Cellular Respiration
So exactly how much energy does photosynthesis capture? THE gummy bear Video
Energy Energy in general comes in many forms, including light, heat, and electricity. It is also stored in things like food and batteries. Energy cannot be created or destroyed, but it can change forms and be stored Cells use food energy to charge special cell “batteries” called ATP
Cell Energy = Adenosine triphosphate (ATP) ATP is the chemical compound that cells use for energy (like a battery) Modified nucleic acid Contains: - adenine (modified piece of DNA) - ribose (sugar) - 3 phosphates
“Dead Battery ATP” = Adenosine diphosphate (ADP) ATP is rechargeable! ADP forms when a “P” is broken off ATP to release energy. ADP can be recharged by using food energy to reconnect the P.
ATP Reminder: cells use ATP for active transport, homeostasis, and any movement ATP powers the cell and keeps you alive!
Respiration ATP is recharged by Respiration a single carbohydrate glucose (sugar) contains enough energy to recharge 90 ATP (but you never get that much out of it).
Cellular Respiration Equation Equation: (pick one to memorize) 6O2 + C6H12O6 → 6CO2 + 6H2O + energy (ATP) oxygen + glucose → carbon dioxide + water + ATP MEMORIZE THIS! (Does it look familiar?!)
Photosynthesis and Respiration together make the Carbon cycle. YES! Respiration is the exact opposite of photosynthesis! Photosynthesis: 6CO2 + 6H2O + energy → 6O2 + C6H12O6 Respiration: 6O2 + C6H12O6 → 6CO2 + 6H2O + energy Photosynthesis and Respiration together make the Carbon cycle.
Respiration ALL cells (including plants) use respiration to recharge their ATP Respiration reverses the work of photosynthesis. It uses oxygen to break down a sugar, releasing CO2 and water as waste Two types of respiration Aerobic (requires oxygen, takes place in cytoplasm and mitochondria, creates around 36 ATP ) Anaerobic (no oxygen needed, takes place in the cytoplasm only, creates only 2 ATP, uses fermentation)
Respiration Stages Three stages (Aerobic requires all ; anaerobic repeats stage one) 1. Glycolysis (cytoplasm): break glucose in half and charge 2 ATP; no oxygen needed 2. Krebs Cycle (mitochondria): finish the job to turn glucose into CO2 and release energy; requires oxygen; 3. Electron Transport Chain (mitochondria): use the energy from stage 1 and 2 to charge 32-34 ATP; requires oxygen
Overview of Cellular Respiration
Gross vs Net ATP Glycolysis (stage one) occurs first. It does not require oxygen, but it does require a little ATP to start. Glycolysis uses 2 ATP to make 4 ATP, so the GROSS production is 4 ATP, but the NET production = 2 ATP
No Oxygen Needed! Glycolysis is so fast that thousands of ATPs can be produced in a few milliseconds! Some small cells can survive with just glycolysis (ex: bacteria, yeast), and therefore NEVER need oxygen!
After Glycolysis If oxygen is present, then the products of glycolysis move on to the mitochondria for stages 2 and 3. There they will be further broken down to create MUCH more ATP energy.
ATP Totals Glycolysis(anaerobic respiration) makes 2 ATP With O2, Aerobic Respiration (all three stages) makes 36-38 ATP Some energy will be lost as heat and used to maintain body temperature
What if oxygen is NOT present? Respiration is BETTER with Oxygen! Without oxygen, cells have to switch to Anaerobic Respiration which is maintained through Fermentation.
Two Types of Fermentation 1. Alcoholic Fermentation: used by yeast only; produces alcohol and CO2 2. Lactic Acid Fermentation: used by animals/bacteria: produces lactic acid; reason for burning muscles when working out
Anaerobic Respiration Reminder The purpose of both types of fermentation is to keep glycolysis going. Fermentation of any type only makes 2 ATP ATP TOTALS to Memorize! (aerobic) = around 36 ATP (anaerobic) = only 2 ATP
Comparing Photosynthesis & Cellular Respiration function energy capture energy releases location chloroplasts mitochondria reactants CO2 and H2O C6H12O6 and O2 products equation 6CO2 + 6H2O → C6H12O6 + 6O2 C6H12O6 + 6O2 → 6CO2 + 6H2O energy energy