We were asked to solve a crime in this lengthy project. We completed many labs in order to gain information on the murder of Carleton Comet and looked at the suspects Nancy Normal, Fred Flimmer, Glen Glee, Theresa Terra, and Sam Sophomore. This project helped us learn many different procedures used in investigations and we had a great time doing so as well. After we had completed most of the labs, a couple detectives from the Novato Police Department came in and presented to us what they do in investigations, as well as took a quick look at what we were doing. Afterwards, we were told to present our evidence in a presentation to a court of "judges" (past STEM students) to obtain an arrest warrant for our suspect. The presentation with all our information and evidence necessary to receive the arrest warrant is as follows:
Fingerprinting
In fingerprinting, we checked the different fingerprints of members in our class to first get accustomed to seeing the multitude of patterns visible on our fingerprints. The main ones of these are whorl, arch, and loop, with the whorl and arch being dominant, the loop co-dominant. We then put this information to the test and looked at fingerprints found near the crime scene, comparing them to the fingerprints of the suspects in order to find out who was nearby. This began with us dusting pieces of glass to look for fingerprints, transporting them over for easier inspection and then comparing them to a sheet of all the suspects
Ink Chromatography
In ink chromatography, we were tasked with finding out who a pen belonged to. At the crime scene, there was a note with the words "You are a dead man" written on it. The police analyzed this pen and found the ink pigments inside of it, shown below:
In ink chromatography, we used an alcohol solution in order to separate the individuals pigments of a pen out from each other. By letting the ink be exposed to the alcohol, the solvent (The liquid in which a solute is dissolved to form a solution), the ink spreads across the paper, the solute (A compound in a solution that is dissolved in the solvent) as it dissolves. This allows us to see the different types of dye inside each pen and ultimately find out who the pen that wrote the note belonged to.
Some more vocab in this section is:
|
DNA Structure
Closer to the beginning of the unit, we started off by learning the basic structure of a DNA/RNA strand, what the differences were, and what went into creating them. DNA is found in a double helix shape, with nucleotides in base pairs of A to T and C to G supported by a sugar phosphate backbone. DNA is found in all cells, more specifically eukaryotes found in the nucleus. Each base is always connected with its pair and the supporting phosphate bond always repeats in the exact same way. The backbone either runs 5 prime to 3 prime, or 3 prime to 5 prime, based on where the chemicals bond with each other. This is used later on in DNA replication. Some differences between RNA and DNA is that RNA has only one chain, it uses ribose for sugar while DNA uses deoxyribose. RNA has uracil as one of its nucleotide bases while DNA uses thymine.
|
Our body is able to take this DNA and use it to create all of the proteins in our body in a process called Protein Synthesis
- DNA molecule unzips to reveal a section of coding for the protein needed
- An mRNA molecule forms along the unzipped section of the DNA molecule
- The mRNA separates from the rest of the DNA molecule
- The mRNA leaves the nucleus and is transported to the ribosomes
- A tRNA molecule brings specific amino acids to the ribosome
- These amino acids join together to form the beginning of a new protein
DNA Replication
In this portion, we learned about DNA replication and the process of "unzipping" a DNA strand and copying it, used in both meiosis and mitosis, as well as throughout all of our body at every given point. The DNA in each cell of the same organism is identical, with two intertwined strands of weak hydrogen bonded nucleotides in no particular order but with the same pattern. From here, replication takes place. In the nucleus, the enzyme "helicase", "unzips" the DNA, exposing the unpaired bases. Two different strands are created through this, a leading and a lagging strand:
|
Genetics
Throughout the entire portion of this project, there were many basic vocabulary words we were required to know that are listed to the right.
|
|
DNA Mutations
In our groups, we researched and made unique presentations, ranging from websites, to videos, to skits, of a few of the many different types of mutations that are present in DNA. Some of the most noteworthy were:
|
Our group specifically did our mini-project on Frameshift Mutation and performed a skit, our document with the research and script is shown below:
|
Chromosomal Disorders
Throughout this project, there were a good amount of chromosomal disorders that we encountered through research on the suspects as following:
- Huntington's Syndrome: This disease affects the elderly and is caused by inheritance from others (ancestry/genetics). It is dominant and leads to the deterioration of brain cells
- Marfan Syndrome: This disease can affect anybody and is caused by inheritance from others (ancestry/genetics). It is also dominant and can be identified by the subject being tall/slender, with longer than average arms, legs, or fingers
- Triple X Syndrome: This syndrome affects only women and is caused by a mutation that results in an extra X chromosome. It is a random genetic disorder and therefore not dominant or recessive. It results in taller than average height, flat feet, seizures, and development issues
- Klinefelter Syndrome: Also known as the XXY Karyotype, it results in an extra X chromosome in only males. It is neither dominant nor recessive due to it being a random genetic disorder. It results in less body hair and breast enlargement
- Down Syndrome: This is caused by an error in cell division, leading to an extra 21st chromosome. As it is due to random chance, it is neither dominant or recessive and is identifiable by a short neck, upward slanting eyes, and a specific facial profile best described as "droopy"
- Jacob's Syndrome: Also known as the XYY Karyotype, this syndrome is found only in males and caused by mutation, therefore cannot be dominant or recessive (not inherited). It results in the subject being taller than normal, with learning problems and weak muscles
Karyotypes
This was the process used in order to find most of the chromosomal disorders. Karyotypes are a visual representation of the number of chromosomes in a species and we looked at human karyotypes. Normally, humans have one X and one Y chromosome, however many of the suspects had unusual disorders caused by their unequal number of chromosomes. The karyotypes of each suspect, as well as their disorders are shown below:
Pedigrees
The other process we used to figure out motive and certain chromosomal disorders were pedigrees, taking an extensive view of each of the suspects' family trees to better find out their situation. Since Carleton Comet, better known as Thomas Sandstone, directly influenced the lives of every single member at the picnic, we are able to figure out how close their relation to him is and how much he has negatively affected their lives. We made smaller pedigrees of each of the suspects and then created one with everyone for our final project. Some identifiable features/information pedigrees are that:
- It is a family history of a specific trait
- Males are square
- Females are circles
- Filled means that they exhibit the trait
- Horizontal line between two symbols means that they are mating
- Vertical line descending from parents to a horizontal line is shared by the offspring
- Diagonal line through symbol means that the individual is dead
- Roman numeral stands for the generation
- Arabic numeral stands for the birth order
- A combination of those stands for specific people
- On certain pedigrees, carriers (one that carries the trait but does not exhibit it) will often be marked out
Reflection
Personally, I think I did really well on this project. I was the one doing most of the work in our group and on task the whole time. I had to complete most of the assignment and the labs myself without help from my group. I didn’t go and talk to other groups unless asking them for their results in a lab or help on a certain portion. I completed the project and was able to obtain an arrest warrant. I followed all of the instructions and finished the labs before the allotted time. Our slideshow was gone over many times and I even photoshopped an image for it on my own time. I had solid evidence and samples throughout the whole project, that directly showed how much work and effort I put in. Some things that could have been done better were the fact that I was less empathetic during this project for good reason. One of our group members was almost always off task and not where he should be. He did not contribute to the project at all, was always distracted, and consistently tried to distract us from doing our work. Therefore he struggled to stay on task and did not complete any of the steps we asked him to do, ending up having to do them ourselves. All in all, I think our group did a good job, with a pretty good presentation and slideshow, obtaining the arrest warrant, however, the amount of work that each of our group members did was very skewed.