Cellular Respiration Stages 2 & 3

 Stages of Cellular Respiration Glycolysis Pyruvate Oxidation Krebs Cycle Electron Transport & Chemiosmosis

 Occurs in the ______________ of the cell.  Overall idea: ______________ molecule is split into _________________ molecules. In the process, ____ ATP molecules are used, ____ ATP molecules are formed, and two ______ molecules are formed.  Net Energetic Molecules Produced: _____ ATP and ____ NADH.  ATP may be used ________________ by the cell, whereas the majority of energy is still trapped in the ________________ and ________________ molecules.

 The two _____________ molecules formed in ______________________ are transported through the two mitochondrial membranes into the ________________.  Three changes to _______________ are catalyzed by a multienzyme complex.

Pyruvate (containing an acetyl group and a _________ group) is transported into the matrix via transport proteins.

 The low-energy carboxyl group is removed as CO2  Catalyzed by the enzyme pyruvate decarboxyl____.

 NAD+ is reduced by the 2C molecule. NAD+ gains 2H atoms (2P + 2e-). the 2C molecule, overall, loses ______________________. Therefore, the ‘pyruvate’ molecule is ______________________. Overall, this is a _________ reaction.  The 2H atoms gained by NAD+ are obtained from food.  Acetic Acid/Acetate (2C) is formed. NAD + + 2p + 2e Let’s break this down... NAD + + 1e  ______ We are still left with __P and ___e (And want to form NADH) NAD + 2P + 1e  NADH + H +

 Coenzyme A (CoA) attached to acetate. CoA contains sulfur  This forms Acetyl-CoA.  C-S bond holding acetyl group to CoA is unstable, making Acetyl- CoA ready for further reactions... (The next reaction in cellular respiration is the ____________________. Where does CoA come from? Where do many coenzymes come from? Organisms obtain CoA by injesting vitamin B5.

 __________ molecules of NADH for each ______________ molecule.

WHAT HAPPENS TO THE PRODUCTS?  The 2 molecules of acetl-CoA enter the Krebs Cycle  The 2 molecules of NADH skip the Krebs cycle (step ___)and go strait to step ____.  The 2 CO 2 are __________ products. This is a reason why we ______________.  The two H+ ions are dissolved in the matrix, where they are most likely taken up by _______________ molecules to form ____________ ions.

 Central molecule in energy metabolism  Acetyl-CoA is multifunctional Can be used to produce ATP (if needed immediately: enters the _______ cycle). Can be used to produce lipids to store ________ for later.

Based on the former information... If ATP levels are high, acetyl-CoA goes on to produce ____________________. If ATP levels are low, acetyl-CoA goes into the _____________________ to increase _____________ production.

 Food = chemical potential energy  Food (which contains stuff to make acetyl-CoA) can be converted into either of the following: 1) lipids (if cells don’t need ______________ immediately)  REMEMBER THAT LIPIDS ARE FOR _____-term storage of energy. 2) ATP (if cells need ____________ immediately)  REMEMBER THAT ATP CAN BE USED ______________.

 to relax in an inert, passive way (World English Dictionary,  to cease working and take it easy; to vegetate. (World English Dictionary, USUALLY WHEN WE “VEG-OUT”,  DO NOT EXPEND MUCH ENERGY  TAKE IN MORE ENERGY (in the form of food) THAN IS USED.  IF ACETYL CoA is not used promptly, it is used to make _________.

 Named after Sir Hans Krebs  Recieved the Nobel Prize in 1953  8-Step Process  Each step catalyzed by a specific _______  Cyclic: oxaloacetate (_______ of step 8) is the _________ in step 1.

We will break down the steps one by one...

 Acetyl group (___C) of Acetyl-CoA condenses with oxaloacetate (___C) to form citrate (___C).  MAIN REACTANT(S):________________________  ATP INVOLVED (+ or -): :_____________  Energy-Harvesting Product(s):____________________________  PRODUCT(S):_________________________

 Citrate (6C) is rearranged to isocitrate (6C).  This is just an __________ of citrate.  MAIN REACTANT(S):________________________  ATP INVOLVED (+ or -): :_____________  Energy-Harvesting Product(s):____________________________  PRODUCT(S):_________________________

Isocitrate (6C) is converted to α-ketoglutarate (5C) by losing a ____and two H atoms. H atoms reduce NAD+ to ______. MAIN REACTANT(S):________________________ ATP INVOLVED (+ or -): :_____________ Energy-Harvesting Product(s):____________________________ PRODUCT(S):_________________________

 α-ketoglutarate (__C) is converted to succinyl-CoA (__C).  A ___ is removed, coenzyme A is added, and two hydrogen atoms reduce _____ to ______. MAIN REACTANT(S):__________________________________ ATP INVOLVED (+ or -): :________________________________ Energy-Harvesting Product(s):____________________________ PRODUCT(S):__________________________________________

 Succinyl CoA (4C) is converted to succinate (4C).  ATP is formed by substrate-level phosphorylation Phosphate group from matrix dispaces CoA from succinyl-CoA. Phosphate group is transferred to guanosine disphosphate (GDP) forming ____________________ (GTP). GTP transfers P to ADP, forming ________. MAIN REACTANT(S):__________________________________ ATP INVOLVED (+ or -): :________________________________ Energy-Harvesting Product(s):____________________________ PRODUCT(S):__________________________________________

 Succinate (__C) is converted to fumarate (__C).  Two hydrogen atoms reduce FAD to _______. MAIN REACTANT(S):__________________________________ ATP INVOLVED (+ or -): :________________________________ Energy-Harvesting Product(s):____________________________ PRODUCT(S):__________________________________________

 Fumarate (___C) is converted to malate (___C) by the _______ of water. MAIN REACTANT(S):_______________________________ ATP INVOLVED (+ or -):________________ Energy-Harvesting Product(s):_______________ PRODUCT(S):________________________________

 Malate (___C) is converted to oxaloacetate (___ C). Two hydrogen atoms reduce ____ to ______. MAIN REACTANT(S):_______________________________ ATP INVOLVED (+ or -):________________ Energy-Harvesting Product(s):_______________ PRODUCT(S):________________________________

 Acetyl group (___C) of Acetyl-CoA condenses with oxaloacetate (___C) to form citrate (___C).  MAIN REACTANT(S):________________________  ATP INVOLVED (+ or -): :_____________  Energy-Harvesting Product(s):____________________________  PRODUCT(S):_________________________ AND THE CYCLE CONTINUES!!!

 Original _____________ molecule is entirely consumed.  The six ____________ atoms leave the process as six low-energy _____ molecules which are released by the cell as _______________. Exhaling?  Energy from the original ______________ molecule is stored in the form of four _____ molecules (2 from glycolysis and 2 from Krebs) and reduced coenzymes. Coenzymes: NADH and FADH 2. ____ NADH from glycolysis ____ NADH from pyruvate oxidation. ____ NADH from the Krebs cycle ____ FADH 2 from the Krebs cycle. __________________________________________ ____ TOTAL COENZYMES. FREE ENERGY STORED IN COENZYMES WILL BE TRANSFERRED TO ATP IN ELECTRON TRANSPORT AND CHEMIOSMOSIS.

Videos!

 Read and make notes on Table 1: Key Features of the Krebs Cycle. Pg. 102 Make sure you understand it!  Make your own version of Figure 16 (Krebs cycle). You may use colour, legends, etc. This may aid in your understranding.  Quiz on the first 3 stages of Cellular respiration on Monday.