Molecules, Cells, and Systems

FACULTY OF SCIENCE & ENGINEERING SCHOOL OF PHARMACY EXAMINATION PAPER _____________________________________________________________________ Module Code : 4PY019 Module Title : Molecules, Cells, and Systems Date : May 2023, Semester 2 Examiners : Dr. Katherine Karakoula and Dr. A. Rahman Time Allowed : 2 Hours _____________________________________________________________________ INSTRUCTIONS TO CANDIDATES  You should attempt 60 questions in total.  There is only ONE correct answer per question.  Your responses should be recorded on the answer sheet provided. MATERIALS REQURIED  You may use a scientific calculator. This must not be programmable and may be inspected during the examination. Student Number ……………………………………………………………………………. 4PY019 (MCS) 2022/23 1 1. Calculate the pH of a solution of 0.4M acetic acid and 0.25M acetate ion. The pKa of acetic acid is 4.8. pH = pKa + log ([A‐] ÷ [HA]) A. 5.10 B. 5.04 C. 4.60 D. 6.10 E. 6.00 2. During the Biuret reaction, how many peptide bonds are involved in formation of the cupric ion coordination complex? A. 1‐2 B. 5‐8 C. 12 ‐ 16 D. 4‐6 E. 8 ‐ 10 3. Which of the following enzymes are involved in regulation of the Krebs cycle? A. aconitase B. hexokinase C. malate dehydrogenase D. α‐ketoglutarate dehydrogenase E. fumarate dehydrogenase 4PY019 (MCS) 2022/23 2 4. The x and y intercepts of the Eadie‐Hofstee plot are, respectively: A. ‐1/Km and 1/Vmax B. ‐Km and Km/Vmax C. Vmax/Km and Vmax D. 1/Vmax and ‐1/Km E. Km/Vmax and ‐Km 5. Enzyme A (MW – 25600 mg/mmol) is a protease that can catalyse hydrolysis of amino acid esters and amides. For the synthetic substrate B, enzyme A exhibits a kcat value of 650s‐1. What is the Vmax for hydrolysis of substrate B when the concentration of enzyme A is 0.3mg/mL? 𝑉𝑚𝑎𝑥 A. 7.6×10‐3 M s‐1 B. 8×10‐3 M min‐1 C. 5.6×10‐2 M s‐1 D. 4.8×10‐3 M min‐1 E. 6×10‐3 M s‐1 𝑘 𝐸 6. Why is adenosine triphosphate NOT formed when oxidative phosphorylation is decoupled? A. The production of reduced coenzymes formed in the mitochondrial matrix is disrupted. B. The proton motive force across the inner mitochondrial membrane is enhanced. C. The inner membrane of the mitochondrion is damaged. D. The proton motive force across the inner mitochondrial membrane is dissipated. E. The production of reduced coenzymes formed in the mitochondrial matrix is enhanced. 4PY019 (MCS) 2022/23 3 7. How do glucokinase and hexokinase regulate the glycolytic pathway? A. Glucokinase phosphorylates glucose when it is scarce, and hexokinase is inhibited by glucose‐6‐phosphate when glucose is abundant. B. Glucokinase phosphorylates glucose when it is abundant, and hexokinase is inhibited by glucose‐6‐phosphate when glucose is abundant. C. Hexokinase phosphorylates glucose when it is abundant, and glucokinase is inhibited by glucose‐6‐phosphate when glucose is abundant. D. Glucokinase phosphorylates glucose when it is scarce, and hexokinase is inhibited by glucose‐6‐phosphate when glucose is scarce. E. Glucokinase phosphorylates glucose when it is scarce, and hexokinase is activated by glucose‐6‐phosphate when glucose is abundant. 8. A stretch of double‐stranded DNA contains 1200 base pairs and its base composition is 48% G+C. How many thymine residues are in this region of DNA? A. 480 B. 420 C. 560 D. 624 E. 400 9. Ribosomes involved in translation in eukaryotic cells consist of which two subunits? A. 40 S and 50 S B. 30 S and 60 S C. 30 S and 50 S D. 50 S and 60 S E. 40 S and 60 S 4PY019 (MCS) 2022/23 4 10. Which of the following cell cycle checkpoints is involved in the control of mitosis? A. DNA damage checkpoint B. DNA replication checkpoint C. RNA replication checkpoint D. spindle attachment checkpoint E. spindle detachment checkpoint 11. Using the Nernst equation, calculate the equilibrium potential for Ca2+ if [Ca2+]0 = 2.5mM, [Ca2+]i = 103 nM. 