Life Processes PDF

# Biology Aid - Life Processes ## Life Processes The basic function performed by living organisms to maintain their life on earth. - Nutrition - Respiration - Transportation - Excretion ## Nutrition The process of intake of nutrients by an organism as well as utilization of the nutrients by the...

# Biology Aid - Life Processes ## Life Processes The basic function performed by living organisms to maintain their life on earth. - Nutrition - Respiration - Transportation - Excretion ## Nutrition The process of intake of nutrients by an organism as well as utilization of the nutrients by the organism. - Carbohydrates - Proteins - Fats - Minerals - Vitamins & Water ### Modes of Nutrition (Methods of procuring/obtaining food) 1. **Autotrophic Nutrition** - The process by which organism synthesizes its own food from simple inorganic substances like carbon dioxide and water present in the surrounding environment is called as autotrophic nutrition. - E.g. - Green plants & Bacteria 2. **Heterotrophic Nutrition** - Organisms that can't synthesize their own food from simple inorganic substances and obtain their food from other organisms. - E.g. - Animals & Fungi ## Nutrition in Plants - Photosynthesis The process by which green plants take in inorganic substances like carbon dioxide and water and convert them into food (like glucose) in the presence of sunlight & chlorophyll is called as photosynthesis. - Oxygen gas is released during photosynthesis - $6CO_2$ + $12H_2O$ + Chlorophyll → $C_6H_{12}O_6$ + $6O_2$ + $6H_2O$ **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 ## Q. Where do plants get each of the raw materials required for photosynthesis? The process of photosynthesis requires two raw materials: 1. Carbon dioxide 2. Water 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 present on the surface of leaves - Responsible for gaseous exchange - Surrounded by a pair of guard cells which control opening & closing of stomata - Water flows into guard cells → Stomata Open - Water flows out of guard cells → Stomata Close ## Nutrition in Animals - Heterotrophic Nutrition ### Saprophytic Nutrition: - In this, the organism obtains its nutrition from decaying organic matter of plants and animals. - E.g. - Fungi ### Parasitic Nutrition: - In this, organism obtains its food from the body of another living organism (host) without killing it. -E.g. - Lice, Ticks etc. ### Holozoic Nutrition: - In this, 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. - E.g. - Amoeba, Man, Dog, fish etc. ## Nutrition in Amoeba 1. **Ingestion:** - Amoeba takes in food using temporary finger-like extensions of the cell surface called as pseudopodia. - Pseudopodia fuse over food particle forming a food-vacuole. 2. **Digestion:** - Various enzymes from cytoplasm enter into food vacuole and breaks down complex substances into simpler ones. 3. **Absorption** - The simple soluble food is absorbed by 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 Paramoecium - Paramoecium, which is also 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 mouth. - Teeths crush and breaks down food into smaller pieces. - The process of digestion starts from mouth. - Salivary glands secrete saliva which contains an enzyme salivary amylase which digests the starch present in food into sugar. - Starch (carbohydrate) → Salivary Amylase → Sugar ### Oesophagus/Food Pipe - The walls of oesophagus 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 stomach secrete gastric juice. - Gastric juice contains: 1. Hydrochloric acid 2. Enzyme Pepsin 3. Mucus - Hydrochloric acid - Creates an acidic medium which facilitates the action of enzyme pepsin. - Pepsin - It is a protein digesting enzyme. - Mucus - Protects the inner lining of the stomach from the action of acid. - The exit of food into small intestine is regulated by 'sphincter muscle'. ## Small Intestine - Small Intestine is the site for complete digestion of food (Carbohydrate, proteins and fats). - Small Intestine receives secretion of two glands: liver and pancreas. ### 1. Liver - Liver secretes bile. - Bile performs two functions: - Makes the acidic food coming from stomach alkaline so that pancreatic enzymes can act on it. - Bile breaks the fat present in the food into small globules (emulsified fat) so that enzymes can act on it and digest them. ### 2. Pancreas - Secretes Pancreatic Juice which secretes digestive enzyme Trypsin and Lipase - Lipase - Breaks down emulsified fat. - Trypsin - Digests Protein. ### Intestinal Juice - The walls of small intestine contains glands which secretes intestinal juice. - Intestinal juice contains enzyme which convert: - Protein → Amino acids - Complex carbohydrate → Glucose - Fats → Fatty acid + glycerol ## The process of absorption starts in small intestine ### Villi: - Small finger-like projections which increase the surface area for absorption and are richly supplied with blood vessels which take absorbed food to each and every cell of the body. - The inner surface of small intestine has millions of villi which absorbs nutrients from digested food. ## Large Intestine - Unabsorbed food reaches large intestine where more villi absorb water. ### Anus: - Rest of the undigested food is removed via anus in the form of faeces. - The exit of faeces is regulated by anal sphincter. ## Respiration - The process of releasing energy from food is called respiration. - The process of respiration takes place inside the cells of the body. ### How Energy Released During Respiration Is Stored: - The energy released during respiration is stored in the form of ATP. - ATP - Adenosine Tri-phosphate - ADP - Adenosine Di-phosphate 1. Energy released during respiration is used to make ATP from ADP and inorganic phosphate. - ADP + Phosphate + Energy → ATP 2. 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 as aerobic respiration. - Glucose is completely broken down into carbon dioxide and water in the presence of oxygen. - Glucose (6 Carbon molecule) + Cytoplasm → Pyruvate (3 Carbon molecule) + Presence of oxygen in mitochondria → CO_2 + H_2O + Energy (38 ATP) 2. **Anaerobic Respiration:** - Respiration which takes place without oxygen is called anaerobic respiration. >**i) Micro-organism like yeast break down glucose into ethanol and carbon dioxide, and release the energy.** - Glucose (6 Carbon molecule) + Cytoplasm → Pyruvate (3 Carbon molecule) + Absence of oxygen (In yeast) → Ethanol + CO_2 + 2ATP > **ii) Anaerobic respiration takes place in our muscles during vigorous physical exercise.** - Glucose (6 Carbon molecule) + Cytoplasm → Pyruvate (3 Carbon molecule) + Absence of oxygen (In our muscle cells)→ Lactic acid + 2ATP - This causes muscle cramps. **Q. Differentiate between aerobic and anaerobic respiration.** | **Aerobic Respiration** | **Anaerobic Respiration** |:---------------------------------------:|:-------------------------------------:| | It takes place in the presence of oxygen. | It takes place in the absence of oxygen. | | In this, complete breakdown of food occurs. | In this, partial breakdown of food occurs. | | End products are carbon dioxide and water. | End products maybe ethanol and carbon dioxide (in yeast) or lactic acid (in animal cells) | | It produces a considerable amount of energy. | Much less energy is produced | ## Human Respiratory System - The main organs of human respiratory system are: - Nose, Nasal Passage (Cor Nasal Cavity), Trachea, Bronchi, Lungs and Diaphragm. ### 1. Nostrils - Air is taken in the body through nostrils. - The air passing in through the nostril is filtered by fine hair that line the passage. - The passage is also lined with mucus. ### 2. Pharynx - The part of throat between the mouth and wind pipe is called pharynx. - From nostril, air enters into pharynx and then goes into the trachea or wind pipe. ### 3. Larynx - The upper end of trachea has a voice box called larynx. ### 4. Trachea - Trachea is a tube which is commonly called wind pipe. - It is composed of rings of cartilage which prevent the collapse of trachea in the absence of air. ### 5. Bronchi - The trachea divides into two smaller tubes called 'bronchi'. ### 6. Lungs - The two bronchi are connected to the two lungs. - The lungs lie in chest cavity which is separated from 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. - Gaseous exchange takes place inside alveoli. - Millions of alveoli in the lungs provide large area for the exchange of gases ## Mechanism of Breathing - 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 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 - This oxygen is carried in the blood by the respiratory pigment Haemoglobin which has a very high affinity for oxygen. - This 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 the blood which carries it to the lungs in dissolved form. ### 2. Exhalation - As we exhale, ribs relax causing the diaphragm to move upward. - This decreases the space in our chest cavity pushing the air out of the lungs. **Q. What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?