Positive selection of thymocytes is necessary to produce a T-cell repertoire capable of interacting with self-MHC molecules. Thus the correct option is A.
<h3>
What is the purpose of positive selection during T cell development?</h3>
To address the necessity that T cells be capable of binding MHC complexes, T cells undergo positive selection. In this process, cells in the thymus present short pieces of proteins known as peptides, on their own MHC class I and class II molecules, allowing immature T cells to bind.
Further the this positive selection process also measures if a T cell will become a CD8+ T cell or a CD4+ T cell. Specifically, if a TCR (T-cell receptor) complex binds strongly to MHC class II, the complex send intracellular signals to induce the expression of a protein called ThPOK. This protein reduces the expression of another key protein, called Runx3, responsible for driving CD8 expression.
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Answer:
a. fats, oils, meats, and nuts.
Explanation:
Lipids are macromolecules that are insoluble in polar solvents like water, but soluble in non-polar solvents like diethyl ether. They made up of hydrocarbon and serve as a functional molecule in living cell membranes. In addition, they are involved in cell signaling and serve as energy stores. Lipids could be in the form of steroids, fats and oils, waxes and phospholipids.
In diets, oils, fats, nuts, meats whole milk, margarine, butter, cheese, fried foods supply lipids in large quantities. They serve as energy stores and also help in the absorption of fat-soluble vitamins in the small intestine.
Answer:
The activation energy required for an exploding firework is less than the activation energy required for a burning candle.
Explanation:
I did this in class. The height of the activation is lower for the firework than the burning candle.
Without being able to see the actual slide - it can only be said for sure that sickle cell blood cells are deformed - it is visually apparent when viewed through a microscope - the deformity deters the blood cell from the cells intended optimal capacity to hold molecules (such as hemoglobin) and it makes it harder for the blood cell to travel efficiently through the body's arteries and veins.
<span>The RNA in telomerase is binded to a complementary sequence on DNA specifically to 3' G overhang and also the Nucleotides associated to RNA component of telomerase are binded to DNA at the 3 end. Now the Telomerase moves through DNA strand that is newly synthesized towards the 3 end. In the same way if there are any additional nucleotides they were all binded to 3 end of the DNA and then the telomerase is removed from the DNA completely. now to fill in the gap left by telomerase the synthesis occurs on the 5 end of DNA strand.</span>