𝐸 A. ‐ 145mV B. + 135mV C. ‐ 165mV D. + 153mV E. ‐ 153mV 61.5 𝑚𝑉 𝐶 𝑙𝑜𝑔 𝑧 𝐶 12. At what stage of mitosis do sister chromatids migrate to opposite poles of the cell? A. Anaphase B. Prometaphase C. Cytokinesis D. Metaphase E. Prophase 4PY019 (MCS) 2022/23 5 13. Which one of the following is a muscle protein that regulates muscle contraction? A. Actin B. Dystrophin C. Glycophorin D. Myosin E. Troponin 14. The female reproductive phases are: menstrual; pre‐ovulatory; ovulation; post‐ ovulatory. What hormone is predominant at the post‐ovulatory phase? A. follicle stimulating hormone B. progesterone C. oestrogens D. luteinising hormone E. cortisol 15. Which of the following cell type(s) is(are) leukocytes? I. II. III. Eosinophils Monocytes Thrombocytes A. I and III only B. III only C. I and II only D. All of the above E. None of the above 4PY019 (MCS) 2022/23 6 16. Which of the following is the cellular precursor of blood platelets? A. natural killer cells B. basophils C. lymphocytes D. megakaryocytes E. erythrocytes 17. Which molecule in the glycolytic pathway is the precursor of the amino acid histidine? A. pyruvate B. phosphoenolpyruvate C. fructose‐6‐phosphate D. fructose‐1,6‐bisphosphate E. Glucose‐6‐phosphate 18. Why can the liver not use ketone bodies as a source of metabolic energy? A. The liver lacks the beta ketoacyl‐CoA hydrogenase enzyme that metabolises ketone bodies. B. The liver contains the beta ketoacyl‐CoA transferase enzyme that synthesises ketone bodies. C. The liver lacks the beta ketoacyl‐CoA transferase enzyme that metabolises ketone bodies. D. The liver lacks the beta ketoacyl‐CoA transferase enzyme that synthesises ketone bodies. E. The liver lacks the beta ketoacyl‐CoA hydrogenase enzyme that synthesises ketone bodies. 4PY019 (MCS) 2022/23 7 19. Which of the following pathologies develop due to insufficient iodine in the diet? A. diabetes mellitus B. hypothyroidism C. diabetes insipidus D. hyperthyroidism E. acromegaly 20. Which hormone is secreted from the adrenal cortex in response to a decrease in blood pressure? A. insulin B. glucagon C. aldosterone D. dehydroepiandrosterone E. cortisol 21. If an enzyme with a molecular weight of 35400 mg/mmol at a concentration of 0.56 mg/mL, catalysed a reaction with a Km of 160 µM, a rate of the reaction (v0) of 1.1 µmol min‐1 and a substrate concentration of 55 µM, what is the turnover number? 𝑣 A. 4.53 s‐1 B. 5.53 s‐1 C. 4.23 s‐1 D. 3.53 s‐1 E. 4.83 s‐1 4PY019 (MCS) 2022/23 Vmax. S S 𝐾𝑚 𝑉𝑚𝑎𝑥 𝑘 𝐸 8 22. Which of the pancreatic islet cells secretes somatostatin? A. Alpha cells B. Delta cells C. Beta cells D. Gamma cells E. Epsilon cells 23. Which of the following is a clinical indication for albinism? A. Melanocytes in a patch B. Autoimmune loss of melanocytes C. Autoimmune gain of melanocytes D. Inherited lack of tyrosinase E. Inherited lack of transferase 24. Which of the following is one of the functions of secretin in the digestive tract? A. Stimulates pancreatic ducts to release bicarbonate B. Stimulates pancreatic ducts to release bile C. Inhibits bicarbonate release from pancreatic ducts D. Inhibits bile release from pancreatic ducts E. Stimulates pancreatic ducts to release chyme 4PY019 (MCS) 2022/23 9 25. At what stage of the nerve action potential does the membrane return to a resting potential? A. Depolarising phase B. hyperpolarising phase C. Stimulus phase D. Repolarising phase E. Resting phase 26. Which part of the heart initiates electrical activity that stimulates a heartbeat? A. Purkinje fibres B. Chordae Tendinae C. Sinoatrial node D. Atrio‐ventricular node E. Papillary Muscle 27. What is the difference between the mechanisms of action of α‐adrenoceptor antagonists (α‐blockers) and β1‐adrenoceptor antagonists (β‐blockers) used for the treatment of hypertension? A. β‐blockers reduce cardiac output and α‐blockers reduce total peripheral resistance. B. β‐blockers increase cardiac output and α‐blockers reduce total peripheral resistance. C. β‐blockers reduce total peripheral resistance and α‐blockers reduce cardiac output. D. β‐blockers increase cardiac output and α‐blockers increase total peripheral resistance. E. β‐blockers reduce total peripheral resistance and α‐blockers increase cardiac output. 4PY019 (MCS) 2022/23 10 28. Donepizel is an acetylcholinesterase inhibitor used to treat dementia that prevents the breakdown of acetylcholine. What is the role of acetylcholine in the function of neurons? A. Acetylcholine is a neurotransmitter that allows neurons to contract. B. Acetylcholine is a neurotransmitter that allows neurons to relax. C. Acetylcholine is a neurotransmitter that allows neurons to communicate with one another. D. Acetylcholine is a neurotransmitter that allows neurons to relax and contract. E. none of the above 29. What are the main functions of the macula densa cells in the wall of the distal tubule in the kidney? A. Maintenance of blood oxygen, electrolyte homeostasis, and blood pressure. B. Maintenance of blood oxygen, electrolyte homeostasis, and blood glucose. C. Maintenance of body fluid, blood protein, and blood pressure. D. Maintenance of electrolyte homeostasis, blood protein, and blood pressure. E. Maintenance of body fluid, electrolyte homeostasis, and blood pressure. 