Mitochondria & Link reaction

• Where is the mitochondrion located within a cell?

  Within the cytoplasm
• What type of organelle is the mitochondrion?

  A membrane-bound organelle
• What separates the mitochondrion from the cytoplasm?

  The outer membrane
• What is the space between the outer membrane and the inner membrane of the mitochondrion called?

  The intermembrane space
• Why are the folds in the cristae important?

  They provide a larger surface area for oxidative phosphorylation
• What builds up in the cristae due to its structure?

  A proton gradient
• Where does oxidative phosphorylation occur in the mitochondrion?

  In the cristae
• What is found in the mitochondrial matrix?

  Circular DNA
• What type of ribosomes are found in the mitochondrial matrix?

  70s ribosomes
• What theory explains the origin of mitochondria as membrane-bound organelles?

  The endosymbiotic theory
• What type of microscope is used to view the ultra-structure of the mitochondrion?

  A transmission electron microscope
• What can be seen clearly in a transmission electron microscope micrograph of the mitochondrion?

  The inner folds of the cristae
• Why is it important to understand the angle at which a mitochondrion is cut in a section?

  It affects the visibility of the inner membrane projections
• What is the structure of biological membranes primarily composed of?

  A phospholipid bilayer
• What process allows pyruvate to enter the mitochondrion?

  Facilitated diffusion
• What is required for pyruvate to move against its concentration gradient into the mitochondrial matrix?

  Active transport
• What is produced as a waste product during the link reaction?

  Carbon dioxide
• What happens to pyruvate during the link reaction?

  It is decarboxylated
• What does the decarboxylation of pyruvate produce?

  A two-carbon acetyl group
• What coenzyme accepts hydrogen ions during the link reaction?

  NAD
• What is formed when NAD accepts hydrogen ions and electrons?

  Reduced NAD
• What does coenzyme A do in the link reaction?

  It picks up the acetyl group
• What is the role of coenzymes in cellular respiration?

  They act like taxis to transport specific molecules
• How many pyruvate molecules are produced from one glucose molecule?

  Two pyruvate molecules
• What are the products of the link reaction?

  Two acetyl CoA, two reduced NAD, and two carbon dioxide
• What happens to carbon dioxide in autotrophic organisms?

  It can be used in the Calvin cycle
• How is carbon dioxide transported in animals after being produced?

  It is picked up by hemoglobin and transported in the bloodstream
• What is the final destination of carbon dioxide in animals?

  It is excreted out of the body through the lungs
• What are the key components of the mitochondrion structure?

  • Outer membrane
  • Inner membrane with cristae
  • Intermembrane space
  • Mitochondrial matrix containing circular DNA and 70s ribosomes
• What are the main stages of the link reaction?

  1. Decarboxylation of pyruvate to form acetyl group
  2. Reduction of NAD to form reduced NAD
  3. Formation of acetyl CoA
• What are the inputs and outputs of the link reaction?

  Inputs:

  • 2 pyruvate

  Outputs:

  • 2 acetyl CoA
  • 2 reduced NAD
  • 2 carbon dioxide
• How do coenzymes function in cellular respiration?

  • Coenzymes transport specific molecules
  • NAD picks up hydrogen ions
  • Coenzyme A carries acetyl groups
• What are the folds in the inner membrane of the mitochondrion called?
• What are the folds in the inner membrane of the mitochondrion called?

  Cristae
• What is the first step of link reaction?


  Oxidative decarboxylation
• What is the name of the two-carbon compound produced from pyruvate? This molecule is then bound to a coenzyme.

  Acetyl
• Which two coenzymes are involved in the link reaction?


  NAD and Coenzyme A
• Where in the cell does the link reaction occur?


  In the matrix of the mitochondria
• What is the end product of the link reaction?


  Acetyl Coenzyme A