NDM Midsemester Exam 2006

1

Which one of the following statements is best supported by evidence?


  For elite endurance athletes in training, the quantity of food consumed is not a factor in weight maintenance.

  Low levels of exercise, such as walking for an hour, have insignificant benefit in weight management.

  Statistics of mortality show that obese patients exhibit several increases in disease conditions, but are relatively protected from heart attack.

  For most Australians, Basal Metabolic Rate accounts for more daily energy expenditure than exercise.

  People living in cold climates need less dietary energy relative to those living in mild climates

2

Juvenile obesity has a number of commonly observed symptoms characteristic of the condition. Which one of the following symptoms is most likely to be UNRELATED to juvenile obesity?


  A generalised redness (erythema) of the body trunk.

  Clinical depression.

  Non-alcoholic fatty liver.

  Hypertension.

  Precocious puberty.

3

Which one of the following statements relating to glucose is CORRECT?


  A blood glucose concentration of 2 mM is a healthy fasting level.

  Glucose is chemically inert by itself and requires enzymes to catalyse all physiological reactions.

  Glucose in solution is in equilibrium between open chain and ring forms.

  The enzyme hexokinase uses ATP to activate glucose to glucose-1-phosphate.

  A significant adverse consequence of the Atkins protein-rich and fat-rich diet is that it leads to hypoglycaemia.

4

Which one of the following statements relating to nutrient uptake by the human intestine is CORRECT?


  Partially digested proteins (oligopeptides) and free amino acids can enter intestinal mucosal cells.

  Partially digested polysaccharides (oligosaccharides and dextrins) can enter intestinal mucosal cells.

  Triacylglycerols can enter intestinal mucosal cells.

  Sucrose can enter intestinal mucosal cells.

  Lactose can enter intestinal mucosal cells.

5

Which one of the following statements relating to protein turnover in humans is CORRECT?


  Muscle turns over protein at such a rate that in a typical daily turnover of 300 g for the body, around 200 g would be cycled within muscle.

  If a typical Australian ate 100 g of protein per day, the gut would probably absorb about 160 g of digested protein due to protein added by normal gut processes.

  Protein in humans cannot be converted to fat.

  Corn is a particularly poor dietary source of the amino acid lysine.

  In nitrogen balance, consumption of 100 g of dietary protein will produce 100 g of urea.

6

Which one of the following statements relating to vitamins in human nutrition is CORRECT?


  Vitamin A deficiency causes extended blood clotting times leading to hemorrhagic problems.

  The Vitamin B group is water soluble and includes the carotene plant pigments.

  Vitamin C (ascorbic acid) is an oxidising agent that converts dietary Fe2+ to Fe3+ in the gastrointestinal tract.

  Vitamin D is readily obtained from leafy vegetables in the diet.

  Vitamin E is a lipid-soluble vitamin, also known as α-tocopherol.

7

Which one of the following is capable of creating significant amounts of ATP from ADP in a test tube when relevant enzymes and cofactors are supplied?


  The action of respiratory complex V isolated from mitochondria.

  Conversion of glucose-6-phosphate to glucose.

  Conversion of fructose-1,6-bisphosphate to fructose-6-phosphate.

  Conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate.

  Conversion of pyruvate to acetyl-CoA.

8

Which one of the following statements relating to pyruvate metabolism is CORRECT?


  Pyruvate derived from glucose is produced in the cytosol and can be taken up into mitochondria by a mechanism involving exchange with mitochondrial ATP.

  Carbon from pyruvate can be further processed to fat, protein or glucose depending on metabolic conditions.

  Lactate is an oxidised derivative of pyruvate.

  Carbon-2 of pyruvate is a chiral carbon leading to L- and D- forms of pyruvate.

  The first step of the Krebs (TCA) cycle is conventionally regarded as the condensation of pyruvate with oxaloacetate to form citrate.

9

Which one of the following statements relating to cAMP in human adipose cell metabolism is CORRECT?


  cAMP is elevated by both adrenaline and glucagon.

  cAMP is elevated by insulin.

  cAMP levels is depressed in times of fright, fight and fasting.

  cAMP binds to and activates hormone sensitive lipase.

  Events mediated by cAMP in adipose cells involve the enzyme phosphorylase kinase.

10

Which one of the following statements relating to leptin in mammalian metabolism is CORRECT?


