Life Processes

What are Life Processes?

·        Life processes encompass a set of interconnected activities within an organism that collectively contribute to its repair and maintenance. These crucial processes include Respiration (R), Excretion (E), Nutrition (N), and Transportation (T), forming the acronym RENT.

·        Nutrition is the transformative process by which an organism acquires external sources of energy, commonly known as food, and transfers it internally for sustenance and vitality.

·        Respiration: The process of acquiring oxygen from outside the body, and using it in the process of break-down of food sources for cellular needs, is called respiration.

·        Transportation refers to the internal mechanism responsible for conveying nutrients and oxygen from one location to another within the body.

·        Excretion is the process through which the body eliminates and expels waste by-products, ensuring their removal from the internal environment and subsequent disposal outside the organism.

Modes of Nutrition

Autotrophic Nutrition.

Heterotrophic Nutrition.

Autotrophs are organisms that derive their nutrition from basic food materials acquired from inorganic sources such as carbon dioxide and water. Notable examples include green plants and certain bacteria.

Heterotrophs, on the other hand, rely on complex substances for their nutritional needs. These intricate compounds must undergo breakdown into simpler forms before being utilized for the maintenance and growth of the organism. To facilitate this process, organisms employ bio-catalysts known as enzymes. Animals and fungi are examples of heterotrophs.

Autotrophic Nutrition:

·        Autotrophic organisms fulfill their carbon and energy requirements through photosynthesis.

·        Photosynthesis is the process whereby autotrophs absorb external substances and convert them into stored energy. This involves the conversion of carbon dioxide and water into carbohydrates in the presence of sunlight and chlorophyll.

·        Surplus carbohydrates produced through photosynthesis are stored in the form of starch.

·        Similarly, in our bodies, a portion of the energy derived from the food we eat is stored in the form of glycogen.

Events Occurring during Photosynthesis:

·        Chlorophyll absorbing light energy.

·        Transformation of light energy into chemical energy.

·        Separation of water molecules into hydrogen and oxygen.

·        Conversion of carbon dioxide into carbohydrates through reduction.

·        Chlorophyll is a crucial component for the process of photosynthesis.

·        The iodine test results in a blue-black coloration in the leaf regions where photosynthesis occurs.

How the plant obtain carbon dioxide?

·        Massive gaseous exchange occurs in leaves via stomatal pores for photosynthesis.

·        Gas exchange extends across the surfaces of stems, roots, and leaves.

·        Stomatal pores close to prevent excessive water loss when carbon dioxide is not needed for photosynthesis.

·        The opening and closing of stomatal pores are regulated by guard cells.

·        Guard cells swell with water influx, causing stomatal pores to open.

·        Conversely, the pores close when guard cells shrink.

Stomata

·        Stomata, pores on leaves, facilitate gas exchange.

·        Predominantly located on the underside of leaves.

·        Guard cells, regulating pore opening and closing, and safeguard each stoma.

·        The functionality of guard cells is influenced by their water content.

Heterotrophic Nutrition:

Saprophytic nutrition refers to the feeding behavior of certain organisms that rely on consuming dead and decomposed organic matter. The food is partially digested outside the body, and then it is absorbed. E.g. Fungi are saprophytes.

Parasitic nutrition involves organisms feeding at the expense of another, causing harm. Parasites live on or within a host organism, extracting nutrients directly from the host's body. Examples include leeches as ectoparasites, Ascaris as an endoparasite, and Cuscuta as a parasitic plant.

 In holozoic nutrition, the digestion happens inside the body of the organism. i.e., after the food is ingested. Most of the animals follow this mode of nutrition.

How do Organisms obtain their Nutrition?

Single-celled organisms Amoeba engulf food through temporary extensions of their cell surface, creating a food- vacuole as these extensions merge over the food particle. Within the food vacuole, complex substances undergo breakdown into simpler ones, facilitating their diffusion into the cytoplasm. Undigested material is transported to the cell surface and expelled by Amoeba. cytoplasm material is transported to the cell surface and expelled by Amoeba. 

Paramoecium, a unicellular organism, maintains a distinct shape and ingests food at a designated location. The entire cell surface, covered with cilia, facilitates the movement of food to the specified intake spot.

Nutrition in Human Beings:

The alimentary canal is a lengthy tube running from the mouth to the anus.

