Lecture 7 PQ PDF

1. 2. 3. 4. 5. 6. Potential Quiz Questions 07. Metabolism, Glycolysis and Fermentation Recommended Chapter 13 Define cellular respiration, metabolism, catabolism, and anabolism? Cellular respiration is the process by which cells break down organic molecules, such as glucose, to generate energy in th...

1. 2. 3. 4. 5. 6. Potential Quiz Questions 07. Metabolism, Glycolysis and Fermentation Recommended Chapter 13 Define cellular respiration, metabolism, catabolism, and anabolism? Cellular respiration is the process by which cells break down organic molecules, such as glucose, to generate energy in the form of ATP; Metabolism refers to all the chemical reactions that take place within an organism, including both catabolic (breaking down) and anabolic (building up) processes (METABOLISN = CATABOLISM + ANABOLISM); Catabolism involves the breakdown of complex molecules into simpler ones, releasing energy in the process; Anabolism involves the synthesis of complex molecules from simpler ones, requiring an input of energy Describe redox reactions. What happens during oxidation of a molecule? What happens during reduction of a molecule? When an electron is picked up, what often comes with it? What type of reaction is this? Oxidation is the loss of electrons by a molecule, leading to an increase in its oxidation state; Reduction is the gain of electrons by a molecule, leading to a decrease in its oxidation state. When an electron is picked up, a proton (H+) often comes with it. This is known as a hydrogen atom. The process of oxidation and reduction together is called a redox reaction Describe why controlled oxidation is more useful for a cell than simple burning of a molecule. Controlled oxidation is more useful for a cell than simple burning because it allows for the gradual release of energy, which can be captured in a form usable by the cell (ATP). Burning, or uncontrolled oxidation, would result in the rapid release of energy, much of which would be lost as heat Describe the three stages of food breakdown. What happens and where does it take place? What is this breakdown of complex molecules called? Digestion: Breakdown of food into small, absorbable molecules (in the GI tract). Breakdown of Simple Subunits into Acetyl CoA, ATP and NADH (in the cytosol). Oxidation of Acetyl CoA and Substantial ATP Production (in the mitochondria). What is the role of glycolysis in catabolism? Where does it occur in the cell? What is the net result of glycolysis? Glycolysis is the initial stage of catabolism. It occurs in the cytoplasm. The net result of glycolysis is the conversion of one molecule of glucose into two molecules of pyruvate, along with the production of ATP and NADH. Use the video and textbook to answer the following questions: a) How many steps are in glycolysis? 10 b) What are the 3 phases or stages of glycolysis? Energy Investment Phase, Cleavage Phase, Energy Liberation Phase c) Summarize each of the 3 phases by the starting molecule, any energy input, any energy output, and the molecule(s) present at the end of that phase. Energy Investment Phase: Requires ATP to start the process. Cleavage Phase: Splits the six-carbon glucose molecule into two three-carbon molecules. Energy Liberation Phase: Generates ATP and NADH, producing pyruvate molecules at the end of glycolysis. 7. How many ATP (gross) are produced by substrate level phosphorylation? What is substrate level phosphorylation? Gross 4, net 2; Substrate level phosphorylation involves the transfer of a phosphate group directly to ADP from a substrate molecule 8. What precursor is needed in order for NADH to be produced? How does the cell use the NADH? NAD+; Used in oxidative phosphorylation to produce ATP 9. Define the function of a kinase, isomerase, dehydrogenase and mutase. Kinase: Adds a phosphate group to a molecule. Isomerase: Converts a molecule into its isomer. Dehydrogenase: Removes hydrogen ions and electrons. Mutase: Shifts a functional group from one position to another. What happens to the products of glycolysis in the absence of oxygen? In the absence of oxygen, the products of glycolysis (pyruvate) can undergo fermentation to generate ATP. 10. There are two types of anaerobic respiration processes (two types of fermentation). Describe the end products of each, including the final molecule produced and the total amount of energy produced. Alcohol Fermentation: End product is ethanol, and energy produced is limited (2 ATP per glucose). Lactic Acid Fermentation: End product is lactic acid, and energy produced is limited (2 ATP per glucose).