Life Processes Class 10 Notes

Life Processes

• The basic function performed by living organisms is to maintain their life on this earth.
• These include nutrition, respiration, digestion, transportation, and excretion.

Nutrition

The process of intake of nutrients (like carbohydrates, fats, proteins, minerals, vitamins, and water) by an organism as well as the utilization of these nutrients by the organism.

Nutrients

A group of food in which protein, fats, vitamins, and minerals are involved is called nutrients.

Types of Nutrition

1. Autotrophic Nutrition: The process by which an organism synthesizes its own food from simple inorganic substances like carbon dioxide and water present in the surrounding environment is called autotrophic nutrition.
   Eg. Green plants and bacteria
2. Heterotrophic Nutrition: Organisms that can’t synthesize their food from simple inorganic substances and obtain their own food from other organisms, this process is called heterotrophic nutrition.
   Eg. Animals and fungi

Nutrition in Plants – Photosynthesis

The process by which green plants take in inorganic substances like Carbon Dioxide (Co2) and Water (H2O) and convert them into food (like glucose) in the presence of Sunlight and Chlorophyll is called Photosynthesis.

Oxygen gas is released during photosynthesis. Photosynthesis is one of the most important topic in Life processes class 10 notes.

6CO2 + 12H2O ———–> C6h12O6 + 6O2 + 6H20 (Chlorophyll and sunlight on the arrow)

Conditions necessary for Photosynthesis:

1. Sunlight
2. Chlorophyll
3. Carbon Dioxide
4. Water

Steps of Photosynthesis:

1. Absorption of light energy by chlorophyll.
2. Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.
3. Reduction of carbon dioxide by hydrogen to form carbohydrates like glucose.

The process of photosynthesis requires two raw materials:

1. Carbon Dioxide: The green plants take carbon dioxide from the air through Stomata.
2. Water: Water required for photosynthesis is absorbed by roots from soil.

Stomata:

• Tiny pores are present on the surfaces of leaves.
• Responsible for gaseous exchange.
• Surrounded by a pair of guard cells that control the opening and closing of stomata.
• Water flows into guard cells ——> Stomata open
• Water flows out of guard cells ——> Stomata close

Nutrition in Animals (Heterotrophic Nutrition)

1. Saprophytic Nutrition: In this, the organism obtains its nutrition from decaying organic matter of the dead plants and animals.
   Eg. Fungi
2. Parasitic Nutrition: This organism obtains food from the body of another living organisms (host) without killing it.
   Eg. Lice, ticks, etc.
3. Holozoic Nutrition: In this, the organism takes in complex organic food by a process called ingestion, which is then digested and absorbed into the body, and waste, undigested part is thrown out of the body through egestion.
   Eg. Amoeba, man, dog, etc.

Nutrition in Amoeba

1. Ingestion: Amoeba takes in food using temporary finger-like extensions of the cell surface called as Pseudopodia.
2. Digestion: Various enzymes from the cytoplasm enter into food vacuole and break down complex substances into simple ones.
3. Absorption: The simple soluble food is absorbed by the cytoplasm of Amoeba through the process of diffusion.
4. Egestion: The remaining undigested material is moved to the surface of the cell and thrown out.

Nutrition in Paramecium

Paramecium is a unicellular organism, the cell has a definite shape and food is taken in at a specific spot by the movement of Cilia which cover the entire surface of the cell.

Nutrition in Human Beings

Mouth

• The food is ingested through the mouth.
• Teeth crushes and breaks down food into smaller pieces.
• The process of digestion starts from the mouth.
• The salivary glands secrete saliva which contains an enzyme called salivary amylase which digests the starch present in food into sugar.

Esophagus/Food Pipe

The walls of esophagus show peristaltic movement (Rhythmic contraction and relaxation of muscles) which pushes the food forward into the stomach.

Stomach

The glands present in the walls of the stomach secrete gastric juice. Gastric juice contains:

1. Hydrochloric Juice: Creates an acidic medium that facilitates the action of the enzyme pepsin.
2. Pepsin: It is a protein-digesting enzyme.
3. Mucus: Protects the inner lining of the stomach from the action of acid.

The exit of food into the small intestine is regulated by the sphincter muscle.

Small Intestine

The small Intestine is the site for the complete digestion of food (carbohydrates, fats, and proteins). The small intestine receives secretion from two glands:

1. Liver: Liver secrets bile juice which performs two functions –
   • Makes the acidic food coming from the stomach alkaline so that pancreatic enzymes can act on it.
   • Bile juice breaks the fat present in food into small globules (emulsified fat) so that enzymes can act on it and digest it.
2. Pancreas: Secretes pancreatic juice which secretes digestive enzymes namely Trypsin and Lipase.
   • Lipase – Breaks down emulsified fat
   • Trypsin – Digests protein

The walls of the small intestine contain glands that secret intestinal juice. This juice contains an enzyme that converts:

The process of absorption starts in the small intestine. Small finger-like projections increase the surface area for absorption and are richly supplied with blood vessels when taking absorbed food to every cell of the body.

