Common ancestry- Addison

     Studying the genetic code of organisms give biologists an idea of common ancestors among organisms. Mammals all have very similar genetic codes and only have a little bit of variance in amino acid sequence that changes their species. This may hint that we all derived from the same species. For example, scientists are able to compare the different bone structures that are similar in different species, and see where other species may have diverged from. Humans have a tailbone, but we do not have a tail. This suggests that we share ancestry with organisms who have a tail, and may have derived from a species that had one. This is because our genetic code is so similar to other mammals who have a tail.

    Membrane bound organelles are also a hint at common ancestors. There is evidence to suggest that mitochondria once was actually a prokaryotic bacterial cell. And over time it worked with and engulfed another to have one organism inside of another. This shows that the common ancestor of mitochondria and other membrane bound organelles are prokaryotes. Over time these different organisms worked together called endosymbiotic theory, and created the membrane organelles that now work in our body.

   All bacterial cells have circular chromosomes, while eukaryotic cells have linear chromosomes. This, again suggests a common ancestry among all prokaryotic organisms and al eukaryotic organisms. Because all prokaryotes have circular chromosomes, we can assume that one prokaryotes had this and passed it on for many generations. The same can be said for eukaryotes. All eukaryotic cells have linear chromosomes, and not circular. This is another reason why eukaryotic organisms are more similar gat prokaryotic ones. Prokaryotes cannot have the linear chromosomes because they did not derive from eukaryotes.

    

Endergonic Vs. Exergonic -Ami

Endergonic: Photosynthesis is an example of an endergonic reaction. An endergonic reaction requires a high amount of activation energy to begin the process. This process would absorb free energy to store within the plants and is nonspontaneous. Nonspontaneous means that they require energy to be input in order for the reaction to occur. The overall change in free energy is positive, and this is an anabolic reaction because it builds up energy.


Exergonic: Cellular Respiration is an example of an exergonic reaction. An exergonic reaction requires a smaller amount of activation energy to start the reaction because the reaction is spontaneous. This means that they can occur without energy input. The overall change in free energy is negative, and this is a catabolic reaction reaction because it gives off energy.

These reactions interact with each other because through energy coupling the use of an exergonic process such as cellular respiration can be used to drive photosynthesis. Both of these are significant reactions because they are necessary to our survival and for plants to survive. 

Artificial Selection -Ami

Artificial selection is basically selective breeding. Humans have impacted this because we choose which traits we want to have and breed out bad traits. For example, with dogs, we have tried to breed out aggression and anger. We want dogs to be playful and happy and in order to do this we have chosen a species to breed again and again to make something more favorable.

Because dogs are kept in home their environment is around children. Because of this people have strayed from wanting aggressive dogs, they may have once used them to guard their land or protect their property but are rarely used for that purpose anymore.

In the future we may need guard dogs or we may need some animals that are aggressive but we have attempted to end these traits. Dogs are seen as house pets and in the future I believe they still will be just house pets. They are playful because of the way we have bred them over time.

Loss of genetic diversity within a crop species- Addison

     Evolution is the change over time. As the environment changes, animals must adjust in order to survive. For example, peppered moths mushy adapt based on the trees that there are in the forest. In a light forest, lighter moths survive because they can be more easily blended in. The same is true for a dark forest but with dark moths. If the moths migrate to a forest with the opposite of their color, they will need to adjust to thier new environment and slowly edit their traits over a span of time.
      Humans are altering the environment by removing forests to build buildings, and they also contribute to global warming. This impacts the environments that different animals live in, causing them to need to change for their new environment. If they cannot adapt over time, their species will die out and become extinct
   

Restriction Mapping of Plasmid DNA

The purpose of this lab was to use restriction enzymes in order to compare the DNA using gel electrophoresis.

Introduction: Restriction mapping of DNA allows sequences of DNA to be recognizable. Restriction enzymes cut the DNA sequence as well as allow you to find the position of the DNA. You can see how far the DNA travels using the method of gel electrophoresis.  How far the segments travel on the gel relates to how long the DNA fragment is. Smaller fragments of DNA move further than longer segments. Smaller segments have less DNA, and less to “carry” so they travel further. DNA has a negative charge and is placed on the negative side of the gel. A current running through allows the DNA to travel to the positive side of the gel. Smaller bands are on the positive side of the gel, while larger pieces stay by the negative side of the gel. You can tell which fragments are smaller, larger, and which may have been been broken off from their original fragment.  

First, we got a pre made gel that had already been set and placed it into a plastic holder. This allowed us to determine which was the positive and negative end.

Next, we loaded the gel. In each well of the gel we placed the different DNA. We used 1 pipet per tube of DNA in order to extract the DNA and place it into the appropriate well without contamination. We made sure to place all of the DNA inside of the well so that it took up the entire space.

Then, the electrophoresis chamber was closed and power was run through it. After the current was applied for some time, the gel started to move from the wells to the other end of the gel. After left for some time, we removed the gels and were able to see the bands that had formed due to the current running through the gel.

    After we removed the gel from the electrophoresis chamber, we used a light box in order to examine where the DNA bands had formed.

Using a bag we marked where each of the bands had been and where the wells were. This allowed us to have a permanent source of data incase something were to happen to our gel or bands so that we could not see where they ended up.

We were then able to measure the bands and find out what the distances were from one band from the next.    

Discussion: We were able to use gel electrophoresis in order to map a plasmid. There are two PstI restriction enzyme cut sites since the channel in he fell shows two markings. There are two SspI sites since the channel cut SspI creates two new fragments from one large fragment cut by PstI. There are two HpaI restriction enzyme cut sites. Since the HpaI creates new two fragments from one large fragment cut by PstI. When the DNA was cut with HpaI,HpaI/SspI, and HpaI/PstI the fragment length of 1093 was made. This means that HpaI cuts the DNA at this point and that it will remain unchanged when oh her restoration enzymes are added to HpaI. The 4700 segment cut by HpaI is cut even more when you add SspI or PstI. When you add SspI the segment is cut into pieces 1986 and 1700 long . When you add PstI the 4700 segment is cut into pieces 2140 and 514 long. Based on these observations we were able to label our plasmid to see which restriction enzymes cut where. Based on our plasmid pictured above, we decided that HPAI cuts both at 514 and 805 are further cut by SSPI which cut at 1159 and PSTI at 1900.We compared this data to our gel to see how many bands each had and compared them to the row before to determine where the next restriction enzyme would cut. We know the largest cut is PSTI because of the distance that it travels and because the other restriction enzymes do not cut that piece of DNA, it is only cut into about half which is still a large piece.

Conclusion: From restriction mapping, we are able to determine where certain restriction enzymes cut. This helps us determine the size of the fragments of DNA. From gel electrophoresis, we are able to compare a test piece of DNA to other fragments of DNA being tested. Also, on the gel by the distance that the DNA fragment travels we are able to tell the relative size. Based on the distance traveled on the gel and the other restriction enzymes we are able to draw a plasmid (pictured above) and determine the cuts in the plasmid for the relative sizes of DNA.