Is Sexual Reproduction Important?

In today's world, producing offspring sexually is very important to the survival of a species, and there are several advantages of sexual reproduction. First, sexual reproduction helps reduce the chance of mutations. In an analogy, there is a manuscript that has been copied over and over by monks in two distant monasteries, leaving more chance for mistake, whereas having sex is like two monasteries copying each other regularly and frequently replacing their versions of the manuscripts. Mutations can be very harmful to species who don't produce sexually, suppose there is a threshold of harmful mutations an individual can carry, in sex the mixing of genes gives some creatures harmful mutations, and these creatures are quickly killed off, leaving the population safe, but if there was no shuffling of genes, the population would be overwhelmed by harmful mutations, therefore going extinct. In addition, over time organisms that don't produce sexually will, over time, be lead to several mutations, and if the last individual, that is not mutated, does not produce offspring then the population eventually goes extinct. Finally, since organisms that do't produce sexually have very similar genes, parasites and viruses, can easily infiltrate their defenses, killing them of, but sexual reproduction helps by mixing genes and making harder for parasites to kill of the species, creating a moving target. Although sexual reproduction is important and necessary, could it be possible for asexuals to thrive and grow, or would it be impossible in the conditions of today's world?

Unit 3 Reflection

In Unit 3, we learned about the function, structure, and importance of the cell. There are two main types of cells, prokaryotes, a simple cell with no nucleus only one chromosome, usually bacteria, and eukaryotes, multi-organelled, nucleus-containing, complex cells. The cell has many different structures that have specialized functions and work together to help sustain life. For example, the nucleus gives the instructions to the cell, the ribosomes assemble the proteins, the endoplasmic reticulum synthesizes the proteins, and the golgi apparatus ships proteins via vesicles throughout the cell. In addition, we learned about osmosis and diffusion, where molecules diffuse from a high concentration to low concentration until equilibrium. During osmosis, water, a solvent, diffuses through the cell towards the higher solute concentration, in order to create an equilibrium. Isotonic solutions have equal solute concentration inside and outside of the cell, hypertonic solutions have a higher concentration of solutes outside of the cell, and hypotonic solutions have a higher solute concentration inside the cell. In the beginning there was a prokaryote, but then there came autotrophs, which could make their own food. Soon, heterotrophs came into play, which could consume its food, and some bacteria survived when eaten by a cell, turning into the first eukaryote, the cell provided protection for the bacteria, while the bacteria provided food for the cell. This became known as the endosymbiotic theory.



Autotrophs use light to create food using photosynthesis, a process that occurs in the leaf of a plant. Inside the leaf chlorophyll contains stacks of thylakoids called granum. There are two main processes in photosynthesis, light dependent reactions, where light is absorbed in the thylakoids an produces NADPH and ATP, by ATP Synthase, and water is split, releasing oxygen and pumping hydrogen ions into the thylakoid membrane, and light independent reactions(Calvin Cycle) in the stroma, where sugar, or glucose, is produced using carbon dioxide, ATP, and NADPH from light reactions. Both heterotrophs and autotrophs do cellular respiration, which is divided into three steps, glycolysis, which occurs in the cytoplasm and creates two ATP and pyruvic acid, the Krebs Cycle, which converts molecules from glycolysis into 2 ATP, carbon dioxide, and NADH and FADH2, and the electron transport chain, which uses oxygen, NADH, and FADH2 to convert ADP into ATP. In total 36 ATP is produced from one glucose molecule.

During the unit, I felt that I understood the material well, but the concepts, at times, could be very tricky to grasp. The number of organelles and their specialized jobs could be confusing and the osmosis and diffusion concept was sometimes vague in my mind. When we got to the photosynthesis and cellular respiration section, the concepts were confusing, but as we did more things to help reinforce the ideas, such as drawing diagrams and reviewing photosynthesis and cellular respiration, I could begin to see the puzzle pieces being put together. Unfortunately, we missed out on some labs because of safety issues, which was a setback and a disappointment, but it was a good lesson about the consequences of not being safe and organized. Despite the setbacks, I felt that I was successful in learning about the cell and how life was created because of this extraordinary thing.

