Is Sexual Reproduction Important?

   In the book, Dr. Tatiana's Sex Advice To All Creation by Olivia Judson, Judson explains about how different organisms reproduce. Mammals and some other organisms reproduce sexually, with a mate, while some organisms, like the Philodina, reproduce asexually. Sex is very important. The benefits of reproducing sexually is that your offspring is a bit different than both parents meaning that if there were to be a disaster, your offspring may survive because it is not identical. This means that their populations are better adapted. Some costs of reproducing sexually is that it is not very efficient, you have to try to look for a mate. According to Dr. Tatiana, herself, males dispense a lot energy to try to win over a female to mate. Asexual beings do not have to do that, so they can more efficiently reproduce (replicate).To reproduce asexually, the organism does not need a mate and the offspring will have the identical genes of the mother. In an asexual population, there are no males, just females that clone themselves. Some advantages of asexuality include how there is a better demographic of population because the female only needs to have one offspring to be balanced and more than one would be extra population. Another pro is that asexuality is much more efficient, in the sense that one can have a child anytime and does not need to depend on any other organism of its own species. According to Miss Philodina, her population is much more efficient and larger than the non-asexual populations. Miss Philodina also argued that her species has been asexual for 85 million years. Cons include the offspring not having any gene difference meaning that if something was to kill some of them , they would likely all die because they are all the same and one is not better protected than the other. According to Muller's hatchet is because the generations did not have any adaptation, it would not survive to any changes. Because of this, many asexual species tend to face extinction relatively soon after the conversion to asexuality. In this upcoming unit, I do hope to further understand why a some organisms choose to reproduce asexually if sexually is clearly better? Another question I have is, what happens to organisms that might lose any way to reproduce sexually/asexually?

Unit 3 Reflection

    In this unit, we started to learn about the cell and all its functions and types. There are two types of cells, prokaryote, no nucleus and no organelles, and eukaryotes, has a nucleus and organelles and has long chains of DNA called chromosomes. Cells are made up of all the different macromolecule.  Eukaryotic cells have nucleus, where DNA is stored it is like the brain of the cell. There are lysosomes that recycle proteins, and endoplasmic reticulum that holds proteins as they are being finished by ribosomes. The cell membrane holds all the content inside, a plant cell will also have a cell wall. The main function of a cell is to produce proteins. There are two types of transports. One of them is passive transport, requiring no energy, there is diffusion, high to low concentration that happen for small molecules, then there is facilitated diffusion which uses proteins to help larger molecules come in. The other form of transport is active transport which requires energy and is only used for the highly needed molecules. Osmosis is the diffusion of water through a lipid layer in the cell. There are autrophic cells, produce own energy, and there are heterotrophic cells, that consume other cells for energy. Photosynthesis only occurs in plant cells and it takes in CO2, water, and light and turns it into oxygen and glucose, which is kept in the cell unlike oxygen, with the help of the chloroplast, which a long time ago was a bacteria, another cell. Cellular respiration occurs in both plant and animal cells. It takes in oxygen and glucose and makes CO2, water, and ATP, energy used by cells, using the mitochondria. During this unit, some of my weaknesses were understanding how photosynthesis and cellular respiration worked, for it took time to go in depth and truly understand how it worked. A strength for me was to easily classify a cell as an eukaryote, prokaryote, autotroph, and/or heterotroph.

     In this unit, we did many labs to further our understanding of the topics. One of the labs included the egg macromolecules lab. This lab consisted in figuring out where each macromolecule was present in each part of an egg, which was used to show a cell. From these experiences, I understand the purpose and the function of the parts of the cell and the cell in a whole new way that makes a lot more sense and makes me understand the basics, so I can now try to deep further into cells. An unanswered question I still have is whether cellular respiration and photosynthesis produce and use up the same as the other produces, so that actually nothing is really being let out of the plant? I would also like to learn more about each specific organelle in a cell, and understand what they bring to a cell. For this upcoming test, I plan to go other all my vodcast notes and read the biology textbook in depth to try to further my understandings of each subject and truly know 100% of what this unit what about. In conclusion, unit 3 was a very useful unit for understanding the basis of biology and what a cell actually does and is.

Organism Lab

Euglena cell magnified at x400. It is unique because it has a flagellum. It is green and purple. It is eukaryotic and autotrophic.

Amoeba cell magnified at x400. It is unique because it has pseudopods, which consumes cells. It looks like jelly and is very colourful. It is eukaryotic and heterotrophic.

Cynobacteria magnified at 400. There no chloroplasts because it is a prokaryotic cell and is autotrophic. It has no nucleus and is green and blue. 

Bacteria cells magnified at x400. Bacteria can be shaped as coccus, bacillus, and spirilum. They are a lot smaller than the other cells. Thay are pink and purple. It is prokaryotic and autotrophic because no nucleus..

Spirogyra cell magnified at x400. It has a cell wall, cytoplasm, and nucleus it is like a strand. Looks like spirals and is blue green. It is eukaryotic and autotrophic.

Ligustrum cell magnified at 400. It is unique because it has veins. It is green and blue. Composed of many dots. It is eukaryotic and it is autotrophic.

Skeletal Muscle Tissue magnified at 400. It is unique because there are muscle fibers. It was pink/purple and had many strands of fiber. It is eukaryotic and heterotrophic.

