Three Feedback Loops & Homeostasis Of Each

Calcium homeostasis refers to the regulation of the concentration of calcium ions in the extracellular fluid. The two most important hormones for maintaining calcium levels in the body are the parathyroid hormone and calcitonin. As shown in the diagram, when the levels of calcium are too high, the thyroid releases calcitonin, causing an increase of calcium deposition in the bones, a decrease of calcium uptake in intestines, and a decrease of calcium reabsorption from urine, causing the calcium levels to fall. When the levels of calcium are too low, the parathyroid releases PTH (parathyroid hormone), causing an increase of calcium release from the bones, an increase of calcium uptake in the intestines, and an increase of calcium reabsorption from the urine, causing the calcium levels to rise.

Circulating levels of glucose are controlled by two enzymes, insulin and glucagon. As shown in the diagram, when the blood glucose level is high (mainly occurs after eating), the pancreas releases insulin, causing the liver to take up glucose and store it as glycogen and the body cells to take up more glucose, which in the end should lower the blood glucose level. When the blood glucose level is low, the pancreas releases glucagon and the liver breaks down glycogen into glucose, which in the end should raise the blood glucose level.

Thermoregulation (body temperature homeostasis) refers to the process of keeping the internal body environment in a steady state, when the external environment is changed. As shown in the diagram, when the internal body temperature rises above normal, thermoregulation in the brain is activated, causing sweat glands to secrete sweat that evaporates, eventually cooling the body, or blood vessels in the skin to dilate, allowing heat to escape, which should allow the internal body temperature to decrease. When the internal body temperature falls below normal, thermoregulation in the brain is activated, causing skeletal muscles to rapidly contract, causing shivering, which eventually generates heat and blood vessels in the skin to constrict, minimizing heat loss, which should allow the internal body temperature to increase. 

Why The Calculated Result & Theoretical Value Of ATP Is Different

Theoretically, aerobic cellular respiration should produce 38 ATP molecules. However, some of the hydrogen atoms in the intermembrane compartment diffuse through the inner mitochondrial membrane, reducing the amount of free energy in the electrochemical gradient, therefore reducing the amount of ATP that could be potentially produced. 

Enzyme Concentration

Amount Of Enzymes (Number Of Hole Punch Disks)	Volume Of Oxygen Produced (in mL)	Amount Of Time For Reaction To Take Place (in seconds)	Rate Of Reaction (in mL/s)
5	445	57	7.80
5	450	24	18.75
5	500	49.5	10.10
10	140	90	1.55
10	415	47	8.83
15	415	31	13.38
15	430	45	9.55
15	450	42	10.71
20	405	42	9.64
20	430	36.4	11.81
25	150	31	4.83
25	355	90	3.94

Note: Based on bubbling (or if oxygen is being released from the reaction), if there was no more bubbles seen, the reaction was stopped. The maximum time for the reaction to take place was 1 minute and 30 seconds, or 90 seconds.

Science Fair Topic

Tuberculosis is an infectious disease that can lead to death if untreated. Tuberculosis usually attacks the lungs but can also affect other parts of the body. It is spread through the air, when people who have the disease cough, sneeze, or spit. In more than nine out of ten patients, tuberculosis can be cured with appropriate treatment. Treatment for tuberculosis usually combines several different anti-biotic drugs that is given for at least six months, sometimes for as long as 12 months. In order for the cure to be effective, the patient must make sure that the right amount of medication is taken for the right amount of time. If too little medicine is taken, or the right amount is taken for a shorter period of time, a cure is less likely. Furthermore, there is a greater chance a person will become drug resistant.

Our science fair topic is to determine whether cocktailing two anti-biotics together would have a more effective result in curing tuberculosis or not.

The job of anti-biotics is to kill bacteria. If bacteria make it past our immune systems and start reproducing inside our bodies, they cause a disease. Anti-biotics kill the bacteria to eliminate the disease. An anti-biotic is designed to kill specific type of bacteria, but not to kill the cells in your body. Although there are a number of different types of anti-biotics, they all work in one of two ways: 1) kills bacteria, or 2) stops bacteria from multiplying.

Hypothesis: If combining two different anti-biotics used to cure the same disease, then will this increase the effect of the medication.