Egg Diffusion Lab

1) When the the sugar concentration increased in the solution, the egg's circumference decreased. This was because the sugar was hypertonic, where the solute concentration(the sugar) was higher, therefore the water inside the cell diffused through the membrane from the high concentration to the low concentration to form an equilibrium. 
2) As the external environment changed, the cell's internal environment changed because of the change of the solute concentration. In the vinegar, the solute concentration was less than the egg, so the solvent, the water, entered the cell, passively diffusing through the membrane, in order to create an equilibrium. Then, in the sugar the solute concentration was higher, therefore the water exited the egg, to form an equilibrium.
3) The biological represented in this lab was osmosis, which is a type of diffusion. Osmosis is when water diffuses in and out depending on the solute concentration outside of the cell. When there is a hypertonic solution the solute concentration is higher than the cell's solute concentration, then the cell will shrink due to loss of water. When there is a hypotonic solution the solute concentration is lower than the cell's solute concentration, then the cell grows due to the gain of water.
4) When vegetables are sprinkled with water, they are kept ripe, because the water makes the vegetables isotonic, so that they do not lose water and turn dry. Salt melts the ice because it is hypertonic, so it makes the ice lose water, and melt. When, roadside plants are salted they lose water, due to the hyertonicity,of the salt, making them wither and die.
5) Based on this test I would like to test the results of growing plants with sugar water and vinegar. The vinegar is hypotonic and the sugar is hypertonic, so which one is better for growing plants, and which one would have a worse affect on the plants?

Egg Macromolecules Analysis

     In this lab, we asked the question: Can macromolecules be identified in an egg cell? We found that it was indeed true that macromolecules could be found in the different parts of an egg. In the egg membrane, we found that it contained lipids because the Sudan 3, when mixed with the egg membrane, turned from a red color into an bright orange color, and on a scale from 1-10 we rated it a "10" for the color change. In a cell, the membrane contains lipids because it made out of phosophoipids, a type of lipid, which help the cell defend from outside substances, contain organelles, and lets molecules in and out. Then, in the egg white, we found that there were proteins contained in it. Testing for proteins, we used biuret to test for the presence of proteins, and once the biuret was mixed with the egg white it turned from blue to a light purple color. We rated it a "7" in a scale from 1-10 for the color change. This is because the cytoplasm in a cell, represented by the egg white, contains proteins and enzymes that break down amino acids in the cell. Finally, we found that there were also lipids in the egg yolk, which we used Sudan 3 for the test. In the solution, the egg yolk turned red to a bright orange, indicating lipids, and on a scale from 1-10 we gave it an "8" for the quantitative amount of the macromolecules. The egg white, or the nucleus of the cell, contains lipids because of the membrane which functions as a barrier, container, and lets things in and out of the nucleus, such as RNA.
     One possible error in lab, was the fact that the the amount of the solution could have been altered when we were putting it in. For example, when dropping in 3 to 5 drops of Sudan 3 someone could have accidentally put 6 to 8 drops, therefore altering the color of the solution and the results of the experiment. This problem could be easily fixed be using graduated cylinders to measure the exact amount of the solution to put in. Furthermore, the color of the solution could have been interpreted differently, such as, for the biuret solution used for proteins, there could have been a different interpretation for the purple color, where one person thinks light purple is 7 o a scale from 1 to 10 but another thinks it is a 9. This problem could be fixed by one person interpreting the color, such as the teacher, for everyone so that the results will be more accurate.
    The purpose of this lab was to find the macromolecules that are found in the different part of the cell. In class we learned that there are lipids in the membranes of organelles, protein in the cytoplasm, and carbohydrates in the mitochondria. The macromolecules can be found everywhere in the cell and are important to the function of the cell and the body, and without macromolecules life could not form. These same macromolecules that can be found in a tiny cell, can be found in the different parts of the cell. If one macromolecule was not existent then the cell could not function, and life could not thrive.