DNA Extraction Lab

The question of the lab was, "How can DNA be separated from cheek cells in order to study it?". We claimed that DNA can be extracted through three different steps, homogenization, lysis, and precipitation, which is where the DNA first becomes visible. Homogenization was when we swished Gatorade in our mouth and spit out cheeck cells, and let the Gatorade break them down. Lysis was when we added salt, detergent, and then the pineapple juice as the protease  to destroy the cell membrane or wall. Precipitation was when we added alcohol and the DNA became visible at the top because the Gatorade is nonpolar and the alcohol is polar. After our procedure was completed, we were able to see small strands of white lines in our alcohol solution which was DNA and after completing the procedure twice we got the same result. This shows that DNA can be extracted from cells and can be seen if following the right procedures.

While our hypothesis was supported by our data, there could have been a few errors. First, the alcohol could have mixed with the Gatorade if you poured it too hard. That would cause the DNA to remain unseen because it would not rise to the top. Second, there could have been too much  Gatorade and/or too little cheek cells . That could have caused the DNA to not show up or not float up to the alcohol during precipitation. Due to these errors, in future experiments, I would recommend to have a measured amount of Gatorade and wipe the inside of the cheek with cotton around ten times. To solve the Gatorade and alcohol mixing, you should tilt the Gatorade test tube and let the alcohol trickle in. 

  This lab was done to demonstrate that DNA could be separated from cheek cells in order to study and observe it. From this lab I learned and what an enzyme help create a reaction an eventually some DNA, this helps me understand how a enzyme works on a larger scale. Based on my experience from this lab, I could apply this knowledge to another situation if I were to maybe look at DNA on more of a molecular level, and needed to re-create someones DNA in that kind of form.

Unit 4 Reflection

This unit was all about sex and why it's so great and interesting! I learned a lot about myself and what helps me learn. In the VARK questionnaire, my visual score was a 7, my aural score was a 9, my reading and writing score was a 2, and my kinesthetic score was a 10. I learned I learn better with hands on activities, and in the case of biology, I learn the best with labs. The Passing on My Genes Mini-Lab and the Coin Sex Lab really helped me understand how new combinations of alleles are made and how they are passed on. My second best learning style is hearing. these are the two things I will use to study for the test. For the kinesthetic part, I will try to find online labs relating to what we learned this unit, specifically on mitosis and miosis. For the hearing part, I will listen to Mr.Orre's vodcasts again and try to take in the information. The themes about this unit was all about the cell cycle and Mendel's laws in genetics. We also learned about genetics and the difference between mitosis and meiosis. My strengths were using Punnett squares to predict what offspring would look like and the autosomal and x linked inheritance. Some things I need to work on are mitosis and meiosis, and how they are different. I learned a lot from the infographic because the infographic made me understand the different topics that were covered in the unit. Pictures and the information brought everything together for me. I am indeed a much better student than I was before this unit started!

Coin Sex Lab

In this lab, we learned how to use punnet squares to predict what our offspring will look like and what traits they will have. The coins served as genes and the two sides of the coins served as alleles. The flipping of the coin modeled meiosis and putting them together modeled recombination, or in other words, sex. The coins also showed how probability of something happening can be different from what actually happens. We did multiple autosomal crosses, where the sex chromosomes are not involved, and one x-linked cross, which is when the sex chromosome are involved. We used two sets of a coin each to represent a monohybrid cross, and two sets of two coins each to represent a dihybrid cross. In a few of our tests we labeled both sides of the coin the same letter to represent a homozygous trait, but in others we labeled the two sides differently to represent a heterozygous trait. When we preformed the di-hybrid cross, we got results that were slightly different than what was expected. The punnet square gave us a phenotype ratio of:

9 Brown Hair, and Brown eyes : 3 Blond Hair, and Brown eyes : 3 Brown Hair, and blue eyes :

1 Blond Hair, and Blue eyes

Our experiment had slightly different results, and gave us the phenotypic ratio of:

8 Brown Hair, and Brown eyes : 4 Blond Hair, and Brown eyes : 2 Brown Hair, and blue eyes :

2 Blond Hair, and Blue eyes

The slight difference between the probability, and what actually happened is due to the fact that probability is not always what is going to happen. It is possible to cross two heterozygotes, and get two recessive alleles in all ten offspring just like you can flip a coin ten times and get heads every time. This lab demonstrated the limits of probability. Probability can give you odds on what can happen, but until the event occurs there is no guarantee it will happen. Relating back to the coin, the probability of getting heads two times in a row is a 25% chance, but until you flip the coin twice you can't know if you will get two heads.

This lab relates to me because if/when I have children, then I can use probability to predict what they might be like, but I have no way to know for sure what traits they will have, until they are born.what traits they might have gotten until they are actually born.

