sobre la membrana de la celula

1. The Cell membrane: A Comprehensive Review Mohamed Salem
I. Introduction
Lab A :
The main Purpose of lab A was to know Information about the permeability of the cell
membrane and we were trying to figure out what portals does the membrane have
Solutes Tested for Presence lab A (Hypothesis) :
1. Iodine
2. Glucose
3. Water
4. Strach
Lab B :
The main purpose of lab B is to know how the speed of osmosis is affected by the concentration
of sucrose
Variables :
Independent - Concentration of sucrose
Dependent - Mass of water
We tested the relationship between two variables by having 6 different cups of water with a
membrane that have different amounts of concentrations of sucrose and the results have proven
that depending on the amount of concentration the mass of the water changes.
II. Background Information
Diffusion : The random spread of chemicals and it happens because all chemicals move and hit
each other and change direction
Osmosis : The movement of water form an area of high to low concentration and osmotic
potential occurs when water molecules keeps moving in the the cell until in bursts or in another
word water move from an area of hypotonic to hypertonic solution
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2. The Cell membrane: A Comprehensive Review Mohamed Salem
3 Different types of solutions that can impact the Size or mass of the cell
Hypertonic : An area where there is less water, more Solute
Hypotonic : An area where there is more water, less solutes
Isotonic : An area where there is equal amount of water and solute
Structure Commonly found in all membranes :
Protein Pump : A protein pump uses energy released within the cell to force substances through
the plasma membrane. Moving substances with a protein pump is an example of primary active
transport. Primary active transport uses energy to do its work, which it gets from ATP
(adenosine triphosphate), a molecule that temporarily stores the energy released when a cell
"burns" food. Cells use active transport to move amino acids and some ions, including
potassium, sodium, hydrogen, chlorine, calcium, and iodide.
Phosphates : Attract water
Fatty acid carbons : Allow the passing of certain amount of water that the cell needs into the cell
Lipid bilayer : The lipid bilayer is the main component of the cell's outer membrane, the plasma
membrane. It consists of two back-to-back layers of lipid molecules. These lipid molecules,
which are made of oxygen, carbon, and hydrogen atoms, are constantly moving, or fluid. This
fluid characteristic allows the bilayer to seal itself if it is broken. Certain atoms and molecules
are able to pass through the bilayer relatively easily, especially those that are small and not
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3. The Cell membrane: A Comprehensive Review Mohamed Salem
positively or negatively charged. Proteins embedded within the lipid layer-ion channels and
aquaporins, for example-allow other molecules to pass through the plasma membrane that the
lipid bilayer does not.
Types of Portals :
- GluT Portal : A transporter is a type of protein that moves molecules into and out of cells
by process called facilitated diffusion. With facilitated diffusion, molecules bind to an end
of the transporter, then move to the other side of the plasma membrane through the
transporter. This type of movement does not require the cell to use energy. The proteins,
however, do need to change shape to allow the molecules to pass through. There are
different types of protein transporters, each specific to certain molecules. The protein
shown here is a GLUT transporter, which allows glucose (sugar) molecules to easily
pass through.
- Aquaporin : Aquaporin are pores , made of proteins , that allows water molecules to
easily pass through the cells plasma membrane
- Ion channel : A channel is a protein that acts as a pore to ions (atoms with either a
negative or positive charge). The channels allow ions to pass freely through the plasma
membrane in either direction. Ion channels are specific to particular ions. For example,
one type of channel is open to potassium ions and another is open to sodium ions.
Some ion channels are "gated." Gated channels can be either opened or closed,
depending on various factors, including chemical and electrical conditions within and
outside the cell.
- Protein Pump : A protein pump uses energy released within the cell to force substances
through the plasma membrane. Moving substances with a protein pump is an example of
primary active transport. Primary active transport uses energy to do its work, which it
gets from ATP (adenosine triphosphate), a molecule that temporarily stores the energy
released when a cell "burns" food. Cells use active transport to move amino acids and
some ions, including potassium, sodium, hydrogen, chlorine, calcium, and iodide.
