Membrane Structure Tutorials

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Membrane Structure Tutorials

1. Go to http://telstar.ote.cmu.edu/biology/MembranePage/index2.htmland read the tutorial on the many types of molecules that come together to make a cell membrane.  Assignment:

Take notes as you carefully read the web page and watch the animations.  This will be in place of a lecture on this topic so make sure you read all sections and watch all the animations provided until you understand the material.

Notes   - the hydrophilic aqueous cytoplasm and the hydrophobic lipid membranes are common in a cell.  Three members of the lipid family of molecules will be discussed in this course: fats (triacylglcerol),phospholipids, and steroids.Lipid molecules are slightly soluble to insoluble in water. Lipids are hydrophobic because the molecules consist of long, 16-18 carbon, hydrocarbon backbones with only a small amount of oxygen containing groups. Lipids serve many functions in organisms. They are the major components of waxes, pigment, steroid hormones, and cell membranes. Fats, steroids, and phospholipids are very important to the functioning of membranes in cells and will be the focus of this tutorial.

: 2. Go to http://www.bio.davidson.edu/people/macampbell/111/memb-swf/membranes.swf This site is a tutorial on the molecules that make up cell membranes and the way that they are arranged in cell membranes. Assignment:      Read through the tutorial on membrane structure to see how the variety of molecules fit together in the fluid mosaic model.     As quizzes appear during this tutorial, type in the questions they ask and the correct answer that you chose.

Quiz Questions and Answers:

-Lipids are the primary determinants of membranne structure while proteins carry out membrane function.

Liplids and proteins

-List the molecular componets common to all phosphoglycercles, phosphate, glycerol, and two fatty acids.

Phosphate, glycerol, and two fatty acids 

-Name the three classes of membrane:

 lipids glycolpids, cholestrol,phospholipids.

-What type of bonding dominates interaction between lipids and limits fluidity 

Van der waals forces

-How is asymmetry preserved?

 Lipid heads are hydrophilic, as are exposed portions of proteins 

-How could you identify a transmembrance helix just by examining the amino acid sequence of a protein?

Transmembrane helices can often be identified from a proteins sequence as characteristic streches of two dozen or so hydrophobic amino acids 

CYSTIC FIBROSIS

Part 1.

In this part of the activity you will visit the Cystic Fibrosis Foundation’s web site to learn about the causes and symptoms of cystic fibrosis.

Use your browser to go to http://www.cff.org/home/

Use the information provided in the “About cystic fibrosis” section to answer the following questions:

1. What are the signs and symptoms of cystic fibrosis?
Very Salty tasting Skwein
Persistent coughing, at all times with phlegm
Frequent lung infections
Wheezing or Shortness of Breath
Poor growth/ Weight gain in spite of a good appetite

2. How common is this disorder?
CF is the most common genetic (inherited) disease. Its affects about 30,000 children and adults in the u.s. and approximately 70,000 worldwideddd

3. How is cystic fibrosis diagnosed?
People with cystic fibrosis have between 2 and 5 times the normal amount of salt in their sweat. Doctors can use a sweat test to measure the amount of salt in a person’s sweat. In newborns, doctors can measure the amount of a protein call trypsinogen in the blood

4. How is cystic fibrosis inherited? Does everyone who has a mutant gene for the protein have cystic fibrosis?
Cystic fibrosis is a recessive disorder, which means that both parents must pass on the defective gene for any of their children to get the disease. If a child inherits only one copy of the faulty gene, he or she will be a carrier. Carrier don’t actually have the disease, but they can pass it on to their children

Part 2.

In this part of the activity you will read an article to learn more about cystic fibrosis.

Use your browser to go to:

http://resources.schoolscience.co.uk/MRC/3/page3.html

Use the information in this article to answer the following questions:

1. Explain the normal function of the protein that is defective in cystic fibrosis.
The normal function of the defective protein in CF is that the protein provides enough water and salt to the mucus, allowing it to flow and move smoothly out of the lungs and air passages

2. What happens to this protein in CF patients and what are the consequences for the health of these individuals?
Chromosome 7 is one of the 23 pairs of chromosomes that are part of each person’s genetic makeup. The CF gene causes the production of a protein that lacks an important amino acid.

