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Across all species, there are three categories in which a fetus develops in utero. While each are different on their own accord, they can all be traced back to the original embryonic egg called microlecithal development. In order to be classified as microlecithal the eggs must have very little yolk, divide uniformly (2,4,8,16, etc.), be of similar size, and go through a complete division before the next stage of development can begin. Organisms that practice this mode of development belong to the amphioxi and lampreys. Mesolectihal development arose next in amphibians like frogs and salamanders. This development is characterized by the formation of two poles in the egg; one vegetal and one animal. The animal pole is the sight of active equatorial division whereas the vegetal pole doesn’t divide as regularly. Amniotes developed the third and final category of development. Macrolectihal development is categorized by a very large yolk sac on which the embryo develops. The top of the egg has a very small disc of rapidly dividing cells which gives rise to the embryo. Once the embryo forms, it envelops the yolk sac and draws nutrients from it so that it can later form surrounding materials and organelles for waste and gas exchange. This process is very similar to that of placental organisms. The only difference is that placental mammals secondarily derived a microlecithal process from the macrolecithal mode of development.  

Insulin plays a key role in facilitating the body's absorption of glucose. After eating a meal, glucose levels rise in the blood. These rising levels stimulate the pancreas to secrete insulin, which binds to the extracellular domain on liver, muscle, and fat cell receptors. The insulin bound to the extracellular domain triggers the intracellular domain to phosphorylate itself, which in turn triggers a whole phosphorylation cascade including several different proteins. This cascade prompts glucose transport proteins originally in the cytoplasm to fuse into the cell membrane. Now that the transport proteins are on the membrane, they are accessible to the glucose on the outside that is flowing through the blood. Thus, the glucose is able to pass through the transport proteins and into the cell, where it can be utilized to provide energy by making ATP. 

Processivity is a measure of how much an enzyme can catalyze reactions without freeing its substrate. Kinesin, a motor protein that moves along microtubules, has notable processivity. It can move over a large number of subunits on the microtubule before it detaches or diffuses away. This is a rare trait for cytoskeletal motor proteins. Myosin spends most of its ATPase either weakly bound to actin or dissociated from it. It is very beneficial for kinesin to have such a high processivity so that new tubulin subunits can be added to the filament before many dissociate, which allows the microtubule to grow rapidly. This is important because microtubules are required to be dynamic and must grow to transport organelles, separate chromosomes, and sometimes facilitate in cell movement.

After you eat a meal, the glucose levels in your blood rise. This stimulates your pancreas to secrete insulin, which binds to receptors on your liver, muscle, and fat cells. When insulin binds to the extracellular domain on these receptors, it causes the intracellular domain to phosphorylate itself, which triggers a whole phosphorylation cascade including different proteins. This cascade prompts glucose transport proteins to fuse into the cell membrane, allowing glucose in the blood to pass through them and into the cell, where it can be utilized to provide energy by making ATP. 

The lipid bilayer that surrounds most cells is an integral part of how life developed. As the name suggests, a bilayer is composed of two different layers of molecules, in this phospholipids. The phopholipid has polar phosphate head and a nonpolar fatty acid tail. The two phosphate heads are pointed toward each other on the inside of the membrane and the fatty acid tails point outwards toward the extracellular environment and inward towards the intracellular matrix. However, this makes it difficult for polar molecules to cross the boundary. Special transmembrane transport proteins are needed to transport different molecules. In the case of water, a critical molecule for life and one that is polar, it falls to the aquaporins to be the transport molecule. Water transports across membranes through osmosis, the diffusive transport of water, but due to the high permeability of epithelial cells, it was suspected that there were additional molecules helping in the transport of water. Some cells leak water and water still moves by osmosis, but cells with aquaporins transport water much more rapidly. Aquaporins are selective in their transport of water molecules in and out of the cell, and do not allow for the passage of other solutes and ions.

Voltage, an electric potential per unit charge and current, electrical current carriers for the resistor, have a positive linear relationship. As voltage increases, current increases and there is a directly proportional relationship. Voltage is equal to the product of the current and the resistor constant. The parameters in the model are the slope and the intercept because the model is a straight line. The y-intercept is 0 because when the potential difference is zero, the current is also zero. The slope of the graph represents the resistance of the circuit. According to the LINEST function, the slope is 96.20658458 and the intercept is -0.01947332587.

Voltage and current for the resistor have a positive linear relationship. As voltage increases, current increases and there is a directly proportional relationship. Voltage is equal to the product of the current and the resistor constant. The parameters in the model are the slope and the intercept because the model is a straight line. The y-intercept is 0 because when the potential difference is zero, the current is also zero. The slope of the graph represents the resistance of the circuit. According to the LINEST function, the slope is 96.20658458 and the intercept is -0.01947332587.

The null hypothesis for this lab is that hair measurement between the caliper measurement and double slit measurement does not match. An alternative hypothesis is that the hair measurement between the two data collections do match. The better method to determine accurate hair thickness is to use the caliper, a tool used for measuring external and internal dimension. The accuracy given by the caliper measurement gives a significant number of 0.01mm this set of measurement is defined as a better method because it has a value with more significant figures the double slit method provided inaccuracy due to the location of the hair strand. Factors that contribute to the uncertainty of the hair’s position are the tilt of the projector’s screen and how the strand of hair is taped against the light projection. The tilt of the projector screen showed the uncertainty is 0.05 mm because the hair is taped against the light projection, the uncertainty was predicted to be less than 0.02 mm.

At 9:50 in the morning I entered Morrill 2 from the front of the building, the side facing the library. I went up one flight of stairs, walked to the back stairwell and left through the two sets of double doors that lead outside, I was now facing Frank dining hall. I turned to face Morrill and at 9:55 in the morning, I took a picture of the spider web in the bottom left corner of the glass pane that was next to the door. I squatted like a duck and held the back of my ucard vertically up to the web so that the Ucard logo was at the top of the card.  I held my ucard vertically so that the back was facing me and the Ucard logo was at the top. At this time there was a little spider about the size of the “A” in “UCARD”. In the image, the ucard is to the left of the spider web and the ucard was held up so it was touching the metal corner of the window frame. The black rubber edging of the glass is about centered in the picture. I then stood up and stood on the curb where the sidewalk ends that is directly across from the doors and took a picture of Morrill that shows the entire doorway and part of the building.

The null hypothesis for this lab is that the hair measurement between the caliper measurement and double slit measurement does not match. The alternative hypothesis is that the hair measurement between the two data collections do match. We think that the ‘better’ method of measurement would be measuring with the caliper the accuracy gets down to the 0.01mm. A set of measurement would be defined as ‘better’ than the other if it is more accurate and has a value with more significant figures. Factors that contribute to the uncertainty of the hair’s position would be the tilt of the projector’s screen, the way the hair is taped against the light projection. For the tilt of the projector screen, we think that the uncertainty would be 0.05 mm. For the way the hair is taped against the light projection, we think the uncertainty would be 0.02 mm. We believe the hair being taped to the projection would be more accurate than the tilt of the screen because the screen seemed more unstable, we couldn’t keep it in exactly the same position.