VOCABULARY

1. AP Biology Ch. 9 – Cellular Respiration VOCABULARY

2. Catabolic pathway • Fermentation • Aerobic respiration • Anaerobic respiration • Cellular respiration • Redox reaction • Oxidation/reduction • Reducing agent • Oxidizing agent • NAD+ • Electron transport chain • Glycolysis • Citric acid cycle • Oxidative phosphorylation • Substrate- level phosphorylation • Pyruvate • Acetyl CoA • Cytochromes • ATP synthase • Chemiosmosis • Proton-motive force • Alcohol fermentation • Lactic acid fermentation • Obligate anaerobes • Facultative anaerobes • Beta oxidation

3. Catabolic Pathway • A metabolic pathway that releases stored energy by breaking down complex molecules • Back to contents

4. Fermentation • Catabolic process that makes a limited amount of ATP from glucose without an electron transport chain and that produces a characteristic end product such as ethyl alcohol or lactic acid • Back to contents

5. Aerobic Respiration • Catabolic pathway that consumes oxygen and organic molecules, producing ATP. • This is the most efficient catabolic pathway and is carried out in most eukaryotic cells and many prokaryotic organisms • Back to contents

6. Anaerobic Respiration • The use of molecules other than oxygen to accept electrons at the end of the electron transport chain • Back to contents

7. Cellular Respiration • The catabolic pathways of aerobic and anaerobic respiration which break down organic molecules for the production of ATP • Back to contents

8. Redox Reaction • Oxidation-Reduction Reaction • A chemical reaction involving the complete or partial transfer of one or more electrons from one reactant to another • Back to contents

9. Oxidation/Reduction • Oxidation – the loss of electrons from one substance in a Redox Reaction • Reduction – the addition of electrons to another substance in a Redox Reaction • Back to contents

10. Reducing Agent/Oxidizing Agent • The electron donor in a Redox Reaction is the reducing agent • The electron acceptor in a Redox Reaction is the oxidizing agent • Back to contents

11. NAD+ • A coenzyme that is the electron carrier that receives the hydrogen atom (1 proton and 1 electron) before it continues on to oxygen in energy releasing steps • Back to contents

12. Electron Transport Chain • A sequence of electron carrier molecules that shuttle electrons during the redox reactions that release energy used to make ATP • Back to contents

13. Oxidative Phosphorylation • The production of ATP using energy derived from the redox reactions of an electron transport chain • The third major stage of cellular respiration • Back to contents

14. Substrate-level Phosphorylation • The formation of ATP by an enzyme directly transferring a phosphate group to ADP from an intermediate substrate in catabolism • Back to contents

15. Glycolysis • The splitting of glucose into pyruvate. • Occurs in almost all living cells • Serves as the starting point for fermentation and cellular respiration • Back to contents • (back to lactic /alcohol fermentation)

16. Pyruvate • Ionized form of pyruvic acid • During glycolysis glucose is split into two three-carbon sugars and these smaller sugars are then oxidized and rearranged to form two molecules of pyruvate • Back to contents

17. The Citric Acid Cycle • Also called the Krebs Cycle • Takes place within the mitochondrial matrix of eukaryotic cells or the cytosol of prokaryotes • Second major phase of cellular respiration • Back to contents

18. Acetyl CoA • Acetyl coenzyme A • Pyruvate is transformed to Acetyl CoA in the citric acid cycle • Back to contents

19. Cytochromes • Iron-containing protein that is a component of electron transport chains in the mitochondria of eukaryotic cells as well as the plasma membrane of prokaryotic cells • Back to contents

20. ATP Synthase • A complex of several membrane proteins that provide a port though which proteins diffuse. This complex functions in chemiosmosis with adjacent electron transport chains, using energy of a hydrogen ion (proton) concentration gradient to make ATP. Found in mitochondrial membrane in eukaryotic cells and the plasma membrane of prokaryotes • Back to contents

21. Chemiosmosis • Mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work such as the synthesis of ATP. Most ATP synthesis in cells occurs by chemiosmosis • Back to contents

22. Proton-Motive Force • The potential energy stored in the form of an electrochemical gradient, generated by the pumping of hydrogen ions across a biological membrane during chemiosmosis • Back to contents

23. Alcohol Fermentation • Glycolysis followed by followed by the conversion of pyruvate to carbon dioxide and ethyl alcohol • Back to contents

24. Lactic Acid Fermentation • Glycolysis followed by the conversion of pyruvate to lactate, with no release of carbon dioxide • Back to contents

25. Obligate Anaerobes • An organism that only carries out fermentation or anaerobic respiration. Such organisms cannot use oxygen and in fact may be poisoned by it • Back to contents

26. Facultative Anaerobes • An organism that makes ATP by aerobic respiration if oxygen is present but that switches to anaerobic respiration or fermentation if oxygen is not present • Back to contents

27. Beta Oxidation • A metabolic sequence that breaks fatty acids down to two-carbon fragments that enter the citric acid cycle as acetyl CoA • Back to contents