Cellular Respiration - Krebs Cycle Test

20 Questions | Total Attempts: 725

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Cellular Respiration - Krebs Cycle Test

Welcome to the Electronic Frontier Classroom of the 21st Century. This test concentrates on the Krebs cycle or Citric Acid Cycle. The second important process in cellular respiration. It takes place within the mitochondria of animal, plant, and along the cell membranes of bacteria. It would be very helpful for you to review the cycle reference sheet. The settings for this test are unlimited number of attempts to aid in the learning and testing of these concepts. Each test will have 25 questions randomized for every attempt. As "fill-in" questions appear in this test, please enter your answer(s) using all lower case letters. Unless, the question site provides you with different instructions. I wish you Good Luck and


Questions and Answers
  • 1. 
    What molecule is formed after isocitrate looses a carbon atom to Carbon Dioxide?
    • A. 

      Succinate

    • B. 

      Guanosine Triphosphate

    • C. 

      Alpha-ketoglutarate

    • D. 

      Pyruvate

    • E. 

      Fumarate

  • 2. 
    4 molecules of Carbon Dioxide are released in 2 turns of the Krebs Cycle to convert both molecules of pyruvate from glycolysis.  (Please use cycle below to obtain correct answer.)
    • A. 

      True

    • B. 

      False

  • 3. 
    Which one of the following acids is NOT found in Krebs Cycle.
    • A. 

      Citric Acid

    • B. 

      Fumaric Acid

    • C. 

      Hydrochloric Acid

    • D. 

      Malate

  • 4. 
    Acetyl CoA is broken down to produce hydrogen atoms, ATP, and Carbon Monoxide.
    • A. 

      True

    • B. 

      False

  • 5. 
    How many carbon atoms does isocitrate have in its structure?  (Hint: enter a number from 0 to 10.)
  • 6. 
    Pyruvic Acid molecules have 6 carbon atoms.
    • A. 

      True

    • B. 

      False

  • 7. 
    How many adenosine triphosphate molecules are produced by the Krebs Cycle after complete break down of pyruvate molecules?
    • A. 

      20

    • B. 

      10

    • C. 

      6

    • D. 

      2

  • 8. 
    How many times must the Krebs Cycle run to completely use 1 molecule of glucose?
    • A. 

      1 time

    • B. 

      2 times

    • C. 

      3 times

    • D. 

      6 times

  • 9. 
    What cellular organelle does the Krebs Cycle take place?
    • A. 

      Golgi Apparatus

    • B. 

      Mitochondria

    • C. 

      Nucleus

    • D. 

      Plasma Membrane

  • 10. 
    Which one of these molecules are formed before alpha Ketogluterate in the Krebs Cycle?
    • A. 

      Acetic Acid

    • B. 

      Citrate

    • C. 

      Fumarate

    • D. 

      Maleate

  • 11. 
    Succinyl-CoA is not found in the Krebs Cycle.
    • A. 

      True

    • B. 

      False

  • 12. 
    Which electron acceptor molecule aids in the transformation of succinate to fumarate?
    • A. 

      ADP - ATP

    • B. 

      FAD - FADH2

    • C. 

      GDP - GTP

    • D. 

      NAD+ - NADH

  • 13. 
    Which one of the following molecules is not a 4 carbon molecule found in Krebs Cycle.
    • A. 

      Fumarate

    • B. 

      Maleate

    • C. 

      Succinate

    • D. 

      Succinyl-CoA

    • E. 

      Citrate

  • 14. 
    How many carbon atoms are found in the molecule Oxaloacetate?  (Hint: please use numerals from 0 to 12.)
  • 15. 
    How many times is the CoA-SH molecules are released during 2 turns of Krebs Cycle?  (Hint: please use numerals from 0 to 12.)
  • 16. 
    Which one of the following molecules are produced first by the Krebs Cycle?
    • A. 

      Malate (4 Carbon atoms)

    • B. 

      Isocitrate (6 Carbon atoms)

    • C. 

      Acetyl CoA (2 Carbon atoms)

    • D. 

      Fumarate (4 Carbon atoms)

    • E. 

      Succinate (4 Carbon atoms)

  • 17. 
    What molecules are used to transform Succinyl-CoA into Succinate?
    • A. 

      AMP and GDP

    • B. 

      GTP and ATP

    • C. 

      CoA-SH and ATP

    • D. 

      CoA-SH and GDP

  • 18. 
    What molecule(s) are released in the formation of alpha-Ketogluterate into Succinyl-CoA?
    • A. 

      FAD --> FADH2

    • B. 

      NAG+ --> NADH + CO2

    • C. 

      FAD --> FADH2 + HOH

    • D. 

      Acetyl CoA + CO2

    • E. 

      NADH + CO2

  • 19. 
    Using the diagram attached to this question, which molecule is found between citrate and isocitrate?
    • A. 

      Succinyl-CoA

    • B. 

      Alpha-Ketogluterate

    • C. 

      Cis-Aconitate

    • D. 

      Malate

    • E. 

      Acetyl-CoA

  • 20. 
    How many carbon atoms are found in a molecule of fumarate? (Please enter your answer in numerals.)