A 10-year-old boy is brought to the clinic because of difficulty seeing at night and a staggering gait. Physical exam reveals retinitis pigmentosa and ataxia. Laboratory tests show an accumulation of phytanic acid. Deficiency in which of the following pathways is the primary cause?

A patient with a history of chronic alcoholism presents with "fruity" breath and altered mental status. In the liver, which of the following serves as the direct precursor for the synthesis of acetoacetate during ketogenesis?

A newborn infant is diagnosed with a deficiency of carnitine palmitoyltransferase I (CPT-I). Which of the following clinical findings is most likely expected?

Calculate the net energy yield (ATP) from the complete aerobic oxidation of one molecule of Palmitic acid (C16) according to recent biochemical standards (Lippincott).

A patient presents with xanthomas and a high risk of atherosclerosis. Lab work shows elevated LDL. Which apolipoprotein is responsible for the recognition of LDL by its receptor in peripheral tissues?

Which of the following is the rate-limiting enzyme in fatty acid synthesis that is allosterically activated by Citrate?

A 6-month-old infant presents with developmental delay and a cherry-red spot on the macula. There is no hepatosplenomegaly. Which enzyme is most likely deficient?

In the "Fed State," which hormone promotes the dephosphorylation and activation of Acetyl-CoA Carboxylase?

A 65-year-old man takes low-dose Aspirin daily to prevent myocardial infarction. Aspirin achieves this by irreversibly inhibiting COX-1 in platelets, leading to decreased levels of:

A patient with asthma is treated with Zileuton. This drug acts by inhibiting which of the following enzymes?

During an acute inflammatory response, which mediator is primarily responsible for causing pain?

A biopsy of a chronic skin lesion shows a collection of activated macrophages (epithelioid cells) surrounded by a rim of lymphocytes. This is characteristic of:

A patient is prescribed Prednisone for an autoimmune condition. Steroids reduce inflammation primarily by inhibiting which enzyme to prevent the release of Arachidonic acid?

Which cytokine is most important in the formation and maintenance of a granuloma?

In the process of wound healing, "granulation tissue" is characterized by:

A child presents with an allergic reaction after a bee sting. Which mediator released from mast cells causes immediate vasodilation and increased vascular permeability?

A patient suffers from glaucoma and is prescribed Latanoprost. This drug is an analogue of:

A 70-year-old male with tremors, bradykinesia, and rigidity is diagnosed with Parkinson’s disease. This condition is primarily due to the loss of neurons producing:

Fluoxetine (Prozac) is a commonly used antidepressant. Its mechanism of action is:

Which neurotransmitter is the primary inhibitory signal in the adult spinal cord?

A patient presents with respiratory depression and pinpoint pupils after a suspected overdose. Which drug is the most appropriate antidote?

Benzodiazepines enhance the effect of GABA by increasing the:

Which opioid receptor is primarily responsible for the supraspinal analgesic and euphoric effects of morphine?

A 25-year-old student uses Methylphenidate to stay awake. This drug acts primarily by:

Acetylcholine is terminated in the synaptic cleft primarily by:

A patient with schizophrenia is prescribed Haloperidol. This drug’s antipsychotic effect is mainly due to the blockade of:

Which neurotransmitter is synthesized from the amino acid Tryptophan?

A 68-year-old man presents with sudden onset weakness on the right side of his body and difficulty speaking. A CT scan shows no hemorrhage. What is the most likely diagnosis?

A 3-year-old child presents with high fever, neck stiffness, and a positive Brudzinski sign. Lumbar puncture shows high neutrophils, low glucose, and high protein. The most likely diagnosis is:

An 80-year-old woman presents with progressive memory loss and disorientation. Brain autopsy reveals neurofibrillary tangles and amyloid plaques. This is characteristic of:

A young man is involved in a motor vehicle accident. He had a brief period of unconsciousness, followed by a "lucid interval," and then rapid clinical deterioration. A CT scan shows a lens-shaped (biconvex) hematoma. This is:

A "thunderclap headache" (the worst headache of my life) is the classic presentation of:

In epilepsy, a seizure that involves both hemispheres from the onset with loss of consciousness is termed:

Which of the following is the most common cause of neonatal meningitis?

A patient with chronic hypertension suddenly develops a severe headache and collapses. CT shows blood within the brain parenchyma of the basal ganglia. This is most likely:

Cerebral Palsy is primarily a:

Status epilepticus is defined as a seizure lasting longer than:

The p53 protein is often called the "guardian of the genome." It primarily functions as a:

Which of the following is an example of a proto-oncogene that becomes an oncogene through a point mutation in many human cancers?

A 50-year-old man with a long history of smoking presents with a cough and weight loss. Lab tests show elevated Carcinoembryonic Antigen (CEA). While not specific, CEA is often used as a marker for:

Mutations in BRCA1 and BRCA2 genes significantly increase the risk of which cancers?

The Philadelphia chromosome (t(9;22)) creates the BCR–ABL fusion protein, which is a:

Which tumor marker is most associated with yolk sac tumors and hepatocellular carcinoma?

In the "Two-Hit Hypothesis" for tumor suppressor genes, what must happen for a tumor to develop?

Which gene is mutated in almost all cases of Familial Adenomatous Polyposis (FAP)?

Apoptosis is regulated by the Bcl-2 family. Which of the following is a pro-apoptotic member?

Telomerase activity in cancer cells allows them to:

A child is given a sticker every time they finish their homework. This is an example of:

In Pavlov’s experiment, the ringing of the bell (after being paired with food) is the:

According to the Atkinson-Shiffrin model, which memory stage has a duration of about 15-30 seconds?

"Chunking" is a technique used to improve the capacity of:

Primary prevention of mental illness includes:

Epidemiology: The number of new cases of a disease in a population over a specific period is the:

A patient learns to avoid a specific food after getting sick once. This is known as:

Which type of memory involves facts and events that can be consciously recalled?

A man stops nagging his wife after she finally cleans the house. From the wife's perspective, the removal of the nagging is:

The study of the distribution and determinants of health-related states in specified populations is:

During implantation, which cells of the blastocyst secrete enzymes to invade the uterine endometrium?

What is the "decidua reaction"?

The epidermis of the skin is derived from which embryonic layer?

Melanocytes, which give skin its pigment, are derived from:

A "vernix caseosa" is:

In the histology of acute inflammation, which cell type is the first to arrive at the site of injury?

The dermis of the skin (except for the face) is derived from:

Fingernails and toenails reach the tips of the digits by which month of gestation?

Ichthyosis is a genetic disorder characterized by:

Which layer of the epidermis contains cells undergoing mitosis?

Mixed Clinical/Integration — A patient with a Vitamin B12 deficiency has impaired myelin synthesis. In which part of the CNS is myelin produced?

Mixed Clinical/Integration — A patient with G6PD deficiency develops hemolysis after taking an antimalarial drug. This is because they cannot generate enough:

Mixed Clinical/Integration — The primary fuel for the brain during prolonged starvation (after 3 days) is:

Mixed Clinical/Integration — Which of the following drugs is a "selective" COX-2 inhibitor?

An infant is born with a tuft of hair over the lumbar spine (Spina Bifida Occulta). This is a defect in the closure of the:

In the "Fast State," the liver produces glucose via

Which neurotransmitter's depletion is most associated with Alzheimer's disease?

A patient has a "pill-rolling" tremor. Which part of the brain is the primary site of pathology?

Which of the following is a classic mediator of "acute phase response" and fever?

A 2-year-old boy presents with intellectual disability and self-mutilation (biting lips/fingers). Lab shows hyperuricemia. This is Lesch-Nyhan syndrome, a defect in