Osmoregulation as a Homeostatic Mechanism using the Comparitive Melting-Point Method for two Crab Species.

After each of the solids were completely dry, each was placed into a MelTemp device. The temperature at which each solid began to melt and completed melting was recorded.

In this lab experiment, half our group observed and measured osmosis using dialysis tubes that were represented as the semipermeable membrane. It is permeable to water and other small molecules but is impermeable to larger molecules such as the sucrose solution used in each of the four beakers and tubing. The other half of our group observed the tonicity of sheep blood to determine whether the blood was isotonic, hypotonic, or hypertonic. The 85 g/dL of NaCl solution was the ideal isotonic number in relation to the sheep blood cells as well as a reference to the other observations of the solutions.

The vial was removed from the heat and cooled to room temperature. The spin vane was rinsed with 2-3 drops of warm water over the conical vial. The vial was cooled to room temperature then placed in an ice bath for 15 minutes. The liquid was decanted from the mixture and the resulting crystals were dried on filter paper. The crystals were then placed on a watch glass for further drying. The crystals were weighed and a small sample was placed into a capillary tube for melting point determination.

In determining the melting point range of the aspirin, a capillary tube (sealed at one end) was one-third-filled with the dried aspirin. The capillary tube and a thermometer were immersed in an oil bath. The temperature at which the solid started to melt and the temperature when the entire sample was completely liquefied were recorded as the melting point temperature range.

In Exercise 1, diaminofluorene is used to determine the hemoglobin concentration in the daphnids. A higher hemoglobin concentration is indicated by a darker blue color. A spectrophotometer was used to determine the absorbance at 610nm. When measuring the absorbance levels a blank is necessary to have a zero reference, the blank is the “starting point” for the measurements of the sample (re-word). The blank consists of 10µL of diaminofluorene(DAF), 50µL of hydrogen peroxide, and 0.5mL of PBS. The PBS acts as a buffer in this experiment. The cuvette with the sample of daphnids consisted of 10µL of DAF, 50µL of hydrogen peroxide, and 0.5mL of the sample of Daphnia. In Exercise 2, the Pasteur pipette was used to obtain the sample of Daphnia. The depression slide used in this experiment isolated the daphnid, cotton was used to keep the daphnid still while the heartbeat was counted. The ocular micrometer on the microscope allows the tail spine length to be measured accurately, as well as using an ocular magnification table.

We then created an ice bath using a 250mL Erlenmeyer beaker. The 50 mL Erlenmeyer beaker was then labeled as “Acid Extract”, and was placed in the

Place the test tube containing cold water in a test tube clamp and hold the test tube above the burning alcohol. Observe the outside of the test tube for evidence of product formation.

Abstract: This experiment introduced the student to lab techniques and measurements. It started with measuring length. An example of this would be the length of a nickel, which is 2cm. The next part of the experiment was measuring temperature. I found that water boils around 95ºC at 6600ft. Ice also has a significant effect on the temperature of water from the tap. Ice dropped the temperature about 15ºC. Volumetric measurements were the basis of the 3rd part of the experiment. It was displayed during this experiment that a pipet holds about 4mL and that there are approximately 27 drops/mL from a short stem pipet. Part 4 introduced the student to measuring

Tube 4 now should only have crude solid in the tube and it is then weighed. The tube is placed into a 50℃ water bath and then approximately 0.5 -1 ml of methanol is added, as well as H2O until the solution gets cloudy, once the solution is dissolved it is cooled to room temperature and then iced. The crystals are then collected using a Hirsh funnel. Next a small amount (~ 0.1g) of the crystals are placed into a melting point tube and placed into the melting point machine to record the unknown neutral substances melting point.

Latour, Bruno , Steve Woolgar, and Jonas Salk. "Introduction." Laboratory Life. 1986.Reprint. Princeton: Princeton University Press, 1986. 11. Print.

The effects of Ocean Acidification on the physiology of marine organisms has long been observed, as the subsequently depletion of calcium carbonate impedes the proper development of marine calcifiers. One such calcifiers, however, has exhibited considerable tolerance to alterations in seawater acidity. Indeed, through the plastic response of gene expression and modulation, the larvae of the Strongylocentrotus purpuratus, or Purple Sea Urchin, have inherited a tolerance to low pH and high temperature conditions; an adaptation which will, undeniably, prove essential for survival in this newly acidic aquatic world. This review presents the Purple Sea Urchin as a case study, to demonstrate the potential of genomic analysis to greatly augment

A 10 mL round-bottom flask was weighed both before and after approximately 1.5 mL of the given alcohol, 4-methyl-2-pentanol, was added. 3 mL of glacial acetic acid, one boiling chip, and 2-3 drops of concentrated sulfuric acid were added to the flask in that order. The reflux apparatus was assembled, the

This experiment was conducted to test the importance of isotonic solutions on living cells. In this experiment we were trying to figure out which solution would make the sheep red blood cells increase in size. The independent variable was the three solutions 5% NaCl, .9% NaCl, and distilled water that we added separately to the sheep red blood cells. The dependent variable being tested was the size of the red blood cells after each solution was added. The control of the experiment was nothing added to the sheep blood. The hypothesis was if you add 5% sodium chloride to the sheep blood, then the cells will undergo crenation and the size will shrink more than 0.9% sodium chloride and distilled water. Osmosis is “the diffusion of water across

An investigation into the effects of varying seawater concentrations on two marine invertebrates’ osmoregulatory abilities; Carcinus maenas and Arenicola marina.

Osmosis is the process in which water diffuses across a semi permeable membrane, and is the reason for cellular stability in a system, generally a cell. The diffusion of water into and out of a cell is due to two main aspects; the concentration of the dissolved substances in the cell, and the concentration of the dissolved substances outside of the cell. This is due to the fact that osmosis is first and foremost a form of diffusion meaning that it moves along a concentration gradient. In osmosis water will travel in and out of a cell due to the cell 's tonicity towards the solution it has been placed in. The cell can either be placed in a hypertonic solution where water will rush out of the cell, a hypotonic solution where water will rush into the cell, or an isotonic solution, where there will be no net movement of water in or out of the cell. In this lab the rate of osmosis will be examined by looking at the movement of water in five different model cells, in order to determine the importance of osmosis to our bodies.