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 CELL BIOLOGY AND BIOCHEMISTRY BIO-4004B 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 Grids 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. Graph paper is provided. Notes are not permitted in this examination. Do not turn over until you are told to do so by the Invigilator BIO-4004B Module Contact: Dr Richard Bowater, 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 these to your booklet for Section A. 1. Which of the following statements is incorrect when describing the interaction between an immunoglobulin (Ig, also known as antibody) and its antigen? a) The variable domains of the Ig are involved b) The binding can result in a conformational shape change c) The interaction is non-covalent d) Only the light chain of the Ig is involved e) Each antibody can only bind one epitope on an antigen 2. Foetal haemoglobin consists of which combination of subunits? a) α2β2 b) α2γ2 c) α2β1γ1 d) α4 e) β2γ2 3. Which of these cellular destinations does not require a signal sequence for a protein to arrive there? a) Endoplasmic reticulum b) Cytoplasm c) Nucleus d) Mitochondrion e) Lysosome 4. During which phase of mitosis does cytoplasmic division occur? a) Metaphase b) Cytokinesis c) Telophase d) G2 e) prophase Section A continues on next page/...

3 3 Section A continued Which of the following is not referred to as a small molecule 2nd messenger? a) Cyclic AMP b) Cyclic GMP c) Diacylglycerol d) Inositol trisphosphate (IP3) e) Zinc ions 6. Intercellular communication between plant cells is facilitated by structures known as: a) plasma membranes b) plasmodesmata c) plasmids d) plastids e) plasmolysis 7. Which theory accounts for the origin of mitochondria and chloroplasts in plant cells? a) Parasitic b) Biotrophic c) Necrotrophic d) Phototropic e) Endosymbiotic 8. Which of the following statements is not correct for integrins? a) Integrins are composed of two subunits b) Integrins contain metal binding sites for divalent cations c) Cytoplasmic domains are absent in the alpha subunit d) Integrins can activate various signalling pathways e) The ligand specificity is mainly defined by the alpha subunits Section A continues on next page/... TURN OVER

4 4 Section A continued Which one of the following features are specifically linked with hemidesmosomes? a) Location at the lateral side of epithelial cells b) Connections to microtubules c) Exclusive binding to extracellular proteoglycans d) Association of the adaptor protein Plectin e) Linked with some diseases including Scurvy 10. The migration of a fibroblast within the extracellular matrix of connective tissues is dependent on which of the following? a) The presence of stable cell-cell contacts b) Decreased oxygen levels c) The presence and coordinate function of multiple cilia d) Specific cell-matrix interactions e) Signalling via gap junctions 11. Which of the following laboratory techniques can be used to identify proteins and their location within cells and tissues? a) Chromatin Immunoprecipitation b) Western blotting c) Immunofluorescent labelling d) Quantitative real time-polymerase chain reaction (qrt-pcr) e) Northern Blotting 12. In eukaryotic cells, name the structure that enables the exchange of molecules between the nucleus and the cytoplasm: a) nucleolus b) cristae c) nuclear pores d) ribosomes e) centrosome Section A continues on next page/...

5 5 Section A continued Which molecules distinguish the rough endoplasmic reticulum (RER) from the smooth endoplasmic reticulum (SER)? a) Ribosomes b) Lysosomes c) Centrosome d) Vesicles e) Peroxisome 14. Which of the following units are associated with the specific activity of an enzyme? a) Moles min -1 mg -1 b) Moles min -1 c) Moles min d) mg min -1 e) Moles 15. How many passes round the citric acid cycle are required to complete the oxidation of one molecule of glucose to six molecules of CO2? a) 1 b) 2 c) 3 d) 4 e) Where is ubiquinone found within a eukaryotic cell? a) Endoplasmic reticulum b) Cytoplasm c) Outer mitochondrial membrane d) Mitochondrial matrix e) Inner mitochondrial membrane Section A continues on next page/... TURN OVER