4PY019 (MCS) 2022/23 11 30. What is the stroke volume (SV), given that the cardiac output (CO) is 5.87 L/min, and the heart rate (HR) is 80 bpm. CO = HR x SV A. 0.0634 L/beat B. 0.0734 L/beat C. 0.0434 L/beat D. 0.1834 L/beat E. 0.1534 L/beat 31. Which one of the following kingdoms does NOT belong to the domain Eukaryota? A. Protista B. Fungi C. Plantae D. Animalia E. Bacteria 32. Which one of the following is a sugar derivative found in peptidogylcan? A. N‐acetylglycine B. N‐acetylglucose acid C. N‐acetylmanic acid D. N‐acetylglucosamine E. N‐acetylmurine acid 4PY019 (MCS) 2022/23 12 33. One of the following amino acids is NOT a component of the tetrapeptide amino acid side chains that link peptidoglycan units in the cell wall of bacteria: A. L‐Alanine B. D‐Glutamic acid C. L‐Lysine D. Diaminopimelic acid E. D‐Aspartic acid 34. Which one of the options given below is a component found in lipopolysaccharide (LPS)? A. Lipid B B. Teichoic acid C. Lipid A D. Peptidogylcan E. B‐antigen polysaccharide 35. Which one of the following represents the sedimentation coefficient of intact bacterial ribosomes? A. 60S B. 80S C. 40S D. 50S E. 70S 4PY019 (MCS) 2022/23 13 36. Which one of the following best describes the function of inclusion bodies in the bacterial cell? A. They aid selective permeability B. They contain the cells’ genetic material C. They are in involved in protein synthesis D. They store carbon, phosphorus and other substances E. They are in involved in cell wall synthesis 37. Which one of the options below best describes the arrangement of flagella on a bacterial cell when the term peritrichous is used to describe them? A. Inside the bacterial cell B. None of these options C. At both ends of the bacterial cell D. Around the bacterial cell projecting in many directions E. Just at one end of the bacterial cell 38. Which one of the following microorganisms produces the antibiotic erythromycin? A. Penicillium chrysogenum B. Streptomyces erythreus C. Streptomyces griseus D. Streptomyces albus E. Penicillium griseofulvin 4PY019 (MCS) 2022/23 14 39. Which one of the following options describe chemotaxis A. Movement of bacteria in response to light B. Movement of bacteria in response to oxygen C. Movement of bacteria in response to chemicals D. Movement of bacteria in response to magnetic fields E. None of the above 40. Which one of the options below represents the percentage of peptidoglycan present in the Gram‐negative cell wall? A. 10% B. 40% C. 25% D. 30% E. 70% 41. Which one of the following pathogens uses neural tissues to spread from their initial site of infection? A. Hepatitis virus B. Coronavirus C. Rhabdovirus D. HIV (human immunodeficiency) virus E. HPV (Human papillomavirus) virus 4PY019 (MCS) 2022/23 15 42. Which one of the following statements refers to a preferred characteristic of an antimicrobial agent with regards to “selective toxicity”? A. Toxic for both microbial and for host cells but with significantly lower toxicity for microbial cells B. Toxic only for microbial cells C. Toxic only for a very small number of microbial species D. Toxic for both microbial and for host cells E. Toxic only for host cells 43. Which one of the following processes is responsible for the resistance of bacterial ribosomes to chloramphenicol? A. Acetylation B. Hydroxylation C. Integration D. Methylation E. Phosphorylation 44. Which one of the following possible actions of bacteriostatic antibiotics is CORRECT? A. Lyses but does not kill bacterial cells B. Effective against retroviruses C. Kills bacterial cells D. Kills cells of Candida albicans E. Inhibits bacterial cell growth 4PY019 (MCS) 2022/23 16 45. Figure 2 shows the general structure of a bactericidal antibiotic in which important components of the structure are identified by boxes i; ii and iii. Which component