Fall 2016: Biol 105 Exam 4 Essay Questions
Please type a statement acknowledging that you understand that this assignment will make up a portion of your Exam 4 grade, that you will complete it independently, and you will not plagiarize or copy from other students, textbooks, presentation materials, or any other source. Any student who plagiarizes or works with another student will receive a zero for their grade.
Read each of the following short essay questions. Answer each question as descriptively as you can and be sure to use specific terms when applicable. Answers should be in complete sentences, with proper spelling & grammar. Point values vary per question.
1. Why are there differences between males and females in terms of expression of X-linked, recessive traits? Can females express these traits? Include the terms hemizygous, Barr body, and mosaic. (4 points)
Y-linked genes typically determine sexual orientation, whereas X-linked genes typically determine an abundance of other traits because it’s much bigger than the Y-chromosome. Males are hemizygous because they lack a second copy of an X chromosome (XY), unlike women who have 2 (XX). This is why its much more common for a man to inherit an X-linked recessive disorder because they don’t have a second X chromosome to compensate. However, women can still express these traits and also be carriers if they are homozygous for the allele. A Barr body forms from the inactive X that