Physical examination of a 49-year-old female with history of diabetes reveals edema of lower extremities. A kidney disease was suspected and a kidney biopsy was performed for evaluation. Which of the following histochemistry stains is best to highlight the patient's carbohydrate-rich glycoproteins in the glomerular basement membrane when examined by light microscopy?

Name a component that would stain with H&E, and therefore be directly visible by light microscopy in a histological section.

Preparation of tissues for light or electron microscopy often involves embedding the tissues in a substance such as wax or plastic. What is the purpose of such embedding?

You are provided with a histological specimen from the fallopian tubes to demonstrate the presence of microtubules in the core of epithelial cilia. Which of the following microscopy preparations would you use to best visualize the intracellular organization of microtubules within cilia?

Which of the following staining methods will clearly show changes in levels of stored glycogen in liver cells under fasting conditions?

A 47-year old patient presents with a cancerous tumor containing cells that seem to be secreting high amounts of proteins into the surrounding tissue. A pathology resident attempting to locate the borders of the mass obtained a biopsy and prepared an H&E stained slide. Since the cancerous cells are highly secretory, which of the following features would you most likely observe in the affected cells?

A 28-year old female suffered a miscarriage at 5-month gestation. She is seeking genetic counselling to understand the cause of death of her child. Histopathological studies revealed abnormally shaped cells from various tissues. EM examination show decreased density of terminal web, abnormal core of microvilli and fewer cytoskeletal tracks for myosin motor proteins. Which of the following cellular fibers is most likely affected?

You receive an H&E stained sample for histopathological study and notice that it consists of clusters of cells with cytoplasmic regions of both basophilia and intense eosinophilia. The nuclei are highly euchromatic and contain prominent nucleoli. Which of the following most likely describes the function of these cells?

You receive an H&E stained sample for histopathological study and notice that it consists of clusters of cells with entirely eosinophilic cytoplasm. The nuclei are centrally located and contain both euchromatin and heterochromatin, nucleoli is not clearly distinguishable from heterochromatin. Which of the following most likely describes the function of these cells?

Consider a cellular modification where you extend the cytoplasm to form a finger-like process. To perform its function this extension needs to be filled with a cytoskeletal fiber that is both dynamic (able to modify its length) and strong. Which cytoskeletal fiber should it contain?

You receive a biopsy for histopathology analysis of the pancreatic secretory cells from a patient exhibiting a wide range of digestive and metabolic symptoms. Analysis revealed abnormal appearance of the cell’s nucleoli. Which of the following functional deficits are these cells most likely to experience?

You receive an H&E stained sample for histopathological study and notice that it consists of clusters of cells with entirely basophilic cytoplasm. You suspect that the cell’s basophilia is caused by its rER content, and thus the cell must be actively involved in protein secretion. Which mechanism of transcellular vesicular transport do these cells most likely use?

A 5-month old baby is brought to the pediatrician after her parents noticed that she has gradually lost the ability to crawl and move. Following a series of examinations, she is diagnosed with Tay-Sachs, a type of lysosomal storage disease affecting neurons. Lysosomes in patients with this condition contain hydrolytic enzymes that are unable to breakdown glycolipids. Histopathological analysis of the affected neurons would most likely reveal:

Which of the following statements concerning PAS staining is FALSE?

Which of the following statements regarding the Golgi apparatus is FALSE?

A characteristic feature of reticulocytes is that they:

A patient with disorder affecting the efficiency of megakaryocytes will be most likely presented with symptoms of:

A characteristic feature of monocytes is that they:

Which blood cell attacks blood-borne larvae of parasites?

In your infectious disease sub-internship, you see a patient who has been experiencing fevers and fatigue. His white cell count comes back and you see that his neutrophil levels are elevated. What type of diagnosis do you suspect?

A 32-year old woman visits her physician due to a month of nasal discharge, coughing and sore throat. She is diagnosed with a subtype of blood cancer resulting in uncontrolled production of abnormal agranulocytes. Erythrocyte and granulocyte counts are within normal limits and their bone marrow precursors appear normal as well. Which of the following is the most likely consequence of this patient’s condition?

A 67-year old man visits the clinic with a 15-year history of coughing, fatigue, and headaches. Patient history reveal he worked for over 30 years as a construction worker in demolition sites known to contain asbestos. As a result of his chronic exposure to air filled with this foreign substance, the resident macrophages of the lungs, dust cells, would have phagocytosed the asbestos for years requiring constant turnover and replacement. Given this patient’s medical history, which of the following cell types would most likely be elevated in a peripheral blood smear?

