Explain the role of major histocompatibility complex (MHC) molecules in T cell activation
What will be an ideal response?
T cell activation begins with a cell processing and displaying antigen fragments on its MHC molecules. It then presents the antigen to a particular T cell clone, which is specific for its individual MHC-antigen complex. When the T cell receptor recognizes and binds this complex, multiple changes are triggered inside the T cell and the process of activation begins. This process is known as clonal selection because the antigen "selects" a particular T cell clone. Full T cell activation requires the interaction of the T cell with other molecules on the cells called co-stimulators.
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Proteins are broken down to amino acids by enzymes called transaminases.
Answer the following statement true (T) or false (F)
Potassium is a(n):
a. Anion b. Cation c. Negion d. Proton
The three major subdivisions of extracellular fluid found in the body are
A) blood, plasma, and lymph. B) blood, interstitial fluid, and cytosol. C) blood, lymph, and cytosol. D) plasma, lymph, and interstitial fluid. E) plasma, interstitial fluid, and cytosol.
Compartments A and B are separated by a membrane that is permeable to K+ but not to Na+ or Cl-. At time zero, a solution of KCl is poured into compartment A and an equally concentrated solution of NaCl is poured into compartment B
Which would be true once equilibrium is reached? A. The concentration of Na+ in A will be higher than it was at time zero. B. Diffusion of K+ from A to B will be greater than the diffusion of K+ from B to A. C. There will be a potential difference across the membrane, with side B negative relative to side A. D. The electrical potential difference and diffusion potential due to the concentration gradient for K+ will be equal in magnitude and opposite in direction. E. The concentration of Cl- will be higher in B than it was at time zero.