50. In a skeletal muscle contraction, which is would be shortened during contraction?
(A)Z-line
(B)Thick filaments
(C)Sarcomere
(D)Thin filaments
(E)Dark band

46. In osmoregulation of freshwater fish and marine fish, which statement is correct? (A)Only freshwater fish gain salt ions from food. (B)Only freshwater fish excrete ions from gills. (C)Only marine fish uptake ions from gills. (D)Only marine fish excrete ions from kidney. (E)Only freshwater fish uptake ions from gills.

47. Which description of the reabsorption and secretion in human kidney below is INCORRECT? (A)The initial filtrate in Bowman’s capsule include H2O, H+, HCO3-, urea and nutrients. (B)In the proximal tubule, nutrients, salt, HCO3-, and H2O are reabsorbed. No secretion. (C)In the loop of Henle, salt and H2O are reabsorbed. No secretion. (D)In the distal tubule, salt, HCO3-, and H2O are reabsorbed. Secretion takes place. (E)In the collecting duct, salt, urea and H2O are reabsorbed. No secretion.

48. Pancreatic hormones regulate blood glucose level. In the statements below, which one is correct? (A)Alpha cells in pancreas release insulin into the blood. (B)Insulin stimulates only liver cells to take up glucose. (C)When the level of blood glucose drops, it diminished the alpha cells. (D)If the regulation of insulin is disordered and thus blood glucose is elevated, this is called hyperglycemia. (E)Type I diabetes is caused by the defective insulin signaling.

49. A woman has experienced several miscarriages due to the low level of a hormone that causes the breakdown of the uterus lining (similar to menstruation). Which hormone could be the insufficient one? (A)LH (luteinizing hormone) (B)FSH (follicle-stimulating hormone) (C)Oxytocin (D)Prolactin (E)Insulin

1. Perform the following mathematic operations, and express the result to the correct number of significant figures.=?(A)188.1272(B) 188.127(C)188.13(D) 188.1 (E)188

 2. Which one of the following statements is correct? (A) The systematic name for TeO32- is tellurate ion.(B) The systematic name for NO2 is nitrogen(IV) oxide. (C) The systematic name for Mg3(SbO4)2 is magnesium antimonate. (D)The systematic name for GaAs is gallium arsenate. (E)The systematic name for Na2O2 is sodium oxide.

 3. A 100.-L flask contains a mixture of methane (CH4) and argon gases at 25℃. The mass of argon present is 228 g and the mole fraction of methane in the mixture is 0.650. The total kinetic energy for methane in the mixture is________ J. (A) 3.94 × 101(B) 3.94 × 104 (C)6.06 × 104(D) 6.06 × 101 (E)1.06 × 10

 4. Given that a sample of air is made up of nitrogen, oxygen and argon in the mole fractions 78% N2, 21% O2 and 1.0% Ar, the density of air at standard temperature and pressure is mg/L. (A) 1.26 × 104 (B) 12.6 × 10-1(C)1.26 × 101(D) 1.3 × 102 (E)1.3 × 103

 5. The overall reaction in a commercial heat pack can be represented as 4Fe(s) + 3O2(g) → 2Fe2O3(s), △H = -1652 kJ. How much heat is released when 1.00 g Fe is reacted with excess of O2? (A) -7390 J(B) -14760 J(C)-1650 J(D) -6600 J (E)-2200 J 

6. A hypothetical reaction, A + B +2C → 2D + 3E, has the rate law as Rate = -(△[A]/△t) = k[A][B]2 . An experiment is carried out when [A]0 = 0.01 M, [B]0 = 3.0 M and [C]0 = 2.0 M. The reaction is started, and after 8 s, the concentration of A is 0.0038 M. Based on the information, the concentration of A after 13 s is__________ M.(A)0.0038(B) 0.30(C)0.025(D) 0.0021 (E)0.00011