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BIOL 1208 Chapter : Writing Assignment 2

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azuremammoth471
15 Mar 2019
School
LSU
Department
Biological Sciences
Course
BIOL 1208
Professor
All

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The null hypothesis was that the rate of hemolysis of ovine red blood cells is not affected by the number of hydroxyl substituents on the molecules present in the given solution. The alternative hypothesis was that the rate of hemolysis of ovine red blood cells is affected by the number of hydroxyl substituents on the molecules present in the given solution. It was predicted that a higher number of hydroxyl substituents on the molecules present in the solution will induce a lower rate of hemolysis. The rate of hemolysis was observed in a stock solution of 2% whole ovine blood by the slit-lamp method. The slit-lamp method consists of a diffuse light source positioned behind a piece of cardboard with a hole in which a black thread is suspended (wischusen et. al. , 2012). Triplicates were prepared in test tubes for three different propanol solutions at 0. 3 molarity: 1- propanol, 1,3-propanediol, and 1,2,3-propanetriol.

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Related Questions

Cell Membranes Lab Report

  1. Diffusion

  1. Compare the following terms: solvent, solute, andsolution.

  1. Go to Lab, Section I, Exercise 1 to explore the factorsinfluencing the rate of diffusion and complete the following:

  1. Predict how molecular mass and temperature may affect theoutcome of this experiment.

  1. Record the data from information in the Lab in the tablebelow.

Time

(min)

Diameter (mm)

5°C MB

5°C PP

23°CMB

23°C PP

0

15

30

45
  1. Construct a line graph of the data from the table above. Yourgraph should include labeled axes, units, and a legend indicatingwhich treatment is presented. Sign, date and prepare an image ofyour graph and include it with this lab report.
  1. Osmosis

  1. Go to Lab, Section II, Exercise 2 to view a demonstration ofosmosis and answer the following questions:

  1. Describe the net movement of water in osmometer 1.
  1. How is the movement of water molecules related to theconcentration gradient of the solution?

  1. Go to Lab, Section II, Exercise 3 to observe the effect ofsolute concentration on the rate of osmosis. Answer the followingquestions:

  1. Was the net movement of water in bags 1 to 4 into or out of thebags?
  1. Explain the results from bags 4 and 5.
  1. Selective Permeability of Membranes

  1. Go to Lab, Section III, Exercise 4 to learn about theimportance of selectively permeable membranes, then complete thetable and answer the following questions:

Contents of Beaker

0 Min

30 Min

Starch

Chloride ion
  1. Which substances diffused through the dialysis membrane?

  1. How does dialysis tubing model the selective permeability of aplasma membrane?
  1. Tonicity

  1. Go to Lab, Section IV, Exercise 5 and 6 to observe plasmolysisin Elodea cells and tonicity in red blood cells. Summarizethe concept of tonicity using blood and Elodea cells asexamples. Your description should incorporate these terms: turgid,plasmolysis, hemolysis, and crenation.

Cells

Isotonic Solution

Hypertonic Solution

Hypotonic Solution

Elodea

RBC

  1. Based on your previous work, reproduce the table below and drawan illustration of a single cell in each box. Include arrows toshow the direction of water flow relative to each cell and dots tosymbolize solutes. Sign, date and prepare an image of your drawingand include it with this lab report.

Cells

Isotonic Solution

Hypertonic Solution

Hypotonic Solution

Elodea

RBC

Summary Questions

  1. Compare diffusion and osmosis. Give an example of each.

2. In which direction will osmosisoccur if a 15% sugar solution is separated from a 25% sugarsolution by a selectively permeable membrane?

3. Why did osmosis, but not diffusionof sucrose molecules, occur across the dialysis membrane containing20% sucrose solution?

4. You are having a party and thecelery is limp. What might you do to make the celery crisp (turgid)again? What will occur in the cells?

