Biology LIFE PROCESSES PDF

# LIFE PROCESSES ## Nutrition - The whole process by which an organism obtains its food is referred to as nutrition. - It is the method of obtaining nutrients from the environment. - Ingestion - Digestion - Absorption - Transportation - Utilization - Egestion - Nutrients are the in-or...

# LIFE PROCESSES ## Nutrition - The whole process by which an organism obtains its food is referred to as nutrition. - It is the method of obtaining nutrients from the environment. - Ingestion - Digestion - Absorption - Transportation - Utilization - Egestion - Nutrients are the in-organic or organic substances required for the maintenance of life and survival of living organisms. ### Modes of Nutrition | Mode of Nutrition | | --- | | Autotrophic Nutrition | | Holozoic Nutrition | | Heterotrophic Nutrition | - Saprotrophic Nutrition | - Parasitic Nutrition | #### Autotrophic Nutrition - It is the process by which organisms take in simple inorganic substances from outside and use them to synthesize organic molecules and then convert into stored forms of energy. - Autotrophs can make their own food. - Examples: Green plants and some bacteria. #### Heterotrophic Nutrition - It refers to the mode of nutrition in which organisms derive their food (nutrients) from other living organisms. - Heterotrophs depend directly or indirectly on autotrophs. - Types of heterotrophic nutrition: - saprotrophic nutrition - parasitic nutrition ##### Saprotrophic Nutrition - It refers to the mode of nutrition in which organisms obtain nutrients from the dead and decaying organic matter. - Examples: fungi, yeast and bacteria. ##### Parasitic Nutrition - It refers to the mode of obtaining food synthesised by others. - The organism which obtains food is called the 'parasite' and the organism from which food is absorbed is called the 'host'. - This nutrition is observed in fungi, bacteria, some plants like Cuscata and some animals like Plasmodium and roundworm. ## Holozoic Nutrition - Ingestive nutrition - It is a mode of heterotrophic nutrition which involves intake of solid pieces of food. - Holozoic nutrition is also called ingestive nutrition. - The food may consist of another animal, plant or its parts. - Depending upon the source of food, holozoic organisms are of three types: - Herbivores - Carnivores - Omnivores ### Heterotrophs - The organisms which cannot make their food and depend directly or indirectly on autotrophs for their survival are called heterotrophs. - Heterotrophs include animals and fungi. #### Herbivores - They are holozoic organisms which feed on plants or plant parts, e.g., Cow, Buffalo, Deer, Goat, Rabbit, Grasshopper, Elephant, Squirrel, Hippopotamus. #### Carnivores - Carnivores are animals which feed on other animals. They are also called predators because they hunt, kill and feed on their preys. - Examples: Lion, Tiger, Leopard, Snake, Hawk. #### Omnivores - Omnivores are holozoic organisms which feed on both plant and animal materials. - Examples: Cockroach, Ant, Pig, Crow, Rat, Bear, Dog, Humans. ## Nutrition in Amoeba - The digestive system is different in various organisms since the food and the way it is obtained differs in these organisms. - The mode of nutrition in Amoeba is holozoic and it is omnivorous. - The steps involved in nutrition of Amoeba: 1. Amoeba comes in contact with food particles, it forms pseudopodia which engulf the prey by forming a food cup. This process is ingestion or phagocytosis. 2. When the tips of encircling pseudopodia touch each other, the food is encaptured into a bag called food vacuole. The food vacuole serves as a temporary stomach secreting digestive juices. 3. The digested food gets absorbed and diffuses into the cytoplasm and then assimilated. 4. Assimilation is the ultilization of digested food in various anabolic and catabolic reactions and conversion (resynthesis) of absorbed food into complex molecules for various purpose such as production of energy growth, repair and storage. 5. The egestion of undigested food takes place at any point on the surface of the body. ## Digestive system of human - The digestive system consists of the alimentary canal and digestive glands. - The digestive system involves mastication, swallowing, digestion of food and elimination of undigested matter. - The digestive system is divided into two parts: 1. Alimentary Canal - Mouth - Buccal cavity - Oesophagus - Stomach - Intestine - Small intestine - Duodenum - Jejunum - Ileum - Large intestine - Caecum - Colon - Rectum 2. Digestive Glands ## Digestive Glands - Human digestive glands include salivary glands, liver and pancreas. They pour their secretions into the gut through their ducts. ### Salivary Glands - Salivary glands: There are three pairs of salivary glands around our mouth cavity that secrete viscous fluid called saliva. - Parotid gland - Submaxillary gland - Sublingual gland ## Transportation - Transpiration takes place through the stomata. Large amount of water is lost in the form of water vapour through stomata is known as transpiration. - Guard cells are kidney shaped cells which cover single stoma. They contain chloroplast also. - Guard cells function to regulate the opening and closing of the stoma and also perform photosynthesis. ### Opening and closing of Stomata - When the guard cells swell (turgid) due to the entry of water, the stomata open. - When the guard cells shrink (flaccid) due to the loss of water, the stomata gets closed. ## Carbon Dioxide - Photosynthesis has been found to take place in a very wide range of CO₂ concentration. - Within the range, the rate of photosynthesis will decrease or increase with decrease or increase in CO₂ concentration, provided other factors are not limiting. - Relatively high concentration of CO₂ reduces the rate of photosynthesis and if given for a considerable period of time, has detrimental effect on the process itself. ## Sunlight - It is the source of energy for photosynthesis. - Photosynthetically active radiations or PAR are 400 - 700 nm. Plants absorb light mostly in violet blue and red parts of visible light. Violet