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100
Which enzyme catalyzes the rate-limiting step of Glycolysis?
Pyruvate kinase
Phosphofructokinase-1
Hexokinase
Aldolase
2. What is Phosphofructokinase-1 (PFK-1)?
Step 3 of glycolysis catalyzes the conversion of fructose-6-phosphate to fructose 1,6-biphosphate = rate limiting step
100
Which shoulder joint is most commonly displaced?
Acromioclavicular
Glenohumeral
Subglenoid
Subclavicular
Subcoracoid
1. What is the AC joint?
100
Which axillary artery branches are in the third division?
Subscapular, lateral thoracic, brachial
Superior thoracic, posterior circumflex, anterior circumflex
Lateral thoracic, thoracoacromial, anterior circumflex
Posterior circumflex, subscapular, anterior circumflex
Thoracoacromial, posterior circumflex, superior thoracic
4.What are the Posterior circumflex, subscapular, anterior circumflex
The axillary artery is divided by the pectoralis minor muscle. The branches are: Screw The Lawyer, Save A Patient! First Division (1 artery): superior thoracic it is the most superior branch point! Second Division (2 arteries): Thoracoacromial, Lateral Thoracic. Third (3 arteries): Subscapular + Anterior/posterior circumflex (circumflex wrap around the neck of the humerus which is clinically relevant)
100
Which of the following muscles is part of the rotator cuff?
A. Teres major
B. Deltoid
C. Supraspinatus
D. Trapezius
E. Latissimus dorsi
C. What is Supraspinatus?
SITS = rotator cuff muscles = supraspinatus, infraspinatus, teres minor, subscapularis
100
Which muscles are exceptions to the median nerve innervation in the anterior forearm?
Flexor pollicis longus and pronator quadratus
Flexor carpi ulnaris and part of flexor digitorum profundus
Flexor carpi radialis and palmaris longus
Pronator teres and flexor digitorum superficialis
2. What is Flexor carpi ulnaris and part of flexor digitorum profundus?
The median nerve innervates most anterior forearm muscles, but there are exceptions: Flexor carpi ulnaris is innervated by the ulnar nerve; The medial (ulnar) half of flexor digitorum profundus is innervated by the ulnar nerve, while the lateral half is innervated by the median nerve (specifically the anterior interosseous branch). The other muscles listed are innervated by the median nerve.
200
A 34-year-old man is brought to the emergency department by ambulance after diving headfirst into a shallow swimming pool. He reports severe neck pain but denies loss of consciousness. A non-contrast CT scan of the cervical spine reveals fractures of the anterior and posterior arches of the C1 vertebra, with lateral displacement of the lateral masses.Which of the following is the most likely diagnosis?
A) Hangman fracture
B) Jefferson fracture
C) Clay-shoveler fracture
D) Odontoid fracture
E) Teardrop fracture
B) What is Jefferson fracture?
200
In Gout, patients present with very painful joints. The pain is due to elevated levels of urate which form crystals that damage what structure?
Lysosome Membrane
Mitochondrial Inner Membrane
Plasma membrane
Peroxisome Membrane
Mitochondrial Outer Membrane
1. What is lysosome membrane?
This results in degradative enzyme release and autolysis of cells. Remember that lysosomes contain degradative enzymes and are responsible for hydrolysis of proteins, lipids, carbohydrates, and nucleic acid. This is the cell’s personal trash compactor!
200
Which artery is a branch of the subclavian and branches into the anterior and posterior spinal arteries?
Vertebral Artery
Brachial Artery
Common Carotid Artery
Axillary Artery
Occipital Artery
What is the Vertebral artery
It is also a content of the suboccipital triangle.
200
Which muscle group forms the erector spinae and what is their innervation?
Multifidus, Rotatores, Semispinalis; innervated by dorsal rami
Trapezius, Latissimus dorsi, Rhomboids; innervated by cranial nerve
Iliocostalis, Longissimus, Spinalis; innervated by dorsi rami
Iliocostalis, Longissimus, Spinalis; innervated by ventral rami
3. What is Iliocostalis, Longissimus, Spinalis; innervated by dorsi rami?
The mnemonic I love spaghetti is to remember them from lateral to medial. All are innervated by dorsal rami of spinal nerve.
200
Which nerve is most vulnerable to injury during lateral epicondyle fractures?