Controlled Variables: anti-biotic A, B, and C

Independent Variables: combined anti-biotics AB, BC, and AC

Dependent Variables: the number of bacteria killed

References

What is tuberculosis?. (n.d.). Retrieved from http://www.news-medical.net/health/What-is-Tuberculosis.aspx

Schoenstadt, A. (2006, October 10). Tuberculosis cure. Retrieved from http://tuberculosis.emedtv.com/tuberculosis/tuberculosis-cure.html

What are antibiotics? How do antibiotics work?. (2009, April 20). Retrieved from http://www.medicalnewstoday.com/articles/10278.php 

Second Law Of Thermodynamics

The second law of thermodynamics states that “in general, the total entropy of any system will not decrease other than by increasing the entropy of some other system.”

Entropy is defined as a “thermodynamic property that is the measure of a system’s thermal energy per unit temperature that is unavailable for doing useful work”.

A common example of increasing entropy is ice melting in a warm room, described in 1862 by Rudolf Clausius as an increase in the “disgregation” (the magnitude of the degree in which the molecules of a body are separated from each other) of the water molecules in ice: order leading to disorder (more random).

In a system isolated from the environment, the entropy of that system will tend to not decrease. In addition, it is impossible for any device operating on a cycle to produce net work from a single temperature reservoir. The production of net work requires flow of heat from a hotter to colder reservoir. As a result, there is no perpetual motion system. A reduction in the increase of entropy in a specific process, such as a chemical reaction, means that it is energetically more efficient.

The entropy of a system that is not isolated may decrease. For example, an air conditioner may cool the air in a room, reducing the entropy of the air in the room. The heat expelled from the room, which the air conditioner transports and discharges to the outside air, will always make a bigger contribution to the entropy of the environment than will decrease the entropy of the air in the room. Therefore, the total entropy of the room plus the entropy of the environment increases. This example proves the second law of thermodynamics.

References

Second law of thermodynamics. (n.d.). Retrieved from http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/seclaw.html

Benson, T. (2008, July 11). Second law of thermodynamics. Retrieved from http://www.grc.nasa.gov/WWW/k-12/airplane/thermo2.html

Laws of thermodynamics. (2010, May 18). Retrieved from http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookener1.html

Understanding Cochlear Implants

Deafness is defined as a degree of impairment such that a person is unable to understand speech even in the presence of amplification. However, should being deaf be considered an impairment, or even a disability?  What is the difference between the two? A disabled person is one with an impairment who experiences disability. Disability is the result of negative interactions that take place between a person with an impairment and his or her social environment. Impairment is therefore part of a negative interaction, but it is not the cause of, nor does it justify, disability. (1)

A mutation is a permanent change in the DNA of a gene. Most mutations are silent (cause no real change) or neutral (cause a change that does not make any real difference). Of those that do make a difference, most are harmful (at least in the organism’s current circumstances), but a small percentage simply cause an alteration in function, or may even provide an advantage. (2) Also, whether a mutation is harmful or not is sometimes situational – a change which is harmful in some situations may actually be beneficial in others. (2)

Depending on the altercation of the genetic code, it would be considered a blessing or a curse. For example, if the genetic code was mutated and there are no obvious changes in the phenotype, this mutation could aid the organism. It is possible that the abnormal protein functions more efficiently than the normal protein, it may be beneficial to the organism.

I disagree with the fact that anyone, even if they are disabled or not, should have the right to abort their child. Abortion should not be allowed where the baby, if born, would suffer from physical or mental handicaps. Allowing this as a reason for abortion is offensive to disabled people because it implies that they, and their lives, are less worthwhile than the lives of “normal” people. Therefore, disabled people should not have the right to abort their child either if they are born “normal”.

Cochlear implants function differently from heading aids. A cochlear implant uses electrical signals to stimulate the auditory nerve. (3) This allows sound to skip around damaged hair cells in the cochlea and go directly to the brain. (3) The user has a speech processor that collects sound and converts it into electrical signals. The processor then sends those signals to the coil on the user’s head (held in place by a magnet under the skin). The coil in turn transmits the electrical signals to the cochlear implant electrodes inside the cochlea. The electrodes stimulate the auditory nerve, and the auditory nerve sends the signals to the person’s brain to be interpreted into sound. (3)

In my opinion, Heather should get the opportunity to get the cochlear implant. She is still at a young age where learning to speak properly is possible. Even though her parents never got the opportunity to interact with the hearing, they should allow Heather to experience what it is like to hear. Heather will still be able to communicate with her parents through sign language. Just like any type of surgery, there will be risks and the costs will be expensive. However, this will allow for Heather to be involved with school and other extra-curricular activities that will eventually shape her personality and change her life in a positive way. 

