IMMS

Question 1

Which of the following is not a component of cell membranes or the receptors associated with them?

1. Cholesterol
2. Dihydrogen oxide
3. Glycolipids
4. Lipoproteins
5. Phospholipids

Answer 1

2. Dihydrogen oxide

Question 2

Which enzyme catalyses 1,3-bisphosphoglycerate to 3-phosphoglycerate in the aerobic glycolysis pathway

1. Aldolase
2. Phosphofructokinase
3. Phosphoglucose isomerase
4. Phosphoglycerate kinase
5. Triose phosphate isomerase

Answer 2

4. Phosphoglycerate kinase

Question 3

Which of the following enzymes is not involved in either aerobic or anaerobic glycolysis?

1. Aldolase
2. ATPase
3. Hexokinase
4. Phosphoglucose isomerase
5. Triose phosphate isomerase

Answer 3

2. ATPase

Question 4

A 45-year-old man is trying to lose weight. How many kcal are there in one unit of alcohol?

1. 28 kcal
2. 40 kcal
3. 56 kcal
4. 72 kcal
5. 90 kcal

Answer 4

3. 56 kcal

Question 5

Which of the following factors will lower the basal metabolic rate of an individual?

1. Caffeine
2. Dieting
3. Fever
4. Obesity
5. Hyperthyroidism

Answer 5

2. Dieting

Question 6

A 60-year-old woman has a lack of cortisol. Which of the following statements concerning steroid hormones is TRUE?

1. They act on plasma membrane receptors
2. They are formed from tyrosine
3. They are stored in secretory granules
4. They are transported in plasma bound to proteins
5. They are water soluble

Answer 6

4. They are transported in plasma bound to proteins

Question 7

Which of the following statements concerning early embryonic life is TRUE?

1. During implantation the morula penetrates the endometrial stroma
2. Epiblasts in a three-week embryo will become ectoderm
3. Implantation occurs 3-4 days following fertilization
4. Paraxial plate mesodermal cells will give rise to the circulatory system
5. The midgut is in continuity with the amniotic cavity

Answer 7

2. Epiblasts in a three-week embryo will become ectoderm

Question 8

What proportion of body water is found within plasma?

1. 7%
2. 26%
3. 33%
4. 66%
5. 100%

Answer 8

1. 7%

Question 9

Which of the following substances is transported into cells by facilitated diffusion?

1. Cholesterol
2. Ethanol
3. Glucose
4. Oxygen
5. Potassium ions

Answer 9

3. Glucose

Question 10

In a slim adult male standing in the anatomical position, which of the following structures lies most distal from the umbilicus?

1. Apex of the heart
2. Glans penis
3. Left patella
4. Right acetabulum
5. Urinary bladder

Answer 10

3. Left patella

Question 11

A genetic disease is present within multiple generations of a family. With each generation, the disease presents earlier and is more severe. What is this an example of?

1. Anticipation
2. Gonadal mosaicism
3. Haploinsufficiency
4. Penetrance
5. Variable expression

Answer 11

1. Anticipation

Question 12

In Evidence Based Medicine, the PICO principle is used to frame and answer clinical questions. What does the C in PICO stand for?

1. Cochrane
2. Computer
3. Consent
4. Control
5. Critical

Answer 12

4. Control
P  		Patient, problem or population
I  		Intervention
C  		Control, comparison or comparator
O  		Outcomes

Question 13

Concerning the safe disposal of sharps, which of the following is TRUE?

1. Items accidentally discarded into a sharps bin should be removed with forceps
2. Sharps bins should be filled to the top before disposal
3. Sharps bins should be kept on the floor
4. Sharps bins should only be carried by their handles
5. Sharps should be carried to the sharps bin in a tray

Answer 13

4. Sharps bins should only be carried by their handles

Question 14

In Sickle Cell disease hypoxia causes the abnormal HbS to...
A. Stay the same
B. Flip from levo- to dextro-isomer 
C. Polymerise
D. Deform
E. Dimerise

Answer 14

C. Polymerise

Question 15

Sickle cell disease can be treated with hydroxyurea because it…
A. Increases the synthesis of normal HbA
B. Interferes with the translation of mutant RNA
C. Increases the synthesis of HbF (Foetal Hb)
D. Prevents the transcription of mutated DNA
E. Reverses the hydrophobic site caused by the point mutation

Answer 15

C. Increases the synthesis of HbF (Foetal Hb)
Hydroxyurea (hydroxycarbamide) is a myelosuppressive agent and is the only treatment known to reduce the frequency of painful episodes. It causes a shift towards production of red cells with HbF. Exact mechanism of action is not completely understood.
HbF is composed of 2 alpha chains and 2 gamma (not beta) chains. It also has a greater affinity for oxygen than HbA.

