Topics 2, 7 & 8 Biochemistry 2.8 & 8.1 Cell Respiration

1 – Cell Respiration and the Mitochondria Read & Consider Understandings , 8.2.2, & Brainstorm: What is ATP, how is it formed, how is it used?

Cell Respiration  Cellular respiration is the controlled release of energy, in the form of ATP, from organic compounds in cells.

ATP – Universal Energy Currency  ATP can be used in different contexts and is continuously recycled.  Moves easily in cells by facilitated diffusion  Takes part in many reactions of metabolism  Delivers energy in small amounts, sufficient to drive individual reactions.

ADP + Pi = ATP The free energy available in ATP is kJ/mol; some of this energy is lost as heat, but much of it is made available for the current reaction.

Mitochondria  Draw, label, and annotate the mitochondria structure.  Indicate how the structure contributes to the function of mitochondrion in the cell

2 – Aerobic Respiration Read & Consider Understandings 2.8.4, What does aerobic mean? What are the benefits of aerobic respiration?

Aerobic Respiration GOAL  convert glucose to usable energy  Aerobic – oxygen is present Cell Respiration: C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + ENERGY

Cell Respiration Overview 1. Glycolysis (cytoplasm) 2. Link reaction (mitochondrial matrix) 3. Krebs Cycle (mitochondrial matrix) 4. Electron transport (mitochondrial membrane)

Oxidation & Reduction Oxidation involves the loss of electrons from an element, whereas reduction involves a gain of electrons; and that oxidation frequently involves gaining oxygen or losing hydrogen, whereas reduction frequently involves losing oxygen or gaining hydrogen.

Glycolysis = Glucose  Pyruvate 1. Glucose is split into two 3-carbon molecules 2. These products are converted to different 3-carbon molecules called pyruvic acid 3. In the cytoplasm pyruvic acid is ionized and is now a pyruvate ion (2 molecules) 4. Additionally, a small amount of ATP is formed using the energy locked up in glucose glycolysis  glucose + lysis

Glycolysis Review 1. Phosphorylation 2. Lysis 3. Oxidation  2 ATP  Pyruvate Fructose Biphosphate

GENERAL STEPS – 1. Glucose enters the cytoplasm 2. Glucose (6-C) is split into 2x 3-C carbon molecules 3. These are then converted to pyruvic acid (also 2x 3-C) 4. It is then ionized and referred to as pyruvate (x2) 5. A small amount of ATP is formed by this process 6. Pyruvate moves into the mitochondria by facilitated diffusion (via enzymes). 7. Hydrogen is removed from pyruvate by H acceptors 8. Oxygen is added to carbon to form CO 2 waste 9. H acceptors react with additional oxygen donating their hydrogen to form water. 10. A large amount of ATP is generated.

Link Reaction: 1. Pyruvate is decarboxylated (carbon dioxide is removed) and oxidized (hydrogen is removed) 2. Hydrogen is added to acceptors NAD+ to form NADH 2 x2 (there are two pyruvate molecules for each glucose molecule) 3. The remaining 2-C fragments (acetyl groups) are attached to coenzyme A to form acetyl CoA

Krebs cycle or Citric Acid Cycle 1. Acetyl CoA enters the cycle and reacts with a 4-C molecule called oxaloacetate or 2. This reaction forms 6-C citrate and coenzyme A (CoA) is released 3. This cyclic reaction converts citrate back into OAA; products:  2 x CO 2  1 ATP  3 reduced NAD+ formed (3 x NADH 2 )  1 reduced FAD+ (1 x FADH 2 ) another type of hydrogen acceptor found in the cycle 4. Because two molecules of pyruvate enter the cycle, the Krebs cycle must occur two times per glucose molecule.

So far… STEPCO 2 ATPNADH 2 FADH 2 glycolysis0220 link reaction2020 Krebs4262 TOTAL64102 Electron Transport Chain: H atoms or more correctly electrons from NADH2 and FADH2 are passed along a series of electron carrier proteins embedded in the smooth double membrane of the mitochondria as well as in the double membrane of the cristae.

1. Electrons from reduced NAD+ and FAD+ (NADH2 & FADH2) are passed along the electron transport chain. 2. As they are passed energy is released in a controlled way. In this way ATP may be formed in great quantities.

Oxidative Phosphorylation & Chemiosmosis

1. Hydrogen is removed from NADH 2 and FADH 2 by dehydrogenase. 2. The Hydrogen ion is then moved to the inner membrane space while the electrons are passed along the electron transport chain. 3. Energy from the electron transport chain drives any additional hydrogen into the inner membrane space lowering pH and creating a chemical gradient. 4. At the end of the electron transport chain hydrogen that will be allowed to flow back in in the next step is combined with oxygen to form the waste product of water. 5. A total of 34 ATP molecules will be formed by oxidative phosphorylation. 6. Hydrogen is allowed to flow back into the matrix activating ATPase which is the enzyme that catalyzes the formation of ATP.

Outcomes

Review  Draw a diagram to show the process of glycolysis.  Include: cytoplasm, lysis, oxidation, ATP formation.  Draw a diagram to show the link reaction  Include: Pyruvate, CoA, Acetyl CoA, oxidation, decarboxylation, mitochondria, matrix.  Draw a diagram of the Krebs cycle.  Include: Acetyl CoA, 4-C compound, 6-C compound, 5-C compound, rearrangement, oxidation, decarboxylation, ATP formation, NAD/FAD reduction.  Draw a diagram showing the stages of the electron transport chain.  Include: H +, e -, integral proteins, e - carriers, NADH, FADH 2, oxidation, return to Krebs cycle, pumping H +, H + concentration, electron transfer, chemiosmosis, O 2, and H 2 O.

3 – Anaerobic Respiration Read & Consider Understanding What organisms regularly use anaerobic respiration? Do humans?

3.7.3 Explain that, during anaerobic cell respiration, pyruvate can be converted in the cytoplasm into lactate, or ethanol and carbon dioxide, with no further yield of ATP.  Yeast  Vertebrates Uptake of oxygen can be an indicator of an organisms energy demands.

Works Cited  "AP Biology Lab 5: Cell Respiration." LabBench. N.p., n.d. Web. 02 July  Crash Course. "ATP & Respiration: Crash Course Biology #7." YouTube. YouTube, n.d. Web. 02 July  La Sala, Michelle. "Boston 2013." Free Play Magazine. N.p., n.d. Web. 1 July  Paine, Chris. "2.8 Cell Respiration." Bioknowledgy. N.p., n.d. Web. 02 July  Shearman, Hayden. “Sprinting Cadence and Power.” A Runner’s Guide. N.p., 13 August 2013, Web. 1 July 2015.