1) Describe the process of muscle contraction. Includea description of the sarcomere structure and what happens to itduring muscle contraction and relaxation. Also describe howthe process is regulated, including the roles of ATP andCa2+. Be sure to include the names and activitiesof relevant molecules.

2) Describe the process of X-chromosome inactivation neededfor X chromosome dosage compensation in femalemammals. Include a description of the two phases (initiationand maintenance) and what is involved in each. Be sure toinclude the names and activities of relevant molecules.