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Photosynthesis and Cellular Respiration. Two ways to get food. “troph” = food Autotrophs Auto = self Autotrophs make their own food Heterotrophs Hetero = different Heterotrophs get their food from something else (they have to eat it). Two ways to get food. Autotrophs Plants
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Two ways to get food • “troph” = food • Autotrophs • Auto = self • Autotrophs make their own food • Heterotrophs • Hetero = different • Heterotrophs get their food from something else (they have to eat it)
Two ways to get food • Autotrophs • Plants • Heterotrophs • Animals
Photosynthesis • Converts the sun’s energy into chemical energy stored in sugar • Takes place in specialized structures inside plant cells called chloroplasts • Chlorophyll is the pigment that absorbs sunlight.
Photosynthesis Reaction • 6CO2 + 6 H2O + light energy → C6H12O6 + 6O2 • The food plants make is called glucose (sugar)
Photosynthesis • 2 different reactions • Light Reactions • Capture light energy for photosynthesis • Calvin Cycle • Produces glucose sugar
Cellular Respiration Breathing Cells
Cellular Respiration • Happens in both plant and animal cells • Overall Reaction: • C6H12O6 + 6O2 → 6CO2 + 6H2O
Cellular Respiration Overview • Depends on whether or not there is oxygen • Aero = oxygen • Aerobic Respiration – makes energy • Anaerobic Respiration – Fermentation (makes alcohol)
Step 1: Glycolysis • The energy that cells make and use is called ATP • Adenosine triphosphate • Glycolysis makes 2 molecules of ATP (energy) • Glycolysis happens in the cytoplasm of the cell
Step 2: Check for Oxygen • If oxygen is present, the cell can make more ATP • If no oxygen is present, the cell has to recycle the pieces from glycolysis and makes alcohol.
Step 3 with oxygen:Cellular Respiration • Oxygen required=aerobic • 2 more sets of reactions which occur the cell’s mitochondria • 1. Kreb’s Cycle – makes 2 ATP • Also called the Citric Acid Cycle • 2. Electron Transport Chain – makes 32-34 ATP
Step 3 without oxygen: Fermentation • The cell must recycle the materials from glycolysis. • This recycling process is called fermentation. • The product of fermentation is alcohol.
Energy Tally • 36 ATP for aerobic vs. 2 ATP for anaerobic • Glycolysis 2 ATP • Kreb’s 2 ATP • Electron Transport 32 ATP 36 ATP • Anaerobic organisms can’t be too energetic but are important for global recycling of carbon