In the first experiment, we attempt to substantiate the hypothesis that active transport of leucine in E-coli would only occur when cells are supplied with glucose since glucose enable the production of ATP (adenosine triphosphate). ATP supply the energy needed for active transport. Leucine is a radioactive aminoacid. Radioactive materials have been able to make biochemical assays less complex and improve the ability for biological researches to follow biochemical reactions in cells. One of the most important uses of radioisotopes is the ability for these isotopes to act as radioactive tracers. These tracers function as a tool for the study of metabolic and transport processes. The presence of a radioisotope does not c

Cellular membranes surround every cell and serves as the barrier between environment and living cells. It is composed of a phospholipid bilayer with the hydrophilic phosphate groups on the outsides of the cell and the hydrophilic lipids in between. There are membrane channel proteins and receptor carbohydrates that function in transport and signaling mechanisms on the exterior as well as the interior part of the membranes. The structure of these biological membranes enables semi-permeability. Materials that are small in size and not highly charged can easily diffuse across without the input of energy (passive transport) while large and highly charged materials need additional aid to pass through. Active transport of large particles require the expenditure of energy in the form of ATP. Osmotic gradients determine the direction of passive transport. When cells are placed in hypotonic solutions, solutions where there are more solute molecules on the inside of cells than the exterior environment, solutes will move down the concentration gradient from cell to environment. When cells are placed in hypertonic solutions, solutions where there are less solutes inside the cell than the cell's environment, solutes will move down the concentration gradient from the environment into the cell. In these experiments we will demonstrate that there is a need for energy in the form of ATP to actively transport the amino acid leucine and diffusion of solutes into the cell and water out of the cell will occur in hypertonic solutions.

Results for the first experiment were not obtained because of lack of time and the instructors were not able to grap

Some common words found in the essay are:
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Approximate Word count = 1122
Approximate Pages = 4 (250 words per page double spaced)