oxidative phosphorylation

• Why do organisms need oxygen to live?

  To use it during oxidative phosphorylation
• What happens when there is a lack of oxygen?

  It can cause dizziness, blackouts, or death
• What is oxidative phosphorylation?

  The final stage of cellular respiration
• What are the two components of oxidative phosphorylation?

  Electron transport chain and chemiosmosis
• What occurs in the electron transport chain?

  Electrons are passed between molecules
• What is formed as a result of energy released in the electron transport chain?

  An electrochemical gradient
• How is ATP produced in chemiosmosis?

  Using energy stored in the electrochemical gradient
• What role does oxygen play in the electron transport chain?

  It accepts electrons and forms water
• What happens if oxygen is not available for the electron transport chain?

  The chain stops, and ATP production halts
• What are the consequences of insufficient ATP in cells?

  Cells can't perform necessary reactions and may die
• What is the significance of oxidative phosphorylation in the body?

  • Provides most of the chemical energy (ATP)
  • Essential for cellular functions
  • Supports metabolic processes
• What is the electron transport chain?

  A series of proteins in mitochondria
• How are electrons passed in the electron transport chain?

  Through a series of redox reactions
• What is captured as a result of the redox reactions in the electron transport chain?

  A proton gradient
• What process uses the proton gradient to make ATP?

  Chemiosmosis
• What do the electron transport chain and chemiosmosis together make up?

  Oxidative phosphorylation
• What are the key steps of oxidative phosphorylation?

  1. Delivery of electrons by NADH and FADH2
  2. Electron transfer and proton pumping
  3. Splitting of oxygen to form water
  4. Gradient-driven synthesis of ATP
• What do NADH and FADH2 do in the electron transport chain?

  Transfer electrons to the transport chain
• What happens to NADH and FADH2 after they transfer electrons?

  They turn back into NAD+ and FAD
• What occurs as electrons move down the electron transport chain?

  They release energy and pump H+ ions
• What is established by pumping H+ ions out of the matrix?

  An electrochemical gradient
• What happens at the end of the electron transport chain?

  Electrons are transferred to molecular oxygen
• What is formed when oxygen splits and takes up H+ ions?

  Water
• How is ATP synthesized during oxidative phosphorylation?

  Through the flow of H+ ions via ATP synthase
• What enzyme do H+ ions pass through to synthesize ATP?

  ATP synthase
• What are Complexes I, III, and IV of the electron transport chain?

  Proton pumps
• How do Complexes I, III, and IV utilize energy from electrons?

  They pump H+ ions from the matrix
• What does the pumping of H+ ions create across the inner mitochondrial membrane?

  An electrochemical gradient
• What is another name for the electrochemical gradient formed by H+ ions?

  Proton-motive force
• Why can't protons pass directly through the phospholipid bilayer?

  The core is too hydrophobic
• What do H+ ions need to move down their concentration gradient?

  Channel proteins
• What is the name of the channel protein that allows H+ ions to move in the inner mitochondrial membrane?

  ATP synthase
• How does ATP synthase function in relation to H+ ions?

  It catalyzes the addition of phosphate to ADP
• What is the process called where energy from a proton gradient is used to make ATP?

  Chemiosmosis
• In what other process besides cellular respiration is chemiosmosis involved?

  The light reactions of photosynthesis
• What happens to the energy stored in the proton gradient if not used for ATP synthesis?

  It is released as heat
• Why might some cells use the proton gradient for heat generation?

  To keep warm, especially in hibernation
• What specialized cells do hibernating mammals have for heat generation?

  Brown fat cells
• What do uncoupling proteins do in brown fat cells?

  Allow protons to pass without ATP synthase
• How do uncoupling proteins affect the energy of the proton gradient?

  They dissipate it as heat