Salivary glands secrete saliva, which contains the enzyme salivary amylase, breaking down complex starch into simple sugars.

Muscles lining the canal contract rhythmically, facilitating peristaltic movements that push food forward throughout the digestive system.

Digestion in the stomach:

·        Gastric glands within the stomach wall secrete hydrochloric acid, the enzyme pepsin, and mucus.

·        Hydrochloric acid establishes an acidic environment, enhancing the effectiveness of the protein-digesting enzyme, pepsin.

·        Under normal conditions, mucus shields the stomach's inner lining from the corrosive effects of the acid.

·        Pepsin functions as a protein-digesting enzyme.

·        The release of food from the stomach into the small intestine is regulated by a sphincter muscle, allowing controlled passage in small amounts.

Length of small intestine:

·        Herbivores, such as those consuming grass, require an elongated small intestine to facilitate the digestion of cellulose.

·        Carnivores, like tigers, with a diet of easily digestible meat, possess shorter small intestines.

·        The small intestine serves as the location for the thorough digestion of carbohydrates, proteins, and fats.

·        Secretions from the liver and pancreas contribute to the digestive processes occurring in the small intestine.

Bile juice from the liver:

·        Bile salts play a role in emulsifying fats, breaking large fat globules into smaller ones, thereby enhancing the efficiency of pancreatic enzymes.

·        The initially acidic food entering the small intestine undergoes alkalization through the action of bile juice, promoting the effectiveness of pancreatic enzymes.

Pancreatic juice from the pancreas:

·        Pancreatic juice includes enzymes such as trypsin, responsible for protein digestion, and lipase, which is involved in breaking down emulsified fats.

·        The small intestine walls house glands producing intestinal juice.

·        Enzymes in the intestinal juice convert proteins to amino acids, complex carbohydrates to glucose, and fats to fatty acids and glycerol.

·        The inner lining of the small intestine has numerous finger-like projections called villi.

Functions of Villi:

·        Enhances the surface area available for absorption.

·        Villi are abundantly supplied with blood vessels, facilitating the distribution of absorbed nutrients to every cell in the body.

·        Unabsorbed food is directed to the large intestine, where its walls extract additional water from the material.

Respiration:

The process by which a living being utilises food to get energy, is called respiration. Respiration is an oxidation reaction in which carbohydrate is oxidized to produce energy. Mitochondria is the site of respiration and the energy released is stored in the form of ATP (adenosine triphosphate). ATP is stored in mitochondria and is released as needed.

Steps of respiration:

·        The breakdown of glucose into pyruvate occurs in the cytoplasm. During this process, a glucose molecule, with 6 carbon atoms, is transformed into pyruvic acid, which consists of 3 carbon atoms.

Fate of Pyruvic Acid in Mitochondria: Pyruvic acid undergoes further breakdown within the mitochondria, and the resulting molecules vary based on the type of respiration specific to the organism. Respiration is categorized into two types: aerobic respiration and anaerobic respiration.

Respiration involves Gaseous exchange: Intake of oxygen from the atmosphere and release

of  CO2 → Breathing. Breakdown of simple food to release energy inside the cell → Cellular respiration.

Types of Respiration

Aerobic Respiration: Aerobic respiration occurs in the presence of oxygen. Pyruvic acid undergoes conversion into carbon dioxide, releasing energy, and culminating in the formation of water molecules. Anaerobic Respiration: Anaerobic respiration occurs in the absence of oxygen. Pyruvic acid is converted into either ethyl alcohol or lactic acid. Ethyl alcohol typically forms in microbes such as yeast or bacteria during anaerobic respiration. Lactic acid is produced in certain microbes and muscle cells during this process.

Pain in leg muscles while running:

·        Intense running triggers anaerobic respiration in muscle cells, driven by an increased demand for energy.

·        The process of anaerobic respiration produces lactic acid, contributing to a throbbing pain in the leg muscles.

·        Resting after the activity helps alleviate the pain caused by the deposition of lactic acid in the muscles.

ATP

·        ATP serves as the energy currency within cells.

·        ATP is an acronym for Adenosine Tri-Phosphate.

·        This molecule is generated as a byproduct of reactions such as photosynthesis and respiration.

·        The three phosphate bonds in ATP are high-energy bonds, and their breaking releases a substantial amount of energy.

·        The released energy is subsequently utilized for various metabolic reactions.