  Obese (Ob/Ob) mice over-express leptin and were the first source for isolation of this hormone.

  Leptin is produced in adipose tissue from essential fatty acids as precursors.

  Leptin moderates eating behaviour by interacting with the pituitary.

  The majority of obese humans have levels of leptin that range from normal to marginally lower than normal.

  Neuropeptide Y levels in the brain are affected by circulating leptin.

11

Which one of the following statements regarding arachidonic acid metabolites is CORRECT?


  Thromboxane is a vasoconstrictor synthesised predominantly in endothelial cells.

  Prostaglandin E2 synthesis in the hypothalamus causes an increase in body temperature.

  Prostacyclin (PGI2) inhibits mucus secretion and increases gastric acid secretion in the stomach.

  All of the leukotrienes are potent bronchoconstrictors.

  Lipoxygenase converts arachidonic acid to prostaglandins.

12

The major source of ATP during a 30-second "all-out", high intensity exercise bout is:


  Creatine phosphate breakdown.

  Intramuscular ATP stores.

  Lactate oxidation.

  Glycolysis of glucose from breakdown of muscle glycogen.

  Glucose from the circulation fuelling mitochondrial oxidative phosphorylation.

13

Regular physical exercise can enhance insulin action and may benefit individuals with type 2 diabetes. One crucial skeletal muscle adaptation contributing to improved insulin action is:


  Increased muscle glycogen levels.

  Lowered FAT/CD36 abundance.

  Enhanced GLUT4 expression.

  Reduced mitochondrial density.

  Depressed hexokinase activity.

14

Which one of the following statements relating to a possible action of Glucagon-like Peptide-1 (GLP-1) is NOT CORRECT?


  GLP-1 stimulates insulin secretion.

  GLP-1 stimulates glucose uptake.

  GLP-1 suppresses appetite.

  GLP-1 inhibits glucagon secretion.

  GLP-1 inhibits gastric emptying.

15

Which of the following neurotransmitters is NOT involved in the “pleasure” pathways related to feeding?


  Enkephalin.

  Dopamine.

  β-Endorphin.

  Anandamide (N-arachidonoylethanolamine).

  Neuropeptide Y.

16

Which one of the following statements is CORRECT?


  Leptin acts on fat cells to increase energy expenditure.

  Surveys published from 2003 onwards show that the prevalence of obesity in Australian adults is 20% or more of the population.

  Leptin deficiency is a very common cause of severe obesity.

  Twin studies demonstrate the dominance of environment over genes in the cause of obesity.

  The intra-pair correlation co-efficient for body weight in identical twins reared together is about 0.3

17

Above the level of the umbilicus the anterior layer of the rectus sheath is:


  Absent.

  Comprised of the aponeuroses of all three layers of the anterior abdominal wall.

  Comprised of the aponeurosis of external oblique and the anterior leaf of the internal oblique aponeurosis.

  Comprised of the aponeurosis of transverses abdominis and the posterior leaf of the internal oblique aponeurosis.

  Comprised of thoracolumbar fascia.

18

A bodybuilder presents with a right indirect inguinal hernia. At surgery, the surgeon identifies a piece of small bowel traversing the length of the inguinal canal and entering the scrotum. The surgeon reduces the hernia and repairs the stretched internal (deep) inguinal ring. The internal (deep) inguinal ring is a deficiency in the:


  Peritoneum.

  Fascia transversalis.

  Transversus abdominus.

  Internal oblique.

  External oblique.

19

On the posterior abdominal wall:


  The lumbar vessels run anterior to the psoas major.

  The kidneys are retroperitoneal viscera and lie on the psoas major.

  Peritoneal reflections pass as mesenteries to surround intraperitoneal viscera.

  The thoracolumbar fascia gives origin to the rectus abdominus muscle.

  The psoas minor is a constant structure present in every individual.

20

Which one of the following statements about metabolic responses to prolonged starvation is CORRECT?


  There is increased synthesis of ketone bodies in the liver.

  The plasma level of fatty acids decreases.

  Gluconeogenesis maintains blood glucose at 5.5 mM or above.

  The rate of degradation of proteins increases with time.

  The citric acid cycle is up-regulated.

21

Which one of the following statements about insulin is CORRECT?


  Insulin causes down-regulation of GLUT4 in muscle.

