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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 (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
Respiration Process that releases chemical energy
from food
Occurs in ALL cells
Reactantsglucose, oxygen
Productscarbon dioxide, energy, water
Photosynthesis Process that converts radiant solar energy
into chemical energy stored in organic molecules
Occurs in cells of autotrophs
Reactantscarbon dioxide, water, light
Productscarbohydrates, 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)
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
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
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)