confers properties such as acid resistance, ß‐lactamase resistance or the ability to cross lipid bi‐layer membranes? A. i B. i and iii C. i and ii D. iii E. ii 4PY019 (MCS) 2022/23 17 46. If the decimal reduction time at 60OC for viable cells of the bacterium Proctodium wulfrunii is 0.75 of a minute, how many minutes would a population of 2 x 106 viable cells/ml need to be heated at 60OC to reduce the viable population to 2 x 10‐6 cells per/ml? A. 6 minutes B. 9 minutes C. 15 minutes D. 1 minute E. 21 minutes 47. Which one of the options below best describes the condition where bacteria are actively growing or multiplying in the blood? A. Bacteraemia B. Uraemia C. Septicaemia D. Bacteriuria E. None of the above 48. Gas gangrene is usually associated with deep tissue wounds and is characterized by foul smell, massive tissue destruction and blackened skin. Which one of the microorganisms listed below causes this condition? A. Clostridium difficile B. Clostridium botulinum C. Clostridium tetani D. Clostridium perfringens E. Staphylococcus aureus 4PY019 (MCS) 2022/23 18 49. Which of the common conditions listed below does the Varicella‐Zoster virus cause? A. Chicken pox and shingles B. Small pox C. Cold sores D. Rabies E. HIV 50. Which of the options below best describes how the abuse of antibiotics could be avoided? A. Using more broad‐spectrum antibiotics B. Stop taking the antibiotic when symptoms subside C. Using antibiotics for common cold D. Using antibiotics for minor cuts and scratches E. None of the above 51. Which one of the attributes described below is associated with the innate immune response? A. Highly specific B. Non‐specific C. Involves T cells D. Involves antibodies E. Total memory of previous encounter 4PY019 (MCS) 2022/23 19 52. Which one of the following statements regarding the innate immune system is INCORRECT? A. Increased capillary permeability is an important feature of acute inflammation B. The surface of mucous membranes provides a barrier to the entry of most microorganisms C. Soluble mediators (complement) do not play a role in fighting pathogens D. Acidic pH of the stomach kills most ingested microorganisms E. The skin has a pH of between 3 and 5, which inhibits the growth of most microorganisms 53. Which one of the following statements regarding immunity is INCORRECT? A. CD4 response against a virus is part of an innate immune response B. IL‐8 attracts neutrophils to inflammatory tissues C. C reactive protein can activate complement D. Stomach acid is inhibitory to most pathogens E. Lysozyme in tears break down bacterial peptidoglycan 54. Administration of protective antibodies in tetanus is an example of which one of the following immunization strategies? A. Active artificial immunization B. Passive natural immunization C. Active immunization D. Active natural immunization E. Passive artificial immunization 4PY019 (MCS) 2022/23 20 55. Which one of the options given below best describes the contents of the BCG vaccine? A. Bacterial envelopes derived from M. tuberculosis B. Inactivated measles, mumps and rubella viruses C. Purified bacterial antigens derived from M. tuberculosis D. Live attenuated bacteria E. Bacterial nucleic acids derived from M. bovis 56. Which one of the following statements regarding cells and organs of the immune system is INCORRECT? A. Macrophages are found in a variety of tissues B. Lymph nodes are primary lymphoid organs C. The thymus is a primary lymphoid organ D. Eosinophils are involved in defense against parasites E. Pluripotent haematopoietic stem cells are formed in the bone marrow 57. Which one of the options below is the classification of an IgM heavy chain? A. Mu B. Alpha C. Gamma D. Kappa E. Delta 4PY019 (MCS) 2022/23 21 58. When describing an immunoglobulin the Fc is an abbreviation for which one of the options listed below? A. Fragment complementary B. Fragment cultivable C. Fragment crystalisable D. Fragment culturable E. None of these options 59. Which one of the classifications listed below is normally used to describe a T helper cell? A. CD1 cells B. CD19 cells C. CD8 cells D. CD4 cells E. CD20 cells 60. An antibody is generated by which one of the cell types given below? A. a T cell B. a plasma B cell C. an immature B cell D. a macrophage E. a neutrophil 4PY019 (MCS) 2022/23 22