  Insulin causes activation of glycogen phosphorylase.

  All actions of insulin are mediated via the insulin receptor.

  Insulin causes activation of hormone sensitive lipase.

  Insulin enters the nucleus to alter the rate of gene transcription.

22

Which of the following statements about the body's handling of nitrogen from protein breakdown is CORRECT?


  Liver is the main site of branched chain amino acid catabolism.

  The most common keto acid accepting nitrogen in transaminations is α-ketoglutarate.

  The urea cycle occurs in muscle.

  Glycine is the major carrier of amino groups from muscle to liver.

  Alanine is selectively broken down (transaminated) in the kidney.

23

Concerning metabolic interaction between tissues, which of the following statements is CORRECT?


  During fasting, skeletal muscle donates glucose from stored glycogen to blood.

  During fasting, branched chain amino acids from muscle are transported to liver where they support gluconeogenesis.

  Glutamate is the major form of transport for nitrogen from extrahepatic tissues.

  The kidney is an important site of gluconeogenesis from glutamine.

  A major fate for lactate from rapidly contracting muscle is conversion to alanine in the liver.

24

Regarding lipoprotein metabolism, which of the following statements is CORRECT?


  The ratio of the plasma concentration of HDL cholesterol to LDL triglyceride is used to predict the risk of heart disease.

  LDL carries dietary triacylglycerol to the liver.

  Apolipoprotein E (ApoE) is associated with LDL.

  HDL donates cholesteryl esters to the liver via interaction with ABCA1.

  VLDL from liver picks up ApoE in the blood.

25

Regarding dyslipidaemia, which of the following statements is CORRECT?


  Mutations in the LDL receptor cause familial hypercholesteraemia (FH).

  Dyslipidaemias are characterised by elevated levels of HDL.

  ApoA-I deficiency is a genetic cause of hypertriglyceridaemia.

  Overproduction of LDL in the liver contributes to hypertriglyceridaemia.

  The statin class of drugs is used to treat hypertriglyceridaemia.

26

Which of the following is CORRECT?


  Reflux esophagitis is due to Barrett’s esophagus.

  Helicobacter pylori polyps are associated with non-steroidal anti-inflammatory drug use.

  Gastritis may be associated with H.pylori infection.

  Celiac disease is associated with villous atrophy in the large intestine.

  Meckel’s diverticulum is associated with the presence of ectopic squamous epithelium.

27

Select the one CORRECT statement with respect to type 1 diabetes.


  In type 1 diabetes, plasma levels of C peptide are raised.

  In most cases, the onset of type 1 diabetes occurs after the age of 35 years.

  Type 1 diabetes accounts for the majority of cases of diabetes mellitus.

  In the early stages of type 1 diabetes, the islets are usually infiltrated with CD8+ and CD4+ lymphocytes.

  Patients with autoimmune adrenalitis have a low risk of developing type 1 diabetes.

28

Which of the following statements related to gastrin is (are) CORRECT? A) Gastrin release is stimulated by products of protein breakdown. B) Gastrin acts on oxyntic (parietal) cell to increase H+ secretion. C) Gastrin release is stimulated by vagal activity. D) A pH of < 3 in gastric antrum increases gastrin secretion.


  If only A, B and C are correct.

  If only A and C are correct.

  If only B and D are correct.

  If only D is correct.

  If all are correct.

29

Which of the following statements related to acid secretion by the gastric gland is (are) CORRECT? A) Acid secretion is stimulated by a pH of < 3.5 in the antrum. B) Acid secretion is inhibited by sodium bicarbonate. C) Acid secretion after a meal is stimulated by secretin. D) Acid secretion is stimulated by H2 receptor agonists.


  If only A, B and C are correct.

  If only A and C are correct.

  If only B and D are correct.

  If only D is correct.

  If all are correct.

30

Which of the following statements related to peptic ulceration is (are) CORRECT? A) Most peptic ulcers can be cured by inhibiting acid secretion. B) Aspiration of gastric juice will lead to hypokalaemia. C) H2 receptor blockers are the most effective way to block acid secretion. D) Aspiration of gastric juice will lead to a metabolic alkalosis.


  If only A, B and C are correct.

  If only A and C are correct.

  If only B and D are correct.

  If only D is correct.

  If all are correct.