Question

Part II – Autopsy Report
• Immediate cause of death was hypoxia (suffocation or lack of oxygen).
• Tissue sections from heart, lung, kidney, and liver all show massive cell death.
• Staining with specific dyes showed major mitochondrial damage within the affected tissues.
• Oxygen levels in the patients’ blood were approximately 110 mm Hg (normal range is 75 – 100 mm Hg).
Questions
1. Recalling your knowledge of the function of organelles, what function of the cells was interrupted in these patients? Could this loss of function lead to the death of these individuals? Why or why not?
2. Given the data in the autopsy, were there any reports that seemed inconsistent with the immediate cause of death?
NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE
“The Mystery of the Seven Deaths” by Michaela A. Gazdik Page 2

Part III – Subcellular Metabolite Analysis
Detailed analysis of the damaged cells showed that ATP levels in the mitochondria were very low. Levels of pyruvate and acetyl coenzyme A (CoA) were normal. You begin to suspect a malfunction of a specific cellular metabolic pathway and so you request a more detailed analysis of the sub-cellular components of the affected cells from the autopsy. The levels of key metabolites are reported below:
Average Metabolite Levels
Metabolite
Glucose Pyruvate NAD+ NADH
Questions
Average Patient Levels
99 μM 27 μM 10 μM 400 μM
Normal Levels
100 μM 25 μM 75 μM 50 μM
NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE
1. For each metabolite listed in the table, describe its role in cellular respiration? Are they substrates or products? What is their main function?
2. Are there any abnormalities in the levels of these metabolites in the victims? Develop a hypothesis about which pathway may be affected based on these abnormalities.
3. Explain your reasoning for your hypothesis.
“The Mystery of the Seven Deaths” by Michaela A. Gazdik Page 3

Part IV – Role of Cyanide
You are now convinced that you know the cause of death for these victims and quickly report it back to the police
as this is a very dangerous situation. After realizing that the electron transport chain was no longer functioning, you started to suspect poisoning and ran a blood test for various poisons that you knew affected the electron transport chain. The test of all seven patients came back positive for cyanide. Cyanide irreversibly binds to cytochrome c oxidase (CcOX) of the electron transport chain and prevents the transfer of electrons to oxygen, the final electron acceptor.
Questions
1. What affect would cyanide have on the electron transport chain and the production of ATP? Explain your answer.
2. Given what you now know about the action of cyanide on cellular respiration, explain why the patients died of lack of oxygen while their blood oxygen levels were normal?
3. Would artificial respiration or oxygenation have saved these people? Why or why not?
4. Looking back at the information you have about the people before they got sick, can you suggest a possible source of the cyanide poisoning? How should public health officials and police respond to this tragedy?

Answer 1

FUNCTIONS INTERRUPTION: cellular respiration.

Yes,this loss of function could lead to possible death as cellular respiration creates energy which is required by the body perform many type of functions.

INCONSISTENCIES :The oxygen level in the patients' were above normal levels,which contradicts the "Lack of oxygen" cause of death.

SUBCELLULAR METABOLITES

Glucose-Reactant in glycolysis which produces pyruvate,2 NADH and 4 ATP pyruvate:formed during glycolysis;a reactant in stage 2 where acetyl-CoA and CO2 formed.NAD+ is reduced form of NADH. NADH :Product ; electron carrier.

ABNORMALITIES/HYPOTHESIS: Significantly lower NAD+level and significantly higher NADH levels.

HYPOTHESIS : ETC was affected because there was s large amount of NADH and a small amount of NAD+.

ROLE OF CYANIDE:

Cyanide impact: Cyanide binds to cytochrome c oxidise of the ETC and prevents the transfer of electrons to KE,which is the final electron acceptor.

CYANIDE AND CELLULAR RESPIRATION:

Cyanide does not allow the transfer of electrons to O2,so although the oxygen is still present,but it is not doing the required functions.

POSSIBLE SOLUTIONS?

We believe that these solutions would not work as it does not counteract the cyanide that is present,and only adds oxygen to the blood,which there is already an excess of.

CYANIDE POISONING:

Contaminated Tylenol as a possible result of drug tampering.Should lead to reforms in the parking of various over the counter substances and also strengthen the number of anti-tampering laws.