** - Since the amount of dissolved oxygen is fairly low compared to the amount of oxygen in the air, the rate of breathing in aquatic organisms is much faster than that of terrestrial organism. ## Respiration In Plants - Respiration in leaves → Through Stomata - Respiration in green stem → Through Stomata - Respiration in woody stem → Through Lenticel 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 ## Human Circulatory System - Blood - Blood is a fluid connective tissue which consists of: - **Plasma:** - It is the fluid medium in which cells are suspended. - **Red Blood Cells (RBC):** - It transports food, carbon dioxide and nitrogenous waste. RBC contains hemoglobin that carries oxygen from lungs to all the cells of the body. - **White Blood Cells:** - They protect us from diseases by fighting infection. - **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. ### Types of Blood Vessels 1. **Arteries:** - Carry blood from heart to all parts of the body. 2. **Veins:** - Carry blood from all parts of the body back to the heart. 3. **Capillaries:** - Narrow, thin walled blood vessels that connect arteries to veins. - The exchange of materials such as O2, CO2, 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 fist. - Human heart has four chambers. - The upper two chambers are called atria (singular 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 muscles 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 left atrium to the 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 different body organs where the process of respiration takes place. Due to this oxygenated blood converts into deoxygenated blood. 4. **Deoxygenated blood reaches right atrium through vena cava (largest vein).** 5. **When the right atrium contracts, deoxygenated blood is pushed into right ventricle.** 6. **When the right ventricle contracts, the deoxygenated blood is pumped into lungs through pulmonary artery.** - In lungs, the deoxygenated blood becomes oxygenated. 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 from heart to lungs and back to the heart is called pulmonary circulation and the circulation of blood from heart to rest of the body and back to heart is called systemic circulation. - In such circulatory system in which blood travels twice through the heart in one complete cycle is called double circulation. - E.g. - 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. ## Transport 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 helped by companion cells) ## Transport of Water & Minerals ### Root Pressure - At the roots, cells in contact with the soil actively take up ions. - This creates a difference in concentration of ions between the root and the soil. - Water moves into the root from the soil to eliminate this difference which results in steady movement of water. ### Transpiration - The loss of water in the form of water vapour from aerial parts of the plant is known as transpiration. - Evaporation of water molecules from stomata creates a suction which pulls water from the xylem cells of roots. - It also helps in temperature regulation. ## Transport of Food ### Translocation - Translocation in phloem is achieved by utilising energy. - Material like sucrose is transferred into phloem tissue using energy from ATP. - 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. - This allows the phloem to move material according to plant's needs. - E.g. : In the spring, sugar stored in root or stem tissue would be transported to the buds which need energy to grow. **Q. What are the differences between the transport of material in Xylem and Phloem?** | Xylem Transport | Phloem Transport | |---|---| | Transports water and minerals | Phloem transports food | | Transport occurs in upward direction | Transport occurs in both upwards and downwards direction | | Transport occurs due to the suction force produced in the evaporation of water in the form of water vapours | Food is transported by utilizing energy from ATP | ## Excretion - The process of removal of toxic wastes from the body of an organism is called excretion. ## Human Excretory System - 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. - Ureter: - The ureter is a long tube which collects urine from kidneys. - Urinary bladder: - Urine is stored in the urinary bladder. - Urethra: - The collected urine is passed out from the body through urethra. ## Nephron - Nephron is the filtration unit of kidney. - Nephron has a cup shaped structure at it's upper end called 'Bowman's capsule'. - The Bowman's capsule contains a bundle of blood capillaries called glomerulus. - The renal artery brings dirty blood containing urea which passes through glomerulus. - Glomerulus filters the blood passing through it. - Small molecules like urea, uric acid, extra glucose, amino acid, salt and water is filtered out and reaches the tubular 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. **Q. Name the nitrogenous waste that is removed from the blood in our kidney?** - Ans. Urea ## 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