Life Processes!!

• Nutrition is the process of transferring source of energy (food) from outside to the body of an organism.
• Respiration is the process of acquiring oxygen from outside into the body and using it for breaking down of glucose to release energy for cellular needs.
• Transportation is the process of carrying food and oxygen from one place to another.
• Excretion is a process of removing by-products from body which are formed during energy generating reactions.
• Carbon based molecules, i.e., food, is used by body from outside to meet its energy need.
• Oxygen is used to oxidise food and release energy.
• Food and oxygen are the basic raw materials used by an organism.
• Transportation system transports waste products away from cells but to discard it from the body to outside excretory system is needed.
• Diffusion is the process used by single celled organisms to carry out basic life processes such as gas exchange, etc.
• Diffusion is insufficient because multicellular organisms like humans have complex body designs and large body size.
• Unlike unicellular, multicellular organisms do not have the cells in direct contact with environment.
• Hence, diffusion cannot meet their oxygen requirements.
• The turgor pressure of guard cells regulates the opening and closing of stomatal pores.
• The stomatal pores are open when guard cells are turgid due to absorption of water and get closed when guard cells are in flaccid condition due to loss of water.
• Nutrition is a necessity for an organism because it provides energy to perform various metabolic processes in body, is essential for growth of new cells and repair of worn out cells, and is needed to develop resistance against various diseases.
• Stomata allow the loss of water from surface of leaves (transpiration) and allow the exchange of gases i.e., intake of carbon-di-oxide and release of oxygen during photosynthesis.
• Herbivores have longer small intestine to facilitate cellulose digestion.
• Cellulose is not digested by human alimentary canal as there is no digestive enzyme that can act upon cellulose.
• Carnivores have shorter length of small intestine as meat is easily digestible.
• Autotrophic Nutrition involves preparing food by the organism itself, requiring raw material to make food, with chlorophyll for trapping sunlight, and is known as producers.
• Heterotrophic Nutrition involves obtaining food from other organisms, with no raw material required, and is known as consumers.
• If mucus is not secreted by gastric glands, it will lead to the destruction of inner lining of stomach causing acidity and ulcer by HCL.
• A patient in hospital had his gall bladder removed and needs a special diet.
• The diet free from fat would be suitable for the patient whose gall bladder is removed because bile stored in gall bladder helps in the digestion of fat.
• Digestive enzymes help to breakdown large and insoluble food molecules into small water soluble molecules.
• The small intestine is the site of the complete digestion of fats, with the upper part receiving bile juice from bileduct which contains bile salts for breakdown of fats into smaller globules thereby increasing the efficiency of the enzyme action, a process known as emulsification.
• Bile also makes medium alkaline so that pancreatic lipase further converts fats into fatty acids and glycerol.
• The walls of small intestine also secrete intestinal juice containing enzyme called lipase that finally convert the fats into fatty acids and glycerol, thus completing fat digestion.
• Maximum absorption of digested food occurs in small intestine due to the following reasons: Digestion is completed in small intestine, inner lining of small intestine is provided with villi which increases the surface area for better absorption, and wall of intestine is richly supplied with blood vessels which take the absorbed food to each and every cell.
• Aerobic Respiration occurs in presence of oxygen, energy is released in large amount (38 ATP), and is most common in plants and animals.
• Anaerobic respiration occurs in absence or lack of oxygen, energy is released in relatively small amount (2 ATP), and is common in anaerobic bacteria and yeast.
• ATP (Adenosine Triphosphate) is the energy currency of cell as it provides energy for doing functions of cells and other organs, it is produced in mitochondria of cell during respiration in the living organisms.
• Haemoglobin efficiently binds with O2 and transports to various parts of body.
• Deficiency of haemoglobin is referred to as anaemia.
• The consequences of such condition is that blood is unable to carry O2 required by body for respiration and produce energy.
• In anaemia, the person feels weak, skin becomes pale, etc.
• Lallu Problem (L.P.) : Why is it necessary to separate oxygenated and de oxygenated blood in mammals and birds?
• Mammals and birds are warm blooded and need energy constantly to maintain their body temperature.
• It is important that their oxygenated blood should not get mixed with deoxygenated blood in order to make circulatory system more efficient.
• The component of transport system in human are Heart- It pumps and receives blood.