Practice multiple choice questions What are the reactants in the equation for cellular respiration? Oxygen and lactic acid Carbon dioxide and water Glucose and oxygen Water and glucose As glucose is broken down, the waste product is in the form of: Lactic acid Carbon dioxide ATP Ammonia

* A ten step process occurring in the cytoplasm Stage One: GLYCOLYSIS * A ten step process occurring in the cytoplasm Stage Two: PYRUVATE OXIDATION * A one step process occurring in the mitochondria Stage Three: KREB’S CYCLE (a.k.a citric acid cycle) * An eight step process occurring in the mitochondria Stage Four: ELECTRON TRANSPORT CHAIN * A multi-step process occurring in the mitochondria

STAGE ONE: GLYCOLYSIS “Sugar Splitting”

Glycolysis First stage of cellular respiration Starts with glucose (6-C sugar) which is split into two 3-C units called pyruvate (pyruvic acid) Occurs in the cytoplasm Each step is catalyzed by a specific enzyme Anaerobic process (does not require oxygen) Net energy produced is 2ATP and 2NADH Recall NAD+ : coenzyme used in your cells, gets reduced into NADH Glycolysis is thought to be the earliest form of energy metabolism

Net Glycolytic Equation: C6H12O6 + 2 ATP + 2 NAD+  2 pyruvate + 4 ATP + 2 NADH + 2 H2O Net gain of 2 ATP from glycolysis

Glycolysis is extremely inefficient at harvesting energy The energy conversion for efficiency of glycolysis is as follows: 2 moles of ATP x 31kJ/mol ATP = 62kJ Total free energy in 1 mole of glucose = 2870kJ efficiency = energy out/energy in x 100% 62kJ/2870kJ x 100% = 2.2% This shows that glycolysis only transfers 2.2% of the potential 100% from each glucose molecule. Extremely inefficient! What should we do…..Ahhhhh!!

1 2 ATP 3 5 4 dihydroxyacteone phosphate (DHAP) 6 7 8 9 10

Step One: ATP phosphorylates glucose Step Two: Isomerase rearranges Step Three: ATP phosphorylates Step Four and Five: Splitting and converting Step Six: NAD+ reduced to NADH Step Seven: Substrate phosphorylation Step Eight: Isomerase rearranges Step Nine: Conversion Step Ten: Substrate phosphorylation After step 10 you have two pyruvate molecules. These pyruvate have two options: aerobic respiration or fermentation.

(Isomerase) (Isomerase)

Homework Section 4.2 p. 172-174 Know it! ☺ https://www.youtube.com/watch?v=8Kn6BVGqKd8 https://create.kahoot.it/details/glycolysis/313f9d0b-8e97-4efe-a5f1-8bbed3252119