Unit 2.2 - Cell Respiration

• Does aerobic respiration use oxygen?

  Yes
• Does fermentation use oxygen?

  No
• What is respiration?

  A series of enzyme controlled reactions that generates ATP by the release of energy from food.
• What is the link between ATP and anabolic and catabolic reactions?

  It is used to transfer energy to cellular processes which require energy.
• What is ATP?

  Adenosine triphosphate. It is an adenosine molecule with three inorganic phosphate (Pi) groups attached.
• When is energy released in ATP?

  When the terminal (last) phosphate is removed.
• What happens during respiration?

  Low energy to high energy.
• What happens during cellular activity?

  High energy to low energy
• What are some examples of cellular activities?

  Muscle contraction, protein synthesis, cell division and nerve impulse transmission.
• Where does stage 1 of aerobic respiration take place?

  Cytoplasm
• What does glucose break down to in stage 1 of aerobic respiration?

  A series of intermediate molecules and finally into pyruvate
• What is stage 1 of aerobic respiration called?

  Glycolysis
• What is part 1 of glycolysis in aerobic respiration called and why?

  Part 1 of glycolysis in aerobic respiration is called the "energy investment phase" because 2 ATP molecules are needed for the phosphorylation of the intermediates (they gain a phosphate)
• What is part 2 of glycolysis in aerobic respiration called and why?

  The second part of glycolysis in aerobic respiration is called energy gain because 4 ATP are generated
• How much ATP is used in aerobic respiration's glycolysis?

  2 ATP are used in total but 4 ATP are generated by glycolysis (net gain of 2ATP).
• What do dehydrogenase enzymes do?

  Remove hydrogen ions and electrons from intermediates.
• What happens after the hydrogen ions and electrons are removed from the intermediates in glycolysis in aerobic respiration?

  They are picked up by NAD (hydrogen carrier/acceptor) to form NADH and carried to the electron transport chain.
• What is the second stage of respiration called?

  The Citric Acid Cycle
• Is oxygen required for the citric acid cycle?

  Yes.
• Where does the citric acid cycle take place?

  The central matrix of the mitochondria
• What is pyruvate broken down to in the citric acid cycle?

  An acetyl group
• What does the acetyl group bind with?

  Coenzyme A
• What does the binding of an acetyl group and conezyme A form?

  Acetyl coenzyme A
• What is released when acetyl conezyme A is formed?

  Carbon dioxide and hydrogen (NADH).
• What does the acetyl from acetly conenzyme A combine with?

  Oxaloacetate.
• What does the binding of acetyl and oxaloacetate form?

  Citrate
• What do electrons and hydrogen combine with in the citric acid cycle?

  NAD
• What does the combination of Hydrogen, electrons and NAD form?

  NADH
• What happens to the NADH created in stage 2?

  It goes to the electron transport chain.
• How much ATP is formed in the citric acid cycle?

  1
• What gas is released during the citric acid cycle?

  Carbon Dioxide
• What happens to Oxaloacetate?

  It is regenerated for the continuation of the cycle
• What is the third stage called?

  The Electron Transport Chain
• What is the electron transport chain?

  A chain of protein molecules attached to the inner membrane of the mitochondria.
• What happens to electrons in stage 3?

  Flow along the electron transport system and release energy.
• What is the energy released in stage 3 used for?

  To pump hydrogen ions across the mitochondrial membrane to the inter-membrane space.
• How does the returning flow of hydrogen in stage 3 go back into the matrix?

  ATP Synthase
• What happens during ATP synthase?

  ATP is formed from ADP+Pi
• What happens at the end of the chain in stage 3?

  Electrons and hydrogen combine with oxygen to form water
• What is the final hydrogen ion and electron accpetor?

  Oxygen