A 45-year old homeless man comes to the emergency department because of a 1-week history of pain in his right foot and a 2-day history of difficulty walking. His sock is blood-encrusted. Physical examination shows a 5-cm wound surrounded by edema on the ball of the right foot. A thick exudate containing abundant dead and dying leukocytes is expressed on palpation of the wound. Which of the following types of leukocytes most likely predominated at the wound site 1 day after the initial injury?

Which of the following cell types secretes substances that prevent blood coagulation and increase the permeability of small blood vessels to allow movement of cells from the blood into adjacent connective tissue?

Which of the following structures of the spleen is correctly matched with its function:

Suspected of having a rare genetic disorder, a patient and her daughter both have biopsies of their thymus. The biopsy of the thymus of the daughter shows a highly cellular thymus that contains many lymphocytes, while the maternal thymus appears less robust, with large areas of adipose tissue and numerous inclusions. What can you conclude based upon the results of this test?

Which of the following lymphatic tissues/organs is correctly matched with its function:

Lymphoid stem cells initially originate from the bone marrow and develop into mature T-lymphocytes in the:

A 3-year-old girl from Tanzania was referred to the Hospital with severe anemia, fever, cough, pallor, weakness and tachypnea that aggravated six day ago. On abdominal examination, she had hepatosplenomegaly, and blood work revealed sickle-cells. Splenomegaly is often observed in children with sickle-cell anemia since damaged red blood cells are filtered at the spleen and removed by:

Filtration of abnormally shaped and old erythrocytes occurs in the absence of specific receptors because of the action of which of the following structures?

This cell produces antibodies by differentiating into a plasma cell:

The zona reticularis is the i. ____________ layer of the adrenal gland cortex, it contains cells that secrete ii. _______________ and whose activity is regulated by iii. ______________

Cell bodies in the hypothalamus that produce oxytocin have axons that terminate at:

The basophils of the anterior pituitary:

Which statement concerning cells in the zona glomerulosa of the adrenal cortex is FALSE?

Which statement regarding the adrenal medulla is FALSE?

ADH producing cells have axons that terminate at:

A 34-year old woman comes to the office with chronic hypertension and irregularities in urine production. She also experienced abnormal menstrual periods and hirsutism (male-pattern hair growth). Laboratory studies reveal elevated blood levels of both androgens and aldosterone, but normal cortisol levels. Which of the following histopathologic findings are most likely to be present in this patient’s adrenal glands?

A 27-year old female has experienced sudden onset and unexplained weight gain with fat deposits throughout her body, most notably in her face giving rise to a more rounded appearance. She also complains of abnormal thirst and urination, loss of libido and amenorrhea (absence of menstruation) and growth of extra facial hair. Radiologic examination revealed a mass in her pituitary gland, as well as adrenal gland hyperplasia (enlargement). Given the combination of symptoms experienced by the patient, which of the following pituitary cell types is most likely affected?

A 32-year old woman comes to the office due to vision problems and frequent headaches. Brain MRI reveals a large anterior pituitary tumor compressing on the optic chiasm. Light microscopy examination of the tumor reveals hormone-secreting basophils. Which of the following processes is regulated by pituitary basophils and is most likely affected in this patient?

During hormone regulation, hormones are released, either directly by an endocrine gland or indirectly through the action of the hypothalamus of the brain, which stimulates other endocrine glands to release hormones in order to maintain homeostasis. Which of the following hormones is NOT secreted nor regulated by the hypothalamus?

Neuroendocrine signalling cascades that regulate cortisol secretion primarily involve coordinated activity amongst which organs?

A 30-year old woman is diagnosed with Addison’s disease, adrenal gland insufficiency most commonly caused by autoantibodies against the adrenal cortex, without affecting chromaffin cells. Histopathological examination of an adrenal gland biopsy confirms the diagnosis by revealing atrophy (cell death) of all three cortical zones. As a result of her condition, this patient will most likely exhibit which of the following symptoms?

A 62-year old man is brought to the office due to recurrent headaches and vomiting. Neurological examination suggests an intracranial mass located in the dorsal midbrain. These types of tumors typically arise from the pineal gland; it is therefore possible for this patient to experience circadian rhythm abnormalities. Which of the following best describes normal regulation of circadian rhythms?

A drug that blocks the secretory activity of pituitary acidophilic cells would most likely:

A 45-year old male experiencing severe headaches visits his local hospital where radiological exams revealed a tumor in the pars distalis of his pituitary gland, but no infiltration or impingement of the pars nervosa. Given the location of the tumor, symptoms of such a condition vary widely depending on the type of cells involved. Secretion of all of the following hormones could be affected, EXCEPT:

Which of the following cells secrete thyroid stimulating hormone under normal conditions?

