BIOL 1103 Lecture Notes - Lecture 5: Australia'S Big Things, Macromolecular Crowding, Lipid Bilayer

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lilacwildebeest616

19 Mar 2018

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In this lab diffusion and osmosis were looked at in many different experiments. Diffusion is the movement of particles from high concentration to low concentration, diffusion is under passive transport which requires no energy (recce et al. , 2014). Osmosis is also another method of passive transport, osmosis however is the diffusion of just water across a membrane. For a cell to be functional and healthy it has to regulate its internal environment and its external environment, this is done by the movement of materials through the cells membrane (biology department, By looking closely at these experiments a better understanding of how diffusion and osmosis work in the cell will become evident. First obtain 4 large plastic test tubes in a test tube rack. Then label the tubes 0, 0. 25, 0. 50 and. After collect one or two pieces of potato on a piece of wax paper and bring it to your lab bench.

Related Questions

Read the following scenarios and indicate which of the following processes they describe.

11. Sodium molecules move randomly around a solution of sodium chloride in water, frequently colliding with other sodium ions and chloride ions. secondary active transport diffusion osmosis facilitated diffusion primary active transport

12. Sodium ions (Na+) move through sodium channels in a synthetic membrane. primary active transport secondary active transport facilitated diffusion osmosis

13. Water molecules move into the cytosol of a cell placed in a hypotonic solution. primary active transport secondary active transport facilitated diffusion osmosis

14. Water molecules move into the cytosol of a cell placed in pure water. facilitated diffusion osmosis secondary active transport primary active transport

15. Water molecules move out of a cell placed in a hypertonic solution. facilitated diffusion primary active transport secondary active transport osmosis

16. The action of sodium-potassium pumps moves sodium ions (Na+) out of a cell and potassium ions (K+) into a cell. facilitated diffusion secondary active transport osmosis primary active transport

17. Glucose molecules move into cells lining the intestine against their concentration gradient driven by the movement of sodium ions (Na+) into the cells down their concentration gradient. osmosis secondary active transport primary active transport facilitated diffusion

18. A beaker of water is separated by a selectively permeable membrane that allows the passage of water but not ions. A solution of 4% sodium chloride (NaCl) is placed on one side of the membrane and pure water is placed on the other side of the membrane. The solutions are allowed to equilibrate. At this point, which process is going on? facilitated diffusion osmosis secondary active transport primary active transport

amaranthelk944

1 Which of the following statements is false?

(a) CO₂ and O₂ can diffuse freely across the cell membranes.

(b) The differences in permeability between artificial lipid bilayers and cell membranes arise from variations in phospholipid content.

(d) Cells expend energy in the form of ATP hydrolysis to maintain ion concentrations that differ from those found outside the cell.

2 Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell. Which of the following ions is the most abundant inside a typical mammalian cell?

(a) Na⁺

(b) K⁺

(d) Cl^â

3 Pumps are transporters that are able to harness energy provided by other components in the cells and drive the movement of solutes across membranes, against their concentration gradient. This type of transport is called _____________.

(a) active transport.

(b) free diffusion.

(d) passive transport.

harlequinbuffalo618

Cell Membranes Lab Report

Diffusion

Compare the following terms: solvent, solute, andsolution.

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

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

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

Time (min)	Diameter (mm)
Time (min)	5Â°C MB	5Â°C PP	23Â°CMB	23Â°C PP
0
15
30
45

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.

Osmosis

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

Describe the net movement of water in osmometer 1.

How is the movement of water molecules related to theconcentration gradient of the solution?

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

Was the net movement of water in bags 1 to 4 into or out of thebags?

Explain the results from bags 4 and 5.

Selective Permeability of Membranes

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

Which substances diffused through the dialysis membrane?

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

Tonicity

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

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

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?

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BIOL 1103 Lecture Notes - Lecture 5: Australia'S Big Things, Macromolecular Crowding, Lipid Bilayer

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