Life Processes Biology PDF 2024

Biology LIFE PROCESSES  Introduction Life processes – The processes that are necessary for an organism to stay alive. Eg. Nutrition, respiration, etc. Criteria of life- Metabolism Response to stimulus Growth Reproduction  Nutrition The process in whi...

Biology LIFE PROCESSES  Introduction Life processes – The processes that are necessary for an organism to stay alive. Eg. Nutrition, respiration, etc. Criteria of life- Metabolism Response to stimulus Growth Reproduction  Nutrition The process in which an organism takes in food, utilizes it to get energy, for growth, repair and maintenance, etc. and excretes the waste materials from the body Types of nutrition 1. Autotrophic nutrition – Autotrophic (self-sufficient for food) E.g. Plants, Algae, blue green Algae( cyanobacteria). 2.Heterotrophic nutrition -Heterotrophic (dependent on others for food). Eg. Animals,fungi. Autotrophic nutrition. Process – Photosynthesis (Photo=light; Synthesis= to combine) Raw materials- (i) Carbon dioxide (ii)Water Energy conversion- Light/Solar energy to Chemical energy Role off Chlorophyll- To trap the sun‘s energy for photosynthesis Chemical equation for photosynthesis  Events/ Steps of photosynthesis- (i) Absorption of light energy by chlorophyll (ii) Conversion of light energy to chemical energy & Splitting of water molecule into Hydrogen & oxygen (iii) Reduction of Carbon dioxide to Carbohydrate Gaseous exchange- (i) Gas used- Carbon dioxide (ii) By product – Oxygen Source of raw materials- (i) Carbon dioxide –Land plants- Air, Aquatic plants- Water (ii) Water & Minerals - Soil Photosynthesis Photosynthesis is a Photochemical Reaction and Anabolic Process Photosynthesis is divided into two parts: 1. Light-dependent reactions (Light Reactions) 2. Light-independent reactions (Dark Reactions). Light Reactions Light reactions need light to produce organic energy molecules (ATP and NADPH). They are initiated by colored pigments, mainly green colored chlorophylls. It occurs in Grana. (NADPH stands for Nicotinamide Adenine Dinucleotide Phosphate Hydrogen. This molecule plays a crucial role in some of the chemical reactions that make up the process of photosynthesis.)  Dark Reactions Dark reactions make use of these organic energy molecules (ATP and NADPH). This reaction cycle is also called Calvin Cycle. ATP provides the energy while NADPH provides the electrons required to fix the CO2 (carbon dioxide) into carbohydrates. Occurs in Stroma. Structure of Chloroplast Gaseous Exchange  Factors for Autotrophic nutrition - (i) Carbon dioxide (ii) Water (iii) Light (iv) Temperature  Heterotrophic nutrition Generally take up energy from plants and animals by using them as food. Mostly of three Types—Saprophytic, Holozoic and Parasitic  (a) Saprophytic nutrition: Organisms feeds on dead decaying plants or animals material. E.g. Fungi, Bacteria (b) Parasitic nutrition: Organisms obtain food from the body of another living (host) Endoparasite : Parasite lives inside the body of the host e.g. tapeworm, roundworm. Exoparasite : Parasite lives on the body of the host. E.g. lice, leech. The parasite benefits while the host is usually harmed e.g. Cuscutta-plant parasite, plasmodium –animal parasite (malarial parasite). (c) Holozoic nutrition: Organism (mostly animals) take in whole food and then digest it into smaller particles with enzyme. Eg.Amoeba, Paramoecium. Animals, human beings. Steps in Holozoic nutrition (i) Ingestion: taking in of food. (ii) Digestion: breaking down of complex food into simpler, absorbable form. (iii) Absorption: the process by which the digestive contents are absorbed by the blood and distributed to the rest of the body. (iv) Assimilation: Utilization of digested food from the body. (v) Egestion: Removing undigested food from the body. Nutrition In Amoeba Nutrition in Human Beings Alimentary Canal- Parts Mouth, Esophagus, Stomach, Small Intestine Large Intestine, Rectum, Anus Associated Glands – Salivary Glands, Liver, Gallbladder And Pancreas Digestive Enzymes And Their Functions Small Intestine The small intestine has three parts: the duodenum, jejunum, and ileum. Large Intestine Different sections of the large intestine are – Cecum Colon Rectum Anal canal Anus The large intestine comprises the cecum (appendix included), the colon, the rectum and the anal canal. Respiration-the process in which nutrients are converted into useful energy in a cells. Respiration Adenosine TriPhosphate (ATP) ATP is the energy currency for most cellular processes. The energy released during the process of respiration is used to make an ATP molecule from ADP and inorganic phosphate. ADP +Pi-----> ATP Gaseous exchange in plants- Process – Diffusion Direction of diffusion depends on- (i) Environmental conditions (ii) Requirement of the plant. Day time- Carbon dioxide given out during respiration is used for photosynthesis. Therefore only Oxygen is released, which is a major activity during the day. Night time – Only respiration takes place. Therefore only Carbon dioxide is released, which is a major activity during the night.  