Photosynthesis and Photosynthesis and Cellular Cellular Respiration Respiration
Mar 27, 2015
Photosynthesis and Photosynthesis and Cellular RespirationCellular 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
Heterotrophs– Animals
Photosynthesis
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
Cells Breathing
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
Kreb’s Cycle (Citric Acid Cycle)
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