The inner surface of the small intestine has millions of villi which absorb nutrients from digested food.

Large Intestine

Unabsorbed food reaches the large intestine where more villi absorb water.

Anus

The rest of the undigested food is removed from the anus.

Respiration

• The process of releasing energy from food is called respiration.
• The process of respiration takes place inside the cells of the body.
• The energy released during respiration is stored in the form of ATP.
  ATP – Adenosine triphosphate
  ADP – Adenosine di-phosphate
• The energy released during respiration makes ATP from ADP and inorganic phosphate.
  ADP + Phosphate + Energy ——-> ATP
• When the cell needs energy, then ATP can be broken down using water to release energy.
  ATP ——> ADP + Phosphate + Energy

The energy equivalent to 30.5 KJ/mole is released in this process.

Types of Respiration

1. Aerobic Respiration: The respiration which uses oxygen is called aerobic respiration. Glucose is completely broken down into carbon dioxide and water in the presence of oxygen.
   Most of the organisms carry out aerobic respiration. Eg. Man, dogs, earthworms, etc.
2. Anaerobic Respiration: Respiration that takes place without oxygen is called anaerobic respiration. Glucose is completely broken down into carbon dioxide and water in the presence of oxygen.
   • Micro-organisms like yeast break down glucose into ethanol and carbon dioxide, and release the energy. This process is known as Fermentation.
   • Anaerobic respiration takes place in our muscles during vigorous physical exercise. This causes muscle cramps.

Difference between Aerobic and Anaerobic Respiration

Human Respiratory System

The main organs of the human respiratory system are the nose and nasal passage (or nasal cavity). Trachea, Branchi, Lungs, and Diaphragm.

1. Nostrils: Air is taken in the body through the nostrils.
   • The air passing in through the nostrils is filtered by fine hair that the line passage.
   • The passage is also lined with mucus.
2. Pharynx: The part of the throat between the mouth and windpipe is called pthe harynx.
   • From the nostril, air enters into the pharynx and then goes into the trachea or windpipe.
3. Larynx: The upper end of the trachea has a voice box called the larynx.
4. Trachea: A Trachea is a tube that is commonly called windpipe.
   • It is composed of rings of cartilage that prevent the collapse of the trachea in the absence of air.
5. Bronchi: The trachea divides into smaller tubes called ‘Bronchi’.
   • The two bronchi are connected to the lungs.
6. Lungs: The lungs lie in the chest cavity which is separated from the abdominal cavity by a muscular partition diaphragm.
   • The lungs are enclosed in a ‘Rib Cage’ made of bones called ‘Ribs’.
7. Bronchioles: Each bronchus divides into smaller tubes called ‘Bronchioles’.
8. Alveoli: These are air-sacs at the end of “bronchioles”.
   • Its walls are very thin and they are surrounded by thin blood capillaries.
   • The gaseous exchange takes place inside the alveoli.
   • Millions of alveoli in the lungs provide a large area for the exchange of gases.

Mechanism of Breathing

Breathing – The inhalation of oxygen and exhalation of carbon dioxide is called breathing. Breathing consists of inhalation and exhalation.

1. Inhalation: As we inhale, ribs lift and the diaphragm moves downward the chest cavity becomes larger. Because of this, air is sucked into the lungs and fills the expanded alveoli.
   • The oxygen in alveolar air is taken up by the alveolar blood vessels to be transported to all cells of the body.
   • The oxygen is carried in the blood by the respiratory pigment Haemoglobin which can store high quantity of oxygen.
   • The pigment is present in the red blood corpuscles.
   • The oxygen reaches the cells where the process of respiration takes place producing carbon dioxide.
   • This carbon dioxide diffuses into blood which carries it to the lungs in dissolved form.
2. Exhalation: As we exhale, ribs relax due to which diaphragm moves upward. This decreases the space in our chest cavity pushing the air out of the lungs.

This is one of the most important topic in Life processes class 10 notes.

Respiration in Plants

1. During the day, CO2 generated during respiration is used up for photosynthesis, hence there is no CO2 release. Instead oxygen release is the major event at this time.
2. At night, when there is no photosynthesis occuring, CO2 elimination is the major exchange activity going on.

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Human Circulatory System

Blood

Blood is a fluid connective tissue which consists of:

1. Plasma: It is the fluid medium in which cells are suspended. It transports food, carbon dioxide and nitrogenous waste.
2. Red Blood Cells: RBC contains haemoglobin which carries oxygen from lungs to all the cells of the body.
3. White Blood Cells: They protect us from diseases by fighting infection.
4. Platelets: They help in clotting of the blood in the case of injury.

