Writing in Biology

You may think that cells just live, grow, and survive on their own, but cells actually need signals that tell them to survive. The survival signal pathway plays an important role for controlling cell survival and programmed cell death. If there are certain changes or mutations in this pathway, it can lead to uncontrolled cell death or survival. The key players in this pathway are RTK, PI 3-kinase, PIP3, Akt, Bad, and Bcl2. When the survival signal binds, it causes cross phosphorylation of RTK to occur. The added phosphates act as a binding site for PI 3 kinase. When PI 3 kinase binds to RTK, it is activated and phosphorylates PIP2, creating PIP3. Once phosphorylated, PIP3 is a binding site for Akt as well as protein kinase 1. Protein kinase 1 and 2 phosphorylate Akt, which leads it to dissociate from PIP3. As a result, Akt can phosphorylate Bad, preventing it from causing programmed cell death. Inactive bad allows Bcl2 to inhibit programed cell death and send the survival signal.

Saving the Labrador Retriever is the most logical decision. The Labrador Retriever is the breed with the largest litters. By saving a pregnant lab mother, there is a better probability of getting a large number of young. With a greater number of young, there is a larger chance of getting both male and female puppies. In addition, when the next generation is then born they will also likely have large litters leading to expanding the population more rapidly. 

Due to the new retrovirus that is killing domesticated dogs and only one vaccine being available, a decision has to be made on which dog breed to try to save. Dogs have earned the nickname “man’s best friend” because they are often loyal, and become a part of the family. All different breeds of dogs have shaped the lives of many Americans. Unfortunately, not all breeds can be saved, so it it important to look at which breed should be saved by thinking credibly, logically, and compassionately. Looking at these categories it becomes clear that the vaccine should be given to a pregnant Labrador Retriever. 

• Why does a multipolar neuron have lots of dendrites but only one axon?

• Multipolar neurons are the most common shape for neurons in your brain--what advantages do multipolar neurons have over unipolar or bipolar neurons?  Are there any disadvantages?

• How many synaptic connections does a single neuron usually make?  Take a guess, or do some outside research to answer this one!

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    The primary function of a neuron is to both transmit information and to process it.  The multipolar neuron is shaped so that it has many dendrites and only one axon. This allows for an efficient processing and integration of information from multiple presynaptic neurons.  These neurons have only one axon because it takes a lot of energy to send information to postsynaptic neurons. Many dendrites allow for multiple presynaptic axons to deliver information to one post synaptic neuron.  The unipolar neurons only have one process, a single axon from the cell body. They are only good seen as sensory neurons. Bipolar neurons have an axon and a dendrite and are also sensory neurons. Multipolar neurons are superior as they can collect more information and be used for both motor or association neurons, allowing for muscle movement or communication among the CNS.  There are no really big advantages and disadvantages as they both perform unique tasks that are needed. Each average neuron is connected to about 10,000 synaptic connections.

This paper dealt with spider web production in terms of web mass and temperatures affect on it. They used 20 female spiders and randomly assigned them to one of their 4 temperature groups. They kept them at the temperature for six days. Fruit flies were dropped into the web with an apparatus. They created a gradient of temperatures by putting two aluminum pans on a hot plate. The pans were positioned in such a way that the entire pan wouldn’t get hot. The different temperature regions were indicated by marking on the pan, not barriers that the spider could not cross. They found that web mass was much lighter in the colder conditions.

Before 2002, the dogma surrounding rod and cone cells was that they were the only cells with photosensitive properties in the retina of the eye. It was also known that light entrainment and the circadian cycles are tuned by environmental influences. Scientists knew that exposure to different light cycles can reset the circadian clock, but did not know how this worked. Humans and mice that lacked rods and cones could still reset their circadian rhythms. They hypothesized that there must be another mechanism in the eye besides rod and cone photoreceptors to allow for this photosensitivity. Their question was: Could melanopsin be a photo pigment protein that allows retinal ganglion cells (RGC’s) to be light sensitive?

The vaccine should be given to a Labrador retriever because the American Kennel Club which is a highly respected organization says that the Labrador Retriever is the number one most popular dog breed. Labs are the number one owned dogs by Americans. If the majority of dog owners in America own Labrador Retrievers, then it is clear that they are great dogs and deserve to be the breed that is saved. 

Saving the Labrador Retriever is the most logical decision. The Labrador retriever is the breed with the largest litters. By saving a pregnant lab mother, there is a better probability of getting a large number of young. With a greater number of young there is a larger chance of getting both male and female puppies. In addition, when the next generation is then born they will also likely have large litters leading to expanding the population more rapidly. 

Reserve 2 is one subunit in a ring formation. There is a hole in the middle of the subunit in order to create some sort of separation and differential interactions between the ferrets. This intended dispersion, due to the ring formation, was created to reduce the disadvantages that a single unit reserve obtains. An example of a disadvantage to a single unit reserve would be that the entire population is affected when an allele is lost, instead of a single subpopulation. Yet, I made Reserve 2 a single unit in order to promote more breeding between the ferrets. The increased breeding results in higher heterozygosity, decreasing the risk of genetic drift and the loss of alleles.

Reserve 1 contains decently sized subpopulations that are connected through smaller columns. The subpopulations are rectangular and stacked on top of each other. The columns that connect each subpopulation allow the ferrets to interact between each section. When making this reserve, I wanted to combine the advantages of subpopulations and large reserve size. The subpopulations allow lost alleles to decrease the negative effects on the total population. The large subpopulation size and the columns connecting the subpopulations allow for more interactions between ferrets, resulting in more heterozygosity. The more heterozygosity in the population, the risk of genetic drift and lost alleles is decreased.