How does this relatively small number of MHC molecules have the potential to bind the huge number of antigenic peptides encountered in the environment, and what features of a peptide determine whether it will be bound by a given MHC molecule?
What will be an ideal response?
MHC molecules have promiscuous binding specificity, which means that one MHC molecule is able to bind a wide range of peptides with different sequences. For all MHC molecules, only a few of the amino acids in the antigen peptide are critical for binding to amino acids in the peptide-binding groove. The critical amino acids in the peptide are called anchor residues; they are the same or similar in all peptides that bind to a given MHC molecule. The other amino acid residues in the peptides can be different. The pattern of anchor residues that binds to a given MHC molecule is called the peptide-binding motif. Hence, a very large number of discrete peptides can bind to each MHC isoform, the only constraint being the possession of the correct anchor residues at the appropriate positions in the peptide. MHC class I molecules also bind peptides that are typically nine amino acids long, whereas MHC class II molecules bind longer peptides with a range of lengths.
You might also like to view...
Choose the item in column 2 that best matches each item in column 1.
1) dermis 2) basal layer 3) keratin 4) subcutaneous layer 5) sebum 6) ichthyoderma 7) onychophagia 8) keloid 9) pallor 10) nevus 11) diaphoresis 12) purpura 13) urticaria 14) macule 15) purulent 16) fissure 17) vesicle 18) decubitus ulcer 19) scabies 20) pediculosis 21) rubella 22) tinea capitis 23) alopecia 24) onychia 25) curettage A) uses a scraper B) ringworm C) middle layer of skin D) baldness E) hives F) a blister G) infected nail bed H) pigmented skin blemish I) primarily composed of fat tissue J) skin hemorrhages due to fragile blood vessels K) pressure sore L) abnormal paleness of the skin M) mite infestation N) deepest layer of the epidermis O) nail biting P) German measles Q) flat, discolored area R) hypertrophic scar S) lice infestation T) crack-like lesion U) containing pus V) oil that lubricates the skin W) profuse sweating X) scaly skin Y) hard protein found in hair and nails
The roles of the elementary teacher should include all of the following EXCEPT:
(a) a perfect lifestyle (b) positive role model (c) helping maintain student health (d) moti-vating students to make wise decisions
Marijuana is administered therapeutically for all of the following reasons EXCEPT
A) to reduce the muscle pain and spasticity caused by multiple sclerosis. B) to control side effects of chemotherapy such as nausea and vomiting. C) to forestall loss of lean muscle mass due to AIDS-wasting syndrome. D) to reduce appetite for weight control.
Throat:
a. Trachea b. Coccyx c. Larynx d. Esophagus e. Pharynx