Cellular Respiration: A CSI Investigation

Today you are an intern working with the Crime Scene Investigation division of the Houston Police Department Forensic unit. It’s your first day and you get to assist on a suspected homicide case!

A call is placed to emergency services by a desperately ill woman…

Operator: 911 State your problem Moaning, gasping voice: I am dizzy, I just threw up and I’ve got a terrible headache. Operator: Can you tell me what happened before you began to feel ill? Moaning, gasping voice: My husband gave me a calcium pill before leaving for work and I feel sick, really sick. I think there is, something, something, terribly wrong. Operator: Stay calm an ambulance is dispatched. Ma’am, are you still with me? (No Response).

What could have caused the woman's death?

What is the importance of oxygen to cells? Why do we need to breathe?

HINT : Rule of A human will die within: 3 weeks without food 3 days without H 2 O 3 minutes without O 2

HISTOLOGY REPORT In the histological analysis, specific staining dyes were used to assess cellular damage. Tissue samples from heart, kidney, liver and lung show massive cell death. A few days later, the histology report is in! Heart Kidney Liver Lung

Does this help?!!! Specific Cellular Staining Indicating Damage to Which Organelle?

Considering what you already know about the function of the organelles in the cell, which cellular function was affected in your patient? Protein synthesis? The mitochondria isn’t responsible for manufacturing cellular proteins! Cellular Respiration? YES! Cellular Respiration. You and your team will have to figure out exactly which part.

Since the autopsy report shows massive cell death. What do you think keeps cells alive? Food?Oxygen?Energy? Yes, but she had eaten and she’s still DEAD Yes, but she was gasping for air and she’s still DEAD RIGHT! Cells need energy to stay alive.

What kind of food provides you with energy? Carbohydrates?Fats?Proteins? **

Why do cells need ATP? Where in the cell is ATP synthesized? If glucose is completely oxidized at the end of the citric acid cycle, now what?

ATP LEVELS IN CYTOPLASM ATP LEVELS IN MITOCHONDRIA NORMALDRASTICALLY REDUCED New information has just come in from the pathology report! BIO-ASSAY ANALYSIS OF ATP LEVELS IN DAMAGED HEART CELLS

ATP ANALYSIS IN DAMAGED HEART CELLS What cellular process/processes do you think are impaired in the woman’s damaged cells? What cellular process produces the maximum ATP in the cell? **

Normal vs. Patient Blood Work Results

Heart Tissue Metabolite Levels

Based on this data, what do you now hypothesize caused the woman's death? What does NAD+ have to do with ATP synthesis? Would supplementation with NAD + have helped save the woman’s life? Explain your reasoning.

FINAL REPORT/GROUP PROJECT Address the following questions in your report: 1. Explain the consequences of blocking the electron transport chain 2. Would a similar block have any effect in a plant or a microorganism? 3. What about a life form that does not require oxygen for survival?