular organisms, humans require a constant supply of oxygen, food, and waste removal. The circulatory system is responsible for performing these functions.

The human circulatory system includes:

1. Heart (the pumping organ)
2. Arteries and Veins (blood vessels)
3. Blood and Lymph (circulatory fluids)

                                                             

 Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

• The lungs provide oxygenated blood to the left atrium of the heart.

• The left atrium relaxes as it fills with blood and contracts to push the blood into the left ventricle. The left ventricle expands as it receives the blood.

• When the left ventricle contracts, it pumps the blood out of the heart to the rest of the body.

• Deoxygenated blood returns from the body to the right atrium of the heart, which expands to receive it.

• The right atrium contracts, transferring blood to the right ventricle. The right ventricle then pumps the blood to the lungs for oxygenation.

• The right ventricle has thicker muscular walls to help pump blood effectively to various parts of the body.

• Valves ensure that blood flows in one direction, preventing it from flowing backward during atrial or ventricular contractions.

Blood Circulation in Humans

• Double Circulation: In this process, blood passes through the heart twice in one complete cycle around the body.

• Direction of Blood Flow:

  • Pulmonary Circulation: Blood flows from the heart to the lungs and returns to the heart.
  • Systemic Circulation: Blood flows from the heart to the rest of the body and back.

Blood

Blood is a fluid connective tissue.

• Solid Components (Blood Cells):

  • Red Blood Cells (RBCs): These cells transport oxygen and carbon dioxide and contain hemoglobin, which gives blood its red color.
  • White Blood Cells (WBCs): These cells defend the body by engulfing pathogens and producing antibodies.
  • Platelets: These help in clotting the blood during an injury.

• Liquid Components (Plasma): Plasma is a yellowish fluid composed of 90% water and 10% organic substances.

Lymph

• Lymph is a yellowish fluid that leaks out of blood capillaries into the spaces between cells.

• It contains fewer proteins than blood.

• Lymph flows from the tissues to the heart, playing a role in transport and the destruction of pathogens.

• Lymph also carries absorbed fats from the intestine and helps drain excess fluid back into the bloodstream.

Types of Blood Vessels

There are two primary types of blood vessels:

1. Arteries
2. Veins

Arteries transport oxygen-rich blood from the heart to various parts of the body, except for the pulmonary artery. They are also known as distributing vessels. Arteries have thick, elastic walls and are located deeper within the body (further from the skin).

Veins carry deoxygenated blood from various body parts back to the heart, except for the pulmonary vein. These are also known as collecting vessels. Veins have thinner, less elastic walls and are located closer to the surface of the body (near the skin) compared to arteries.

Transport in Plants

Plants have two primary transport systems:

1. Xylem
2. Phloem

Xylem transports water and minerals from the roots to the rest of the plant, and this process does not require energy.

Phloem transports the products of photosynthesis from the leaves to other parts of the plant, a process that requires energy from ATP.

Transpiration and Its Functions

Transpiration is the process by which water is lost in the form of vapor from the aerial parts of a plant.

Functions:

• (a) It aids in the absorption and upward movement of water and minerals by creating a pull.
• (b) It helps regulate the temperature within the plant.

The transport of food (products of photosynthesis) from the leaves (the plant's food production sites) to other parts of the plant is called Translocation.

Excretory System in Humans

The excretory (or urinary) system includes:

1. Kidneys: The main excretory organs.
2. Ureters: Tubes that transport urine from the kidneys.
3. Urinary Bladder: A storage organ for urine.
4. Urethra: The tube that carries urine out of the body.

 Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

Excretion

(i) The metabolic processes in the body produce various types of waste, including nitrogenous wastes, which can be harmful if accumulated. Therefore, these wastes must be eliminated. Excretion is the process through which these harmful substances are removed from the body.

(ii) Unicellular organisms eliminate waste through simple diffusion.

Excretory wastes

 Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

Functions of Organs in the Excretory System

Each kidney contains numerous filtration units known as nephrons.

• Nephrons consist of a network of tiny blood vessels called the glomerulus, which is encased in a cup-like structure called Bowman’s capsule. These structures are connected to a long tube that leads out of the capsule.

• The renal artery supplies oxygenated blood to the kidneys, carrying nitrogenous wastes like urea and uric acid, along with various other substances.

• Blood is filtered through the glomerulus, and the resulting filtrate enters the tubular part of the nephron.

• As the filtrate moves through the tubule, useful substances such as glucose, amino acids, salts, and excess water are selectively reabsorbed by the surrounding blood vessels.

• The extent of water reabsorption depends on: (i) The level of excess water present in the body

• Amount of Nitrogenous Wastes to be Excreted

  1. The fluid flowing through the tubules now becomes urine, which is collected in the collecting ducts of the nephrons.

  2. These collecting ducts merge to form the ureter, which transports the urine away from the kidneys.

  3. Each ureter directs the urine to the urinary bladder, where it is stored until the bladder's expansion creates the urge to excrete it through the urethra.

  4. The urinary bladder is a muscular organ, controlled by the nervous system.

  5. While approximately 180 liters of filtrate is produced each day, only about 2 liters of this is excreted as urine, with the remainder being reabsorbed by the body.

  .

  

   Life Processes  | Class 10 Life Process notes | life processes class 10 Notes | Chapter 6 Science Class 10 Notes

  
  

Functions of Nephron

• The nephron helps in excreting nitrogenous wastes.
• It also plays a key role in maintaining the balance of water and ions in the body (osmotic regulation).

Artificial Kidney

• Hemodialysis: This is the process used to purify the blood in patients with kidney failure. It is carried out using an artificial kidney.

Excretion in Plants

Plants use various methods to get rid of waste:

• Oxygen and carbon dioxide are released through the stomata.
• Excess water is expelled via transpiration.
• Plants may also shed some of their older parts, like leaves and tree bark, to remove waste.
• Other waste products, such as resins and gums, accumulate in old xylem cells and can be discarded by the plant.
• Some plants also secrete waste into the surrounding soil.

Formation of Urine in Humans

Urine formation in humans involves three main steps:

1. Glomerular Filtration: Nitrogenous wastes, glucose, water, and amino acids are filtered from the blood into the Bowman’s capsule of the nephron.

2. Tubular Reabsorption: The useful substances from the filtrate are reabsorbed by the capillaries surrounding the nephron.

3. Secretion: Extra water, salts, and urea are secreted into the tubule, which eventually opens into the collecting duct and then the ureter.

Thank You for reading this post. You can check out more articles like this on www.physicswallah.in .


If you have any doubts then you can post a comment below.