Topic 6: Respiration

• What is the process called that cells use to extract energy from food to generate ATP?

  Cellular respiration

  
• What is the relationship between energy transfer and electron movement in cellular respiration?

  Energy transfer is closely linked to the movement of electrons.
• Why is the transfer of electrons important in cellular respiration?

  It allows the cell to transfer food energy in small packages captured in ATP.

  
• What does the acronym REDOX stand for?

  Reduction and oxidation reactions
• What does OILRIG stand for in the context of redox reactions?

  Oxidation Is Loss, Reduction Is Gain
• What is the oxidized state of Nicotinamide Adenine Dinucleotide (NAD)?

  NAD+
• What is the reduced state of NAD?

  NADH
• How many electrons and protons does NADH carry compared to NAD?

  NADH carries 2 electrons and 1 proton more than NAD.
• What is the role of electron carriers in cellular respiration?

  They shuttle electrons to electron transport chains where ATP is produced.

  
• What are two other examples of electron carriers besides NAD?

  FAD+ and NADP+
• What is the structure of ATP?

  ATP is a nucleotide with three phosphate groups attached.

  
• What happens when the phosphate bond in ATP is broken?

  Energy is released.

  
• What is phosphorylation?

  Adding a phosphate group to a molecule.
• What is dephosphorylation?

  Breaking the high energy bond and removing a phosphate group.
• How is ATP generated in living systems?

  Through an endergonic reaction where ADP undergoes phosphorylation.

  
• What is the equation for the phosphorylation of ADP to form ATP?

  ADP + Pi → ATP

  
• What is substrate-level phosphorylation?

  A coupled exergonic reaction that produces ATP.
• What percentage of ATP is produced by chemiosmosis?

  90%
• Where does glycolysis occur?

  In the cytoplasm.
• Where does the Link Reaction occur?

  In the mitochondrial matrix.
• Where does oxidative phosphorylation occur?

  On the stalked particles on the cristae of the inner mitochondrial membrane.

  
• Where does the Krebs Cycle occur?

  In the mitochondrial matrix.
• What is the overall equation for cellular respiration?

  C$_6$H$_{12}$O$_6$ + 6 O$_2$ → 6 CO$_2$ + 6 H$_2$O + ~36 ATP
• What is produced at the end of glycolysis?

  2 pyruvate molecules, 2 ATP molecules, and 2 reduced NAD molecules.

  
• What happens to pyruvate after glycolysis?

  It is pumped into the mitochondrial matrix for further processing.
• What occurs during the Link Reaction?

  Pyruvate is dehydrogenated and decarboxylated to form Acetyl Coenzyme A.
• What are the outputs of the Krebs Cycle per glucose molecule?

  4 ATP, 6 CO2, 10 NADH, and 2 FADH2.
• What is the main purpose of oxidative phosphorylation?

  To produce the majority of ATP during cellular respiration.

  
• What is the role of the electron transport chain in oxidative phosphorylation?

  It shuttles electrons from NADH and FADH2 to O2.

  
• What is created as a byproduct of the electron transport chain?

  Water (H2O).

  
• What is chemiosmosis?

  It uses kinetic energy from protons falling down their gradient to form ATP.

  
• How many ATP are generated by cellular respiration per glucose molecule?

  38 ATP.
• What happens to NAD+ when oxygen is lacking during glycolysis?

  Fermentation regenerates NAD+ to prevent glycolysis from halting.

  
• What are the two common types of fermentation?

  Lactic acid fermentation and alcohol fermentation.
• What is the role of lactate dehydrogenase in lactic acid fermentation?

  It catalyzes the conversion of pyruvate to lactate.

  
• What is the process of alcohol fermentation?

  Pyruvate is converted to CO2 and acetaldehyde, which is then converted to ethanol.
• How do catabolic pathways for carbohydrates, lipids, and proteins connect to cellular respiration?

  They eventually connect to glycolysis or the citric acid cycle pathways.

  
• What are some examples of sugars that contribute to glycolysis?

  Maltose, lactose, galactose, fructose, mannose, and sucrose.
• What regulates cellular respiration?

  Hormonal control, enzyme reversibility, pH sensitivity, and feedback controls.
• How do high concentrations of ADP and NAD+ affect cellular respiration?

  They indicate a low energy state and stimulate respiratory pathways.