Genetics Infographic

Because this infographic is too small, click for a larger version here

Unit 3 Reflection

This unit was about cells, their structure, and their function. It was also about the concepts of photosynthesis and cellular respiration. My strengths are the function of cells and all their parts. I know the organelles by heart (ribosomes, nucleus, ER, Golgi body, mitochondria, cell wall, cell membrane, cytoplasm, lysosome, chloroplast, etc.) I know the functions of all these organelles and how they complement each other. At first I didn't understand diffusion at all, but the egg diffusion lab really helped me understand it better. I got a wider understanding of hypertonic and hypotonic solutions. I really learned how diffusion affects a cell's size. I understand photosynthesis a little better after Mr. Orre explained it in detail with the diagrams in class. However, my weakness in this unit is cellular respiration. I get the products and reactants, but I don't understand the details of it yet. Maybe to study, I will watch Mr. Orre's vodcast again and draw diagrams without my notes and label them. The lab with the microscope was really fascinating to me because I got to see some organelles up close with different cells. I am still curious about what ribosomes look like, although they are very hard to see with our microscopes. I want to learn more about the process of photosynthesis because it really fascinates me. I look forward to the next unit.

Egg Diffusion Lab

The purpose of this lab was to find out how a cell's internal environment changes as its external environment changes. We took two eggs that were both dissolved in vinegar to dissolve the shell and expose the membrane, and we put one of them in deionized water and one of them in sugar water. We took the mass and circumference of each egg before we placed them in the solutions, and took the same measurements after we put them in the solutions. Them we knew if the cell shrunk or grew in the different solutions, so we would have a conclusion for our question. 

Our class data showed that the mass and circumference decreased as the sugar concentration increased. Because the cell had more water(solvent) in it than the outside and passive diffusion goes from high concentration to low concentration, or in other words, the sugar water was a hypertonic solution, the water diffused out of the cell, and as a result, the cell shrunk.  

A cell's internal environment as its external environment changes. If the external environment has many solutes in  it, then the water will diffuse out of the internal environment of the cell and make the cell shrink. Meanwhile, if there a little or no solutes in the external conditions, then the water diffuses into the internal environment of the cell and makes the cell grow. This is all because of the concept of diffusion and the different types of solutions. Vinegar is a hypotonic solution, where there was more water outside than inside the cell, so the egg grew from when it had its cell.   

This lab demonstrated the concentration of diffusion, which we also learned in class. We learned that when its a hypertonic solution, water diffuses out and the cell shrinks, and when it is hypotonic, the water diffuses in and the cell grows. 

This lab can also relate to real life.Fresh vegetables are sprinkled with water because the water is hypotonic, so the vegetable becomes bigger which makes it more appealing. Salt along roadsides kill plants because salt is hypertonic, which will make the plant cells shrink. When they shrink, they can't function which also means the plant can't function. 

If I were to test another thing based on this, I would test the affect on salt water on the body. I would want to see what exactly happens to the human cell. 

Egg Macromolecules Lab

For this lab, we asked the question, " Can macromolecules be identified in an egg cell?" We found that in an egg yolk and an egg membrane, monosaccharides were present. Lastly, we found out that in an egg white, proteins are present. In the monosaccharide test, both egg yolk and the egg membrane tested positive. In the egg yolk test, it turned blue, but also with a hint of green. With the membrane, it turned to almost complete blue. This evidence supports our claim because for a monosaccharide to be present, the solution had to turn blue, and for those two parts, it did. In the polysaccharide test, the egg white tested positive. The solution turned to a darker blue and almost purple color. This supports our evidence because for it to have proteins, it had to turn form blue to purple, and it did.

One possible error in this experiment could have been the perception of color from different eyes. If I thought that a dark blue was not close enough to purple, I could have said that proteins were not present in the egg yolk, but if someone else decides that it is basically purple, they can say that proteins are present in an egg yolk, which would lead to two different results. One way to fix this error is to possibly have a scale and compare your solution to that one. This will lead to more consistent results throughout the class. Another error that could have occurred is that egg was not separated properly into the different test tubes. For example, the egg membrane could have mixed with the yolk and when the solution was added there could have been an extra color change. This could tell the analyzer that there is a specific macromolecule in the yolk, when the macromolecule was not supposed to be found there. One recommendation is when you are separating the egg yolk, you can use a strainer to get only the yolk.

The purpose of this lab was to find out what macromolecules are in the different parts of an egg cell. In class, we learned about the different macromolecules and their function, and this lab tells us where they are located in an egg cell. We now know what types of macromolecules we are getting when we eat an egg. This could be applied in putting macromolecules in other foods that have egg contents. I look forward to learning more about macromolecules in the future.