Question 16

This enzyme causes the double helix to unzip:
A. Topoisomerase
B. DNA polymerase
C. Glycosylase 
D. Helicase
E. Amylase

Answer 16

D. Helicase

Question 17

The process in which mRNA is used to specify the amino acids required for protein formation is known as:
A. Translocation
B. Transcription
C. Translation
D. Transference
E. Telophase

Answer 17

C. Translation
Transcription – is where DNA is transcribed / copied into mRNA which then leaves the nucleus
Translocation – is where genetic material is exchanged between chromosomes
Translation – is where mRNA is used to specify the amino acids required to make proteins
Transamination – is the reaction in which an amino group is removed from an amino acid during metabolism
Telophase – is a phase during cell division

Question 18

Concerning ribosomes, which of the following is false?
A. They are assembled outside the nucleus
B. They consist of rRNA and proteins
C. They are assembled inside the nucleus
D. They have a large and a small subunit
E. They can attach to the rough endoplasmic reticulum

Answer 18

A. They are assembled outside the nucleus
Ribosomes are assembled inside the nucleus and then translocate to the cytoplasm through nuclear pores where they remain free or can be attached to the rough endoplasmic reticulum.

Question 19

A protein with a number of sub units held together by cross links has this type of structure:
A. Primary structure
B. Tertiary structure
C. Quaternary structure
D. Secondary structure

Answer 19

C. Quaternary structure

Question 20

In Sickle Cell disease an acute pain crisis is typically caused by capillary occlusion in the…
A. Brain
B. Skin
C. Bone
D. Cardiac Muscle
E. Spleen

Answer 20

C. Bone
Early presentations can be pain in the hands and feet with severe pain in bones such as femur, humorous, ribs and pelvis occurring in older children. These are due to vaso-occlusive events in the small vessels. Repeated events in the bones can lead to chronic infarcts.

Question 21

Which of the following is defined as ‘A weak attractive interaction between two atoms due fluctuating electrical charges’ 
A. Van der Waals force
B. Hydrogen bond
C. Hydrophobic force
D. Disulphide bond

Answer 21

A. Van der Waals force
Disulphide bond – covalent bond between side chains of cysteine residues
Hydrogen bond – A type of Vander Waals force. It is the strongest of them and is the interaction between dipoles, involving an hydrogen and an oxygen/nitrogen/fluorine.
Van der Waals force – A weak attractive interaction between two atoms due fluctuating electrical charges’
Hydrophobic force - the attraction of hydrophobic protein side chains which form tightly packed cores on the interior of proteins which exclude water molecules

Question 22

In Sickle Cell disease capillary occlusion is now thought to occur by…
A. The sickle cells causing capillary spasm
B. Sickle cells binding together to form a ‘plug’
C. Sickle cells binding with platelets
D. Endothelial damage causing multicellular (platelets, white cells) aggregates which occlude the capillary

Answer 22

D. Endothelial damage causing multicellular (platelets, white cells) aggregates which occlude the capillary

Question 23

Alpha helixes and beta sheets are examples of protein…
A. Primary structure
B. Quaternary structure
C. Secondary structure
D. Tertiary structure

Answer 23

C. Secondary structure

Question 24

Specific amino acids bind to:
A. Single strand DNA
B. Messenger RNA
C. Transfer RNA
D. Double strand DNA
E. Double stranded RNA

Answer 24

C. Transfer RNA

tRNA carries specific amino acids to the ribosome and checks they are incorporated in the right location.