6 6 Section A continued The energy released during glycolysis is transferred to the enzymes of oxidative phosphorylation by which molecule? a) O2 b) ATP c) NADH d) Pyruvate e) CO2 18. Which of these amino acids is both ketogenic and glucogenic? a) Isoleucine b) Valine c) Histidine d) Arginine e) Leucine 19. Which of the following techniques can be used to separate proteins by their charge? a) Ultracentrifugation b) Anion exchange chromatography c) Size exclusion chromatography d) Immunoprecipitation e) Affinity chromatography 20. In the Michaelis-Menten description of enzyme kinetics Vmax is proportional to what? a) Substrate concentration b) Km c) Time d) Product concentration e) Enzyme concentration Section A continues on next page/...

7 7 Section A continued... For all remaining questions in Section A, please use an answer booklet. Remember to attach your multiple choice answer grid to the booklet. 21. Briefly describe two differences and two similarities between the proteins myoglobin and haemoglobin. [4 marks] 22. Answer BOTH parts (a) and (b). (a) Why are steroid hormone receptors typically located within both the cytoplasm and nucleus of a responding cell? [2 marks] (b) Briefly explain the functions of activated steroid hormone receptors. [2 marks] 23. How is the structure of plant root apical meristem distinct from the shoot apical meristem? [4 marks] 24. Briefly explain the differences between transcription and translation in bacteria and eukaryotes, with reference to location and timing. [4 marks] 25. Contrast the effects that glucagon and insulin have on glucose metabolism. [4 marks] END OF SECTION A START YOUR ANSWER TO THE NEXT SECTION IN A NEW BOOKLET Section B begins on next page/... TURN OVER

8 8 SECTION B: DATA HANDLING QUESTION Answer ALL PARTS of this question [30 marks] 26. (a) p-nitrophenol has an extinction coefficient (ε) of µm -1 cm -1 at 405 nm. What is the concentration (µm) of p-nitrophenol in a solution that that gives an absorbance of 0.37 at 405 nm in a 1 cm path length cuvette? Assume that p- nitrophenol is the only molecule in the cuvette that absorbs at 405 nm. [6 marks] (b) Alkaline phosphatase is an enzyme that catalyses the formation of p-nitrophenol from p-nitrophenyl phosphate. As you are told above, p-nitrophenol has an absorbance at 405 nm; in contrast, p-nitrophenyl phosphate has no absorbance at 405 nm. Describe how you would obtain experimentally the initial rate of p- nitrophenol formation catalysed by alkaline phosphatase from p-nitrophenyl phosphate and explain your answer. [6 marks] (c) From such an experiment you obtain the data in table 1 below. Using a graphical method, determine the KM and Vmax for the enzyme alkaline phosphatase. [18 marks] p-nitrophenyl phosphate concentration, mm Velocity, µmol min Table 1. Initial velocities for the formation of p-nitrophenol in reactions catalysed by alkaline phosphatase END OF SECTION B START YOUR ANSWER TO THE NEXT SECTION IN A NEW BOOKLET Section C begins on next page/...

9 9 SECTION C: ESSAY QUESTION Answer ONE question [30 marks] 27. With reference to the various components of a membrane explain how the structure of a membrane contributes to its functions. 28. Epithelial tissue is one of the four main tissue types in animals. Briefly describe the types and function of epithelial cells/tissue and the cell junctions that allow the interconnection of epithelial cells and their cytoskeleton. (Credit will be awarded for appropriately annotated diagrams.) In your answer, give two specific examples of epithelial cell/tissue types and how they are specialised for their roles in the body. 29. Compare and contrast the metabolic pathways of glycolysis and gluconeogenesis paying particular attention to the bypass reactions. END OF PAPER

10 UNIVERSITY OF EAST ANGLIA School of Biological Sciences Main Series UG Examination FUNDAMENTALS OF CELL BIOLOGY AND BIOCHEMISTRY BIO-4004B Registration Number 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