blue light carries more energy as compared to red light. - Electrons and protons (Hydrogen ion) help in producing ATP and NADPH, popularly called assimilatory power. ## Water - Plants absorb water from the soil with the help of root system. - The effect of water deficiency on the rate of photosynthesis is indirect one. - Decrease in H₂O content of the leaves may cause partial or complete closure of stomatal opening, and hence a reduction in the rate of diffusion of CO₂. - A partial drying of the cell walls cause decrease in its permeability to CO₂. Another indirect effect of water deficiency is that the accumulation of sugar within the cells increases the rate of respiration and thus decreases apparent photosynthesis. - Water splits into its components with the help of light energy. This phenomenon is called photolysis of water. - Oxygen is evoved in this process. - 2H₂O- Light 4H++4e+O₂↑ - Enzymes ## Heterotrophic Nutrition - The type of nutrition in which organisms derive their food (nutrients) from other living organisms. - In heterotrophic nutrition, the energy is derived from the intake and digestion of the organic substances, normally of plant or animal tissue. - The survival of heterotrophs depends directly or indirectly on autotrophs. - Heterotrophic mode of nutrition are of different types: - saprotrophic nutrition - parasitic nutrition ## Excretion - A number of waste products are formed as by-products of metabolism. - They are usually toxic and removed from the body. ## Irritability - Every living organism is aware of its surroundings. It responds to changes in the environment. ## Life Processes - The maintenance functions of living organisms must go on even when they are not doing anything particular. - The processes which together perform this maintenance job are called life processes. - To maintain various life processes and to prevent damage and breakdown, energy is required. - Energy is required to perform life processes such as: - nutrition - transportation - respiration - excretion ## Cellular Organization - All organisms are made up of cells. ## Sensitivity - Giving response to stimuli (Stimulus = change in environment) (Response = visible effect because of stimulus) - Consciousness is one of the most important definite life feature. - Example: Plants grows towards light, pupil dilate in dark etc. ## Respiration and Energy Utilization - Respiration is the process in which nutrients are converted into useful energy in a cell. - Energy produced during respiration is used to perform many kinds of works with in the body. ## Internal growth - It is a characteristic feature of living organisms. - Living organisms grow internally, - Their cells increase in number and size. ## Homeostasis - All organism maintain relatively constant internal conditions in different environments, known as homeostasis. ## Regulation - All organism have neural or chemical regulatory mechanism that co-ordinate internal processes. ## Reproduction - It is a process of producing young ones of their own kinds. - Heredity character are passed from parent to the offsprings during reproduction. ## Metabolism - The sum total of all the chemical & physical changes that are constantly taking place in living organisms & are necessary for life. ## Types of Metabolic Pathways - **Anabolic pathways:** Biosynthetic pathways, in which complex substances are synthesized from simpler ones. - Examples: Photosynthesis (Endothermic reaction - energy is used) - **Catabolic Pathways:** Break down of complex organic substances into simpler ones. - Examples: Respiration. (Exothermic - energy released) ## Introduction If an organism is alive, it must keep repairing and maintaining its structures. The maintenance functions of living organisms must go on even when they are not doing anything particular. The processes which together perform this maintenance job are called life processes. To maintain various life processes and to prevent damage and breakdown, energy is required. Energy is taken from the food (complex organic matter). The process which involves taking of food inside the body and utilizing it for various activities is called nutrition. The digested food and inhaled oxygen are transported to every cell of the body through blood by the circulatory system, this process is called transportation. Oxidation of food takes place inside every cell of the body by a process called respiration. In respiration, energy is generated and waste products are formed. These waste products are required to be removed from the body by a process called excretion. ## Some Characteristics of Living Organisms 1. **Cellular organization:** All organisms are made up of cells. 2. **Sensitivity:** Giving response to stimuli ( **Stimulus** = change in environment) ( **Response** = visible effect because of stimulus). 3. **Respiration & Energy utilization:** Respiration is the process in which nutrients are converted into useful energy in a cell. Energy produced during respiration is used to perform many kinds of works with in the body. 4. **Internal growth:** It is a characteristic feature of livings. 5. **Homeostasis:** All organism maintain relatively constant internal conditions in different environments, known as homeostasis. 6. **Regulation:** All organism have neural or chemical regulatory mechanism that co-ordinate internal processes. 7. **Reproduction:** It is a process of producing young ones of their own kinds. Heredity character are passed from parent to the offsprings during reproduction. 8. **Metabolism:** The sum total of all the chemical & physical changes that are constantly taking place in living organisms & are necessary for life. 9. **Excretion:** A number of waste products are formed as by-products of metabolism. They are usually toxic and removed from the body. 10. **Irritability:** Every living organism is aware of its surroundings. It responds to changes in the environment. *** ***Note: This is a summary of the document provided, not a complete copy. I was unable to fully decipher some parts of the document, so I have provided a broad overview.***