Pre-Clinical Medicine

SAQs, MCQs and EMQs

Calver Pang, Ibraz Hussain, John Mayberry

• Publisher: CRC Press
• Year: 2017
• ISBN:
  9781351659192
• Edition: 1
• Topic: Medicine
• Subtopic: Medical Theory, Practice & Reference

Filling a gap for a pre-clinical phase revision guide, this book will help medics pass their intermediate exams in order to proceed to the clinical years. It is based on the SAQs, EMQs and MCQ school curriculum as set out by the GMC. By covering each module individually but also integrating other disciplines of medicine into the questions, it helps students to think laterally as well as thoroughly revising each module. With a minimum of4 SAQs, 7 MCQs and 3 EMQs in each chapter, this book offers comprehensive revision practice as well as providing all the answers with clear explanations.

Chapter 1

CELLULAR STRUCTURE AND FUNCTION

1. A young girl is on the ward with a history of long bone fractures resulting from only minor injuries. Her sclerae appears blue, her skin is hyperextensible and she has difficulty in hearing.
   1. Name two important functions of collagen (1)
   2. Why can disorders of collagen affect so many tissues? (1)
   3. Explain the effects of dietary deficiency of vitamin C on collagen (2)
   4. Inherited collagen disorders commonly show a dominant pattern of inheritance. Explain this observation (1)
   5. Collagen has an abnormally high content of glycine and proline. Explain the importance of these amino acids to the structure of collagen (2)
   6. Name three post-translational modifications that collagen undergoes during its synthesis, indicating whether they occur intracellularly or extracellulary (3)
2. Amylase is a major group of enzymes found in the pancreas and salivary glands. It hydrolyses dietary starch into disaccharides and trisaccharides which are then converted to glucose via different enzymes to provide energy to the body.
   1. Define the term Km (1)
   2. Describe the function of an enzyme ‘active site’ and briefly explain how features of its structure are related to its function (2)
   3. Define the term allosteric regulation as applied to enzymes (1)
   4. Give an example of an enzyme known to be regulated in an allosteric manner. Indicate two of the regulatory processes concerned, stating whether they are activating or inhibiting (3)
   5. Describe how the effect of one of the allosteric regulatory mechanisms you have mentioned is achieved (3)
3. A 2-year-old boy has been admitted to hospital following recurrent chest infections. One of his parents is known to have cystic fibrosis (CF). A sweat test has been carried out showing a chloride level of 80 mmol/L. A diagnosis of CF has been made.
   1. What type of inherited condition is CF? (1)
   2. If two parents both with CF are to have children, what is the probability that the child will also have CF? (1)
   3. What exactly is the protein deficiency in people with CF? Explain the consequences of this (3)
   4. How would you screen for CF carriers? (1)
   5. Name four symptoms of CF (2)
   6. Why are people with CF more likely to develop respiratory infection? (1)
   7. What is meant by gene penetrance? (1)
4. James, a 5-year-old boy, has been complaining of leg cramps. His mother takes him to see his GP. He is suspected to have Duchenne muscular dystrophy (DMD).
   1. What is the pattern of inheritance for DMD? (1)
   2. The mutation rate in the DMD gene is relatively high. What is the most likely explanation for this? (1)
   3. Given that James’ mother is not a carrier, provide two possible genetic explanations for James inheriting the mutation. For each explanation, include an estimation of the risk of recurrence of DMD in future offspring (2)
   4. What are the three main types of muscle tissue? Give a histologically distinguishing feature for each type (3)
   5. Name three specific biochemical markers which indicate muscle damage (1)
   6. What reaction does creatine kinase catalyse and what is the importance of this? (2)
5. Ms. J. G., an 18-year-old African-Caribbean girl, goes to her GP complaining of tiredness and lethargy. Investigations show that she has iron deficiency anaemia.
   1. Name two possible causes of iron deficiency anaemia (1)
   2. Concerning erythropoiesis, where does it occur? Give two cofactors that are required (2)
   3. On the graph below, draw and label an oxygen dissociation curve for foetal haemoglobin and myoglobin (2)
      
   4. Explain how the oxygen dissociation curve for Hb is related to its molecular structure, and how the oxygen dissociation curve for myoglobin relates to its structure (2)
   5. Give three factors that affect the oxygen dissociation curve for haemoglobin and give the effect(s) of each (3)
6. A young girl with known Ehlers–Danlos syndrome presents to A&E with a left elbow dislocation. Below is a diagram of a sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS–PAGE) showing type III collagen in this patient.
   1. Which protein has higher molecular weight and why? (2)
      
   The site at which the restriction enzyme acts was mutated in the patient. This enzyme has a 110 base sequence. This sequence was amplified by polymerase chain reaction (PCR) from a normal individual and the patient, digested by the restriction enzyme. The normal individual shows two bands of size 70 base pairs and 40 base pairs.
   2. Indicate the expected band size if the mutated strip was put into a solution with restriction enzymes, and why (2)
   3. What is the key property of tropocollagen and how does this benefit the function of collagen? (2)
   4. What is the function of hydroxyapatite in bone? (1)
   5. Which cells form collagen in bone? (1)
   6. Which cells form collagen in cartilage? (1)
   7. Which type of cartilage forms the epiglottis? (1)
7. Male aged 18 years has a partner who is 15 weeks pregnant, with a baby of unknown gender. He is known to have sickle cell trait. His father had sickle cell anaemia and his mother was unaffected. His partner is also unaffected. He has a sister who is unaware of whether she has sickle cell trait or not. Her husband and her two daughters are unaffected.
   1. What is the inheritance pattern of sickle cell anaemia? (1)
   2. What is the base pair mutation in sickle cell anaemia and what is the resultant amino acid change in the β-haemoglobin protein? (2)
   3. What are the genotypes for mum and dad of the unborn child using the allele notations Bs for the sickle cell allele, and B for the normal allele? (1)
   4. Draw and annotate a pedigree with the information given above (3)
   5. Calculate the probability of a child being born with sickle cell naemia if one parent has sickle cell anaemia and the other has sickle cell trait. (1)
   6. Give one possible ethical implication to consider prior to genetic testing and potential diagnosis of sickle cell anaemia in the unborn baby for:
      i. the child itself (1)
      ii. the child’s parents (1)

MCQ

For the following questions, select the single best answer.

1. A 38-year-old man p...

Table of contents

• Title Page
• Copyright Page
• Table of Contents
• Preface
• Acknowledgements
• Authors
• Abbreviations
• Blood test reference ranges
• 1 Cellular Structure and Function
• 2 Body Tissues
• 3 Metabolism
• 4 Membranes and Receptors
• 5 Mechanism of Pathology
• 6 Infection and Immunity
• 7 Gastrointestinal System
• 8 Cardiovascular System
• 9 Respiratory System
• 10 Urinary System
• 11 Musculoskeletal System
• 12 Reproductive System
• 13 Nervous System
• 14 Head and Neck
• 15 Clinical Pharmacology
• 16 Society and Medicine
• 17 Answers
• Index