BIOM9420 Clinical Laboratory Science Sample Final Exam Questions Final Exam 2011 Course Code BIOM9420 Course Title Clinical Laboratory Science Day Fri Date 28/10/2011 Start Time 9.00am – 12.00 pm Location BioMed Theatre C Candidate Materials Calculator UNSW Approved Exam Format SECTION A 20 questions, 1 mark each SECTION B 8 questions, 5 marks each SECTION C 4 questions, 10 marks each Example Questions The following questions are multiple choice, 1 mark each. Circle the most correct answer. 1. 2. The resting cardiac output for Mr Bean is 5 L/min with a resting heart rate of 70 beats per minute. During exercise Mr Bean’s stroke volume would be: (a) 70 ml/min (b) the same as his stroke volume at rest (c) increased proportional to exercise intensity (d) decreased proportional to exercise intensity (e) a maximum of 130 ml/min In the investigation of possible kidney disease, a blood sample is often taken for determination of various solutes in serum. Which of the following is probably not of interest to the nephrologist? (a) Potassium (b) Bicarbonate (c) LDL-cholesterol (d) Creatinine (e) Urea 3. 4. 5. 6. The technique of nuclear magnetic resonance can be applied to: (a) any radioactive nucleus (b) nuclei with an odd atomic number or odd atomic weight (c) nuclei with an odd atomic number that are NOT radioactive (d) 1H, 13C, 32P and 23Na (e) only to water Aerobic respiration occurs in: (a) mitochondria (b) cytoplasm (c) glycolysis (d) krebs cycle (e) yeast White blood cells: (a) are the most abundant cell type found in blood (b) cannot be sorted by flow cytometry as their cell sizes are similar (c) are derived from megakaryocytes (d) are a major source of antibodies and host defence (e) are involved in the clotting cascade The general equation for the initial velocity of a two-substrate enzyme reaction is ݒൌ ܸ௫ ቀ ሾௌಲ ሿ ಲ ାሾௌಲ ሿ ቁቀ ሾௌಳ ሿ ቁ. The terms controlled by the enzyme alone are: ಳ ାሾௌಳ ሿ (a) v, KmA, KmB (b) SA (c) KmA, KmB, Vmax (d) SB (e) Vmax 7. White blood cells: (a) Are important because they make factors that control clotting (b) Are referred to as “white” because they form a white layer on the sedimented red cells after centrifugation (c) Are not as important as red blood cells (d) Are difficult to sort out because their cell volumes are similar (e) Are the major source of antibodies and haemoglobin The following questions are TRUE/FALSE statements, 1 mark each. Circle either TRUE or FALSE after each statement. 8. An enzyme assay has a reproducibility of 0.045 mg/ml and an accuracy of 0.3 mg/ml. This may be because the materials used to make the standard curve are pure, but the sample is not. TRUE FALSE TRUE FALSE Mean arterial pressure is the average over a cardiac cycle and is determined by the cardiac output, systemic vascular resistance and central venous pressure. TRUE FALSE 11. Blood transports waste from the kidneys. TRUE FALSE 12. Antibodies are useful in diagnostics because they are specific and never give false positives TRUE FALSE 13. The chemical equilibrium between ATP and ADP favours the formation of ADP however cells maintain ATP at 1000 TRUE fold higher concentration than ADP so that they are capable of doing work. FALSE 9. A good diagnostic marker is highly specific for a certain disease. 10. Sample 5 mark questions 14. The concentration of oxygen (molecular weight 32 Da) in water at 37oC and 100 mmHg is 0.14 mM. What volume of red blood cells, expressed as the haematocrit (as a percent), is required to carry as much oxygen as water? Assume : • haemoglobin concentration in a red blood cell is 330 g/L • molecular weight of haemoglobin is 64,500 Da • each haemoglobin molecule binds 4 oxygen molecules. H = haematocrit Hb = haemoglobin g 330 molHb L 5.1 mmol g RBC L 64500 mol molHb 4molO2 [O2 ] H RBC molHb 20.5mmolO2 [O2 ] H L [O2 ] 0.14mM H 0.68% mmolO2 20.5mM 20.5 L 15. What are five functions of plasma? Intravascular osmotic effect that maintains fluid and electrolyte balance. Transport of insoluble substances by allowing them to bind to protein molecules Protein reserve for the body Clotting Inflammatory response and protection from infection – antibodies Participation in the maintenance of the acid-base balance Regulation of cell function and maintenance of homeostasis (inorganic ions). Loss of potassium causes death. Sample 10 mark question 16. George, a 70kg adult, has 6L of blood circulating in his body. The heart pumps blood at approximately 5L/min and the normal haemoglobin (MW 65000 Da) count in males is 16 g per deciliter of blood. (a) How much oxygen is carried by blood per day per kg of body tissue? [5 marks] (b) If one oxygen is required per NADH and six NADH are produced per glucose metabolised, how much glucose, in grams, is metabolised per day per kg of body tissue? [2 marks] (c) How many 60g mars bars, assuming all glucose, must George eat each day to sustain this blood flow? [2 marks] (d) What does this imply about the body’s oxygen consumption? [1 mark] (a) Flow rate of haemoglobin = 5000 mL/min × 16 g/100mL × 1440 min/day = 1152 kg/day = 1152 kg/day ÷ 65000 g/mol = 17.72 mol/day Oxygen flow rate = 4 × 17.72 mol/day ÷ 70 kg = 1mol/day/kg (b) Glucose consumption rate 1 mol/day/kg ÷ 6 = 0.17mol/day/kg = 30 g/day/kg (c) Mars bars = 30 g/day/kg ÷ 60 g/mars bar × 70 kg = 35 mars bars/day (d) Not all oxygen supplied is used in each cardiac cycle.