Epinephrine

     Epinephrine, which is also commonly known as adrenaline, is a hormone and neurotransmitter that is produced in the in inner part of the adrenal gland, called the medulla.  Epinephrine is a positive feedback loop, meaning that it increases system output in contrast to a negative feedback loop, which would decrease it.  Any hormone produced by the adrenal gland is called a catecholamine.  Epinephrine is derived from tyrosine, an amino acid.  Epinephrine is a hydrophilic, water-soluble hormone that can diffuse through the plasma of blood but not through plasma membranes of cells.  Instead, they attach to receptor proteins on the cell surface and activate secondary messengers.

     Our bodies use epinephrine in our “fight or flight response.” Fight or flight response occurs when a person is subjected to threat. This prompts a signaling process that causes our bodies to react to the danger. When a threat is received, a signal is sent to the brain, and the brain then sends impulses to the adrenal glands in the kidneys.  Once this signal reaches the adrenal glands, the medulla releases epinephrine into the bloodstream.  Carried around to various cells in the body, epinephrine initiates several responses, but the collective purpose is to provide energy so that our major body muscles can respond to the perceived threat.  The four main areas epinephrine affects are the liver, lungs, skin, and heart. In the liver, epinephrine, along with the hormone glucagon, breaks down glycogen and thus releases stored energy.  In the lungs, epinephrine causes smooth muscles and thus the bronchioles to relax, enabling intensified respiration. In the skin, epinephrine bonds to alpha-adrenergic receptors inhibiting blood supply to the skin and also contracts smooth muscle cells in skin to raise hairs on the skin’s surface. Finally, in the heart, epinephrine binds to beta-epinephrine receptors on heart muscle cells, increasing heart contraction rate and thus leading to increased blood supply to body tissues.

Forensics Quiz

The bullet entered on the lateral side and traveled through the frontal plane on a 45 degree angle. First, the bullet likely went past the 8th rib and fractured it. The bullet was misdirected from the impact and came out around the umbilical region. The bullet would've gone through the heart causing massive internal bleeding, which would've caused the death. This diagnosis is best as it provides a short route for the bullet and is most plausible in route.

Other possible diagnoses:

1) Death from obstructed breathing: this diagnosis is implausible because with the suggested path of the bullet based on the injuries, the bullet would have not passed through the lungs. 

2) As the exit wound shows signs of a fragmented bullet, one possible diagnosis is that the bullet split up and damaged a wide range of organs, causing massive organ failure and eventual death. This theory could be checked by thoroughly checking all organs for signs of bullet penetration.

3) It is possible that the bullet would've fractured multiple ribs and perhaps affected the pelvic bone or spinal cord, causing the man to fall to the ground and not be able to get to help before bleeding to death. This could be again be check by thorough checking all ribs, bones, and surrounding area.

Lab Report: Cell Respiration

Abstract: In this lab, we tested if/how temperature affects the rate of cell respiration.  We used yeast -adding sucrose, warm water, and salt to induce cell respiration - and testing 3 different vials, each at different temperatures. Attached to each vial was a syringe and tubing used to check how much carbon dioxide was released through cell respiration. Although several factors affected the results of our experiment, our results showed that an increase in temperature initially increased the rate of cell respiration.

Introduction: In cell respiration, chemical energy from glucose is transferred into ATP.
The glucose is converted to ATP through a series of three steps called Glycolysis, The Krebs Cycle, and the Electron Transport System.  The formula for cellular respiration is C6H12O6 + 6O2 --> 6H2O + 6CO2 + ATP. This lab is designed to measure the CO2 produced from this reaction in order to proportionately measure the rate of cellular respiration.

Hypothesis: Compared to the control test tube at room temperature, the heated test tube will produce more CO2 and thus have a higher respiration rate, because at a higher temperature there is higher molecular movement that would increased the reaction rate. Accordingly, the chilled test tube will produce less CO2 and have a slower respiration rate, because at lower temperature there is slower molecular movment.

Materials:  

1. 105 mL warm water
2. 3g yeast
3. 3g sucrose
4. 0.3g salt
5. Beaker
6. Hot plate
7. Ice bucket
8. Scale
9. Stopwatch
10. 3 vials
11. 3 syringes
12. Graduated cylinder

Procedure:

1. Pour 35mL of water into each of the 3 vials.
2. Add 1.0g sucrose into each vial.
3. Add 0.1g salt into each vial.
4. Cover, shake, and then uncover each vial. Let them sit for 5 minutes.
5. Plug each tube with the stoppers attached to the syringes. 
6. Pull up each syringe to the 2mL mark.
7. Place each vial in their respective temperature conditions and start the stopwatch.
8. Record the new volume of CO2 in the syringe after every minute. After every recording, lightly press the syringe down.
9. Graph data.

Results: 

Conclusion:

     

     Our experimental results supported our hypothesis completely. The yeast in the heated vial produced the most  CO2 and therefore had the highest respiration rate. Conversely, the yeast in the chilled vial produced the least CO2 and had the lowest respiration rate. Although these results were what was expected, several sources of error might have affected our experimental results. The most prominent error was that the heated vial exploded and overflowed in the early part of the experiment. Therefore the CO2 volume readings are inaccurate, but should be around the correct range. Another source of error came from difficulty using the syringes and getting them to come back up after pressing down after each reading. 

Works Cited:

 Quick, Kevin, Holly, Kiamanesh, Rosie Montague, Jennifer Blanchette, and Barbara Akre. The Webb Schools Honors Biology Textbook. Claremont; CK-12 Foundation, 2012. eBook.