A genetic code is degenerate when
A) a nucleotide triplet can code for more than one amino acid
B) a tRNA can be charged by more than one synthetase
C) an amino acid can be coded for by more than one nucleotide triplet
D) an aminoacyl tRNA synthetase can charge more than one tRNA species
E) the third base in an anticodon is not important for coding

Which one of the following statements concerning the well-fed state is correct?
A) Most enzymes that are regulated by covalent modification are active in the phosphorylated form.
B) Hepatic fructose 2,6-bisphosphate is elevated.
C) Synthesis of gluconeogenic substrates concentrations are elevated.
D) Insulin stimulates the transport of glucose into hepatocytes.
E) The synthesis of glucokinase is repressed.

A 45-year-old woman has the sudden onset of severe headaches. During one of these
episodes, her blood pressure is 190/115 mm Hg. Her usual blood pressure is 130/90 mm Hg. Her
sister had similar episodes several years ago. Urinalysis shows increased concentrations of
metanephrine and vanillylmandelic acid. The patient is most likely to have a neoplasm that secretes
which of the following?
A) ACTH
B) Aldosterone
C) Cortisol
D) Epinephrine
E) Renin

The reason why some glycosaminoglycans can act as lubricants in joints is that
A) They absorb a lot of water and the water gives ‘fluidity’ to the joint.
B) They are uncharged and hydrophobic thus acting as a kind of oil.
C) They are all negatively charged and hence repel and slide against each other
D) They are all positively charged and hence repel and slide against each other
E) They are amphipathic - having both nonpolar and polar moieties in their structure

A 67-year-old man has a restricted diet that includes no fresh citrus fruits or leafy
green vegetables. His teeth are loose and his gums bleed easily. This patient's disorder most likely
results from a defect in collagen synthesis that involves which of the following amino acids?
A) Arginine
B) Cysteine
C) Histidine
D) Hydroxyproline
E) Leucine

The lateral mesoderm is divided into two distinct layers by the formation of the
A) extraembryonic coelom
B) intraembryonic coelom
C) cariogenic region
D) notochrod
E) yolk sac

: Proteins synthesized on membrane-bound polyribosomes normally may undergo each
of the following EXCEPT
A) intracellular transport
B) release from polyribosomes into cytosol
C) secretion
D) sequestration in lysosomes
E) transfer to the cisternal space

A rapid way to purify proteins that are targeted to lysosomes would be to use afnity
chromatography. AN appropriate antibody to use on an afnity chromatography column would be one
directed against
A) acid hydrolyses
B) clathrin
C) glucose-6-phosphate
D) mannose-6-phosphate
E) sialic acid

A 49-year-old man is admitted to the emergency department complaining that he has
difculties walking. Physical examination reveals that the patient sufers from peripheral vascular
disease. An ultrasound examination reveals an occlusion of his femoral artery at the proximal portion
of the adductor canal. Which of the following arteries will most likely provide collateral circulation to
the thigh?
A) Descending branch of the lateral circumflex femoral
B) Descending genicular
C) Medial circumflex femoral
D) First perforating branch of deep femoral
E) Obturator artery

Which of the following proteins is not part of the apoptosome which initiates apoptosis
by the intrinsic pathway?
A) Apaf-1
B) Bcl-2
C) Cytochrome c
D) Procaspase 9
E) CARD

Adrenal medullary chromafn cells that secrete catecholamines (epinephrine and
norepinephrine) are innervated directly by:
A) pre-ganglionic sympathetic cholinergic fibers
B) pre-ganglionic parasympathetic cholinergic fibers
C) postganglionic sympathetic cholinergic fibers
D) postganglionic sympathetic noradrenergic fibers
E) hormones through the blood only - not by autonomic fibers

Which of the following best describes the glenohumeral joint?
A) Ball & socket
B) Condyloid
C) Hinge
D) Pivot
E) Saddle