Question 25

``` This enzyme unwinds supercoiled DNA: A. Helicase B. Glycosylase C. Amylase D. Topoisomerase E. DNA Polymerase ```

Answer 25

D. Topoisomerase Helicase unzips the double helix DNA polymerase is involved in the synthesis of DNA using deoxyribonucleotides. DNA polymerase reads the existing DNA strands (3’ to 5’) to create two new strands. Topoisomerase unwinds the supercoiled DNA strand to give an uncoiled DNA strand Glycosylases are involved in the repair of damaged bases in DNA Amylase is an enzyme present in saliva which starts the breakdown of starch to sugars

Question 26

Sickle cell anaemia (HbS) is caused by: A. An autosomal dominant inherited condition substituting an amino acid in the beta globin chain B. An autosomal recessive inherited condition substituting an amino acid in the alpha globin chain C. A random genetic mutation in the beta globin chain D. An autosomal recessive inherited condition substituting an amino acid in the beta globin chain E. An autosomal dominant inherited condition substituting an amino acid in the alpha globin chain

Answer 26

D. An autosomal recessive inherited condition substituting an amino acid in the beta globin chain Sickle cell anaemia is an autosomal recessive inherited condition which substitutes valine for the normal glutamine in the beta globin chain.

Question 27

In Sickle Cell disease the HbS structural change causes sickling by… A. Changing the charge across the cell membrane B. Altering nuclear transcription of cytoskeletal proteins C. Dehydrating the cell by osmotic action D. Binding to the cytoskeleton E. Pulling on the cell membrane

Answer 27

D. Binding to the cytoskeleton Deoxygenated HbS polymerises and binds to the cell cytoskeleton which distorts the normal cell shape into the classic sickle shape.

Question 28

GP suspects that his young patient has cranial diabetes insipidus. This is a disorder in which the pituitary gland fails to release ADH when stimulated to do so. She is referred for a water deprivation test during which she is nil by mouth? If the patient does have diabetes insipidus and is not producing any ADH which of the following is MOST LIKELY to show her blood and urine osmolality after 3 hours of water deprivation? (Normal serum osmolality275-295mOsm/Kg; urine osmolality varies from very dilute (50) to very concentrated (1400mOsm/Kg) A. Blood 220/urine 100 B. Blood 220/urine 1200 C. Blood 300/urine 1200 D. Blood 300/urine 100 E. She won’t produce urine

Answer 28

D. Blood 300/urine 100 During the water deprivation test the body should detect an increased serum osmolality (300) and produce ADH in order to promote water retention. As she is unable to produce ADH she will produce dilute urine (low osmolality, 100) instead of concentrated urine.

Question 29

You examine a patient and note he has lower leg pitting oedema. You also note that his blood albumin level is low. Which statement correctly describes the relationship between albumin and oedema? A. A low albumin causes an increase in oncotic pressure and water diffuses out of the blood into interstitial fluid B. Low albumin is not related to oedema C. A low albumin causes an increase in oncotic pressure and water diffuses from the interstitial fluid into the blood D. A low albumin causes a decrease in oncotic pressure and water diffuses from the interstitial fluid into the blood E. A low albumin causes a decrease in oncotic pressure and water diffuses from the blood into the interstitial fluid

Answer 29

E. A low albumin causes a decrease in oncotic pressure and water diffuses from the blood into the interstitial fluid

Question 30

A healthy student drinks 2 litres of water in 5 mins. Which of the following correctly describes the physiological response? A. Osmolality rises - ADH secretion stops - urine volume increases B. Osmolality falls - ADH secretion stops - urine volume increases C. Osmolality falls - ADH secretion increases - urine volume increases D. Osmolality rises - ADH secretion increases - urine volume increases

Answer 30

B. Osmolality falls - ADH secretion stops - urine volume increases The excess fluid causes a decrease in blood osmolality (osmolarity) which in turn causes a reduction / stopping of Anti Diuretic Hormone release. The kidneys therefore excrete more water leading to increased urine volume.

Question 31

What is the site of synthesis of aldosterone? A. Adrenal cortex B. Distal tubules and collecting ducts of nephron C. Juxtaglomerular cells D. Posterior pituitary E. Hypothalamus F. Anterior pituitary

Answer 31

A. Adrenal cortex Steroid hormone released from the adrenal cortex in response to stimulation by angiotensin II. It promotes sodium reabsorption and potassium secretion in the distal tubules of the kidneys.

Question 32

What is the principal site of renin production? A. Juxtaglomerular cells B. Hypothalamus C. Anterior pituitary D. Distal tubules and collecting ducts of nephron E. Posterior pituitary F. Adrenal cortex

Answer 32

A. Juxtaglomerular cells

Question 33

``` Osmolarity can be calculated from blood results. Which of the following IS a factor in calculated osmolarity? A. Magnesium B. Bicarbonate C. Phosphate D. Urea E. Chloride ```

Answer 33

D. Urea

Question 34

``` What is the most prevalent ion in intracellular fluid? A. Na+ B. K+ C. HCO3- D. Cl- E. Lactate ```

Answer 34

B. K+

Question 35

``` Which of the following is an example of insensible fluid loss? A. Water from respiration B. Urine C. Diarrhoea D. Fluid in abdominal surgical drain E. Vomiting ```

Answer 35

A. Water from respiration Insensible fluid loss is loss that is not easily measured e.g. sweating, water lost from respiration, evaporation during abdominal surgery. Sensible fluid loss is that which is easily measured e.g. urine output, vomit, fluid in surgical drains.

Question 36

What is the site of synthesis of ADH (antidiuretic hormone)? A. Adrenal cortex B. Distal tubules and collecting ducts of nephron C. Anterior pituitary D. Posterior pituitary E. Hypothalamus F. Juxtaglomerular cells

Answer 36

E. Hypothalamus Synthesised by the supraoptic and paraventricular nuclei of the hypothalamus. However it is then stored in the posterior pituitary gland.

Question 37

``` Which of the following CORRECTLY describes the action of renin? A. Angiotensinogen to angiotensin 2 B. Angiotensin 1 to angiotensin 2 C. Angiotensinogen to angiotensin 1 D. Angiotensin 2 to angiotensin 1 ```

Answer 37

C. Angiotensinogen to angiotensin 1 | Renin is a proteolytic enzyme which activates angiotensinogen to produce angiotensin I.

Question 38

``` Total body water (TBW) is distributed into three compartments (Intracellular/interstitial/intravascular). How is the TBW distributed by volume? (Assume healthy 70 Kg man) A. 28L/14L/3L B. 28L/11L/3L C. 42L/11L/3L D. 24L/11L/3L E. 24L/14L/3L ```

Answer 38

B. 28L/11L/3L