Cellular Respiration and Photosynthesis

ATP Adenosine Triphosphate Main energy source for animal cells Energy is stored in the bonds between phosphate atoms Give off LOTS of energy when broken!

ATP ATP is made from ADP A new phosphate gets added to ADP to make ATP Enzymes catalyze these reactions ATPase: breaks down ATP ATP synthase: makes ATP from ADP The ATP and ADP molecules get reused over and over again BUT energy does NOT get reused.

Cell Respiration Energy stored in glucose is released through a process called Cell Respiration. This occurs in all living organisms. Two types of Cell Respiration: Aerobic – requires O2 Anaerobic – Does not require O2

C6H12O6 + O2  CO2 + H2O + ATP + Heat Cellular Respiration The process of transferring the energy in carbohydrates into a useable form of energy for the cell (ATP) Occurs in the cytoplasm and mitochondria of Autotrophs and Heterotrophs C6H12O6 + O2  CO2 + H2O + ATP + Heat

Cellular Respiration Three phases Glycolysis Anaerobic Citric Acid Cycle (Krebs Cycle) Aerobic Electron Transport Chain

Phase I: Glycolysis Anaerobic: does NOT require O2 Occurs in the cytoplasm Series of chemical reactions that break down one glucose into two sugar molecules Produces 4 ATP molecules But it takes 2 to get the reaction started for a net production of TWO ATP!

Phase II: Citric Acid Cycle Also known as Krebs Cycle Aerobic: requires O2 Occurs in the mitochondria Glucose is broken down even further Products: 2 ATP and CO2

Phase III: Electron Transport Chain Aerobic: requires O2 Occurs in mitochondria inner membrane Electrons from CAC pass thru a chain of proteins Products: 32 ATP and H2O

Fermentation After glycolysis, if no O2 then fermentation occurs Fermentation is an ANAEROBIC process! Allows cell to continue using glycolysis to generate ATP 2 kinds of Fermentation Lactic Acid Fermentation Alcoholic Fermentation

Fermentation Lactic Acid Fermentation Alcoholic Fermentation In animals and some bacteria Results in the production of lactic acid If too much builds up, can result in muscle soreness Alcoholic Fermentation Yeasts, plants Used in bread and alcohol manufacturing

Fermentation Lactic Acid Fermentation Alcoholic Fermentation Bacteria in a closed container of milk are in an anaerobic environment so they use fermentation to make ATP and the lactic acid produced curdles the milk. This is what produces cheese, yogurt, sour cream, and cottage cheese. Alcoholic Fermentation Yeasts in bread dough are also in anaerobic environment. CO2 gas is produced as a by product and is what makes dough rise. Alcohol evaporates out of bread during baking.

32 ATP

Total: Aerobic Respiration Total: Anaerobic Respiration Energy Summary (number of ATP molecules formed in each step of respiration) Glycolysis 2 ATP Kreb’s cycle Electron Transport 32 ATP Total: Aerobic Respiration 36 ATP Glycolysis 2 ATP Fermentation 0 ATP Total: Anaerobic Respiration

Photosynthesis CO2 + H20 + Light  C6H12O6 + O2 Meaning “making with light” Photosynthesis is the process of converting the sun’s light energy into stored carbohydrates (glucose) Takes place in in the chloroplasts of autotrophs The green pigment chlorophyll is required for photosynthesis CO2 + H20 + Light  C6H12O6 + O2

Chemical Reactions Two phases Light Dependent Reactions Turns light energy into ATP Light Independent Reactions Conversion of CO2 into Glucose

Light Dependent Reactions Light energy transfers to electrons in chlorophyll Excited electrons pass through a chain of proteins electrons loose energy at each step, creating ATP H20 is split to replace electrons Gives off O2

Light Independent Reactions Also known as the Calvin Cycle DON’T CONFUSE WITH KREBS CYCLE!!! Series of reactions that use ATP to convert CO2 into Glucose LOTS of enzymes used That Mrs. Ball is nice enough to NOT make you know!