Question

Question 1 essay writing-just one page

part A

Nitric oxide is involved in firefly flashing. Studying this could provide information to help us understand the action of nitric oxide in other systems. What processes are regulated in humans by nitric oxide? Look online and find a few. Give some examples.

part B

In what way would understanding python digestion mechanisms help humans?

   Read the paper on python digestive physiology (python digestion paper 1 on Blackboard)
• Write a page IN YOUR OWN WORDS about what changes after meals and how understanding it better could help us (and why).

Answer 1

Answer for part A:

Nitric oxide soluble and highly reactive gas that is also involved in signalling transduction pathway. It is produced by both plants as well animals from amino acid Arginine. Since it is a very small molecule, it has a higher ability to diffuse across the cell membrane. Nitric oxide helps in mediating and activation of guanylyl cyclase or causes nitrosylation of proteins. It also causes inhibition of oxygen consumption by mitochondria, and this functioning causes the flashing process in the fireflies. Fireflies have light producing units called Photocytes. They have a protein called Luciferin that is acted upon by an enzyme luciferase. The luciferin-luciferase reaction occurs in the peroxisomes of the photocytes. Luciferin is activated by luciferase in the presence of ATP dependent step where a luciferin-adenylyl intermediate is formed. In the presence of oxygen, this intermediate is degraded into oxyluciferin and emitted photon. Nitric oxide inhibits the usage of oxygen by the mitochondia of photocye immediately, which this causes the triggereing of light producing reaction in the peroxisomes.

SOME OTHER PROCESSES IN HUMAN BODY REGULATED BY NITRIC OXIDE:

1.DILATING OF BLOOD VESSELS- During the inflammatory reactions in the body, bradykinin and histamine are secreted that causes the release of nitric acid. It has a half life of merely 6 seconds so it is readily released from the endothelial cells as soon as they are produced. As the nitric oxide diffuses out, the smooth muscles activates the guanylate cyclase and leads to increase in cGMP levels that in turn causes relaxation of smooth muscles.

2. PLATELETS AGGREGATION- Platelets have plethora of growth factors to mediate the process of angiogenesis. These includeEndostatin and Vascular Endothelium Growth Factor. The ability of platelets to adhere to endothelium and their aggregation primarily depends upon the nitric oxide. This further helps in regulating the inflammatory process.

3. INTERACTION WITH ENZYMES- Nitric oxide interacts with various enzymes to alter ther functions. For example, it inhibits iron-containing enzymes functioning in mitochondrial Electron transport chain. It also contributes to tumoricidal activity on macrophages. It has a tendency to inhibit the transcriptional events by blocking the action of NF-kB.

4. NEUROTRANSMISSION- Nitric oxide acts as a neuro-transmitter. Due to its small size and higher solubility, it can diffuse readily and can act upon other neurons which are not connected by the synapse but are in the vicinity.