All primary oocytes are formed by
A) week 4 of embryonic life
B) month 5 of fetal life
C) birth
D) month 5 of infancy
E) puberty

A 21-year-old man presents to the emergency department following an injury to his
shoulder that he sustained while playing football. His shoulder appears flattened, and he is not able to
abduct his arm. He is found to have a fracture at the surgical neck of his humerus. The muscle that is
most likely injured in this patient receives innervation from which of the following nerve roots?
A) C3-5
B) C5-6
C) C6-7
D) C7-8
E) C8-T1

Which of the following best describes the placental components of dizygotic twins?
A) One placenta, two amniotic sacs, one chorion
B) One placenta, two amniotic sacs, two chorions
C) Two placentas, two amniotic sacs, one chorion
D) Two placentas, two amniotic sacs, two chorions
E) One placenta, two amniotic sacs, two chorions

Least soluble in water at neutral pH
A) Arginine
B) Glutatmate
C) Histidine
D) Serine
E) Tryptophan

Total RNA extracted from hepatic cells hybridizes only 5-10% of the DNA sequences
present in that cell. Factors that contribute to this include:
1) Gene expression is controlled at the level of transcription
2) Gene expression is controlled at the level of translation
3) Many DNA sequences do not code for proteins
4) Some DNA sequence rearrangement occurs in the liver
A) 1,2,3 only
B) 1,3 only
C) 2,4 only
D) 4 only
E) All are correct

Single amino acid substitution in protein
Mutation?
A) Frameshift
B) Nonsense
C) Both
D) Neither

A 45-year-old male arrived at the emergency department with injuries to his left elbow
after he fell in a bicycle race. Radiographic and MRI examinations show a fracture of the medial
epicondyle and a torn ulnar nerve. Which of the following muscles would be most likely to be
paralyzed?
A) Flexor digitorum superficialis
B) Biceps brachii
C) Brachioradialis
D) Flexor carpi ulnaris
E) Supinator

Oxaloacetate is a substrate for
1) citrate syntehtase
2) phophoenopyruvate carboxykinase
3) malate dehydrogenase
4) citrate lyase
A) 1,2,3 only
B) 1,3 only
C) 2,4 only
D) 4 only
E) All are correct

A 24-year-old man is unable to flex his right forearm at the elbow joint. Which of the
following best describes the nerve likely afected in this case?
A) Median
B) Axillary
C) Musculocutaenous
D) Radial
E) Ulnar

A new drug, Drug X, relieves pain by interacting with a specific receptor in the body.
Drug X binds irreversibly to this receptor, resulting in a long duration of action. Which of the
following types of bonds is most likely formed between Drug X and its receptor?
A) Covalent
B) Hydrogen
C) Hydrophobic
D) Ionic
E) van der Waals

: Parathyroid hormone influences plasma concentrations of calcium by
1) directly inhibiting the release of calcitonin
2) influencing the absorption of calcium in the distal renal tubule
3) regulating the intestinal absorption of cholecalciferol (vitamin D)
4) regulating the mobilization of calcium from bone
A) 1,2,3 only
B) 1,3 only
C) 2,4 only
D) 4 only
E) All are correct

A patient was born with a congenital mutation in an enzyme that severely afected its
ability to bind an activation-transfer coenzyme. As a consequence, which one of the following is most
likely to occur?
A) The enzyme will be unable to bind the substrate of the reaction
B) The enzyme will be unable to form the transition-state complex
C) The enzyme will normally use a diferent activation-transfer coenzyme
D) The enzyme will normally substitute the functional group of an active-site amino acid residue for
the coenzyme
E) The reaction may be carried out by the free coenzyme, provided the diet carries an adequate
amount of its vitamin precursor

We eventually stop growing taller because
A) sex steroid stimulate a growth spurt that exhausts ability of chondrocytes to proliferate
B) sex steroid stimulation of ossification overtakes chondrocyte proliferation to close the epiphysis
C) sex steroid stimulation of chondrocyte proliferation overtakes ossification to close the epiphysis
D) growth hormone decreases with age
E) if we didn’t, no one could fit through doorways without bending over

