2016_FRQ_by_topics_Application_topics_ANS_Updated

NANYANG JUNIOR COLLEGE H2 Biology Free Response Questions Application Syllabus 1 J2/2016 Free Response Questions – Application Syllabus Isolating, Cloning and Sequencing DNA 1. Describe the natural function of restriction enzymes and its role in formation of recombinant DNA molecule. [8] 1. Restriction endonucleases / restriction enzymes are naturally found in bacteria; 2. They protect the bacterial cells against foreign DNA from viruses i.e. phages; 3. They work by hydrolysis / breaking of phosphodiester bonds of the foreign DNA; 4. The bacterial DNA is protected by the addition of methyl groups ( -CH3) to adenines or cytosines; 5. Restriction enzyme has active site that recognise short specific nucleotide sequence / restriction site that are palindromic; (b) Explain the formation of recombinant DNA molecule. Instructions to students:  Revise the relevant section/s of your lecture notes, tutorials, tests and exams after looking at each question.  Memorize these relevant section/s before writing your answers. If you forget any point while writing, revise again and re-write the entire answer. Do not cheat by just looking at the notes and adding on the points to your answer – you are merely cheating your own learning!  The marks allocated for each question is a rough gauge of how many points there should be in your answer – they are not the absolute number of points. Thus, if you have more points than the marks allocated, write everything down. Highlight / underline all the key words and phrases in your answers. This set of answers can serve as your revision notes in future, if it is well done.  Pace your learning. Attempt 10 questions a day, everyday and you will finish revising and memorizing the Biology syllabus before the end of Term 3!

NANYANG JUNIOR COLLEGE H2 Biology Free Response Questions Application Syllabus 2 J2/2016 1. Recombinant DNA refers to DNA molecules containing DNA from two or more sources. 2. Restriction enzyme cleave the phosphodiester bonds in the sugar-phosphate backbone of both DNA strands at specific restriction sites creating sticky ends; 3. Gene-of-interest and plasmid is cut with the same restriction enzyme; 4. The single-stranded DNA can form hydrogen bonds with complementary sticky ends on the gene of interest by complementary base pairing; 5. DNA ligase catalyzes the formation of phosphodiester bonds between two nucleotides to produce recombinant DNA molecule OR 6. Restriction enzyme cleave the phosphodiester bonds in the sugar-phosphate backbone of both DNA strands at specific restriction sites creating blunt ends; 7. Gene-of-interest and plasmid is cut with the same restriction enzyme;

NANYANG JUNIOR COLLEGE H2 Biology Free Response Questions Application Syllabus 3 J2/2016 8. Linker DNA Nucleotides are is added to 3’ ends by terminal transferases to form complementary sticky ends / Specific linker DNA are added to blunt end