z Review the basic steps of ATP production (i.e., cellular respiration, lactic acid fermentation).
z Identify the molecular steps involved in muscle contraction.
z State the importance of ATP generation to muscle contraction.
z Understand the relationship between rigor mortis and muscle contraction.
Steve Knox is a hard-working research biochemist. He has been married to his wife Jackie for over
eight years. The project he is working on is a continuation of a project he began in graduate school
examining metabolic processes in the mitochondria of Xenopus laevis frogs. His technician Leslie is
also very devoted to the project and often works late hours on the weekends with Steve.
Late one Saturday evening, Steve and Leslie are alone in the lab trying to finish up an experiment. As a
surprise, Jackie has decided to bring Steve and Leslie a late-night snack since both of them have missed
dinner. Around 11:30 p.m., Jackie enters the lab with drinks and brownies. The lights are on but no one
seems to be around.
“I wonder where they are,” Jackie muses to herself. “Steve? Leslie? I brought you a surprise!”
Turning a corner into the back of the lab, Jackie sees Steve and Leslie involved in a passionate kiss near
the fume hood. Shocked, Jackie drops the food onto the floor, making a clatter. Looking equally
shocked, Steve and Leslie immediately disentangle themselves and start sputtering excuses and
straightening their clothes.
“Hi, honey, uhhhh … what are you doing here?” mutters Steve.
Jackie is enraged. She lunges toward Steve, grabbing his shoulders and shaking him. “What are you
doing? Don’t you love me any more? I HATE YOU! I HATE YOU!”
Steve suddenly loses his balance and begins to fall. On his way down, he hits his head on the corner of
the lab bench, falling unconscious. Jackie screams.
Leslie, meanwhile, has been watching in horror. Seeing Steve on the floor, she fears for her own safety.
Jackie might attack her next! Reacting quickly, she grabs a flask of a clear solution sitting on the
counter in the hood and tosses the liquid into Jackie’s face, and then runs out of the lab.
Early Monday morning, a colleague discovers Steve and Jackie’s dead bodies and calls 911. The
coroner later releases information about the estimated time of death for the two based on the extent of
rigor mortis. Steve, whose body was still warm and barely stiff, is estimated to have died approximately
five hours before being discovered. Jackie, whose body was completely cold and stiff, is estimated to
have died approximately 30 hours before being discovered.
Claudia Bode, Biology Department, University of Kansas
Allison Jablonski, Biology Department, Lynchburg College
1. Construct a time-line of the events from Saturday evening through Monday morning as described
in the story.
2. Cellular Respiration Questions:
a. Which part of cellular respiration uses 2 ATP and produces 4 ATP per glucose molecule?
Where does this set of reactions occur in the cell?
b. Which part of cellular respiration produces the most ATP? How does it work?
c. Which part of cellular respiration produces the most NADH? How many?
d. What molecules are needed to produce ATP by oxidative phosphorylation?
3. In a living organism, what happens to ATP production when there is no oxygen available
4. What are the characteristics of a dead body?
5. Consider the processes involved in muscle contraction. Summarize in a few sentences the
relationship between ATP and muscle contraction.
6. What is rigor mortis? Why does rigor mortis develop? What are the different stages of rigor mortis.