Time allowed: 2 hours Answer ALL questions in Section A, ALL PARTS of the question in Section B and ONE question from Section C.

Transcription

1 UNIVERSITY OF EAST ANGLIA School of Biological Sciences Main Series UG Examination FUNDAMENTALS OF MOLECULAR BIOLOGY AND GENETICS BIO-4003A Time allowed: 2 hours Answer ALL questions in Section A, ALL PARTS of the question in Section B and ONE question from Section C. Write answers to EACH SECTION in the Answer Grid or SEPARATE booklet. The maximum number of marks available for your answers in SECTION A is 40 marks The maximum number of marks available for your answer in SECTION B is 30 marks The maximum number of marks available for your answer in SECTION C is 30 marks The TOTAL number of marks available for the paper is 100 Numbers in square brackets [ ] indicate the relevant mark applied to each part of the question. Notes are not permitted in this examination. Do not turn over until you are told to do so by the Invigilator. BIO-4003A Module Contact: Kay Yeoman, BIO Copyright of the University of East Anglia Version 1

2 2 SECTION A: MULTIPLE CHOICE AND SHORT ANSWER QUESTIONS Answer ALL questions. Answer multiple choice questions in the answer grid provided and attach this to your booklet for Section A. 1. Which of these statements about Frederick Griffiths classic experiment is correct? a) Avirulent and smooth Streptococcus pneumoniae cells were transformed to virulent and rough b) Avirulent and rough Streptococcus pneumoniae were transformed to virulent and smooth c) Avirulent and smooth Escherichia coli cells were transformed to virulent and rough d) Avirulent and rough Escherichia coli were transformed to virulent and smooth e) Transgenic mice were generated 2. Which of these is a base not found in RNA? a) Adenine b) Cytosine c) Guanine d) Thymine e) Uracil 3. The covalent bonds between nucleotides in a DNA molecule are which of the following? a) Peptide bonds b) Glycosidic bonds c) Disulphide bridges d) Hydrogen bonds e) Phosphodiester bonds 4. Which of these is not a component of eukaryotic ribosomes? a) 28S RNA b) 18S RNA c) 8S RNA d) 5.8S RNA e) 5S RNA Section A continues on next page/...

3 3 Section A continued In E. coli most DNA replication is carried out by which DNA polymerase? a) DNA Polymerase I b) DNA Polymerase II c) DNA Polymerase III d) DNA Polymerase IV e) DNA Polymerase V 6. Approximately how many base pairs are there in the haploid mouse genome? a) 250 thousand b) 2.5 million c) 25 million d) 250 million e) 2.5 billion 7. Which of these statements about nucleosomes is incorrect? a) Nucleosomes are composed of DNA wrapped around a histone core b) A nucleosome is a 6 nm x 11 nm disc c) Each nucleosome has 147 base pairs of DNA d) Histone H1 is not part of the nucleosome core e) Each nucleosome core contains six histone protein molecules 8. DNA sequences are copied into RNA by a process known as: a) transposition b) translation c) transaction d) transcription e) transformation 9. Which scientist won a Nobel Prize for deciphering the genetic code? a) Crick b) Watson c) Avery d) McCleod e) Nirenberg Section A continues on next page/... TURN OVER

4 4 Section A continued Which enzyme was used to synthesise RNA molecules in vitro for deciphering the genetic code? a) Polynucleotide Kinase b) Polynucleotide phosphorylase c) Polynucleotide polymerase d) Polynucleotide ligase e) Polynucleotide lyase 11. How many codons specify translation termination? a) 64 b) 32 c) 2 d) 1 e) In Mendel s di-hybrid crosses in pea what ratio of the four possible phenotypic classes did he observe in the F2 progeny? a) 3:1:1:1 b) 12:2:1:1 c) 15:1:1:1 d) 9:5:1:1 e) 9:3:3:1 13. Eukaryotic genes are interrupted by non-coding sequences called: a) transposons b) exons c) exits d) introns e) cistrons 14. Cystic Fibrosis is an example of which type of genetic disorder? a) X-linked recessive b) X-linked dominant c) Y- linked d) Autosomal dominant e) Autosomal recessive Section A continues on next page/...

