UNIVERSITI TUNKU ABDUL RAHMAN
FOUNDATION IN SCIENCE
SESSION 2015/10
1
TUTORIAL
MOLECULAR GENETICS I
FHSC1234 MODERN BIOLOGY
Instructor’s Guide: 1. Standard answers are not encouraged. Discuss with the students and lead them to the correct answer. 2. Allow and push the students to express and explain the answers, at the same time, correct their mistakes or concepts. 3. If the tutorial questions are not yet covered in the lecture, it should be carried forward to the next tutorial.
[Source : Final Examination Sept 2015] 1. A bacterium consisting of a radioactive DNA molecule is transferred into a non-radioactive medium and left to replicate n times. At the end of the process, a total of four DNA molecules are formed. Out of the four DNA molecules, two are composed of one radioactive strand and one non-radioactive molecules. The other two are composed entirely of non-radioactive strands. (i) Determine the number of times, n replication takes place that results in the formation of four DNA molecules. (1 mark)
(ii) State the replication model indicated by the experiment and briefly explain about it. (3 marks)
(iii) Identify the protein(s) involved in the initiation of DNA replication that are responsible for: (A) Unwinding parental double helix at replication forks. (1 mark)
(B) Relieveing overwinding strain ahead of replication forks. (1 mark)
(C) Stabilizing single-stranded DNA until it is used as a template. (1 mark)
(D) Starting an RNA chain using parental DNA as template. (1 mark) [Source : Final Examination April 2015] 2. Figure 2.1 shows a piece of nucleic acid undergoing a cellular process.
Figure 2.1 Answer the following questions based on Figure 2.1.
