Cellular Respiration 1 Instructions Review Carbons Overview Glycolysis

Review: Photosynthesis v The goal of photosynthesis is to produce glucose (C 6 H 12 O 6). v Photosynthesis is necessary because glucose is needed for energy. v The energy required to synthesize (make) glucose comes from light. The materials needed to synthesize glucose come from CO 2 and H 2 O. v 6 CO 2 + 6 H 2 O + light energy C 6 H 12 O 6 + 6 O 2 2 Instructions | Review | # Carbons | Overview | Glycolysis | Acetyl Co. A | Krebs Cycle | Electron transport | Summary | Fermentation

Why cellular respiration? v Cells carry out the reactions of cellular respiration in order to produce ATP is used by the cells for energy. v All organisms need energy, therefore all organisms carry out cellular respiration. v The energy needed to produce ATP comes from glucose. Glucose is produced by photosynthesis. v The equation for cellular respiration is: C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O + 36 ATP Notice that it is the reverse of the equation for photosynthesis. 3 Instructions | Review | # Carbons | Overview | Glycolysis | Acetyl Co. A | Krebs Cycle | Electron transport | Summary | Fermentation

Review: Oxidation and Reduction Oxidized atom Electron is donated Energy is donated Reduced atom Electron is received Energy is received

Review: Oxidation and Reduction This atom served as an energy carrier. It picked up an electron from the atom on the left and gave it to the on the right. Oxidized atom Electron is donated Energy is donated Reduced atom Electron is received Energy is received

C 6 etc. v In the slides that follow, the designations listed below will be used. » C 6 = a molecule that contains six-carbon atoms (example: Glucose) » C 5 = a five-carbon molecule » C 4 = a four-carbon molecule » etc. v Each of these (C 6, C 5, etc. ) also have hydrogen and oxygen atoms but these will be ignored. 9 Instructions | Review | # Carbons | Overview | Glycolysis | Acetyl Co. A | Krebs Cycle | Electron transport | Summary | Fermentation

Glucose glycolysis 2 ATP 2 Pyruvate Overview of Cellular Respiration The first step is called glycolysis. It occurs in the cytosol. Glycolysis During glycolysis, a glucose molecule (6 carbons) is converted to two pyruvate molecules (3 carbons each). It does not require oxygen (it is anaerobic). A total of 2 ATP are gained as a result of these reactions. Details of these reactions will be discussed later.

Glucose 2 ATP xy O 34 more ATP ge n 2 Pyruvate Aerobic respiration occurs in the mitochondrion. Aerobic Respiration Aerobic respiration It requires oxygen (it is aerobic). It produces an additional 34 ATP.

Glucose 2 ATP xy O en yg ox Fermentation occurs if there is no oxygen present. 0 ATP o Aerobic respiration N 34 more ATP ge n 2 Pyruvate Fermentation It does not produce additional ATP. Alcohol + CO 2 (yeast, plants) Lactate (animals)

Glucose 2 ATP xy O en yg ox Fermentation The waste products of fermentation are alcohol or lactate. 0 ATP o Aerobic respiration N 34 more ATP ge n 2 Pyruvate Fermentation Alcohol + CO 2 (yeast, plants) Lactate (animals)

Summary of Glycolysis glucose (C 6) 4 ATP produced 2 ATP - 2 ATP consumed 2 ADP 2 ATP net 2 C 3 2 ADP 2 NAD+ 2 NADH 2 ATP 2 ADP 2 ATP 2 pyruvate (C 3) 2 NADH are also produced

glucose (C 6) Glycolysis 2 ATP Summary - Glycolysis 2 ADP 2 C 3 2 ADP 2 ATP 2 NAD+ 2 NADH 2 ADP 2 ATP 2 pyruvate (C 3) This diagram summarizes glycolysis. As the discussion of cellular respiration proceeds, we will add to this diagram.

Two Acetyl Co. A Molecules v Each glucose molecule that initially began cellular respiration produce two acetyl Co. A molecules (previous slide). The two acetyl Co. A molecules will now enter the Krebs cycle. v The next several slides show the reactions that occur to one molecule of Acetyl Co. A. Remember that the reactions must be repeated two times because there are two molecules of acetyl Co. A for each glucose molecule that began cellular respiration. 28 Instructions | Review | # Carbons | Overview | Glycolysis | Acetyl Co. A | Krebs Cycle | Electron transport | Summary | Fermentation

