Chapter 9: CELLULAR RESPIRATION!!! Mr. Freidhoff

Metabolism Metabolism: Is the set of chemical reactions that occur in living organisms in order to maintain life. – Catabolism: Breaking down – Anabolism: Building up

Aerobic vs. Anaerobic Aerobic Process: Requires Oxygen. If no oxygen is present, reaction will NOT occur. Anaerobic Process: Doesn’t require oxygen.

Cellular Respiration Inputs: Glucose, Oxygen. Outputs: Carbon dioxide, water, and ATP. Does any of these inputs/outputs look familiar?

Cellular Respiration Equation Glucose + Oxygen  Carbon Dioxide + Water + 38 ATP

Reactions Photosynthesis and Cellular Respiration are opposite reactions.

ATP Cycle ATP is recyclable. ADP and Phosphate group can be restored to ATP. – Input of energy – Where? – Food 10 million ATP can be regenerated in 1 minute

Cellular Respiration Includes both aerobic and anaerobic respiration but is often used to refer to aerobic respiration

Cellular Respiration 3 Steps 1.Glycolysis 2.Krebs Cycle 3.Electron Transport Chain

NAD/NADH Each NADH represents stored energy. NADH passes the electrons to the electron transport chain (ETC). NAD + are recyclable.

FADH/FADH2 Different chemical formula that NAD+. Each FADH2 represents stored energy. – Also transport electrons to ETC. FADH are recyclable.

Glycolysis Glyco = sugar; lysis = breaking Occurs in Cytoplasm. 1 glucose molecule gets broken down into 2 (three carbon) pyruvates.

Glycolysis Inputs: – Glucose Outputs: – 2 NADH are produced. – Net of 2 ATP. 2 ATP are consumed in reaction. 4 ATP are produced. – 2 pyruvates.

Oxidative decarboxylation Small transitional step between Glycolysis and Krebs Cycle. Converts Pyruvates to Acetyl CoA. CO 2 is released, NADH is produced. Requires oxygen to occur. Occurs twice. – Why?

Krebs Cycle Also known as TCA or Citric Acid Cycle. Discovered By Hans Krebs. Cycle occurs twice for every glucose molecule. – Why? – You receive 2 pyruvates from glycolysis.

Krebs Cycle Occurs in the mitochondrial matrix. Several enzymes change compounds. – Add/remove hydrogens and carbons. Reactants: 2 Acetyl CoA Products – 6 NADH – 2 FADH 2 – 2 ATP – 4 CO 2

Krebs Cycle

Electron Transport Chain Located at the Inner Mitochondrial Membrane Inputs: 10 NADH and 2 FADH 2 Where are the NADH and FADH2 molecules coming from? – Glycolysis and Krebs Cycle Membrane proteins transport electrons around membrane. – Similar to photosynthesis ETC. – Binding sites for NADH and FADH 2.

Electron Transport Chain Electron Transport Hydrogen Ion Movement ATP Production ATP synthase Channel Inner Membrane Matrix Intermembrane Space

ETC ATP Production NADH and FADH 2 molecules donate their hydrogen atoms and electrons at protein sites. Electrons travel through paths of proteins in the phospholipid bilayer. For every NADH molecule, 3 ATP are created. For every FADH 2 molecule, 2 ATP are created.

ATP SYNTHASE!!! Mr. Freidhoff’s favorite enzyme! Located in the membrane of mitochondria. Link

ATP SYNTHASE!!! Bonds ADP and a phosphate group to make ATP. Powered by protons donated by NADH and FADH 2. Rotates in the membrane!! #bioswag

The Role of oxygen Final hydrogen/electron acceptor in the ETC. Combines to form water.

ETC Products 34 ATP from ATP Synthase – Highest amount of ATP Yield out of the 3 steps. 6 H 2 O – By-product of the ETC.

Energy Yield from Glucose Metabolism 10 NADH  30 ATP 2 FADH 2  4 ATP

Mitochondrion Substrate-level phosphorylation ATP Cytosol Glucose Pyruvate Glycolysis Electrons carried via NADH Substrate-level phosphorylation ATP Electrons carried via NADH and FADH 2 Oxidative phosphorylation ATP Citric acid cycle Oxidative phosphorylation: electron transport and chemiosmosis

Anaerobic Respiration Not an efficient method of ATP production. Also known as fermentation. There are two primary fermentation processes: – Lactic Acid Fermentation – Alcohol Fermentation

Lactic Acid Fermentation In muscle tissues during rapid and vigorous exercise, muscle cells may be depleted of oxygen. Muscles then switch from respiration to lactic- acid fermentation.

Alcohol Fermentation Occurs within some yeasts and bacteria. Creates products such as wines and beers. Fermentation also creates bread.

Lactic Acid Fermentation Glycolysis is the only stage that occurs. Glucose  Pyruvic acid  Lactic acid + energy Notice that glycolysis doesn’t use Oxygen!

Why is fermentation important to evolution? 3.5 billion years ago, there was no oxygen on Earth. Organisms evolved around the atmosphere at that time.

ATP Production Aerobic Respiration: With Oxygen Steps – Glycolysis: 2 ATP – Krebs Cycle: 2 ATP – Electron Transport Chain: 34 ATP Total ATP: 38 ATP Products: CO 2, H 2 0 Anaerobic Respiration: Without Oxygen Steps – Glycolysis: 2 ATP Total ATP Production: 2 ATP Products: Lactic Acid