5 5 Section A continued Which of the following human loci is involved in sex determination? a) SRY b) Tsix c) Xic d) Xist e) Isoglutinogen 16. Which of the following techniques can give information on protein-protein interactions? a) Yeast one-hybrid system b) Yeast two-hybrid system c) Yeast four-hybrid system d) E.coli two-hybrid system e) E.coli one-hybrid system 17. Which of these describes the process of glycosylation? a) The addition of (poly)saccharide to a protein molecule b) The addition of H + ions to a protein molecule c) The addition of a CH3 group to a protein molecule d) The addition of S to a protein molecule e) The addition of NH3 to a protein molecule 18. Soluble proteins and proteins targeted to the mitochondria, chloroplasts and peroxisomes are completely synthesized on? a) Ribosomes bound to the rough ER membrane b) Free ribosomes c) Ribosomes associated with the mitochondria d) Ribosomes bound to the smooth ER membrane e) Ribosomes associated with peroxisomes Section A continues on next page/... TURN OVER

6 6 Section A continued Which of the following two are not folding accessory proteins 1. Protein disulphide isomerases 2. Proteases 3. Molecular Chaperones 4. Green Fluorescent protein 5. Peptidyl Prolyl Cis-Trans Isomerases a) 1 and 3 b) 3 and 4 c) 1 and 5 d) 2 and 4 e) 2 and The Thermodynamic Hypothesis states that the 3D structure of a native protein is the one in which the Gibb s free energy of the whole system is at: a) Its highest b) 0 c) Its lowest d) A mid point e) 0-1 For all remaining questions in Section A, please use an answer booklet. Remember to attach your multiple choice answer grid to the booklet. 21. Human telomeres have multiple copies of the 6-nucleotide sequence 5 -TTAGGG-3. Briefly describe why telomeres have this specific repeat sequence. [4 marks] 22. Explain how targeted gene modification can be achieved in eukaryotic cells using Zinc Finger Nucleases. [5 marks] 23. How is the regulation of GFP expression controlled in the pglo plasmid? [6 marks] 24. With examples, briefly explain what is meant by affinity chromatography. [5 marks] END OF SECTION A START YOUR ANSWER TO THE NEXT SECTION IN A NEW BOOKLET Section B begins on next page/...

7 7 SECTION B: DATA HANDLING QUESTION Answer ALL PARTS of this question [30 marks] 25. The linkage relationships of three recessive genes for yellow body (y), ruby eyes (r) and singed bristles (sn) were investigated by three-point analysis. A pure breeding triple mutant female (y/y, r/r, sn/sn) was crossed to a wild type male (y +, r +, sn + ). All of the F1 males exhibited the triple mutant phenotype, while all of the F1 females were wildtype in appearance. (a) What can be deduced about the chromosomal location of the three genes? Provide evidence for your answer in the form of a Punnett square. [6 marks] The F1 males and females were allowed to interbreed and 1091 F2 progeny were analysed. The phenotypes and frequencies of the various F2 individuals are listed below in table 1. Phenotypes of F2 individuals Phenotypes of F2 individuals singed bristles, ruby eyes, yellow body 360 wild type bristles, ruby eyes, yellow body 12 wild type bristles, wild type eyes, wild type body 370 singed bristles, wild type eyes, wild type body 11 wild type bristles, ruby eyes, wild type body 65 singed bristles, ruby eyes, wild type body 100 wild type bristles, wild type eyes, yellow body 106 singed bristles, wild type eyes, yellow body 67 Table 1. Phenotypes and frequencies of F2 individuals Use this data to determine the following: (b) Non-crossover (NCO), single crossover (SCO) and double crossover (DCO) classes. [6 marks] (c) The gene order along the chromosome. [4 marks] Section B Q25 continues on next page/... TURN OVER

8 8 Section B Q25 continued... (d) A genetic linkage map of y, r and sn. [14 marks] END OF SECTION B START YOUR ANSWER TO THE NEXT SECTION IN A NEW BOOKLET SECTION C: ESSAY QUESTION Answer ONE question [30 marks] 26. Answer BOTH parts (a) and (b) (a) When considering animal sex chromosomes, what is meant by the term dosage compensation and what (potential) problem does it avert? [10 marks] (b) Describe and compare the mechanisms of dosage compensation in mammals and Drosophila melanogaster. [20 marks] 27. Answer BOTH parts (a) and (b) (a) Describe the structure of the Escherichia coli origin of replication, oric. [10 marks] (b) Describe the events that lead to the initiation of DNA synthesis from oric. [20 marks] 28. Discuss how proteins fold in the cell and how protein misfolding can lead to disease. END OF PAPER

9 Registration Number UNIVERSITY OF EAST ANGLIA School of Biological Sciences Main Series UG Examination FUNDAMENTALS OF MOLECULAR BIOLOGY AND GENETICS BIO-4003A SECTION A: Answer Grid (for Multiple Choice Questions only) Place a single cross in the appropriate box Question No. A B C D E Marks given Marks available

10 10 BIO-4003A EXAMINATION MARKERS [Do not print this when printing to take to Examinations Office! This is for our information only.] Question No. 1 st Marker 2 nd Marker Section A Q1 Prof Kay Yeoman Dr Helen James 24 Section B Q25 Dr Colwyn Thomas Prof Kay Yeoman Section C Q36 Dr Mark Coleman Prof Kay Yeoman Section C Q27 Dr Mark Coleman Prof Kay Yeoman Section C Q28 Dr Andrew Hemmings Prof Kay Yeoman