General Botany Plant Physiology PDF

Osmosis Colloids Enzymes Metabolism (Respiration & Photosynthesis)  Water relation Water is the major constituents of plant protoplasm Water is the solvent for dissolving minerals and help in movement of minerals from soil to plant and within plants cells in a tissue or organs. Wa...

Osmosis Colloids Enzymes Metabolism (Respiration & Photosynthesis)  Water relation Water is the major constituents of plant protoplasm Water is the solvent for dissolving minerals and help in movement of minerals from soil to plant and within plants cells in a tissue or organs. Water is the medium of metabolic reaction and cellular activities Water act as vital reactant in various metabolic reactions In photosynthesis, water is the source of hydrogen which is incorporated into organic compounds. It is the main factor for cell turgidity which maintains their form and structure. It is the metabolic end product of respiration. Water involve in many physiological processes such as transpiration, opening and closing of stomata and opening and closing of flowers.  Diffusion Diffusion is movement of molecules , ions or particles from an area of high concentration to an area of low concentration till equilibrium. The diffusion of particles of one substance is independent of the diffusion of other substances Factors affecting diffusion Temperature Pressure Concentration gradient  Osmosis Osmosis is the movement of water molecules from a hypotonic solution to a hypertonic solution through a semi-permeable membrane Types of membrane ? What is the origin of osmotic potential? What is the importance of osmosis to the plant ?  Osmosis takes place from hypotonic (of low conc ) to hypertonic (of high conc ) soltion  Determination of Osmosis through thistle funnel  Water potential Osmosis depends on movement of solvent molecule (water ) So water potential play the key role affecting osmosis. Water potential is the free energy of per mole of water. Components of water potential Ψw = Ψp + Ψs + Ψm Where Ψp pressure potential Ψs osmotic potential Ψm matric potential The relation between wp components and relative cell volume  It is the system which consist of two phases dispersion medium (dominant ) and dispersed phase Dispersed phase are not single atoms but are aggregating particles (micelles)  Preparation of a colloidal system Condensation methods Dispersion methods A) Double decomposition A) Grinding As2O3 + H2S B) Peptization As2S3+ 3H2O C) Emulsification B) Hydrolysis Fe Cl3 + 3 H2O Fe(OH)3 + 3 H Cl  Types of colloidal systems Lyophobic Lyophilic e.g. Clay in water e.g. Starch in water Stability of colloidal systems is due to Similar electric charge Presence of water film  Colloidal properties of protoplasm Filterability Colloids can pass through ordinary filter paper But can not pass through ultrafilters Dialysis : Separation of colloids from crystalloids through semipermeable membrane Precipitation Addition of electrolytes Salting out  Adsorption It is a surface attraction force Mechanical adsorption : MB-charcoal Chemical adsorption : iodine-starch Electric adsorption : MB-filter paper  Tyndall phenomenon Appearance of the pass of light beams through colloidal system When a beam of light passes through a colloid, the colloidal particles present in the solution do not allow the beam to completely pass through. The light collides with the colloidal particles and is scattered (it deviates from its normal trajectory, which is a straight line). This scattering makes the path of the light beam visible  Brownian movement Continuous movement of cytoplasm due to continuous repulsion and collisions Electric properties Electric double layer Isoelectric point it is pH value at which the particles lose their charges and precipitate  Imbibition It is an intermolecular attraction between solid and liquid affected by environmental factors such as temperature and pH. Depends on the nature and amount of dry matters Application : germination of seeds  Enzymes Biocatalyst : catalyze biological reactions inside the cell Properties of enzymes *they are protein in nature * they have high specificity *they have high turnover number (N substrate/E/min.) * It decrease the activation energy of reaction E + S E-S complex E +P Enzyme Structure simple conjugated Apoprotein Conjugated portion coenzyme Prosthetic group  Classes of enzymes according to type of reaction Oxidoreductase Transferase Hydrolase Lyase Isomerase Ligase  Nomenclature of enzymes Old nomenclature Recent nomenclature Scientist name generic nomenclature systemic nomenclature Descriptive name EC nomenclature  EC nomenclature Each enzyme has four-digit number The first : class of the enzyme The second : Subclass of the enzyme describe the target action The third : Sub sub class of the enzyme describe the mechanism The fourth : the product formed Oxidoreductase )Catechol oxidase( Hydrolase Lyase Isomerase Ligase  Factors affecting enzyme activity Temperature pH Water content  Factors affecting enzyme activity Enzyme concentration Substrate concentration * Km constant  Inhibitors Non-Competetive inhibitors Competetive inhibitors  Respiration Types of respiration Presence of oxygen aerobic bacterial Abesence of oxygen anaerobic fermentation  Equation of aerobic respiration C6H12O6 + 6O2 6CO2 +6H2O + 38 ATP Equation of bacterial respiration 2NH3 + 3O2 2H2O + E + 2HNO2 2HNO2 + O2 E + 2HNO3 2H2S + O2 2H2O + E + 2S S +2H2O + 3O2 E + 2H2SO4 Equation of anaerobic respiration C6H12O6 2CO2 + 2C2H5OH + 8ATP Glycolysis Formation of acetyl coA Kerbs cycle Electron transport chain Energy output 38 ATP Glycolysis 8 ATP Kerbs cycle 30 ATP GTP / ATP ---------- 1 FADH2 ---------- 2 ATP NADH + H ------------ 3 ATP  Factors affecting respiration 1.Temperature Oxygen concentration CO2 concentration Water content  Respiratory substrate Carbohydrate Lipids Organic acids protein RQ = Volume of evolved CO2 Volume of consumed Oxgen