The human blood circulatory system consists of the heart and blood vessels. There are three types of blood vessels:

• Arteries: Carry blood from heart to all parts of the body.
• Veins: RBC contains haemoglobin which carries oxygen from lungs to all the cells of the body.
• Capillaries: Narrow, thin walled blood vessels that connects arteries to the veins. The exchange of materials such as O2, CO2, and food between blood and cells takes place through capillaries.

Human heart

• Heart pumps blood around the body.
• It is triangular in shape and roughly the size of our closed fist.
• Human heart has 4 chambers.
• The upper two chambers are called Atrium and lower two chambers are called Ventricles.
• These chambers are separated by a partition called “Septum”.
• Valves present inside heart prevents the backflow of blood.

Blood Circulation

1. When the muscle of all the four chambers are in relaxed state, the pulmonary vein brings oxygenated blood from the lungs into the left atrium.
2. Oxygenated blood is pushed from the left atrium to left ventricle.
3. The muscles of left ventricle contract and the blood is pushed through Aorta (largest artery) to the whole body (except lungs).
   The oxygenated blood reaches the cells of the different body organs where the process of respiration takes place. Due to this oxygenated blood coverts into deoxegenated blood.
4. Deoxygenated blood reaches right atrium through vena cava (largest vein).
5. When the right atrium contracts, deoxygenated blood is pushed innto right ventricle.
6. When the right ventricle contracts, the deoxygenated blood is pumped into lungs through pulmonary artery.

In lungs, the deoxygenated blood becomes oxegenated. This oxygenated blood is again sent to left atrium by pulmonary vein for circulation in the body.

Double Circulation

In human circulatory system, the circulation of blood from heart to lungs and back to the heart is called Pulmonary Circulation and the circulation of blood from heart to the rest of the body and back to heart is called Systemic Circulation.

In such circulatory system in which blood travels twice through the heart is one complete cycle is called double circulation. Eg. Humans

Single Circulation

Fishes have a two-chambered heart and thus show single circulation.

Lymphatic System

• Lymphatic system contains lymph which is another type of fluid involved in transportation.
• Lymph is colourless and contains less protein than blood.
• Lymphatic system carries digested and absorbed fat from intestine and drains excess fluid from cellular space back into the blood.
• Lymphatic system plays role in the immunity of our body.

Transportation in Plants

Plants have two transport systems:

1. Transport of water & minerals – Conducted by Xylem (Xylem vessels & xylem tracheids)
2. Transport of food – Conducted by Phloem (Primarily by Sieve tubes which helped by companion cells)

Difference between Root Pressure & Transpiration

Translocation

1. Translocation in phloem is achieved by utilising energy.
2. Material like sucrose is transferred into phloem tissue using energy from ATP.
3. This increases the osmotic pressure of the tissue causing water to move into it. This pressure moves the material in the phloem to tissues which have less pressure.
4. This allows the phloem to move material according to plant’s needs.
5. Eg. In the spring, sugar stored in root or stem tissue would be transported to the buds which need energy to grow.

Difference between Xylem and Phloem

Excretion

The process of removal of toxic wastes from the body of an organism is called excretion.

Human Excretory System

1. Kidney: Kidney are bean shaped organ.
   • We have a pair of kidney.
   • Function of kidneys is to clean our blood by filtering it to remove unwanted substances present in it.
2. Ureter: The ureter is a long tube which collects urine from kidneys.
3. Urinary Bladder: Urine is stored in the urinary bladder.
4. Urethra: The collected urine is passed our from the body through urethra.

Nephron

• Nephron is the filtration unit of kidney.
• Nephron has a cup shaped structure at its upper end called Bowman’s capsule.
• The bowman’s capsule contains a bundle of blood capilaries called glomerulus.
• The renal artery brings dirty blood containing urea which passes through glomerulus.
• Glomerulus filters the blood passsing through it.
• Small molecules like Urea, Uric Acid, Extra glucose, Amino acid, Salt and Water is filtered out and reaches the tubalar part of nephron.
• In the tubular part of nephron, selective reabsorption of useful substances such as Glucose, amino acid, salt and water takes place.
• The remaining liquid from various nephrons forms urine which is collected in the collecting duct.
• From collecting duct, urine is passed into ureter. From ureter, urine passes into urinary bladder where it is stored for some time and ultimately passed out of the body through urethra.

Excretion in Plants

Plants excrete:

• Gaseous waste = Through stomata/lenticels
• Solid/liquid waste = Through shedding of leaves
• In the form of gum and resins
• In the surrounding soil.

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