Part 3.

In this part of the activity you will read about how cystic fibrosis is treated.

Use your browser to go to:

http://www.mayoclinic.com/health/cystic-fibrosis/DS00287

Use the information in the different sections of the article to answer the following questions:

1. Explain at least 3 treatments for the symptoms of cystic fibrosis.

Medicatation up to date.ion:
You can take mucus thinning drugs and antibiotics to keep the mucus moist. Also, you can take bronchodialators to relax the airways

Lung Transplant
When a lung isn’t able to function they need to replace it with a donor

Physical Therapy
Loosening the mucus. Feels better and slows process


2. Discuss at least 3 ways for parents to help their children who have cystic fibrosis.

Three Ways: Drink enough fluids, make sure they wash their hands and are clean, keep immuniz

Microscopes

For this assignment we had to use  the microscope, and when i used the microscope i used a paracite to see if i could use it right. When i finally centered the glass and focused in on it i saw a small brown arm from that paracite.

After this we had to use the microscope again but move it up to a higher power. Witch means that we zoomed in on this paracite and we had to refocus it in. After  this is what i saw with the arm. You can see the lightness around the edges of the arm. Also the darkness right in the middle of it, with a brownish color mixed in with it.

Over all the microscopes are a big help for when we have to look at small substances for a project or a lab. You can really see what the substance is when it is under the microscope.

Osmosis Lab

 This lab was actually pretty cool.  We started by Getting some dialysis tubing. After this i mixed a substance of corn syrup and water into a beaker. Then when i mixed it good i used a pipet to transfer the water from the beaker inter the dialysis tubing. After we tied off the ends of the bags with string.  When this was done we weighed it on the scale.

I weighed it and it came out to be .73 on this scale. When i finished this i filled a beaker full of distilled water and dropped the dialysis tube with the substance in it, into the beaker.  We left it over night to see what would happen. When i came into class the next morning the substance had expanded in the bag.

Then i weighed  the bag again and the substance weighed more that it did the day before. It weighed out to be 1.65 on the scale the second time. After this i concluded that the water from the beaker had gone into the bag to make a reaction with the corn syrup that would expand it. The water level had lowered in the beaker and the water from that went into the bag with the corn syrup in it.

Diffusion and Osmosis lab

     
  Diffusion and Osmosis are important to any living organism, because water and certain solutes move in and out of cells by these processes. During these two processes molecules only more from regions of higher concentration to lower concentration. The way this works is cells often need to absorb molecules from regions in which the concentration of the molecules may be lower than the concentration already inside the cell. Absorption of glucose from the blood frequently occurs under these circumstances.Diffusion and Osmosis do not require any added energy. In this experiment we measured diffusion of small molecules through a selectively permeable membrane (dialysis tubing). What is Dialysis tubing? Dialysis tubing is made of a membrane contain gin tiny pores. The size in the pores is what determines what molecules can exit or enter the bag.  For this experiment we used iodine,starch, dialysis bag, sting, beaker and water. 
      The first step to this was we opened the dialysis bag. On one end we tied a string to it so it stayed closed. After tying it closed we got the starch and put about three droplets full of it into the dialysis bag.  We than tied the top with sting so the starch wouldn't empty out. Next we filled up the beaker with water from the sink about half way and added Iodine into the water until it turned a dark yellow color. Next we added the Dialysis bag filled with starch into the water and iodine. We let the bag sit in the solution until the next class day(about 24 hours). 
      When we came into the class the next day after the letting the starch sit in the mixture of water and iodine  we looked to make observations about what happened. The solution of water and iodine was not a dark yellow color any more it was clear. After pulling the dialysis tube out of the water it had a purplish color at the bottom. 
     As a class and group we came up with the conclusion that the Iodine reacted with the starch in the Dialysis bag. Which made the Iodine enter the bag through its pores. This process would be the Osmosis part because the Iodine entered the bag. The Glucose from the starch exited the bag into the water which was diffusion.