Page 1 :
._ io Bae &€, , , , , , , , , , , 1, Characteristics of Plant Respiration, , @ All living organisms need energy for carrying out daily life activities like transport, movement,, absorption, reproduction as well as breathing., , @ All the energy required for these activities is obtained by oxidation of some macromolecules, which are components of food,, , @ Blue green algae and all green plants synthesize their food through photosynthesis. However, not all parts of green plants perform photoynthesis., , e Hence. even in green plants, all other organs, tissues and cells that are non-green need food for, oxidation. Hence, food has to be translocated to all non-green parts., , e All animals are heterotrophic and obtain food directly or indirectly from plants., Saprophytes like fungi obtain food from dead and decaying matter., Ulumately all the food that is respired by various organisms for life processes comes from, photosynthesis., , e@ The mechanism of breakdown of food materials through oxidation within the cells leading to, release of energy is called respiration., , e The compounds that get oxidized during respiration are respiratory substrate. Usually, it is, carbohydrate but proteins, fats and even organic acids can be used as respiratory substrate., , e The energy contained within a respiratory substrate is released in a slow step-wise reactions, controlled by enzymes and it is trapped as chemical energy in the form of ATP., , e The energy released by oxidation in respiration is not used directly but is used to synthesize, ATP which is broken down whenever energy needs to be utilized., , ATP is the energy currency of the cell., , The energy trapped in ATP is utilized in various energy requiring activities of the organisms, and the carbon skeleton produced during respiration is used as precursors for biosynthesis of, other molecules in the cell., , Plants do not breathe as animals do but they possess efficient mechanism for gaseous exchange., Plants possess stomata and lenticels for the purpose of gaseous exchange but they lack specialized, respiratory organ as found in animals., , e Plants do not require the development of respiratory organ because of following reasons:, (Q) Each plant part takes care of its own gas-exchange needs., (a) There is very little transport of gases from one plant part to another., (ui) Roots, stem and leaves respire at rate lower than animals do, hence plants do not present, great demand for gas-exchange., () The distance that gases must diffuse even in large bulky plants is not great. Each living cell, of the plant is located quite close to the surface of the plant., , e During respiration, complete combustion of glucose takes place resulting into production of, CO, and H,O as end products. The energy released is mostly given out as heat as shown in, following equation:, , C,H,,O, + 60, —— 6CO, + 6H,O + Energy, , , , Respiration in Plants | 41