5. A small amount of fertilizer(mineral salts) will stimulate plant growth, but over fertilizationcan kill plants? Why?

6. Michael adds sugar to his coffee.Explain what in this drink is the solvent, solute, and solution.

7. You add a cube of sugar to yourdrink. How could you speed up the diffusion of sugar moleculeswithout stirring?

8. How is dynamic equilibriumestablished within a solution?

1. In lecture, we described a simple osmotic pressure gradient when discussing osmosis. For question #1, describe the simple osmotic pressure gradient, in terms of osmotic pressure, that exists across the red blood cell plasma membrane when red blood cells are suspended in a severely hypotonic solution, such as a 0.2% NaCl solution. Use scientific terminology.

2. We mentioned in class that biological systems are always in a state of osmotic equilibrium due to a combination of solute diffusion in some cases and osmosis in others. In this experiment, when you add the red blood cells to a severely hypotonic solution, what substances are moving across the red blood cell plasma membrane to achieve osmotic equilibrium, Na+ and Cl- or water? Explain why based on your understanding of the permeability characteristics of biological membrane. Always use scientific language.

CAN QUESTIONS 1 AND 2 BE ANSWERED DIRECTLY AND ADEQUATLEY PLEASE.

HERE IS AN INTRO TO THE LAB EXPERIMENT

Intro:

We have known for a very long time that the mammalian red blood cell plasma membrane is very permeable to water. Even the introductory biology student understands that if you put mammalian red blood cells in water, they will rapidly swell and break open (hemolyze) due to the rapid osmosis of water into the cell. The experimental question we are asking in today's lab experiment is "Is the high water permability of mammalian red blood cell plasma membrane due solely to the lipid bilayer, or are there water channels present in the membrane?"

Experimental Design:

It has been shown by several investigators that water movement through water channels can be blocked by the known K+ channel blocker, tetraethylammonium chloride (TEAC). Brooks, Regan and Yool (2000) showed that TEAC reduces the water permeability of human water channels expressed in the plasma membranes of frog ocytes. After preincubation of the oocytes for 15 min with 100 microM TEAC, the water permeability of frog oocyte plasma membrane containing human water channels was reduced 20 to 40%. The investigators concluded that treatment of cells with TEAC can be useful in determining the presence of aquaporins in membranes.The specific objective of today's experiment is to uncover the presence of water channels in mammalian red blood cell plasma membrane by determining the effect of tetraethylammonium chloride on the water permeability of mammalian RBC plasma membrane.

We mentioned in class that biological systems are ... We mentioned in class that biological systems are always in a state of osmotic equilibrium due to a combination of solute diffusion in some cases and osmosis in others. In this experiment, what substance is moving across the red blood cell plasma membrane to achieve osmotic equilibrium, Na+ and Cl- or water? Explain why based on your understanding of the permeability characteristics of biological membrane. Always use scientific language. HERE IS AN INTRO TO THE LAB EXPERIMENT Intro: We have known for a very long time that the mammalian red blood cell plasma membrane is very permeable to water. Even the introductory biology student understands that if you put mammalian red blood cells in water, they will rapidly swell and break open (hemolyze) due to the rapid osmosis of water into the cell. The experimental question we are asking in today's lab experiment is "Is the high water permability of mammalian red blood cell plasma membrane due solely to the lipid bilayer, or are there water channels present in the membrane?" Experimental Design: It has been shown by several investigators that water movement through water channels can be blocked by the known K+ channel blocker, tetraethylammonium chloride (TEAC). Brooks, Regan and Yool (2000) showed that TEAC reduces the water permeability of human water channels expressed in the plasma membranes of frog ocytes. After preincubation of the oocytes for 15 min with 100 microM TEAC, the water permeability of frog oocyte plasma membrane containing human water channels was reduced 20 to 40%. The investigators concluded that treatment of cells with TEAC can be useful in determining the presence of aquaporins in membranes.The specific objective of today's experiment is to uncover the presence of water channels in mammalian red blood cell plasma membrane by determining the effect of tetraethylammonium chloride on the water permeability of mammalian RBC plasma membran