Ulnar nerve
Median nerve
Radial nerve
Musculocutaneous nerve
3. What is Radial Nerve?
The lateral epicondyle is located on the side of the humerus and is closely related to the radial nerve, which wraps around the radial groove but is more vulnerable to mid-shaft fractures. The ulnar nerve passes posterior to the medial epicondyle of the humerus, making it vulnerable to injury during fractures or trauma at the medial epicondyle.
300
Biochem A 25-year-old man presents for evaluation after an overnight fast. His blood glucose level is 65 mg/dL. A glucagon injection is administered. Which of the following best describes the effect of glucagon on hepatic glycolysis in this patient?
A) Activates enzymes to promote glycolysis
B) Inhibits enzymes to prevent glycolysis
C) Activates enzymes to promote glucose uptake
D) Inhibits enzymes to promote glycolysis
B) What is inhibits enzymes to prevent glycolysis?
Glucagon activates a signaling cascade that phosphorylates and inhibits key glycolytic enzymes preventing glycolysis in the liver and shifting metabolism toward gluconeogenesis to increase blood glucose.
300
Which of the following enzymes is responsible for initiating the cross-link formation in collagen by modifying lysine residues?
Procollagen peptidase
Lysyl oxidase
Collagenase
Hydroxylase
Transglutaminase
2. What is lysyl oxidase?
It deaminates some of the lysine residues in collagen to initiate spontaneous linking to allysine forming mature collagen fibers.
300
Which alpha2 globulin protein converts Fe2+ to Fe3+ and is deficient in Wilson’s disease?
Haptoglobin (Hp)
alpha2 -macroglobulin
Ceruloplasmin
Prothrombin
C1q
3. What is Ceruloplasmin
300
What is the primary difference between intrinsic & extrinsic back muscles?
Intrinsic muscles move the limbs and extrinsic muscles move the spine
Intrinsic muscles move the spine and extrinsic muscles move the limbs
There is no functional difference between them
Intrinsic muscles are superficial and extrinsic muscles are deep
2. What is Intrinsic muscles move the spine and extrinsic muscles move the limbs?
Intrinsic back muscles (e.g., erector spinae, transversospinalis) are deep muscles that act primarily on the vertebral column to maintain posture and control spinal movements. Extrinsic back muscles (e.g., trapezius, latissimus dorsi, rhomboids, levator scapulae) are primarily limb movers, especially of the upper extremity, even though they are located on the back. D is wrong because extrinsic muscles are superficial, intrinsic are deep.
300
A 35-year-old woman presents with weakness extending her elbow and diminished sensation along the posterior arm. You suspect injury to the C7 spinal nerve. Which deep tendon reflex should you test to best evaluate the integrity of the C7 nerve root?
Patellar reflex
Triceps reflex
Biceps reflex
Brachioradilais reflex
What is Triceps Reflex?
Patellar reflex = L2-L4; Biceps = C5-C6; Brachioradilais = C6
400
Why are patients with G6PD deficiency more susceptible to hemolytic anemia when exposed to oxidizing agents?
They have defective hemoglobin synthesis
They cannot produce enough ATP
Their cell membranes are inherently weak
Their red blood cells cannot maintain adequate levels of reduced glutathione
4. What is their red blood cells cannot maintain adequate levels of reduced glutathione.
In G6PD deficiency, the pentose phosphate pathway is impaired, which ↓ NADPH production. NADPH is required to regenerate reduced glutathione, a key antioxidant that protects RBCs from oxidative damage. Without enough reduced glutathione, oxidizing agents (e.g., sulfa drugs, fava beans, infections) cause oxidative injury to hemoglobin and the RBC membrane, leading to hemolysis.
400
Which of the following is primarily responsible for the anomalous physical properties of water, such as its high boiling point, surface tension, and solid-state expansion?
Ionic bonding between water molecules
Hydrogen bonding between adjacent water molecules
Dipole-induced dipole interactions with surrounding gases
London dispersion forces within individual water molecules
Covalent bonds between between water molecules
What is Hydrogen bonding between adjacent water molecules
This and the polarity lead to water's high boiling point, freezing point, heat capacity and cohesiveness.
400
Deficiency of which plasma protein causes Emphysema:
Thyroxine binding protein (TBP)
Alpha2 macroglobulin
Transferrin
C-reactive protein (CRP)
Alpha1 anti-trypsin
5. What is Alpha-1 antitrypsin (AAT)
This is a protease inhibitor that protects tissues (especially lung tissue) from enzymes like neutrophil elastase, which can degrade elastin in the alveolar walls.