Respiration in Humans

·        The human respiratory system is a complex network crucial for breathing, gas exchange, and cellular respiration.

·        A well-organized respiratory system is essential for efficient breathing and gas exchange.

·        Breathing involves inhaling oxygen and exhaling carbon dioxide.

·        Gas exchange occurs in the lungs, where oxygen is supplied to all cells in the body.

·        Cellular respiration takes place in every cell, contributing to overall energy production and cellular function.

Respiratory System

The human respiratory system involves the nose, nasal cavities, pharynx, larynx, trachea/windpipe, bronchi, bronchioles, and alveoli.

Bronchioles and alveoli are enclosed in a pair of lungs. The rib cage, muscles associated with the rib cage, and diaphragm all help in the inhalation and exhalation of gases.

The exchange of gases takes place between an alveolar surface and surrounding blood vessels. Alveoli provide a large surface area for the exchange of gases.

Inhalation and Exhalation

Inhalation is the process of taking in air rich in oxygen. Exhalation is the process of expelling air rich in carbon dioxide. Individuals breathe multiple times throughout the day. The frequency of breaths in one minute is referred to as the breathing rate.

Cellular Respiration

Cellular respiration involves a series of metabolic reactions within cells, transforming the biochemical energy derived from food into a chemical compound known as adenosine triphosphate (ATP).

Respiration in Plants

In contrast to animals and humans, plants lack specialized structures for gaseous exchange. Gaseous exchange in plants occurs through stomata in leaves and lenticels in stems. Plant roots, stems, and leaves exhibit a considerably lower respiratory rate compared to animals.

Transportation:

All living organisms, including animals, rely on essential components like air, water, and food for survival, obtained through processes such as breathing, drinking, and eating. Transportation systems, like vascular tissue in plants and specialized circulatory systems in animals, facilitate the distribution of necessary substances to cells and tissues.

Transportation in Humans

The circulatory system in humans serves as the primary transportation mechanism.

Comprising blood, blood vessels, and the heart, it facilitates the supply of oxygen and nutrients while eliminating carbon dioxide and other excretory products.

Additionally, the circulatory system plays a vital role in the body's immune response, aiding in the fight against infections.

The HEART is a muscular organ, which is composed of cardiac muscles.

The heart, compact enough to fit within an adult's wrist, serves as a vital pumping organ for blood circulation.

Comprising four chambers—right atrium, right ventricle, left ventricle, and left atrium—the human heart orchestrates the rhythmic processes of systole (contraction of cardiac muscles) and diastole (relaxation of cardiac muscles).

Through systole and diastole, the heart efficiently propels and circulates blood, ensuring essential oxygen and nutrients reach the body's tissues and organs.

ARTERIES

Thick-walled blood vessels transport oxygenated blood from the heart to various organs, except pulmonary arteries.

Pulmonary arteries deviate from the norm by carrying deoxygenated blood from the heart to the lungs, where the blood undergoes oxygenation.

VEINS

These are thin-walled blood vessels that carry deoxygenated blood from different organs to the heart, pulmonary veins are exceptions because they carry oxygenated blood from the lungs to the heart. Valves are present in veins to prevent backflow of blood.

Capillaries: are blood vessels distinguished by their single-cell walls.

Blood, a connective tissue, functions as the carrier for various substances in the body and is comprised of three main components: 1. Plasma, 2. Blood cells, and 3. Platelets.

Blood Plasma: This is a light-colored fluid primarily composed of water, constituting the matrix of blood.

Blood Cells: There are two main types of blood cells: Red Blood Cells (RBCs) and White Blood Cells (WBCs). Red Blood Cells (RBCs): These cells are red due to the presence of the pigment hemoglobin. Hemoglobin readily binds with oxygen and carbon dioxide, facilitating the transport of oxygen. Additionally, a portion of carbon dioxide is transported through hemoglobin.

White Blood Cells (WBCs): These cells are pale white and play a crucial role in the immune system.

Platelets: Responsible for blood coagulation, platelets serve as a defense mechanism preventing excessive blood loss in the event of an injury.

LYMPH

Lymph resembles blood but lacks red blood cells (RBCs). Formed from leaked fluid in tissues, lymph is collected by lymph vessels and returns to blood capillaries.

Lymph, a yellowish fluid with fewer proteins than blood, plays a vital role in the immune system.

It flows from tissues to the heart, assisting in transportation and germ destruction.

