Gaseous exchange in insects e.g., grasshopper takes place across a system of tubes penetrating into the body known as the tracheal system. The main trachea communicate with atmosphere through tiny pores called spiracles. Spiracles are located at the sides of body segments; Two pairs on the thoracic segments and eight pairs on the sides of […]
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GASEOUS EXCHANGE IN ANIMALS All animals take in oxygen for oxidation of organic compounds to provide energy for cellular activities. The carbon (IV) oxide produced as a by-product is harmful to cells and has to be constantly removed from the body. Most animals have structures that are adapted for taking in oxygen and for removal
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GASEOUS EXCHANGE IN LEAVES OF TERRESTRIAL PLANTS Gaseous exchange takes place by diffusion. The structure of the leaf is adapted for gaseous exchange by having intercellular spaces that are filled. These are many and large in the spongy mesophyll. When stomata are open, carbon(IV)oxide from the atmosphere diffuses into the substomatal air chambers. From here,
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AQUATIC PLANT STEMS The water lily, Salvia and Wolfia whose stems remain in water are permeable to air and water. Oxygen dissolved in the water diffuses through the stem into the cells and carbon (IV) oxide diffuses out into the water. Gaseous Exchange in Roots Terrestrial Plants Gaseous exchange occurs in the root hair
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GASEOUS EXCHANGE IN PLANTS AND ANIMALS Necessity for Gaseous Exchange in Living Organisms Living organisms require energy to perform cellular activities. The energy comes from breakdown of food in respiration. Carbon (IV) oxide is a by-product of respiration and its accumulation in cells is harmful which has to be removed. Most organisms use oxygen for
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GASEOUS EXCHANGE IN PLANTS Oxygen is required by plants for the production of energy for cellular activities. Carbon (IV) oxide is required as a raw material for the synthesis of complex organic substances. Oxygen and carbon (IV) oxide are obtained from the atmosphere in the case of terrestrial plants and from the surrounding water in
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Making of beer and wines. Ethanol in beer comes from fermentation of sugar (maltose) in germinating barley seeds. Sugar in fruits is broken down anaerobically to produce ethanol in wines. In the dairy industry, bacterial fermentation occurs in the production of several dairy products such as cheese, butter and yoghurt. In production of organic acids
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SUBSTRATES FOR RESPIRATION Carbohydrate, mainly glucose is the main substrate inside cells. Lipids i.e. fatty acids and glycerol are also used. Fatty acids are used when the carbohydrates are exhausted. A molecule of lipid yields much more energy than a molecule of glucose. Proteins are not normally used for respiration. However during starvation they are
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COMPARISON BETWEEN ENERGY OUTPUT IN AEROBIC AND ANAEROBIC RESPIRATION Aerobic respiration results in the formation of simple inorganic molecules, water and carbon (Iv) oxide as the by¬products. These cannot be broken down further. A lot of energy is produced. When a molecule of glucose is broken down in the presence of oxygen, 2880 KJ of
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BIOLOGY PRACTICAL ACTIVITIES To Show the Gas Produced When the Food is burned A little food substance e.g., maize flour or meat is placed inside a boiling tube. The boiling tube is stoppered using a rubber bung connected to a delivery tube inserted into a test-tube with limewater. The food is heated strongly to bum.
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MEANING AND SIGNIFICANCE OF RESPIRATION Respiration is the process by which energy is liberated from organic compounds such as glucose. It is one of the most important characteristics of living organisms. Energy is expended (used) whenever an organism exhibits characteristics of life, such as feeding, excretion and movement. Respiration occurs all the time and if
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ALLERGIC REACTIONS An allergy is a hypersensitive reaction to an antigen by the body. The antibody reacts with the antigen violently. People with allergies are oversensitive to foreign materials like dust, pollen grains, some foods, some drugs and some air pollutants. Allergic reactions lead to production of histamine by the body. Histamine causes swelling and
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IMPORTANCE OF VACCINATION A vaccine is made of attenuated, dead or non¬virulent micro-organism that stimulate cells in the immune system to recognise and attack disease causing agent through production of antibodies. Vaccination protects individuals from infections of many diseases like smallpox, tuberculosis and poliomyelitis. Diseases like smallpox, tuberculosis and tetanus were killer diseases but this
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ABO BLOOD GROUPS There are four types of blood groups in human beings: A, B, AB and O. These are based on types of proteins on the cell membrane of red blood cells. There are two types of proteins denoted by the letters A and B which are antigens. In the plasma are antibodies specific
IMMUNE RESPONSES Immune response is the production of antibodies in response to antigens. An antigen is any foreign material or organism that is introduced into the body and causes the production of antibodies. Antigens are protein in nature. An antibody is a protein whose structure is complementary to the antigen. This means that a specific
STRUCTURE AND FUNCTION OF BLOOD Composition of Blood The mammalian blood is made up of fluid medium called plasma with substances dissolved in it. Cellular components suspended in plasma include; Erythrocytes (red blood cells), Leucocytes (white blood cells) Thrombocytes (platelets) Blood proteins. Plasma This is a pale yellow fluid consisting of 90% water. There
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TRANSPIRATION Transpiration is the process by which plants lose water in the form of water vapour into the atmosphere. Water is lost through stomata, cuticle and lenticels. Stomatal transpiration: This accounts for 80-90% of the total transpiration in plants. Stomata are found on the leaves. Cuticular transpiration: The cuticle is found on the leaves,
INTRODUCTION TO TRANSPORTATION Transport is the movement of substances within an organism. All living cells require oxygen and food for various metabolic processes. These substances must be transported to the cells. Metabolic processes in the cells produce excretory products which should be eliminated before they accumulate. The excretory products should be transported to sites of
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DIGESTIVE SYSTEM AND DIGESTION IN HUMANS Organs that are involved with feeding in humans constitute the digestive system Digestive System and Associated Glands Human digestive system starts at the mouth and ends at the anus. This is the alimentary canal. Digestion takes place inside the lumen of the alimentary canal. The epithelial wall that faces the
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OBESITY What is Obesity? Obesity is a condition whereby one takes in excess calories than the body requires. The excess calories are converted into fat and stored under the skin and around vital internal organs. Obesity is caused by: Excess intake of carbohydrates and fats. Lack of adequate exercise. Eating junk food. Sedentary lifestyles.