Extra credit 1). Propose an experiment to test the importance of this property for transmembrane protein insertion and orientation. Up to 2.5 pts¬¬ Generally, transmembrane proteins tend to be solubilized only by agents that disrupt hydrophobic associations and destroy the lipid bilayer. The most efficient substance to use are detergents, because they are small amphipathic molecules that tend to form micelles in water. This experiment will be intended to define the unfolded state of a transmembrane protein and see if they adopt different types of amphiphilic structures. I will create an experiment to determine if the unfolded state of membrane proteins in detergent micelles is different from that in the thermal denaturation experiments. When …show more content…
Propose a simple experiment to demonstrate that the location of the positive (basic) amino acids determines the orientation of the transmembrane segment as shown above. Up to 2.5 pts An experiment that would demonstrate that the location of the positive (basic) amino acids determines the orientation of the transmembrane segment would be to have multiple polypeptide protein chains that are very similar in their amino acid sequence. All the amino acids in the protein chain would share similarity except for the amino acid that flanks the start transfer sequence. By altering the flanking amino acid on the STS with an amino acid that has a differing polar property and charge, it will alter the way the protein inserts into the membrane as well how it folds itself. By having positively charged amino acids before the STS is attached or after its attached, you will different orientations of polypeptide chain segments embedded into the
The group of scientists hoped to determine the structure of the channel-forming domains in CFTR. The key experiment, called substituted-cysteine-accessibility method or S.C.A.M, consisted of mutating and substituting 9 consecutive residues in the M1 membrane spanning segment with cysteine in Xenopus oocytes, or eggs. If the mutated channels with cysteine still function, then they assumed that the structures of the mutated and normal channels were similar. Next, they determined the accessibility of the cysteine residue by adding the reagents MTSEA and MTSES, which are highly specific reagents that form a mixed disulfide with a free sulfhydryl covalently linking the reagent to the cysteine. In other words, if the MTSEA and MTSES bond with the cysteine residue and alter the conduction, they can assume the accessibility of the residue and then infer that the side chain of the corresponding wild type residue, or the residue before substitution, lines the channel. This process had been used to determining the structures of ion ch...
Obesity a risk factor in which excess body fat accumulates and can have negative effects on your health. Here we identify how the hormone insulin reacts in 3T3-L1 fibroblasts and its role on adipogenesis. Adipogenesis is the development of fat cells from pre adipocytes. Insulin is an important factor in the differentiation of 3T3-L1 pre adipocytes to mature adipocytes. Oil Red O (ORO) is used to demonstrate the presence of lipids in each different treatment. A spectrophotometer is used to get the optical density of liquid at the different insulin concentrations. One factor CREB is revealed from preadipocytes to mature adipocytes. By demonstrating how insulin triggers transcription factors. When cells are insulin induced CREB is activated in differentiation. Insulin increased the rate of differentiation and the amassing of triglycerides in 3T3-L1 cells . Insulin was able to induce adipogenesis by observing cell morphology and optical density of liquid from ORO stain. Insulin at 1 µg/ml had the optimal rate of differentiation compared to the other insulin concentrations. Morphology of cells changed significantly from Day 0 to Day 7 at 1 µg/ml and appeared larger and
“Enzymes are proteins that have catalytic functions” [1], “that speed up or slow down reactions”[2], “indispensable to maintenance and activity of life”[1]. They are each very specific, and will only work when a particular substrate fits in their active site. An active site is “a region on the surface of an enzyme where the substrate binds, and where the reaction occurs”[2].
This occurs when special carrier proteins carry solutes dissolved in the water across the membrane by using active transport. When the concentration gradient can not allow travel from one side of the membrane to the other fast enough for the cell’s nutritional needs, then facilitated diffusion is used. The transport protein is specialized for the solute it is carrying, just as enzymes are specialized for their substrate. The transport protein can be
c. Na+ and K+ gates are closed. Na+ are concentrated outside the cell; K+ are concentrated inside the cell.
In biology class, we were learning about enzymes. Enzymes are proteins that help catalyze chemical reactions in our bodies. In the lab, we were testing the relationship between the enzyme catalase and the rate of a chemical reaction. We predicted that if there was a higher percentage of enzyme concentration, then the rate of chemical reaction would increase or it would take less time. We placed 1 ml of hydrogen peroxide into four depressions. Underneath the first depression, we place 1 ml of 100% catalase and make 50% dilution with 0.5 ml of water. We take 50% of that solution and dilute with 0.5 ml of water and we repeat it two more times. there were four depressions filled with catalase: 100%, 50%, 25% , 12.5 % with the last three diluted
The aim of this report is to investigate the responses of plants in regards to growth on the basis of varying directional sunlight. In order analyze this; pea plants will be used within a conducted experiment.
“The plasma membrane is the edge of life, the boundary that separates the living cell from its nonliving surroundings. The plasma membrane is a remarkable film, so thin that you would have to stack 8,000 of these membranes to equal the thickness of the page you are reading. Yet the plasma membrane can regulate the traffic of chemicals into and out of the cell. The key to how a membrane works is its structure” (Simon, 02/2012, p. 60).
C) The photo of prokaryotes on slide 6 of module 14 shows that it ...
Transport is a vital process to move substances from one place to another inside a cell. There are two different types of transport, passive and active transport. Passive transport is when no additional energy is needed for molecules and substances to transfer across the membrane or cell. In passive transport, the molecules are moving from an area of high concentration to an area of lower concentration. There are three types of passive transport which are diffusion, facilitated diffusion and osmosis (Ed. Allan B., 2010). Facilitated diffusion is when transport proteins provide the force to move ions and small molecules across the membrane from high to low concentration. Transport proteins are proteins that facilitate the movement of substances or waste through the plasma membrane (Transport Proteins, 2000).
its original shape and shape. Within the phospholipid bi-layer there are proteins, and these. proteins are made up of polypeptide chains which are joined together. by hydrogen, hydrophobic and peptide bonds. Once the temperature has increased above 40°C the molecules vibrate so energetically that these bonds break easily and therefore create holes within the cell wall.
...bic, they are able to bind to the exposed hydrophobic surface of the non-native polypeptide. Mutations which substitute these non-polar amino acids with polar residues result in the abolition of polypeptide binding.
In experiment 1, the exchange of substances, through passive transport, was observed. In this experiment, a dialysis membrane was used to simulate a cell membrane, however, the dialysis membrane is not alive. In addition, the dialysis membrane is semipermeable meaning that, depending on size, only certain substances will be able to go through. During the experiment, the membrane was half filled with glucose and, the other half, filled with starch solution. The membrane was placed into a beaker with iodine solution.
explain the formation of micelles and bi-layers from lipid amphiphilicity. A variety of books were
Hydrogen bonding- this bonding occurs between the hydrogen and oxygen or nitrogen between amino acids opposite each other. This bond occurs because the oxygen is slightly negative and the nitrogen/hydrogen is slightly positive so there is an attraction between them when they come close together. This is a fairly weak bond however it forms a vital part in helping the structure stay strong and in the right