A 27-year-old man receives a neurologic evaluation following a gunshot would received
5 days previously. A 9-mm bullet had passed through both the medial and lateral heads of the
gastrocnemius muscle. The exit wound on the lateral head of the muscle was somewhat deeper than
the entrance wound in the medial head. The bullet did not strike bone or significant arteries although
significant tissue damage, suppuration, and swelling were found around the exit wound. Neurologic
examination reveals losses of dorsiflexion and eversion of the left foot. The patient cannot feel
pinprick or touch on the dorsum of the left foot or anterolateral surface of the left leg. Which nerve
was most likely involved in the injury?
A) Sciatic nerve
B) Femoral nerve
C) Sural nerve
D) Common fibular (peroneal) nerve
E) Tibial nerve

A 12-year-old boy is brought to the ED by his mother after being pushed out of the
neighbor’s tree house, about 10 ft of the ground. He can walk but his right heel hurts every time he
puts weight on it. When his foot is examined, it is found to be tender to pressure on both the medial
and lateral aspects of the heel inferior to the tibia. Plain films of his right lower extremity are ordered
because of suspicion that he has fractured which one of the following?
A) Calcaneus
B) Fibula
C) Tibia
D) Navicular
E) Cuneiform

Which structure is derived from the same embryonic primordium as the kidney?
A) Gonads
B) Epidermis
C) Pineal gland
D) Liver
E) Adrenal medulla

Consider adrenergic efects only. Select the INCORRECT match of tissue and response.
A) Skeletal muscle; lipolysis
B) Vascular smooth muscle; contraction
C) Kidney; Na+ reabsorption
D) Sweat glands; secretion
E) Liver; glycogenolysis

The glycolytic enzyme triose phosphate isomerase acts upon a phosphorylated triose
carbohydrate. Which of the following is an example of a ketotriose?
A) dihydroxyacetone
B) erythrose
C) glyceraldehyde
D) ribose
E) ribulose
F) threose

The intermaxillary segment of the developing upper jaw contributes to the formation of
the
1) philtrum of the lip
2) primary or anterior palate
3) premaxillary part of the maxilla
4) posterior or secondary palate
A) 1,2,3 only
B) 1,3 only
C) 2,4 only
D) 4 only
E) All are correct

A laboratory researcher makes a solution containing D-glucose and ATP at
concentrations similar to those found in cells. Nothing happens. Next she adds a small amount of the
enzyme hexokinase, and the ATP reacts with the glucose forming glucose 6-phosphate. Which of the
following explains these observations? Relative to the uncatalyzed reaction, the enzyme
A) decreases Delta Gf for the reaction.
B) increases Delta Gf for the reaction.
C) provides a higher energy pathway from reactants to products.
D) provides a lower energy pathway from reactants to products.
E) shifts the equilibrium towards products.
F) shifts the equilibrium towards reactants

Question #92: Enzyme reactions involving methylation
A) Biotin
B) Cyanocobalamin (vitamin B12)
C) Pyridoxine (vitamin B6)
D) Riboflavin (vitamin B2)
E) Thiamine (vitamin B1)

Which of the following statements about smooth muscle contraction is most accurate?
A) Ca++ independent
B) Does not require an action potential
C) Requires more energy compared to skeletal muscle
D) Shorter in duration compared to skeletal muscle

In the reflex examination, the patellar tendon is briskly tapped with a reflex hammer.
The pathway chiefly responsible for initiating this reflex is the:
A) I-B fibers
B) II fibers
C) Gamma motorneuron fibers
D) I-A fibers
E) Alpha motorneuron fiber

Somites may diferentiate into which of the following?
A) Urogenital ridge
B) Kidneys
C) Notochord
D) Epimeric and hypomeric muscles
E) Epithelial lining of the gastrointestinal tract

Which one of the following statements is true for eukaryotic transcription?
A) Rifampicin binds to RNA polymerase and changes its conformation
B) RNA Polymerase III synthesizes tRNA
C) mRNA carries informations for more than one gene
D) 7-methylguanosine is attached at the 3’ end of the mRNA
E) Elongation of RNA is always in 3’ 5’ direction

In which of the following nuclear structures is DNA actively transcribed to rRNA?
A) Envelope
B) Lamina
C) Matrix
D) Nucleolus
E) Pore