How much DNA does a primary spermatocyte contain?
A) 1N
B) 2N
C) 4N
D) 6N
E) 8N

The technique known as Northern Blot is based on the analysis of
A) DNA
B) Hydrothermal layers in currents of the Arctic Ocean
C) Messenger RNA
D) Protein
E) Protein-DNA interactions

Excitation–contraction coupling in skeletal muscle involves all of the following events EXCEPT
one. Which one is this EXCEPTION?
A) ATP hydrolysis
B) Binding of Ca++ to calmodulin
C) Conformation change in dihydropyridine receptor
D) Depolarization of the transverse tubule (T tubule) membrane
E) Increased Na+ conductance of sarcolemma

Which of the following best describes a sesamoid bone?
A) Humerus
B) Vertebrae
C) Scaphoid
D) Sternum
E) Patella

A young woman enters puberty with approximately 40,000 primary oocytes in her
ovary. About how many of these primary oocytes will be ovulated over the entire reproductive life of
the woman?
A) 40,000
B) 35,000
C) 480
D) 48
E) 12

Usain Bolt of Jamaica, the current world record holder for the 200-m sprint, runs 200 m
in about 19.3 seconds. He consumes some glucose to provide the energy necessary for this muscular
activity. Under these conditions, what will be the most probable final fate in his muscles of the
glucose used?
A) Converted to citrate for fatty acid synthesis
B) Converted to oxaloacetate
C) Decarboxylated to acetyl coenzyme A
D) Oxidized to lactate
E) Oxidized to ethanol and CO2
F) Reduced to ethanol and CO2
G) Reduced to lactate

Which one is not a derivative of the middle trunk of the brachial plexus?
A) Median nerve
B) Ulnar nerve
C) Radial nerve
D) Axillary nerve

A 3-month-old child presents with hyperuricemia which responds to treatment with
allopurinol. Assay of a fibroblast culture shows increased levels of PRPP coupled with decreased IMP
and GMP. The most likely diagnosis is
A) Orotic aciduria
B) Purine nucleoside phosphorylase deficiency
C) Adenosine deaminase deficiency
D) Lesch-Nyhan syndrome
E) Gout

Octreoside is a pharmaceutical product which, among other efects, inhibits the release
of glucagon by the pancreas. Assuming that this is the only relevant efect of this drug, which of the
following efects would you most likely see after administration of octreoside?
A) Decreased activity of phosphofructokinase-1
B) Increased activity of adenlyate cyclase
C) Increased activity of fructose-2,6-bisphosphatase-2
D) Increased activity of phosphofructokinase-2
E) Increased activity of protein kinase A

Pyruvate kinase deficiency is one of the common causes of hemolytic anemia. Various
mutations can result in this enzyme having abnormal properties including abnormal response to
allosteric efectors. Which of the following substances is an allosteric efector of this enzyme?
A) cAMP
B) fructose-1,6-bisphosphate
C) fructose-2,6-bisphosphate
D) glucose-6-phosphate
E) lactate

A 23-year-old female maid was making a bed in a hotel bedroom. As she straightened
the sheet by running her right hand over the surface with her fingers extended, she caught the end of
the index finger in a fold. She experienced a sudden, severe pain over the base of the terminal
phalanx. Several hours later when the pain had diminished, she noted that the end of her right index
finger was swollen and she could not completely extend the terminal interphalangeal joint. Which one
of the following structures within the digit was most likely injured?
A) The proper palmar digital branch of the median nerve
B) The vinculum longa
C) The insertion of the tendon of the extensor digitorum onto the base of the distal phalanx
D) The insertion of the flexor digitorum profundus tendon
E) The insertion of the flexor digitorum superficialis tendon

Which of the following amino acids is most compatible with an alpha-helical structure?
A) tryptophan
B) alanine
C) proline
D) cysteine
E) lysine