* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Cell Respiration SAT II Review
Butyric acid wikipedia , lookup
Lactate dehydrogenase wikipedia , lookup
Mitochondrion wikipedia , lookup
Metalloprotein wikipedia , lookup
Phosphorylation wikipedia , lookup
Basal metabolic rate wikipedia , lookup
Nicotinamide adenine dinucleotide wikipedia , lookup
Photosynthesis wikipedia , lookup
NADH:ubiquinone oxidoreductase (H+-translocating) wikipedia , lookup
Photosynthetic reaction centre wikipedia , lookup
Light-dependent reactions wikipedia , lookup
Electron transport chain wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Adenosine triphosphate wikipedia , lookup
Biochemistry wikipedia , lookup
Microbial metabolism wikipedia , lookup
Cellular Respiration ● Cellular Respiration is the process of converting food energy into ATP energy (i.e. – the controlled release of energy from organic compounds in cells to form ATP): C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + 36 ATP The Pathway of energy in living organisms cellular Chemical Chemical Light photosynthesis respiration energy for use energy stored energy in the form of in glucose, from the sun ATP fats, or carbohydrates A Heterotroph Must Convert: To ATP in order to perform work (ATP is form of chemical energy that is usable by the cell). What is Cellular Respiration? • The process of converting food energy into ATP energy because organic compounds contain stored (potential) chemical energy in their bonds (the steps of cellular respiration can be traced using glucose as an example ) C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + 36 ATP • ATP is a form of chemical energy and cellular enzymes can easily make use of this energy source (when that energy is released, cells can use it for metabolism) • All living organisms must perform cellular respiration (plants and animals) to get ATP. Cell Respiration “Big Picture” Cellular Respiration – The Big Idea Glycolysis is the first step in cellular respiration Two types of cellular respiration: Aerobic (uses oxygen) and anaerobic (without oxygen) Two types of anaerobic respiration: Lactic acid fermentation (humans) and alcoholic fermentation (yeast) Glycolysis “Big Picture” Glycolysis “Big Picture” Flower Warm-up Glycolysis “Big Picture” consists of two major phases “Big” Overview of Glycolysis A closer look at the energy investment phase A closer look at the energy payoff (yielding) phase The Link Reaction - A Segue To the Mitochondrion Link Reaction “Big Picture” Oxidation of Pyruvate /Link Reaction • When Oxygen is present, the 2 Pyruvates are translocated to the matrix of the mitochondrion where they are converted into 2 Acetyl CoA (C2). • Each Pyruvate releases CO2 (decarboxylation) to form Acetate. • The Acetate is oxidized and gives electrons and H+ ions to 2 NAD+ → 2 NADH. • The Acetate is combined with Coenzyme A to produce 2 Acetyl CoA molecules. – Next stop is the Kreb’s cycle • 2 NADH’s carry electrons and hydrogens to the Electron Transport Chain. The Link Rxn Krebs Cycle “Big Picture” The Krebs Cycle • Acetyl-CoA will now contribute its acetate, to the starting step of the Krebs cycle for further oxidation. • During this cycle CO2 is released • Substrates are oxidized give electrons and H+ ions to NAD+ → NADH. • For each entering acetate, 3 molecules of NADH are produced. • Another electron acceptor is FAD (flavin adenine dinucleotide) which is reduced to FADH2. This will also pass on electrons (like NADH) to ETC. • After all the steps, the same compound (the starting point, oxaloacetate) is returned, hence a cycle. The Link Rxn The Buzz Terminology Link & Krebs CoA Anaerobic Matrix C4 + C2 → C6 →C5→C4→C4→ Mitochondria Phosphorylation FADH2 SLP Decarboxylation NADH ATP Oxidation What Happens to all the Reduced Coenzymes and Oxygen? • NADH and FADH2 produced earlier, go to the ETC • NADH and FADH2 release electrons to carriers/proteins embedded in the membrane of the cristae. • NADH and FADH2(less energy) both hand over the electrons to ETC, but at different levels. • As the electrons are transferred, H+ ions are pumped from the matrix to the intermembrane space up the concentration gradient. • Electrons are passed along a series of carriers until they are ultimately donated to an Oxygen molecule. ½ O2 + 2 electrons + 2 H+ (from NADH and FADH2) → H2O. • The H+ diffuses down its gradient through channels provided by ATP synthases and the enzyme uses this flow to drive the oxidative phosphorylation of ADP to ATP Electron Transport Chain and Oxidative phosphorylation /ATP synthesis Cell Respiration “Wrap Up” The Buzz Terminology Ox Phos Oxygen ETC Chemiosmosis Inner Membrane space Inner Membrane Phosphorylation NADH ATP FADH2 cristae ATPase Proton pump The account in terms of ATP output Each NADH will result in ~ 3ATPs (except for cytosol derived products), and each FADH2 in ~2 ATPs , through ETC and chemiosmosis. From glycolysis • 2 ATP (SLP) • 2 NADH (ox phos) ATPs 2 6 (4) From Krebs cycle • 8 NADH (ox phos) • 2 FADH2 (ox phos) • 2 ATP (SLP) 24 4 2 After ETC and Chemiosmosis 38 (36) Oxidative phosphorylation will stop in the absence of electronegative oxygen that pulls electrons down the transport chain. Fermentation Overview • An extension of glycolysis • A process in which ATP is produced without the help of oxygen. • Without the electronegative oxygen to pull electrons down the transport chain, oxidative phosphorylation ceases • ATP generated soley by Substrate level phosporylation • Sufficient supply of some oxidizing agent is required (usually, NAD+, which needs to be recycled). • No ETC since there is no oxygen • NAD+ gets recycled by use of an organic hydrogen acceptor forming lactate or ethanol. • Common in prokaryotes and very useful to humans. Fermentation Factoids Two Types of Fermentation • Alcoholic Fermentation – – – – Produces ethyl alcohol and CO2 Yeast/Fungi and some prokaryotes Used to make wine and beer CO2 released by yeast as a byproduct causes bread to rise • Lactic Acid Fermentation – Produces lactic acid when O2 isn’t available – Animals and most bacteria – A build up of lactate in your muscles from over exerting yourself and not taking in enough oxygen causes muscle fatigue (i.e.“rubbery feeling”) and leads to some soreness. Alcohol Fermentation • Pyruvate is converted to ethanol in two steps. • Alcohol fermentation by yeast is used in brewing and winemaking. Lactic Acid Fermentation • Pyruvate is reduced directly by NADH to form lactate • Lactic acid fermentation by some fungi and bacteria is used to make cheese and yogurt • The waste product, lactate, is converted back to pyruvate in the liver. The metabolism of all macromolecules is tied to cellular respiration • Excess intermediates of glycolysis and the Kreb’s cycle can be converted to stored carbohydrates, fats and proteins. Pathway for synthesis of RNA, DNA Fats Glycogen or starch Glucose Phospholipids Fatty acids Pruvate Acetyl CoA Lactate (from fermentation) Krebs cycle Several intermediaries used as substrates in amino acid synthesis A Visual Guide to Cellular Respiration and Fermentation