glucose (C 6) Glycolysis 2 ATP 2 ADP 2 C 3 2 NAD+ 2 ADP Summary – Glycolysis, Acetyl Co. A, Kreb’s Cycle 2 ATP 2 NADH Formation of Acetyl Co. A 2 ADP Krebs Cycle 2 C 2 (acetyl Co. A) 2 C 6 2 CO 2 2 ATP 2 acetyl groups (C 2) 2 pyruvate (C 3) 2 NAD+ 2 NADH 2 C 4 2 NADH 2 FADH 2 2 CO 2 2 ATP 2 NADH 2 C 5 2 NADH Instructions | Review | # Carbons | Overview | Glycolysis | Acetyl Co. A | Krebs Cycle | Electron transport | Summary | Fermentation

glucose (C 6) Glycolysis 2 ATP 2 ADP 2 C Summary – Glycolysis, Acetyl 3 Co. A, Kreb’s Cycle, Electron Transport 2 ADP 2 NAD+ 2 NADH 2 ATP Formation of Acetyl Co. A 2 ADP Krebs Cycle 2 C 2 (acetyl Co. A) 2 C 6 2 CO 2 2 ATP 2 acetyl groups (C 2) 2 pyruvate (C 3) 2 NAD+ 2 C 4 2 NADH 2 FADH 2 10 NAD+ 2 CO 2 2 ATP 2 NADH 2 C 5 2 NADH 2 FAD electron transport 32 ATP 1/2 O 2 H 2 O Instructions | Review | # Carbons | Overview | Glycolysis | Acetyl Co. A | Krebs Cycle | Electron transport | Summary | Fermentation

ATP Yield per Glucose Pathway Glycolysis Substrate-Level Phosphorylation Oxidative Phosphorylation Total ATP 2 2 NADH (= 4 ATP) 6 Glycolysis occurs in the cytoplasm of the cell. NADH produced in the cytoplasm must be brought into the mitochondrion before ATP is produced. Each NADH produced in glycolysis results in 2 ATP. 59 Instructions | Review | # Carbons | Overview | Glycolysis | Acetyl Co. A | Krebs Cycle | Electron transport | Summary | Fermentation

ATP Yield per Pathway These NADH result in the production of 2 ATP Glucoseeach because they are produced outside the mitochondrion and must be transported in. Substrate-Level Phosphorylation Oxidative Phosphorylation Total ATP Glycolysis 2 2 NADH (= 4 ATP) 6 Formation of Acetyl Co. A 0 2 NADH (= 6 ATP) 6 Acetyl Co. A is formed in the mitochondrion. Because the NADH produced is already in the mitochondrion, each NADH results in the production of 3 ATP. 60 Instructions | Review | # Carbons | Overview | Glycolysis | Acetyl Co. A | Krebs Cycle | Electron transport | Summary | Fermentation

glucose (C 6) Glycolysis 2 ATP 2 ADP 2 C 3 Fermentation 2 ADP 2 NAD+ 2 NADH 2 ATP Fermentation does not involve the formation of acetyl Co. A, the Krebs Cycle, or oxidative phosphorylation. Formation of Acetyl Co. A 2 ADP Krebs Cycle 2 C 2 (acetyl Co. A) 2 C 6 2 CO 2 2 ATP 2 acetyl groups (C 2) 2 pyruvate (C 3) 2 NAD+ 2 C 4 2 NADH 2 FADH 2 10 NAD+ 2 CO 2 2 ATP 2 NADH 2 C 5 2 NADH 2 FAD electron transport 32 ATP 1/2 O 2 H 2 O Instructions | Review | # Carbons | Overview | Glycolysis | Acetyl Co. A | Krebs Cycle | Electron transport | Summary | Fermentation

Substrate-Level Phosphorylation Phosphate groups High-energy molecule ADP Enzyme Continued on next slide

Substrate-Level Phosphorylation Continued on next slide

Substrate-Level Phosphorylation Low-energy molecule ATP Return

NAD+ (Nicotinamide Adenine Dinucleotide) Organic Molecule + NAD+ Organic + Molecule NAD+ + 2 H NADH + H+ v NAD+ functions in cellular respiration by carrying two electrons. With two electrons, it becomes NADH. v NAD+ oxidizes its substrate by removing two hydrogen atoms. One of the hydrogen atoms bonds to the NAD+. The electron from the other hydrogen atom remains with the NADH molecule but the proton (H+) is released. v NAD+ + 2 H NADH + H+ v NADH then donate the two electrons (one of them is a hydrogen atom) to another molecule. Continued on next slide

Review: NAD+ + 2 H NADH + H+ Energy + 2 H NAD+ is an electron carrier. Return

Review: A Cyclic Metabolic Pathway A B F A+F B C D D F+E E D Return