Gaseous exchange in animals- Terrestrial animals- take Oxygen from the atmosphere. Aquatic animals- take Oxygen dissolved in water. (Oxygen content is low in water, therefore they breath faster. Human Respiratory System  Human Respiratory Pathway External nostrils → Nasal cavity → Trachea→ Bronchi → Bronchioles →Alveoli Rings of cartilage present in the throat ensure that the trachea (air passage) does not collapse when there is less air in it. Lungs – (i) Present in the thoracic cavity. (ii) They are spongy, elastic bags consisting of Bronchi, Bronchioles and Alveoli Mechanism of breathing It includes : (i)Inhalation (ii) Exhalation Gaseous Exchange In Alveoli  Some common features of Respiratory organs- (i) Large surface area- for greater rate of diffusion of respiratory gases. (ii) Thin permeable walls – to ensure easy diffusion & exchange of gases. (iii) Extensive blood supply- Respiratory organs are richly supplied with blood vessels for quick transport of gases. Transport In Human Beings- The transport of materials in humans is done by Circulatory System. Parts of circulatory system Heart, Blood, blood vessels Blood- (i) It is a fluid connective tissue. (ii) Components- (1) Fluid medium- Plasma (2) Red blood corpuscles (RBC) or erythrocytes (3) White blood corpuscles (WBC) or leukocytes (4) Platelets or thrombocytes Composition Of Blood Plasma: Plasma is slightly alkaline non-living intercellular substance. It is pale yellow but transparent and clear fluid. It constitutes about 55% of blood. Constituents of plasma and their functions: Water (90-92%): It is a good solvent. It transports vitamins, hormones, enzymes, nutrients etc. Plasma proteins (6-8 %): It includes: Fibrinogen: It is a plasma glycoprotein synthesised by the liver. It plays a role in the clotting of blood. Globulin: It is the major protein of the plasma. It protects the body against foreign bodies. It acts as antibodies. Albumin: It is the major protein of the plasma. It helps in maintaining the fluid volume within the vascular space. It also regulates the blood pressure. Glucose, amino acids, lipids and cholesterol: It is meant for energy production and growth. Inorganic constituents: Na+, K+, Mg2+, Cl–, HCO32– regulates osmosis etc. Ca2+ ions help in blood clotting and muscle contraction. Gases like CO2, O2, N2 etc. for transport. Plasma without clotting factors is known as Serum. Serum = Plasma − Clotting factor  Composition Of Blood Formed elements (RBC, WBC and platelets) It constitutes about 45% of blood. (i) Erythrocytes or Red Blood Cells (RBC): Red blood cells are the most abundant cells in the blood. Average lifespan: 120 days Count: 5 − 5.5 million/ mm3 of blood. Formed in: Bone marrow. Other features: Biconcave and devoid of nucleus. These cells contain a red colour pigment called haemoglobin. Normal Hb level: 12-16 gm/ 100 ml of blood Worn-out RBCs are destroyed in spleen, hence spleen is called the graveyard of RBCs. Function: Involved in transport of respiratory gases.  Composition Of Blood (ii) Leucocytes or White Blood Cells (WBC): White blood cells are colourless cells without haemoglobin. They are the largest cell of the blood. Count: 6000 − 8000/ mm3 of blood Average lifespan: Generally short lived (1- 15 days). Formed in: Bone marrow, lymph glands, spleen. Other features: Colourless.,Nucleated,Different types Function: They have a major role to play in defence system of body. Types Of WBC (iii)Platelets (Thrombocytes): Platelets are small irregular bodies present in the blood. Count: 1.5 − 3.5 × 105/ mm3 of blood Average lifespan: 7 days. Formed in: bone marrow. Function: Blood clotting. Types of Leucocytes (WBCs): Granulocytes and Agranulocytes Functions Of Blood- (i) Transport of respiratory gases. (ii) Transport of nutrients. (iii) Transport of waste products. (iv) Defence against infection Structure Of Human Heart Blood Flow Through the Heart Blood vessels- Types Of Blood Vessels (i) Arteries (ii) Veins (iii) Capillaries Difference Between Artery, Vein And Capillary The Human Circulatory System The human circulatory system is a double circulatory system. It has two separate circulations and blood passes through the heart twice: the pulmonary circulation is between the heart and lungs. the systemic circulation is between the heart and the other organs. Types Of Circulatory System Pulmonary circulation Systemic circulation  Pulmonary Circulation The circulatory system which transports deoxygenated blood away from the heart, through the pulmonary artery, to the lungs and returned, oxygenated, to the heart through the pulmonary vein.  