Photosynthesis & Cellular Respiration Chapter 9

Energy in Living Systems Organisms require a constant source of energy to maintain HOMEOSTASIS Organisms use and store energy in the chemical bonds of macromolecules Autotrophs (producers) make their own food Heterotrophs (consumers) get their food from eating autotrophs Glucose

Metabolism Involves either Using energy to build macromolecules Breaking down macromolecules to release the energy stored in their bonds Enzymes (remember those…) allow the “building and breaking” of the bonds in macromolecules to occur much FASTER & MORE EASILY

Key Players Chloroplasts Mitochondria Converts light energy into chemical energy Has outer and inner membrane Thylakoids contain the pigment chlorophyll that absorbs light Mostly found in plants Mitochondria Have outer and inner membrane Inner membrane is highly folded to increase surface area (chem. rxns occur here) Found all eukaryotic cells

Energy enters an ecosystem when autotrophs use sunlight during photosynthesis (chloroplasts) to convert CO2 and water molecules into glucose and oxygen. During Cellular respiration, mitochondria break down glucose and oxygen, release ATP (used to power the cell) and make CO2 and water The Cycle

Draw the Diagram that Follows

Mitochondrion Chloroplast ATP Carbon Dioxide & Water Mitochondrion Chloroplast Glucose & Oxygen Photosynthesis Respiration

You MUST memorize these! Equations: You MUST memorize these! Photosynthesis: Sunlight + 6CO2 + 6H2O = C6H12O6 + 6O2 + ATP Cellular Respiration: C6H12O6 + 6O2 = 6CO2 + 6H2O

Anaerobic Respiration Cellular respiration can be with (aerobic) or without (anaerobic) oxygen In the absence of oxygen, some organisms can go through a process called fermentation Lactic Acid fermentation can occur in the muscles of animals during vigorous exercise