As Biology (7401/1) Paper 1 Specimen 2014 Study Guide Graded A+

04 . 2) Scientists determined that a sample of DNA contained 18% adenine. What were the percentages of thymine and guanine in this sample of DNA? [2 marks] {Ans: 1. Thymine 18(%); 2. Guanine 32(%);}05 . 3) Scientists investigated the effect of hunting on the genetic diversity of otters. Otters are animals that were killed in very large numbers for their fur in the past. The scientists obtained DNA from otters alive today and otters that were alive before hunting started. For each sample of DNA, they recorded the number of base pairs in alleles of the same gene. Mutations change the numbers of base pairs over time. Figure 6 shows the scientists' results. The scientists obtained DNA from otters that were alive before hunting started. Suggest one source of this DNA. [1 mark] {Ans: Bone/skin/preserved remains / museums;}09 . 1) Read the following passage. Herpes simplex virus (HSV) infects nerve cells in the face, including some near the lips. Like many other viruses, HSV can remain inactive inside the body for years. When HSV becomes active, it causes cold sores around the mouth. Human cells infected with a virus may undergo programmed cell death. While HSV is