Systemic Circulation The circulatory system which transports oxygenated blood away from the heart through the aorta from the left ventricle to the rest of the body, and returns oxygen-depleted blood back to the heart through vena cava. Circulatory System Blood Pressure (BP) Blood pressure is the pressure of circulating blood on the walls of blood vessels. Most of this pressure is due to work done by the heart by pumping blood through the circulatory system. The systolic pressure is the pressure in the arteries as the heart contracts pushing the blood forward. The diastolic pressure is the pressure in the arteries as the heart relaxes. Blood Pressure (BP) Normal blood pressure is 120/80 mm of Hg. Increased blood pressure- Hypertension Decreased blood pressure- Hypotension A Sphygmomanometer is a device used to measure blood pressure. Transportation In Plants Plants need less energy - because they do not move and therefore have a slow transport system. Transport is done in plants by xylem and phloem. Difference Between Xylem And Phloem  Excretion The biological process of removal of harmful metabolic wastes in living organisms. Excretion In Human Beings Organs of excretory system- (i)A pair of Kidneys (iii) Urinary bladder (ii)A pair of Ureters (iv) Urethra Human Excretory System  Kidneys- (i) Two in number (ii) Bean shaped (iii)Present in abdomen on either side of the backbone (iv)Basic unit is nephron. KIDNEY AND NEPHRON Structure Of Nephron Structure Of Nephron a) Glomerulus- Group of capillaries (cluster) present in Bowman‘s capsule to receive blood from renal artery and filters it. b) Bowman‘s capsule- Cup shaped structure, which contains glomerulus. c) Convoluted tubule- is long and reabsorbs vital nutrients like glucose, amino acids, salts, urea and water. Structure Of Nephron Function Of The Glomerulus The main function of the glomerulus is to filter blood to produce glomerular filtrate, which passes down the length of the nephron tubule to form urine. Mechanism of Urine Formation Urine is formed in three main steps- glomerular filtration, reabsorption, and secretion. It comprises 95 % water and 5% wastes such as ions of sodium, potassium, and calcium, and nitrogenous wastes such as creatinine, urea, and ammonia. Mechanism Of Urine Formation  Anti Diuretic Hormone (ADH) ADH is also called Vasopressin. It's a hormone made by the hypothalamus in the brain and stored in the pituitary gland. It tells your kidneys how much water to conserve. ADH constantly regulates and balances the amount of water in your blood. Regulation Of Urine Formation  Dialysis Dialysis is the process of removing excess water, solutes and toxins from the blood in people whose kidneys can no longer perform these functions naturally. Excretion in Plants Plants have no special organs for the removal of waste. The excretory products in plants are eliminated from the plant body by different mechanisms. The waste products of respiration and photosynthesis are used as raw materials for each other. Oxygen gas produced as a by-product of photosynthesis is used up during respiration and carbon dioxide produced during respiration is used up during photosynthesis. Excretion is carried out in the plants in the following ways: The gaseous wastes, oxygen, carbon dioxide, and water vapor are removed through the stomata of leaves and lenticels of stems. Some waste products collect in the leaves and bark of trees. When the leaves and bark are shed, the wastes are eliminated. Some waste products are rendered harmless and then stored in the plant body as solid bodies. tannins, resins, gum, rubber, and essential oils are some such wastes The oil produced from orange, eucalyptus, and jasmine, latex from the rubber tree, papaya tree, and gums from acacia, are different forms of stored waste products. Sometimes waste products are excreted into the soil. Excretion in plants Oxygen, a waste product of photosynthesis is released. Excess water is removed by transpiration. Some waste products may get stored in the leaves which fall off. Many waste products are stored in vacuoles. Some waste products are stored as resins and gums in old xylem. Plants excrete some waste materials into the soil around them. THANK YOU