GLYCOLYSIS II & PYRUVATE OXIDATION

Last class... Intro to cellular respiration C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + 36 ATP * A series of oxidizing reactions converts the energy stored in C-C bonds of glucose to form ATP molecules

Last class... 2 reactions: 1. Substrate-level Phosphorylation - Directly produces ATP from ADP + P i  ATP 2. Oxidative Phosphorylation -Indirectly produces ATP through the use of electron carriers -NAD + + 2e + 1p  NADH + H + -FAD + 2e + 2p  FADH 2

Last class... 4 steps in the process of cellular respiration: 1.Glycolysis 2.Pyruvate Oxidation 3.Krebs Cycle 4.ETC/Chemiosmosis

Last class... Glycolysis I

Today... *In Glycolysis I, we have broken glucose down into two 3- carbon molecules called G3P (Glyceraldehyde-3-phosphate) * We need to transform those molecules into more usable forms *In Glycolysis II, G3P is converted to PYRUVATE! ** Pyruvate also has 3-carbons * IMP: we will only talk about 1 set of reactions from now on, although it happens twice (for each G3P molecule)

Glycolysis II

Step 1: G3P picks up a P i and is reduced by NAD + to form 1,3 – BISPHOSPHOGLYCERATE [BPG] *Note: NAD+ removes a H (2 e, 1p) from G3P to form NADH + H + Glucose G6P F6P F1,6-BP DHAP  G3P BPG

Glycolysis II Step 2: BPG loses a phosphate group to form 3-PHOSPHOGLYCERATE [3PG] *Note: The loss of P i from BPG from is used to form ATP ADP + Pi  ATP Glucose G6P F6P F1,6-BP DHAP  G3P BPG 3PG

Glycolysis II Step 3: 3PG rearranges to form 2-PHOSPHOGLYCERATE [2PG] *Isomerization reaction! Glucose G6P F6P F1,6-BP DHAP  G3P BPG 3PG 2PG

Glycolysis II Step 4: 2PG loses 2 H’s and 1 Oxygen as water to form PHOSPHO-ENOL-PYRUVATE [PEP] Glucose G6P F6P F1,6-BP DHAP  G3P BPG 3PG 2PG PEP

Glycolysis II Step 5: PEP loses a phosphate group, P i, to form PYRUVATE *Note: The loss of P i from PEP from is used to form ATP ADP + Pi  ATP Glucose G6P F6P F1,6-BP DHAP  G3P BPG 3PG 2PG PEP PYRUVATE

Glycolysis - SUMMARY -We have converted glucose into two 3-carbon molecules, PYRUVATE that will be further converted GLYCOLYSIS ENERGY TALLY ATP USED ATP produced NADH produced FADH 2 produced 2420

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PYRUVATE OXIDATION *TRANSITION REACTION*

PYRUVATE OXIDATION * Now that we have produced two molecules of PYRUVATE, we need to break it down even further to obtain all the energy possible from the C-C bonds in glucose. * Glycolysis occurred in the CYTOPLASM, * Pyruvate oxidation transports the molecules across the inner membrane into the mitochondrial matrix * There are 3 steps in one transition reaction

PYRUVATE OXIDATION Steps: 1. CO 2 is removed from PYRUVATE to form an acetyl group 2. NAD + removes 2 e + 1p from pyruvate to form NADH + H + 3. CoA combines to the remaining molecule to form ACETYL-CoA *Co-enzyme A is used to shuttle the acetyl group across the membrane

PYRUVATE OXIDATION - SUMMARY -Pyruvate, produced from glucose, is converted into a more useful form, ACETYL-CoA, that can be transported across the mitochondrial membrane PYRUVATE OXIDATION ENERGY TALLY TOTAL ENERGY TALLY ATP USEDATP producedNADH producedFADH 2 produced 0020 ATP USEDATP producedNADH producedFADH 2 produced 2440