400
What determines the ABO blood group phenotype at the molecular level?
Modifications of glycoproteins with specific sugar residues based on inherited alleles
Varying amounts of hemoglobin in red blood cells
Different lipid compositions in cell membranes
Different protein structures on red blood cell surfaces
1. What are modifications of glycoproteins with specific sugar residues based on inherited alleles?
The ABO blood group phenotype is determined by the presence or absence of specific antigenic sugar residues added to glycoproteins and glycolipids on the red blood cell surface. The A and B alleles encode different glycosyltransferases that add N-acetylgalactosamine (A antigen) or galactose (B antigen) to the H antigen backbone. The O allele results in a nonfunctional enzyme, so the H antigen remains unmodified.
400
Why are alcoholics susceptible to hypoglycemia?
Alcohol directly inhibits glucose absorption
High NADH from alcohol metabolism interfered w/ gluconeogenesis
Alcohol stimulated insulin secretion
Alcohol depleted glycogen stores rapidly
2. What is high NADH from alcohol metabolism interfered w/ gluconeogenesis?
Alcohol metabolism in the liver generates large amounts of NADH, which alters the NAD⁺/NADH ratio.
This high NADH shifts metabolic pathways, promoting conversion of pyruvate to lactate and oxaloacetate to malate, depleting key gluconeogenic substrates.
As a result, gluconeogenesis is inhibited, impairing the liver’s ability to produce glucose during fasting, leading to hypoglycemia.
500
A 24-year-old man falls on his outstretched hand while playing basketball. He has wrist pain and tenderness in the anatomic snuffbox. Initial wrist radiographs are normal. The patient is placed in a thumb spica splint. Two weeks later, repeat imaging shows a fracture through the waist of the scaphoid. Which of the following complications is this patient at greatest risk for?
Carpal tunnel syndrome
AIN nerve compression
Avascular necrosis of the proximal fragment
Claw hand
Hand of Benediction
3. What is AVN?
500
Which of the following correctly matches the joint with its primary motion?
Atlanto-occipital: Pure rotation of the head; Atlantoaxial: Flexion and extension of the head
Atlanto-occipital: Flexion and extension of the head; Atlantoaxial: Pure rotation of the head
Atlanto-occipital: Lateral bending of the head; Atlantoaxial: Pure rotation of the head
Atlanto-occipital: Flexion and extension of the head; Atlantoaxial: Lateral bending of the head
2. What is the atlanto-occipital joint (C0–C1)
This joint (OA) allows flexion and extension (“yes” motion). The atlantoaxial (AA) joint (C1–C2) allows pure rotation (“no” motion).
500
Superficial lymph nodes that drain the lateral side of the hand follow which vein and to which lymph node?
Cephalic vein, supratrochlear LN
Basilar vein, axillary LN
Cephalic vein, infraclavicular LN
Median cubital vein, supratrochlear LN
Basilar vein, infraclavicular LN
3. What are the Cephalic vein and infraclavicular LNs?
BONUS 500 pts: what is the next LN of this pathway?
500
How does fetal hemoglobin (HbF) compare to adult hemoglobin (HbA) in terms of oxygen binding?
HbF cannot bind oxygen at all
HbF has lower oxygen affinity than HbA
HbF and HbA have identical oxygen affinities
HbF has higher oxygen affinity than HbA
1. What is HbF has higher oxygen affinity than HbA?
HbF binds oxygen more tightly, resulting in less oxygen released to tissues than HbA. This is shown w/ the dotted line showing the oxygen binding curve. (Y class is oxygen saturation %. Fetal Hb is shifted to the left meaning higher oxygen affinity which facilitates oxygen transfer from maternal blood (HbA) to fetal blood (HbF) across the placenta, because fetal blood holds onto oxygen better at lower pO₂.
500
What is the primary fuel source for maintaining blood glucose during a 3-day fast?
Glycerol
Ketone bodies
Liver glycogen stores
Fatty acid
1. What is Glycerol?
During a prolonged fast (like 3 days), liver glycogen stores are mostly depleted within the first 24 hours, so they cannot maintain blood glucose after that. The body relies on gluconeogenesis to maintain blood glucose, and glycerol (released from triglyceride breakdown in fat cells) is a key gluconeogenic substrate. Ketone bodies are produced in large amounts during fasting but serve primarily as an alternative fuel for the brain and muscles, not as a glucose source. Fatty acids cannot be converted into glucose; they provide energy directly but do not contribute to gluconeogenesis.
