Exam 2 Review

Exam 2 Review - Bio Exam 2 Review Chapter 8 Role of ATP:...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Bio Exam 2 Review Chapter 8 Role of ATP: the release of free energy by ATP may be coupled to an endergonic process via the formation of a phosphorylated intermediate Cell is more efficient at using ATP than ATP in a test tube, because cell couples ATP hydrolysis with endergonic reactions. However, less ATP is produced in the cell because glucose is converted to other products too, which are used in other cell pathways. Enzymes do NOT change the free energy of a reaction Induced fit : enzyme changes its shape slightly as the substrate binds to it Allosteric regulators (bind to allosteric enzymes): a protein’s function at one site is affected by the binding of a regulatory molecule to a separate site (which causes the protein to change in shape). The allosteric enzyme is initially oscillating between an active and an inactive state. When a regulator binds, it stabilizes one of these two states. o High levels of ADP act as an allosteric activator of catabolic pathways (there is a high demand for energy) o Citric Acid and ATP are both allosteric inhibitors of catabolic pathways, because high concentrations of these means that catabolism is already occurring at a fast rate o AMP is an allosteric activator of catabolic pathways Cooperativity : a type of allosteric activation; a substrate (allosteric activator) binds to an active site, priming the molecule to accept more substrate Chapter 9 Oxidation of glucose and other fuels allows energy to be released in the cell. Oxidation occurs in a controlled series of steps (ETC), and every electron travels with a proton (H+) through the reaction. NAD+ is an electron acceptor that functions as an oxidizing agent. During cellular respiration, it is reduced to NADH, which represents STORED ENERGY in the form of electrons. Pathway of electrons: glucose NADH ETC Oxygen As electrons travel down the ETC, they are passed to more and more electronegative compounds. The compound that gives up electrons is oxidized, and the next one is reduced. NADH and FADH2 are both oxidized back to NAD+ and FAD when they donate their electrons to the chain (they are recycled for re-use in glycolysis and the citric acid cycle). Glycolysis : glucose is split into 2 molecules of pyruvate. Per glucose molecule, 2 ATP and 2 NADH are produced. Citric Acid Cycle : acetyl CoA (pyruvate has been converted to this after the loss of 1 CO2) enters the cycle. 3 NADH and 1 FADH2 are produced. 1 ATP is produced by substrate level phosphorylation. o
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/31/2010 for the course BISC 220 taught by Professor Mcclure during the Spring '09 term at USC.

Page1 / 4

Exam 2 Review - Bio Exam 2 Review Chapter 8 Role of ATP:...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online