39-year-old male farmer is brought to the emergency department. Three hours
previously he had been spraying fields with an insecticide called Fenoxycarb. He did not use any
respiratory protection and has inhaled the vapor. He shows rippling of the muscles under the skin,
blurred vision and complains of chest tightness. He is unable to walk. Fenoxycarb is a
non-competitive inhibitor of the enzyme acetylcholinesterase, an important mediator of
neurotransmitter action. Which of the following best describes the efect of this poison on the
enzyme?
A) Vmax is reduced, Km is unaltered
B) Vmax is unaltered, Km is increased
C) Both Vmax and Km are reduced
D) Both Vmax and Km are unaltered
E) The lineweaver-Burk plot becomes non-linear

Cytotoxic T cells can elicit self-destruct mechanisms on target cells by interacting with
A) Ras ligand
B) Fas ligand
C) Fas receptors
D) adaptor proteins
E) procaspase

Smooth muscle contraction is terminated by which of the following?
A) Dephosphorylation of myosin kinase
B) Dephosphorylation of myosin light chain
C) Efux of Ca++ ions across the plasma membrane
D) Inhibition of myosin phosphatase
E) Uptake of Ca++ ions into the sarcoplasmic reticulum

Which of the following intracellular signal molecules regulates the catalysis of the
conversion of GTP to cGMP?
A) cAMP
B) Ceramide
C) cGMP
D) Diacylglycerol
E) Malonyl CoA
F) Nitric oxide

Select the correct name of the sequence on a mRNA which is required in prokaryotes to
facilitate the binding to the 30S ribosomal subunit to correctly initiate protein synthesis.
A) Pribnow box
B) -35 sequence
C) Hogness box
D) TATA box
E) Shine-Dalgarno sequence

In a patient with hereditary nonpolyposis colon cancer many small loops of unpaired
DNA were found. This is a result of a mutation afecting which of the following?
A) Chain break repair
B) Base excision repair
C) Depurination repair
D) Mismatch repair
E) Homologous recombination repair

Question #104: In a normal adult, the conus medullaris is found at what vertebral level?
A) L3
B) T9
C) Tll
D) Ll
E) S1

The release of epinephrine from the chromafn granules of the adrenal medulla into the
bloodstream in response to neural stimulation is mediated by which of the following?
A) Acetylcholine
B) Gamma-Aminobutryic acid (GABA)
C) Cortisol
D) Dopamine
E) Serotonin

An adequate supply of purines and pyrimidines is supplied by normal metabolic
pathways rather than the diet. Which one of the following statements about purine and/or pyrimidine
biosynthesis is CORRECT?
A) Thymidine 5'-phosphate is formed in a reaction involving the direct participation of PRPP and
thymidine.
B) Only the de novo synthesis of pyrimidines is inhibited by methotrexate.
C) The ring structures of purines and pyrimidines are built first and then are attached to PRPP.
D) The committed step in pyrimidine biosynthesis is catalyzed by orotate decarboxylase.
E) AMP and GMP cross-regulate each other’s rate of synthesis.

A 26-year-old woman with a history of psychiatric problems has been brought to the
emergency room with high fever, sweating and tremors after ingesting approximately 100 aspirin
tablets in a suicide attempt. High fever associated with salicylate overdose is explained by
A) Excessive ADP phosphorylation
B) Excessive increase in proton concentration gradient
C) Rupture of mitochondrial membranes
D) Stimulation of thermogenin
E) Uncoupling of electron transport from ATP synthesis

Select the correct statement regarding stabilization of tertiary structure in proteins
A) Ionic bonds in the proteins enhances the solubility of the protein
B) Methionine, a Sulphur containing amino acid is responsible for the covalent bonding in the side
chains
C) Lysine and aspartate contribute for the ionic interactions in the protein molecule
D) There dimensional stability of the structure mainly due to the presence of hydrogen bonds
E) Hydrogen bonds can be formed between glutamate and aspartate

During the synthesis of a daughter DNA molecule the chain elongation enzyme wrongly
inserts adenine instead of guanine in the daughter strand. Which activity of the DNA-synthesizing
enzyme removes the wrong base?
A) 5’ - 3’ DNA polymerase activity
B) 3’ - 5’ DNA polymerase activity
C) 3’ - 5’ exonulease activity
D) 5’ - 3’ proofreading activity
E) 3’ - 5’ endonulease activity