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A Rigorous Investigation
Transcript of A Rigorous Investigation
By: Minh Chau Ho, Anna-Maria Andreeva, Melody Voo, Serena Markose, Ruth Varner
Mrs. Jeanie Reid
Location: Biology lab working with XENOPUS LAEVIS frogs
The couple Steve and Jackie Knox were found dead early Monday morning.
Steve loses his balance and falls unconscious.
Jackie was hit on the head with a flask containing an unknown clear solution.
Victims: Steve and Jackie Knox, a married couple
Leslie and Steve are alone in the lab trying to finish up an experiment
Jackie arrives at the lab at 11:30 p.m.
Jackie catches Steve cheating
Jackie lunges towards Steve shaking his shoulders wildly
Steve suddenly loses his balance, falls down and hits his head on a corner of the lab bench, falling unconscious
Leslie sees and tosses a clear solution into Jackie's face and leaves.
Jackie dies immediately (30 hrs before discovery)
Steve dies (5 hrs before discovery)
The process that releases energy by breaking down glucose and other food molecules in the presence of oxygen; located in the Cytoplasm
C6H12O6 + 6O2 → 6CO2 + 6 H2O + 36 or 38 ATP
The first step in releasing the energy of glucose in which the molecules of glucose is broken into 2 molecules of pyruvic acid
This process takes place in the cytoplasm of a cell, using 2 ATP molecules and producing 4 ATP and 2 NADH
In a living organism, when there is no oxygen present, the cell only gets two molecules of ATP, providing little energy.
The cycle cannot continue cellular respiration with this little amount of energy from anaerobic respiration resulting in death.
Production of ATP and NADH
The electron transport chain is a series of molecules embedded in the mitochondrial membrane uses the high-energy electrons from the Krebs cycle to convert ADP to 34 ATP.
At the end of the chain, the spent electrons join with H+ ions and oxygen to make molecules of water.
Molecules Needed to produce ATP
ADPa free phosphate molecule
Coenzyme A and Coenzyme Q
all enzymes of glycolosis an the Kreb’s Cycle
all cofactors of them, and all the proteins of the electron transport chain
One of the recognizable signs of death, caused by chemical changes in the muscles, which causes the limbs of the corpse to become stiff and difficult to move or manipulate.
ATP is responsible for the release of the muscles. Without ATP, muscles keep contracting and making the body go rigid.
Rigor mortis begins around 3 hours after death.
The muscles reach the maximum state of stiffness at about 12 hours following death.
This begins to change when the muscles begin to decompose 72 hours after death.
What It Is
The failure of Aerobic Cellular Respiration ceases the production of ATP, leading to muscle contraction. When a muscle contracts after a person has died, rigor mortis steps in to make the body stiff and ready for decay.
Characteristics of a Dead Body
The Krebs cycle converts the energy contained inside pyruvate molecules into 8 NADH and 2 FADH2 molecules.
The release of energy from the reaction of ATP to ADP using myosin ATPase causes myosin-actin cross bridges (calcium ions) to pull actin over myosin, thus contracting the muscles.
With the help of ATP, muscle fibers contract and pull in calcium ions.
When they relax, muscles use ATP again to pump calcium ions out of the cells.
Controlled by the central nervous system
The neuron signals pass from the spinal cord through your cell's axons, or neurological pathways, into the motor end plates of each fiber of the contracting muscle.
"Cellular Respiration." Cellular Respiration. N.p., n.d. Web. 18 May 2014.
"The Process of Muscle Relaxation & Contraction." LIVESTRONG.COM. LIVESTRONG.COM, 16 Aug. 2013. Web. 20 May 2014.
"26 Stages of Death." N.p., Apr.-May 2005. Web. 21 May 2014. <http://www.anomalies-unlimited.com/death/stages.html>.
How did they find out??
Steve Knox- dead for 5 hours
starting signs of rigor mortis
-purpling of the skin
-pooling of blood
-eyes sunken into the skull
Jackie-dead for 30 hours
after rigor mortis, decomposition
-body is the temperature of the surrounding environment
-the head neck are now a greenish-blue color
-strong smell of rotting meet
-face is no longer recognizable