Saturday, April 29, 2017

Weekly Bio Journal #8 April 29

This week revolved around our transpiration lab. Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere. Our task was for each group to test a different variable and observe how it may affect a plants rate of transpiration. My group tested how changes in pressure can alter the transpiration rate. Our actual results were difficult to interpret because the initial set up of the pressure vacuum was difficult to create and may have been done incorrectly. We placed the plant stem and leaves upside down in flasks and stoppered the end with a tube connected to a pipette that would measure the rate of transpiration. What ended up happening because the experimental plant was in a closed environment (in order to create a pressure vacuum), the water levels would drop only to rise again later as all the water cycled through had no where to evaporate to except back into the water well. We shall see how we interpret our findings next week. We also completed a packet on the structure of neurons and took notes on Paul Anderson's Podcast on animal communities, and animal ecosystems.

Friday, April 7, 2017

Weekly Bio Journal #7 April 7

This week in biology we started off by taking a quiz on inheritance. This took most of class so we spent the remainder discoing 4.11 and 4.12. That night we watched a 15 minute video on the evolution of stickleback fish and how after generations of living in freshwater, something in their genetics stopped coding for a pelvic spine. From observing these fish scientists learned that our DNA can still possess a gene but choose not to express it through a process called gene regulation. These regulatory switches known as "enhancers" in eukaryotes are specific areas in the DNA where specific activator proteins will bind to turn the gene on or off. What is interesting is the same gene can be expressed in one location on the organism while not expressed in another. While it is the same gene throughout the body, there are multiple switches that can enable or disable it in the selected region.
We studied the first section of the regulation unit this week as well and learned about developmental genetics. The key information here was how every cell in our body can contain the same DNA yet have vastly different functions, Enter the process of differentiation where at the cells early stages it recieves signals from surrounding cells that determine its developmental pathway. We also learned about transposable elements which are non-coding DNA segments that catalyze their own replication and movement throughout the genome. Wednesday the Juniors were out taking the SAT and we spent the next two days working on a specific presentation of a regulation system (circulatory, exretory. nutritional, ect.). This is to famiiorize ourselves with the systems we will study this unit of regulation

Saturday, April 1, 2017

Weekly Bio Journal #6 April 1

This week in bio we focused on modes of inheritance. The biggest part of the week was our virtual fruit fly lab. Here we were tasked with crossing specific traits from fruit flies and from the resulting phenotypes of offspring from first and second generations, we were to predict the genotype of the parents and the inheritance pattern of the traits. We would test our hypothesized inheritance pattern by entering the expected values as predicted by the ratios given by the inheritance pattern, into a chi-square analysis. The first two crosses of fruit flies went swimmingly and I was easily able to predict the inheritance pattern. But the third and fourth crosses gave me particular trouble. The root of the problem for cross three was because when I got home I accidentally gave the wrong gender the trait of white eyes. This trait was supposed to be sex linked and giving it to the wrong sex altered the outcomes from what was originally intended. The fourth cross was one of our own design and after dealing trying fruitlessly to solve what I had done wrong in the third cross, my patience was thin come the dihybrid of the fourth cross and I was unable to accurately predict the inheritance pattern. When I am given known genotypes it is easy for me to predict the probability of certain outcomes, but it is harder for me to work backwards and determine inheritance patterns because there ares so many patterns from, autosomal dominant, recessive, sex linked, co-dominance, incomplete dominance, or perhaps the homozygous dominant or other genotype is fatal. I will need more practice to get it all down,
This week we also completed the Vodcasts on Mendelian extensions in which we learned some of the other modes of inheritance that go beyond the simple Dominant/recessive relationship. We also learned of some specific human conditions and how they are inherited like hemophilia and cystic fibrosis. Thursday we worked on more Mendelian genetics problems and practiced some grid in questions that would appear on the AP exam. Friday we worked on multiple choice questions from an actual AP Exam of a couple years ago in spirit of the up coming exam now only 37 days hence.