The right shoulder of a 78-year-old female had become increasingly painful over the
past year. Abduction of the right arm caused her to wince from the discomfort. Palpation of the
deltoid muscle by the physician produced exquisite pain. Imaging studies reveal intermuscular
inflammation extending over the head of the humerus. What structure was inflamed?
A) Subscapular bursa
B) Infraspinatus muscle
C) Glenohumeral joint cavity
D) Subacromial bursa
E) Teres minor muscle

The retinoblastoma protein controls
A) Crossing-over
B) Centrosome duplication
C) Transition from G1 to S phase
D) Pairing of homologous chromosomes
E) Expression of cyclin D

Reinforcers have been found to be most efective when they
A) are concurrent with the behavior
B) follow the behavior
C) precede the behavior
D) sometimes precede and sometimes follow the behavior

A second-year medical student is under a lot of stress due to her impending
biochemistry examination. She knows that her psychological stress leads to the release of
endogenous glucocorticoid, which increases the glucose levels in her body. To raise glucose levels,
glucocorticoids act via the enzyme phosphoenolpyruvate carboxykinase to increase which of the
following?
A) Acetyl-CoA
B) Malate
C) Oxaloacetate
D) Phosphoenolpyruvate
E) Pyruvate

Most anti-neoplastic analogs of purine and pyrimidine bases are administered either as
the nucleoside or the base. Which of the molecules below represents a base without the ribose
attached?
A) Adenosine
B) Uridine
C) Inosine
D) Guanosine
E) Hypoxanthine

A 50-year-old man was admitted into the hospital of a leading research university with
a diagnosis of hepatitis and early cirrhosis of the liver. HIs past medical history is significant for heavy
smoking and only occasional consumption of alcohol. He did not use any drugs, and he had no viral
infections. DNA studies showed that he as homozygous for the Z allele of alpha1-antitrypsin,
produced by a missense mutation that prevents the proper folding of the protein. A liver biopsy would
most likely show accumulation of a proteinaceous substance in which of the following sub cellular
sites?
A) Endoplasmic reticulum
B) Extracellular matrix
C) Golgi apparatus
D) Inclusion bodies
E) Lysosomes

Question #126: Residue(s) present in sphingomyelin
A) Choline
B) Glycerol
C) Both
D) Neither

A 23-year-old male medical student fell asleep in his chair with Netter’s Atlas wedged into
his axilla. When he awoke in the morning, he was unable to ex- tend the forearm, wrist, or fingers. Movements of
the ipsilateral shoulder joint appear to be normal. Which of the following nerves was most likely compressed,
producing the symptoms described?
A) Lateral cord of the brachial plexus
B) Medial cord of the brachial plexus
C) Radial nerve
D) Median nerve
E) Lateral and medial pectoral nerves

: Which of the following is the most energy-efcient precursor for gluconeogenesis?
A) Glucogenic amino acids
B) Glycerol from lipid catabolism
C) Ketogenic amino acids
D) Lactate from muscle and erythrocytes
E) Pyruvate from glycolysis

Proteins synthesized on ______________ eventually become a cytoskeletal protein
A) Attached polyribosomes
B) Free polyribosomes
C) Both
D) Neither

Cyclin dependent kinases which control progression through cell cycle checkpoints are
fully activated by which of the following:
A) binding to cyclin, plus phosphorylation by a Cdk activating protein kinase
B) binding to cyclins
C) phosphorylation by a Cdk activating protein protein kinase
D) phosphorylation by a tyrosine kinase

One of the following will not be needed during Glycogen degradation:
A) Phosphoglucomutase
B) Inorganic phosphate
C) Acid maltase
D) Lysosomal alpha 1,4 glucosidase
E) UDP-Glucose
F) Glucose-6-Phosphatase
G) Vitamin B6

A 22-year-old woman who is a professional tennis player presents to the physician
with pain on the lateral aspect of her elbow radiating down her forearm. Repetitive use of which of the
following muscles most likely lead to this patient’s condition?
A) Biceps
B) Extensor carpi radialis
C) Extensor carpi ulnaris
D) Flexor carpi ulnaris
E) Pronator teres