A.Rt IO B.Rt IR C.Rt LR D.Rt SO E. Rt SR
ANS.E. The superior rectus muscle can elevate and adduct the eye from the neutral position. From the abducted position, it is the only muscle that can elevate the eye. The inferior oblique muscle (choice A) can elevate and abduct the eye from the neutral position. From the adducted position, it is the only muscle that can elevate the eye. The inferior rectus muscle (choice B) can depress and adduct the eye from the neutral position. From the abducted position, it is the only muscle that can depress the eye. The lateral rectus muscle (choice C) can abduct the eye. The superior oblique muscle (choice D) can depress and abduct the eye from the neutral position. From the adducted position, it is the only muscle that can depress the eye. FOR MORE IN DENTISTRY: VISIT
A. Alanine B. Arginine C. Isoleucine D. Leucine E. Phenylalanine The correct answer is B. This question requires two logical steps. First, you need to appreciate that hydrophilic amino acids are more likely to appear on the surface of a protein molecule, whereas hydrophobic amino acids are most likely be found in the interior. Next, you need to figure out which of the amino acids listed is hydrophilic. If you recall that arginine is a basic amino acid that is positively charged at physiologic pH, you should be able to answer this question right away.
All the other choices have neutral side chains and are uncharged at physiologic pH. They would most likely be found in the hydrophobic core of the protein structure. Alanine (choice A), isoleucine (choice C), and leucine (choice D) all have aliphatic side chains; phenylalanine (choice E) and tryptophan have aromatic side chains.