Purpose of a Plasma Membrane :
- To allow to passing and movement of molecules or chemicals in and out of the cell
Materials and chemicals needed :
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4. The Cell membrane: A Comprehensive Review Mohamed Salem
Lab A
Solution of glucose ( 15%) Starch (1%) H2o ( 84%)
Cell membrane
Iodine Solution
Glucose Strip
Cup
Step-By-Step Explanation
1.) Rub membrane under H2o to open it
2.) Tie one side of the membrane
3.) Measure 15ML of solution of glucose
4.) Fill ¾ of the cup with water
5.) Test the water for starch and glucose
6.) Tie other end of the membrane
7.) Weight the cell
8.) Soak the membrane with all the chemicals in the water for 25 minutes
9.) Dry it off
10.) Weight the cell
11.) Test the water for starch by adding 30 drops of iodine solution
12.) Test the cell for glucose
Lab B
In lab 2 we are doing about the same thing but the difference is that we are changing the
glucose with sucrose and we are testing for sucrose and how the speed of osmosis is affected
by the concentration of sucrose
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5. The Cell membrane: A Comprehensive Review Mohamed Salem
6 different types of Sucrose concentration
Cell membrane
Rub membrane under H2O to open it
Tie one of the sides of each membranes
Put 15 millimeter of sucrose in the membranes ( each one with a different concentration)
Tie other end
Weight it
Put in water for 30 minutes
Weight it
III. Data/Results
LAB A Solution in membrane Water in cup
Glucose At Start Positive for glucose Negative
Glucose After Low Positive Low positive
Starch Before Positive for Starch Negative
Starch After Positive Negative
Mass Before 15.5 ¾ of the cup
Mass After 16.6 increased in mass
LAB B
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6. The Cell membrane: A Comprehensive Review Mohamed Salem
Percent sucrose initial mass final mass change in mass % change
0% 15g/15.1g 15.2g/15.0g -2 / -.1 1.3/-.7 .6%
2% 13.2g/13.7g 14.0g/14.6g +.8/.9 6%/6.1% 6%
4% 15.3g/14.5g 16.9/16.5 1.6/2 10.4%/12%
11.2
6% 15.6g/16.1g 19.4/18.5 3.8/2.4 24.3%/14.9% 19
8% 13.9g/16.4g 17.3/20.5 3.4/4.1 24.5/25 24.6
10% 17.7g/16.3g 22.1/20.5 4.4/4.2 24.8/25.7 25
IX Conclusion
Lab A :
This shows that starch wasn't able to go out of the cell as when we added the iodine to the cell
membrane it ended up turning dark and the water stayed clear. The table shows that glucose
was able to pass through in and out of the membrane. In addition this shows that iodine was
able to pass and enter the cell though it wasn't able to get out because it reacts with starch. As
water moves from and area of high to low concentration the water keeps moving in form a
hypotonic to hypertonic solution which causes osmotic potential which causes the cell to burst.
Results proof about the structure of the membrane
- There is a GluT Portal
- There is a ION Portal
- There is a Aquaporin Portal
- No Portal for scratch
● There is a trend in what can and can't go through the cell membrane as big chemicals
can't go through the membrane whie small chemicals can
Lab B :
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7. The Cell membrane: A Comprehensive Review Mohamed Salem
There is a direct connection between the sucrose concentration and the and the change in the
cell mass as when the concentration increases the mass increases as shown in the table when
the percent of the concentration of sucrose increases the overall mass increases
● This lab connects to cystic fibrosis. There has to be a portal for salt to pass through and
make the water pass through and make the mucus which has bacteria and viruses and
stops them from entering the lungs slippery so you can cough in and get all these things
out of your body . The problem with cystic fibrosis is that the portal responsible for salt is
not working so the water stays with the salt so the mucus with all these viruses and
bacteria gets thicker and as the bacter keeps reproducing and eventually enters the lung
and causes this disease . This relates to our lab because our lab has to do with portal
and chemicals able to move in and out of the cell.
Electronic copy available at: https://ssrn.com/abstract=4182126