Glycolysis Krebs Cycle Cellular Respiration Lecture 2 Cellular

Glycolysis & Kreb’s Cycle Cellular Respiration Lecture 2

Cellular Respiration Overview Review • What are the major reactants of cellular respiration? • What are the major products of cellular respiration? • In what organelle in eukaryotes does cellular respiration occur?

Match the following names to the structures: a) Mitochondrial matrix b) Inner membrane space c) Inner Membrane d) Outer Membrane

The first step in cellular respiration = ________ GLYCOLYSIS CYTOPLASM • happens in the ________ outside the mitochondria • occurs _____________ with or without oxygen

Glycolysis ENERGY Requires ______to get it started.

Evolutionary Significance • Most widespread metabolic pathway – ancient prokaryotes probably used glycolysis to make ATP before oxygen was present – Glycolysis happens in cytoplasm • Evidence: – Earliest fossil bacteria present 3. 5 billion years ago – large amounts of oxygen not present until 2. 7 billion years ago – eukaryotes appeared 1 billion years after prokaryotes (Endosymbiotic theory)

SUBSTRATE LEVEL PHOSPHORYLATION = creating ATP from removing a phosphate from the substrate MITOCHONDRION and adding it directly to ADP

Redox Reactions • Oxidation is loss of electrons – Glucose is oxidized • Reduction is gain of electrons – NAD+ is reduced to NADH • Used as an electron carrying molecule to store energy until later steps

Glycolysis • What are the reactants? • What are the products?

PYRUVIC ACID MOVES TO NEXT STEP = ANAEROBIC IF THERE IS NO OXYGEN (_______) IF THERE IS OXYGEN (_______) = AEROBIC

Pyruvate is transported into mitochondrion and Acetyl Co. A produced For each pyruvate converted into acetyl Co. A 1 molecule of CO 2 is released; NAD+ ---> NADH; Coenzyme A (from B vitamin)

Kreb’s Cycle = Citric Acid Cycle occurs in mitochondrial matrix OAA CITRIC ACID Reactants? Products?

Kreb’s Cycle • 2 C atoms from pyruvate → exit as CO 2 For each pyruvate that enters: 2 CO 2 released 3 NAD+ reduced to 3 NADH; 1 FAD+ reduced to 1 FADH 2 (riboflavin, B vitamin); 1 ATP molecule