reviewing chapter 8

what is the overall chemical equation for the complete breakdown of glucose to CO2 and H2O? Explain how this is an oxidation-reduction reaction.

-C6H1206 + 602 → 6C02 + 6H20 + energy -The glucose has been oxidized because it has lost electrons and oxygen has been reduced because it has gained electrons.

What are the main events of the citric acid cycle?

-Glucose molecules are broken down into carbon dioxide and water molecules in the Krebs cycle (citric acid cycle). -After the glucose, C6H12O6, is broken apart, the chemical energy that was in the C-H bonds in the glucose is used to excite an electron to send along an electron transport chain to run the second stage of cellular respiration, called oxidative phosphorylation, in which ATP is made.

What are NAD+ and FAD? What are their functions?

-NAD+ and FAD are both electron carriers. -When a metabolite is oxidized, NAD+ accepts 2 electrons plus a H+ and results in NADH. The high-energy electrons received by NAD+ are usually carried to the electron transport chain. Only a small amount of NAD+ is needed in the cell because NAD+ can be used over and over again. -FAD accepts 2 electrons and 2 hydrogen ions to become FADH2.

What is the electron transport chain, and what are its functions?

-The electron transport chain is a group of compounds that pass electrons from one to another via reactions that create a proton gradient that drives ATP synthase. -NADH and FADH2 bring electrons to the ETC. -As the electrons move down the chain, energy is captured and used to form ATP. -For every pair of electrons that enters by way of NADH, 2 ATP results. -For every pair of electrons that enters by way of FADH2, 2 ATP results. -Oxygen is the final acceptor of the electrons and combines with 2 H+ to become water.

Describe the organization of protein complexes within the cristae. Explain how the complexes are involved in ATP production.

-The electron transport chain is located on the cristae. -As electrons move from one protein complex to another, hydrogen ions are pumped from the matrix into the inner membrane space. -As hydrogen ions flow down a concentration gradient from the inner membrane space into the mitochondrial matrix, ATP is synthesized by the enzyme ATP synthase. -ATP leaves the matrix by way of a channel protein.

What are the main events of glycolysis? How is ATP formed?

-The main events of glycolysis are the energy-investment step and the energy-harvesting step and takes place in the cytoplasm. -ATP is formed through a complex enzyme-driven process. One example being glycolysis when glucose is broken down into 2 pyruvate which creates 2 ATP molecules per glucose.

Give examples to support the concept of the metabolic pool.

Certain substrates recur in various key metabolic pathways, and therefore they form a metabolic pool. In the metabolic pool, these substrates serve as entry points for the degradation or synthesis of larger molecules. Degradative reactions break down molecules and collectively participate in catabolism. The cellular respiration pathway makes a significant contribution to catabolism.

Compare the structure and function of chloroplasts and mitochondria. Explain the flow of energy concept.

Chloroplasts and mitochondria have 2 membranes. The chloroplast builds glucose in order to store energy for the cell. It uses carbon dioxide and water and releases oxygen during this process of photosynthesis. The mitochondrion breaks glucose down in order to get the energy out to make ATP. The process uses glucose and oxygen and releases carbon dioxide and water during cellular respiration. There is a flow of energy through chloroplasts to carbohydrates and then through mitochondria to ATP molecules.

phase 3-

Citric Acid (Krebs) Cycle takes place in the matrix. As oxidation occurs, NADH and FADH2 results, and more CO2 is released. The citric acid cycle is able to produce one ATP per turn. 2 acetyl groups enter the cycle per glucose molecule, the cycle turns twice.

phase 4-

ETC is a series of carriers on the cristae. NADH and FADH2 give up electrons to the chain. Energy is released and captured as the electrons move from a higher-energy to a lower-energy state. After oxygen receives electrons, it combines with hydrogen ions and becomes water.

What is fermentation, and how does it differ from glycolysis? mention the benefit of pyruvate reduction during fermentation. What types of organisms carry out lactic acid fermentation, and what types carry out alcoholic fermentation?

Fermentation is an anaerobic process that reduces pyruvate to either lactate or alcohol and CO2. Fermentation results in a gain of only 2 ATP per glucose vs 32-34 ATP in glycolysis. Pyruvate is the ending product of glycolysis. Animals carry out lactic acid fermentation and produces lactate. Bacteria and fungi carry out alcoholic fermentation and produces ethyl alcohol and CO2.

phase 1-

Glycolysis does not require oxygen (anaerobic) and takes place in the cytoplasm. It is the breakdown of glucose into 2 pyruvate molecules. Has net gain of 2 ATP.

give the substrates and products of the prep reaction. Where does it take place?

Pyruvate is broken down into a 2-carbon acetyl group and 1 carbon molecule is released. The Prep Reaction takes place in the matrix.

Calculate the energy yield of glycolysis and complete glucose breakdown. Compare the yields from substrate level ATP synthesis and from the electron transport chain.

Substrate-level ATP synthesis during glycolysis and the citric acid cycle accounts for 4 ATP. The electron transport chain accounts for 32 or 34 ATP, and the grand total of ATP is 36 or 38 ATP. Cells differ as to the delivery of the electrons from NADH generated outside the mitochondria. If they are delivered by a shuttle mechanism to the start of the ETC, 6 ATP result; otherwise, 4 ATP result.

phase 2-

The Preparatory Reaction takes place in the matrix. Pyruvate is broken down to a 2-carbon acetyl group and CO2 is released.