Presentation on theme: "A Lecture Presented by: Mrs. Knopke FUHS Science Dept."— Presentation transcript:
A Lecture Presented by: Mrs. Knopke FUHS Science Dept.
6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O + 36 ATP This equation summarizes all of the chemical reactions that occur during the process of cellular respiration Notice that it is the same equation as photosynthesis in reverse Although proteins, lipids and other carbohydrates can be used to make ATP we use a common source: glucose.
Reduction: gaining electrons, hydrogen or losing oxygen Oxidation: Losing electrons, hydrogen or gaining oxygen Redox (reduction / oxidation) reactions: gain or release chemical energy in a reaction NAD and FAD: electron hydrogen carrier. Carries them to the Electron Transport chain. When carrying they are called NADH and FADH
Review: Oxidation and Reduction Oxidized atom Electron is donated Energy is donated Reduced atom Electron is received Energy is received
Review: Oxidation and Reduction Reduced atom Electron is received Energy is received Oxidized atom Electron is donated Energy is donated
Why Cellular Respiration? Cells carry out the reactions of cellular respiration in order to produce ATP. ATP is used by cells for energy All organisms need energy, therefore all organisms carry out cellular respiration. The energy needed to produce ATP comes from glucose. As we saw in the previous slides on Photosynthesis were glucose was produced. 6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O + 36 ATP The reverse of Photosynthesis
Introduction –Cars and humans need fuel –Chemical energy used to perform work –Hunger is adaptation to refuel Fuel for living –All energy comes from the sun –Plants convert solar energy into chemical energy Sunlight energy –Sun - a giant thermonuclear reactor –Photosynthesis - solar to chemical Comparing Cellular respiration with how a car works!
Phosphorylation: Phosphorylation: adding a phosphate group to a molecule Substrate-level phosphorylation: Organic molecule is split or used in conjunction with an enzyme to add a phosphate to ADP to make ATP Oxidative phosphorylation: Occurs by using an electron transport chain, chemiosomosis and ATP synthase to add a phosphate group
The Mitochondria 2 layers of phospholipid Membrane This is where ATP is manufactured!
Cells and cars use same basic process –Using potential energy to do work –Breaks bonds to release energy Cars mix gas with O 2 to cause explosion which moves pistons –25% of potential energy converted to kinetic energy –CO 2 and H 2 O released Cells do it less explosively –More efficient - 40% potential energy –60% released as heat energy
Why do you feel warm in a room at 70 degrees when body temp is 98.6? Produce heat from cellular respiration Calorie -1 gram water 1 degree Celsius Kilocalorie calories –Food calories determined by burning food –Measuring how much heat produced Living organisms use food to make ATP TPAdenosine TriPhosphate –Three phosphates have stored energy
ATP used continuously Recycled continuously –By addition of phosphate group to ADP –Cell respiration used to make ATP –Working muscle cell recycles 10 million per second per cell!
Cellular respiration and breathing related but not the same Breathing in lungs –Intake of O 2 –Release of CO 2 Cellular respiration –O 2 diffuses into cells –CO 2 diffuses out of cells –O 2 used to burn food fuel to make ATP Glucose is common food / fuel C 6 H 12 O 6 + 6O 2 > > > 6CO 2 + 6H 2 O + ATP
Purpose of cellular respiration? To release energy from food molecules and make ATP! Why do we need ATP? To run chemical reactions that keep us alive and functioning.
The 4 major steps of Cellular Respiration and their locations 1) Glycolysis: occurs in cytoplasm 2) Pyruvate oxidation : at mitochondrian outer membrane 3) Kreb’s Cycle: mitochondrian matrix 4) Electron Transport Chain: inner membrane of mitochondria
STEP #1 Glycolysis
1) Cell Resp. needs an initial 2 molecules of ATP to start 2) 2 PGALs are intermediate products 3) 4 NADH, and 4 ATP are produced 4) 2 Net total of ATP 5) 2 pyruvic acids are the end products 6) Oxidative reactions
STEP #2 Pyruvate Oxidation
Pyruvate from Glycolysis tries to get into Mitochondria Too big, must remove a CO 2 to fit CO 2 released into atmosphere NAD takes H’s and e- to E.T.C. Process uses up 2 ATP Acetic acid is the end product pyruvate CO 2 NAD NADH NAD 2 acetic acid molecules
Pyruvate needs to get into mitochondria!
STEP #3 Kreb’s Cycle or Citric Acid Cycle
Kreb’s Cycle = Citric Acid Cycle 2 Acetic Acid molecules imediately bind to a coenzyme called CoA thus making : AcetylCoA Oxalacetate is the sugar backbone Citric Acid is a intermediate product Glucose is obliterated and no carbon is left 2 acetyl CoA CO 2 ADP ATP NAD NADH FAD FADH
STEP #4 Electron Transport Chain
Where are all of the FADH, NADH carriers going? Why did we make them? 1) To the electron transport chain!! 2) To make ATP O2O2O2O2
36 ATP is the net total 2 ATP in Glycolysis 2 lost in Pyruvate Oxidation 3 ATP per NADH in ETC 2 ATP per FADH in ETC 4 NADH in Glycolysis 2 NADH in Pyruvate Oxidation 4 NADH in Kreb’s Cycle 3 FADH in Kreb’s Cycle
Fermentation or anaerobic respiration –Defined as harvesting energy w/out O 2 Occurs when O 2 supply to cells can’t keep up with demand Spending more ATP than can be generated by aerobic respiration Glycolysis still runs but Krebs cycle can’t –How much ATP does glycolysis make? –Not much compared to aerobic respiration
What if there is no oxygen to drive the electron transport chain in cellular respiration? Organisms still need ATP to survive! The Answer: Anaerobic Respiration Fermentation
Fermentation: A type of anaerobic respiration
Lactic Acid: In our muscles Alcoholic: In yeast cells
–Animals use this anaerobic process –Get some ATP profit –NADH is recycled to NAD+ To keep glycolysis running –End product lactic acid Makes muscles sore –Only a short term solution –Lactic acid converted back to pyruvic acid in liver cells when O 2 is available –Oxygen debt repaid by breathing hard Lactic acid Fermentation
Yeast cells can do –Aerobic (w/oxygen) respiration or –Anaerobic (w/out oxygen) respiration In an anaerobic environment –Forced to ferment sugars –Produces ethyl alcohol instead of lactic acid –Releases CO 2 Makes alcohol bubbly Makes bread rise Fungi and bacteria can cause –Fermentation of milk to yogurt and cheese –Lactic acid gives them distinctive taste Alcoholic Fermentation