Chapter #6 and 7 Photosynthesis and Cellular Respiration

The Need For Energy Heterotrophs get energy from food Heterotrophs require energy for all of life’s processes -digest food -grow -maintenance -repair -synthesis

ENERGY All energy ultimately comes from the sun Autotrophs -producers Heterotrophs -consumers

ENERGY (2) Photosynthesis -stores the energy Respiration -releases the energy Both photosynthesis and respiration have an ATP-ADP Cycle -provides the energy to the cells

ATP Adenosine Triphosphate Components: -adenine, ribose, 3 phosphates Phosphorylation: -process of freeing a phosate from ATP (enzyme ATPase) making ADP -ATP synthetase then reattaches the phosphate group making ATP

ATP-ADP Cycle

Respiration Process that releases chemical energy from food Occurs in ALL cells Reactants glucose, oxygen Products carbon dioxide, energy, water

Photosynthesis Process that converts radiant solar energy into chemical energy stored in organic molecules Occurs in cells of autotrophs Reactants carbon dioxide, water, light Products carbohydrates, oxygen

Basis of Photosynthesis Absorption of Sunlight Light Dependent Reactions Light Independent Reactions (Calvin-Benson Cycle) (all occurs within the chloroplast)

Chloroplast Chlorophyll -light absorbing pigments 3 membrane system -granum (stacks of thylakoid) -stroma (fluid) -increases the surface area for light absorption

Light Dependent Reactions Occurs in the Thylakoids (grana) First Stage -convert light to electrical energy using electron transport chain (photosystem I) -uses water, releases oxygen Second Stage -convert electrical energy to chemical energy (ATP) (phtotsystem II)

Light Independent Reactions (Calvin-Benson Cycle) CO2 and ATP enter the stroma Binds to RuBP(5 carbon molecule) RuBP splits into PGAL (3 carbon sugar made with the addition of Hydrogen from NADPH and ATP) PGAL generates 1 glucose and regenerates RuBP to start the cycle over again Completes 6 turns to get glucose (6 carbon sugar)

Alternative Pathways C4 (corn, sugarcane, crabgrass) -more efficient at fixing carbon to form sugars CAM (desert plants) -close stomata during the day to prevent water loss -trap carbon dioxide for the Calvin-Benson Cycle at night

Cellular Respiration Aerobic -in the presence of oxygen Anaerobic -occurs when oxygen is not present -causes fermentation (alcoholic and lactic acid)

Three Parts of Cellular Respiration… Glycolysis Kreb’s Cycle Electron Transport Chain

Three Parts of Cellular Respiration… Glycolysis Kreb’s Cycle Electron Transport Chain

GLYCOLYSIS Occurs in the cytoplasm Turns glucose into pyruvic acid Net 2 ATP -4 are made and two are used 2 NADH -electron carrier to be used during the last step of respiration

KREB’S CYCLE Pyruvic acid turns into Acetyl-CoA -Produces 2 NADH Enters the mitochondria Produces -2 ATP -2 FADH2 -6 NADH

Products so far… 4 ATP 10 NADH 2 FADH2

Electron Transport Chain 2 FADH2 and 10 NADH enter the ETC 1 FADH2 yields 2 ATP 1 NADH yields 3 ATP Total -4 ATP from FADH2 -30 ATP from NADH

How many ATP from respiration? 38 ATP TOTAL

Fermentation Occurs in the cytoplasm Lactic Acid -muscle cells Alcoholic -Yeasts -Bacteria

Anaerobic Respiration Respiration w/o oxygen Glycolysis Glucose broken down to pyruvic acid (2ATP) Oxygen is needed for pyruvic acid to enter the mitochondria so the process stops Pyruvic Acid breaks down to Lactic Acid (animals) Pyruvic Acid breaks down to Alcohol (yeast)

CHROMATOGRAPHY