 Double circulation:

The heart receives oxygenated blood from the lungs, pumps it to various parts of the body, and then receives it back for another circulation. Consequently, the blood completes a full round through the body, passing once through the right half as deoxygenated blood and once through the left half as oxygenated blood.

Transportation in Plants

Transportation is a crucial process in plants. It encompasses the movement of water and essential nutrients throughout the plant to support its survival.

Plants conduct the transportation of food and water through distinct pathways.

The xylem is responsible for transporting water. Phloem, on the other hand, is dedicated to the transportation of food.

Transport of water

Root cells in contact with the soil actively absorb ions, establishing a concentration difference between the root and the soil. Water moves into the root from the soil to equalize this ion concentration difference. Additionally, the evaporation of water molecules from leaf cells generates suction, drawing water from the xylem cells in the roots.

Transpiration

Transpiration refers to the loss of water in vapor form from the plant's aerial parts.

This process aids in the absorption and upward transport of water and dissolved minerals from the roots to the leaves, contributing to temperature regulation.

Transport of food and other substances

The movement of soluble products resulting from photosynthesis is termed translocation, and it takes place within the vascular tissue section called the phloem.

Energy is harnessed to accomplish translocation in the phloem. Substances such as sucrose are actively transferred into phloem tissue, utilizing energy derived from ATP.

              Xylem

·        Transports water and minerals from the roots to various parts of plants.

·        No energy is used.

PHOLEM

·        Transports the products of photosynthesis from the leaves to other parts of the plant.

·        Energy is used from ATP (adenosine triphosphate).

Excretion

The human excretory system comprises two kidneys, two ureters, a urinary bladder, and a urethra.

·        Animals exhibit an advanced and specialized excretory system.

·        In contrast, plants lack a well-developed excretory system similar to that of animals.

·        Plants do not possess specialized organs for excretion.

·        Consequently, excretion in plants is not as complex as it is in animals.

Human Excretory System

The human excretory system consists of a pair of kidneys. Each kidney is connected to the urinary bladder by a tube called the ureter.

Urine is gathered in the urinary bladder and expelled through the urethra as needed

The excretory system of human beings includes a pair of kidneys, A urinary bladder, A pair of ureters, and a urethra.

Kidney:

The kidney, a bean-shaped organ, is situated near the vertebral column in the abdominal cavity. comprising numerous filtering units known as nephrons. The nephron is recognized as the functional unit of the kidney.

Nephron

 Nephrons are the structural and functional unit of the kidney. Each kidney comprises millions of nephrons, serving as the fundamental structural and functional unit. A nephron consists of two parts: the Malpighian body and the renal tubule.

The Malpighian body includes Bowman's capsule, a cup-like structure, and the glomerulus, a cluster of capillaries. Working collaboratively, they filter waste materials and various useful substances.

The renal tubule features three regions: proximal convoluted tubule, Loop of Henle, and distal convoluted tubule.

These regions absorb useful substances back into the blood and filter the remaining waste substances.

The collective output from nephrons is termed urine.

Haemodialysis

Kidney failure leads to complications, and to address this, the technology of dialysis has been developed.

Dialysis employs a machine filter known as a dialyzer or artificial kidney.

The purpose is to eliminate excess water and salt, balance electrolytes, and remove metabolic waste products.

Blood is extracted from the body and passes through tubes with a semipermeable membrane.

On the other side of the membrane, a dialysate flows, drawing impurities through the membrane.

Excretion in Plants

Cellular respiration, photosynthesis, and metabolic reactions in plants result in the production of various excretory products.

Major plant excretory products include carbon dioxide, excess water from respiration, and nitrogenous compounds from protein metabolism.

Plants release two gaseous waste products: oxygen during photosynthesis and carbon dioxide during respiration. Gaseous waste excretion in plants occurs through stomatal pores on leaves. Oxygen released during photosynthesis is utilized for respiration, while carbon dioxide from respiration is used for photosynthesis. Excess water is excreted through transpiration. Plants store organic by-products in different forms in various parts, including gums, oils, latex, and resins. These waste products are stored in plant parts like bark, stems, leaves, etc., and are eventually shed off.

 Examples of plant excretory products include orange oil, eucalyptus oil, jasmine oil, latex from rubber trees, papaya trees, and gums from acacia. At times, plants release excretory substances into the soil.