   In this lab, we asked the question: what are the key features of autotrophs, heterotrophs, prokaryotes, and eukaryotes. We observed different samples of cells under the microscope to see the characteristics. Based on our observations, we could identify whether the cell was an autotroph or a heterotroph and whether the cell was an eukaryote or a prokaryote.  Autotrophs have a key characteristics of being plant cells and some bacteria. Because of this, they have chloroplasts ,vacoules ,and cell walls, unless they are bacteria. Heterotrophs are consumers, meaning they consume other cells to get their energy. Heterotrophs do not have vacoules, chloroplasts, and cell walls. For a cell to be an eukaryote, it must have a nucleus and a nuclei. While a eukaryote has a nucleus, prokaryotes do not have a nucleus and also have no organelles. Eukaryote cells are bacteria and other cells with no nucleus and no organelles. In conclusion, we learned about identifying cells as an autotroph or a heterotroph and whether the cell was an eukaryote or a prokaryote.

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 left two eggs in a deionized water and sugar water for 48 hours, and later observed what occurred. Based on the class data, the mass decreased and the circumference decreased as the sugar concentration increased. Because the sugar water has a lower concentration of water than the egg itself, the water in the egg diffused out of the egg from high concentration(the egg) to low concentration(the sugar water), which is known as a passive diffusion(requiring no energy). This then caused the egg to lose water, meaning a lose of mass causing the egg to shrink. On average, the egg, which stayed in sugar water, lost around 43.5% of mass and 26.16% of circumference. The solvents leave the inside of the egg to balance the amount of solutes inside and outside the egg.    

       A cell's internal environment changes as its external environment changes because diffusion causes both external and internal environments to change, for the change will occur from a molecule going in or out of the membrane, so both environments are effected. When the egg was placed in vinegar, the egg expanded as the solvent came in the egg. Both the internal and external condition changed. Then when the egg was placed in the sugar water, the egg shrunk because the water was diffused out and into the sugar water, meaning both the internal and external environments changed, they became equal in concentration.

      This lab demonstrated the biological principal of diffusion, which was taught during class. This lab showed how diffusion works in real life. Because the egg in the sugar water was hypertonic, the solvent(water) went from high concentration(the egg) to low concentration(the sugar water). This was a passive diffusion and caused a change in the internal and external environment of the egg.

       What this lab taught us can also be applied to real life. For example, fresh vegetables are sprinkled with water at markets, so that the vegetables do not diffuse the water in them. This would cause the vegetables to shrink and would be harder to sell. With the sprinkling water, the vegetables stay nice and plump with no wrinkling. Another example of diffusion in real life, is the salting of roads to melt ice. Because of this salting, the plants along the roadsides lose their water inside and either die or become less big and massive. This is caused because the salt diffuses the water out of the plants because the salt has a much lower concentration of water than plants.

     Based on the Diffusion Lab, I would want to test whether an egg that has shrunk would go back to its normal mass if placed in water. I would like to test this, so that I could know whether diffusion is a reversible process or if instead once the cell shrinks, it can never come back to how it was before.                

Egg Macromolecules Lab

   In this lab we asked the question, can macromolecules can be identified in an egg cell. We found that in the egg membrane, protein was abundant. During the test, it scored a 10 out of 10 for the presence of proteins, turning the sample a dark purple. Because the cell membrane uses protein channels to let in/out molecules, then the egg membrane will also have proteins in it. We found that in the egg whites, lipids, monosaccharides, and proteins were abundant. During all three tests, the egg white sample scored a 6/10 for the presence of lipids, monosaccharides, and proteins. Lipids are used to store energy; monosaccharides are simple sugars, which release energy; and proteins( enzymes) used to stop germs. All these macromolecules are all key for letting an embryo grow, for it needs energy, storage of energy, and needs enzymes( a sort of immune system). Last but not least, we found that proteins and polysaccharides were present in the egg yolk. The yolk scored a 8/10 in the protein test and a 7/10 in the polysaccharide test. Proteins are present because an embryo needs to have enzymes, and proteins are also used to make muscle. Polysaccharides are also present because they are complex sugars that provide stored energy needed for the embryo to start its transformation form embryo to baby chick.

 

   Our data contradicts the expected results because our group predicted that the egg yolk would test high for lipids, for the membrane of the egg yolk is mostly made of lipids. This may have happened because the egg yolk's consistency. Because of the egg's consistency, the Sudan III and NaOH+CoSO4 did not mix with the egg  well. Another error that happened was the instructions did not specify the quantity of egg membrane needed in each test tube. Due to these errors, in future experiments I would recommend to specify how to apply the agent, to find lipids, onto egg yolks, or to dilute the egg yolk in water to make it more liquid. I would also recommend to specify the quantity of egg membrane in milligrams, so that there is an exact amount in each test. 

   This lab was done to demonstrate what type of macromolecule was in each part of a cell with the metaphor of an egg. From this lab, I learned that some marcomolecules are necessary for the function of the each part of a cell, which helps me understand what each part of a cell does based on the macromolecules it needs for its function. Based on my experience from this lab, I could apply my new found knowledge towards better understanding in depth the function and structure of each part of a cell.