Respiration

Free Energy Is Released and Incorporated into a Form (ATP) that can Be Readily Used for the Maintenance and Development of the Plant cell

Definition Oxidation of Carbohydrates Carried out by Enzymes and Living Systems Net Reaction Appears as the Reverse of PS The individual reactions that occur to achieve the net effect are entirely different

Cells Net Chemical Reaction C 6 H 12 O O ADP + 40 Phosphates 6 CO H 2 O + 40 ATP

Respiration Means to Turn Carbohydrates into Usable Chemical energy (ATP) for many other Plant Reactions including Photosynthesis All Living Plant and Animal Cells Carry out Respiration Respiration Occurs At same Time as Photosynthesis During the Night In Developing and Ripening Fruit In Dormant Seeds

Where does it occure ? Occurs in Mitochondria of Cells Mitochondria are membrane-enclosed organelles distributed through the cytosol of most eukaryotic cells. Their main function is the conversion of the potential energy of food molecules into ATP

Aerobic respiration Requires Oxygen Main Type of Respiration that Occurs in most Situations in Plants and Animals Involves Complete Breakdown of Glucose back to CO 2 and Water

Main steps of respiration Glucose Pyruvate Acetyl Co A GlycolysisATP NADH Glycolysis

Acetyl Co A Citric Acid cycle Co A 2 CO 2 8 e - Oxidative phosphorylation ATP TCA cycle

Anaerobic respiration

Fermentation Occurs in Low-Oxygen Environments Wet or Compacted Soils for Plants After Strong Exertion for Animals ATP Is still Produced from Glucose but not as Efficiently as with Aerobic Respiration Glucose + Oxygen →2 Ethanol + 2 Water + 2 ATP

Factors Affecting Respiration Kind of Cell or Tissue Young and Developing Cells (Meristematic Areas) usually Have Higher Respiration Rates Developing and Ripening Fruit and Seeds, too Older Cells and Structural Cells Respire at Lower Rates

Temperature Respiration generally Has Higher Optimum and Maximum Temps than PS Can Have Net Dry Matter Loss at High Temps where Respiration Exceeds PS Temp Refers to Temp Inside Plant or Animal Cell, not Air Temp Using Irrigation to Help Cool the Plant Can Keep the Plant in Net Gain Range

Oxygen Low O 2 Can Reduce Aerobic Respiration and Increase Anaerobic Respiration Low O 2 Can Reduce Photorespiration Light Can Enhance Rate of Photorespiration Does not Directly Affect other Forms of Respiration

Glucose Adequate Glucose Needed to Carry out Respiration CO2 Higher CO 2 Levels Reduce Rate of Respiration Feedback Inhibition ATP Higher [ATP] Reduces Rate of Respiration Feedback Inhibition

Plant Injury Injury will Increase respiration, Plant’s Growth Rate Increases in Attempt to Recover Plant Synthesizes Compounds to Fight Pests Diseases Some Herbicides Kill Plants by Disrupting or Affecting Respiration