Why is Sex so Great?

     Sex is a driving force of life, and it is essential to help species thrive. While asexual reproduction has its benefits, sexual reproduction is more efficient and advantageous.With asexual reproduction, each female only needs to have one offspring for the population to stay the same, however with sexual reproduction, two offspring are needed. Asexual reproduction also has disadvantages. Since all asexual organisms like the philodina have very similar genes, it is easier for disease to take them over, as they are all almost the same.

     In "Wholly Virgin," it is said that the Philoldina Roseola has reproduced asexually for the past 85 million years without meiosis. The chaetonotid gastrotrichs is a species that seemed to be asexual at first, but it was found that they actually thrived by hiding the males in the roots of the weeds. Bacteria also reproduce asexually by dividing, while eukaryotic organisms like the moose reproduce sexually through meiosis after the fusion of sperm and egg.

      In this unit I want to learn exactly how mutations happen and what the exact process is for asexual reproduction.

Unit 3 Reflection

     Unit 3 was about cells and the processes that take place in them. We learned about the different parts of the cells and their functions, and processes like osmosis, photosynthesis, and cellular respiration. We started with the basic functions and types of cells, and then we went into more detail about all the complicated things that happen inside of cells. Overall, this unit was very interesting and packed with information. Most of the general information, like the different organelles and functions were easy for me to understand. I also had an easy time understanding the processes of osmosis and diffusion, and how they take place. It was a little more difficult for me to remember the details of photosynthesis and cellular respiration, as they are both very complicated and detailed.

      Throughout this unit I learned that visual components, such as pictures really help me grasp a concept even better than just reading about it. For photosynthesis, the diagrams that we copied down in class really helped me understand the process better. I also learned that I have learned a lot about these concepts before, and the vodcasts just help me revive and enrich the knowledge I already have.

     In the future, I want to learn more about the smaller details of cells that were not covered in the vodcasts. I would also like to learn more about how all the organelles in cells work together. I also wonder about the huge variety of cells that exist and what makes them all unique. For the test I plan on studying the diagrams and pictures more than I did for previous tests.

Egg Diffusion Lab

24 hour time lapse of our Egg Diffusion Lab. Egg on left in corn syrup, egg on right in DH2O pic.twitter.com/wdfujQyBXM

— Mr. Orre's Class (@OrreBiology) October 5, 2016

     In this lab we placed two different eggs of about the same size in deionized water and corn syrup to see the effects on the circumfrence and mass of the eggs. Both the eggs had their shells dissolved off in vinegar, so substances could leave and enter the egg.

     According to the class data, when the sugar concentration increased, both the mass and the circumfrence of the egg decreased. This is because the corn syrup is a hypertonic solution. There is more sugar, which is a solute, outside of the egg than inside of the egg, so water and solvents from inside the egg leave, making the egg smaller in size. According to www.exploratorium.edu egg white is about 90% water and corn syrup is about 25% water. Due to this the water moves from an area of high concentration to an area of low concentration to create equilibrium with the solute. This is an example of passive diffusion.

     As the external environment of the egg changed in terms of concentration of water and solute, the interal conditions of the cell changed as well. When the outside of the cell was highly concentrated with solute, the water diffused out from inside the cell, and when there was less solute outside (deionized water) the water diffused into the egg. And when the egg was put in vinegar, the shell was dissolved off, leaving only the membrane.

     The lab demonstrated the biological of diffusion, which we learned in class. The lab was a good way of showing how the concentration gradient can really affect the size of the cell. We learned how cell membranes don't allow large solute molecules through, which was shown to be true by the lab, as the corn syrup didn't enter the egg, only water came out.

      Fresh vegetables are sprayed with water at markets, to prevent them from drying out. The water gets absorbed into the vegetable, as there is probably more solute in its cells. When salt is sprinkled onto the road, plants along the road are dried out and dehydrated. Salt is a solute and since, there is a higher concentration of salt outside of the plant, water diffuses out of the plant cells, drying out the plant.

     Based on this experiment, I would like to test how much water a cell can hold before popping. I would also want to find a way to maximize the amount of water it can hold, or maximize the amount that the cell can shrink as water diffused out. 

Egg Cell Macromolecules Lab

      In this lab we asked the question: Can macromolecules be identified in an egg cell? We identifies which macromolecule was present in each part of the egg. We found that the egg membrane tested positive for lipids because it turned from red to orange in Sudan III. Lipids are found in egg membranes, because cell membranes, which are the equivalent of egg membranes, are made of phospholipid bilayers. We also found that the egg white contains protein because it turned the blue biuret solution purple. The egg white would contain protein because it is like the cytoplasm of a cell, which contains many proteins and ezymes, which are a type of protein. Finally, the egg yolk tested positive for protein because it turned the biuret solution purple. This is because the yolk is like the nucleus of the cell, which contains structural proteins.

     A possible error that could have occurred was two parts of the eggs accidentally mixing together. For example, if some of the egg white got into the beaker with the yolk, then the yolk may have tested positive for a macromolecule that was actually in the egg white. Another error could have been that there was not enough of each substance in the test tubes, so the color change may have been less drastic or obvious. This could make it seem like there was a smaller presence of the macromolecule, even when there was a lot of it. Due to these errors, I recommend devising an easier way to separate the different parts of the egg, and maybe have students put a larger amount of each part in the test tubes.

     This lab was done to demonstrate that different macromolecules are found in different parts of cells. This lab enforced the knowledge of where different macromolecules are found in the cell, which was taught in the vodcasts. For example, we found that the egg membrane had lipids in it, which was explained in the vodcast. This knowledge can help people know what they are getting from eggs. For example, body builders need protein to build muscle, so they can eat the yolk.