References

1. About mutation. (2004, September 25). Retrieved from http://www.cod.edu/people/faculty/fancher/Mutation.htm
2. Chadwick, A. (n.d.). Defining impairment and disability. Retrieved from http://www.leeds.ac.uk/disability-studies/archiveuk/Northern%20Officers%20Group/defining%20impairment%20and%20disability.pdf
3. Berke, J. (2011. June 22). What is a cochlear implant. Retrieved from http://deafness.about/com/cs/cochlearfeatures/a/cochlearimplant.htm

How Does Nature Protect Our Genetic Code?

What Is The Genetic Code?

The genetic code has three important characteristics.

1. The genetic code is redundant. This means that more than one codon can code for the same amino acid. There are only three coons that do not code for any amino acid. These codons serve as “stop” signals to end protein synthesis.
2. The genetic code is continuous. This means that it reads as a series of three-letter codons without spaces, punctuation, or overlap. Therefore, knowing exactly where to start and stop protein synthesis is essential. A shift of one or two nucleotides in either direction can alter the codon groupings and result in an incorrect amino acid sequence. (1)
3. The genetic code is nearly universal. The universality of the genetic code means that a codon in the fruit fly codes for the same amino acid as in a human. This has important implications for genetic techniques, such as cloning. A gene that is taken from one kind of organism and inserted into another organism will produce the same protein. (1)

Cells utilize numerous repair processes to safeguard their DNA from damage.

1. As DNA replication proceeds, the replication complex through which DNA is threaded simultaneously builds a new strand of DNA and proofreads the work. Proofreading involves many of the enzymes of the replication complex, but DNA polymerase III plays perhaps the most important role. When DNA polymerase III inserts an incorrect nucleotide in a growing strand of DNA, it usually recognizes their mistake immediately, removes the nucleotide, and replaces it with the correct nucleotide. This proofreading mechanism alone greatly reduces to error rate of DNA replication. (2)
2. After DNA replication is completed, a second mechanism similar to the proofreading mechanism scans the new strand of DNA for errors missed by proofreading. When errors are found, incorrect nucleotides are removed and replaced by DNA polymerase III. This mechanism is called mismatch repair. (2)
3. During the life of a cell, there is always the potential for damage to the cell’s DNA, which in turn could result in the production of non-functional proteins. The DNA may be exposed to different mutagens which can chemically alter nucleotides, for example ultraviolet light. To guard against this type of damage, specialized enzymes continuously scan the cell’s DNA for any damage such as mismatched base pairs or even extra nucleotides. When damage is encountered, short stretches of DNA may be removed. These stretches are then replaced with the proper nucleotides through the activity of DNA polymerase and DNA ligase. This type of repair is called excision repair. (2)

References

1. The genetic code. (2010, April 22). Retrieved from http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Codons.html
2. Dna proofreading and repair. (n.d.). Retrieved from http://www.sci.uidaho.edu/bionet/biol115/t6_cell_growth/PDF/T6L2M2_DNA_proofreading_and_repair_transcript.pdf

Genetic Breakthrough PowerPoint Slide

Post lingual non-syndromic hearing impairment is a rare form of progressive deafness in males.

University of Miami Miller School of Medicine researcher Xue Zhong Liu lead a team that recently discovered a gene that provides instructions for making an enzyme that helps produce a molecule involved in making purine and pyramidine nucleotides. This gene plays an important role in the development and maintenance of the middle ear. It was found to be an interesting example of a human disease gene in which gain or loss of function mutations causes several different and distinct hereditary disorders.

Resources

Researcher wins new grant to explore molecular mechanisms of genetic hearing loss. (2012, July 9). Retrieved from http://med.miami.edu/news/researcher-wins-new-grant-to-explore-molecular-mechanisms-of-genetic-hearin/