A 24-year-old male moved from Canada to Australia to attend medical school, and as expected he experienced feelings of jet-lag. One month after his flight he is still experiencing difficulty falling asleep at night time and fatigue throughout the daytime. After attending the endocrine lecture in his histology class, he self-diagnoses as having abnormal levels of melatonin. If his diagnosis is correct, this is most likely indicative of abnormal secretory activity of which of the following glands?

Meiosis is a central part of the human reproductive process and guarantees some genetic variation between parents and potential siblings. The process is complex and precisely controlled in order to minimize possible mistakes. What is produced at the end of Telophase I?

A long gene is prominently expressed in pancreatic beta cells to produce one large and abundant mRNA. The protein that this mRNA should produce would be 650 amino acids long. However, when investigators use very specific tools to identify this protein for study, they are only able to detect trace amounts. Instead, they find 3 abundant proteins of 250, 143, and 97 amino acids in length. What TYPE of modification has produced these 3 unexpected proteins?

After DNA replication and immediately before entering meiosis, the n and c numbers of a germ cell are:

A common clinical presentation of Edward's Syndrome which does not occur (or rarely occurs) in Down or Patau Syndromes is:

Gower's maneuver (or Gower's sign) is most likely to be observed in a child with which of the following diseases?

Which of the following is a common clinical presentation found in Wolf-Hirschhorn Syndrome?

Which of the following diseases has an autosomal recessive mode of inheritance?

A common clinical presentation in Cri-du-Chat Syndrome is:

If a mother is a carrier of a mutant allele on an X-chromosome, what is the probability that she would pass that allele onto a son?

Which of the following chromosomes is able to undergo a Robertsonian translocation?

Regarding Turner syndrome, which of the following is TRUE?

What is the mode of inheritance of Rett syndrome?

The most common cause of monosomy is

An example of an unbalanced chromosomal rearrangement is:

Below is a patient with Wolf-Hirschhorn Syndrome. Although she does not show the typical 'Greek helmet' facial appearance, she does have microcephaly, dysmorphic facies and mild mental retardation. Genetic analyses of this patient would reveal:

In diploid organisms, every individual carries two copies of a gene. During reproduction, one copy is passed onto each of the offspring via the gametes. This is known as Mendel's Law of:

An autosomal dominant disease is caused by a specific gene mutation, however some individuals who carry the mutation do not manifest the disease at all. This is an example of…

The mode of inheritance of Marfan Syndrome is:

In many autosomal dominant diseases, homozygotes are more severely affected than heterozygotes. This phenomenon is known as

Which of the following diseases has an autosomal recessive mode of inheritance?

What is the mode of inheritance of Fragile X syndrome?

If testing revealed higher than normal sodium levels in the sweat of a newborn girl, which of the following diseases is most likely to be diagnosed?

The mode of inheritance of Achondroplasia is.

Which of the following sequences is most likely recognized by a restriction endonuclease?

What is the correct name for a purine or pyrimidine base linked directly to a pentose sugar?

What DNA Sequence is complementary to: GCAAGTGAC

What facilitates the coiling of the 10 nm fiber into the 30 nm fiber?

Which of these structures could be considered "euchromatin"?

If a sequence of DNA duplex contains 22% T, then it also contains ___ G.

What property of the core histones (H2A, H2B, H3, and H4) allow them to wrap a DNA duplex around their outer surface (the surface of the core nucleosome structure)?

DNase I is a DNA nuclease that is commonly used to analyze chromatin structures. It is able to digest naked DNA but not DNA bound by proteins.  Which part of the DNA within chromatic is digested by DNase I?

What are the 3 basic steps in a single cycle of PCR?

Doxorubicin is a quinolone derivative that potently inhibits cell replication by interfering with DNA synthesis. This activity makes it a potent chemotherapeutic drug - most commonly used to treat leukemias and Hodgkin's Lymphoma.  It is observed in cells treated with this compound that DNA synthesis begins normally, but active replication forks slowly grind to a halt and seem to be "stalled." Which of the following enzymes must this substance inhibit?

One disadvantage for example, is that for diagnostic purposes, PCR is generally limited to amplifying sequences of:

During prokaryotic DNA replication two DNA polymerases, DNA polymerase I and DNA polymerase III, play key roles in synthesis of the new DNA strands.  Which of the following is an activity found in DNA polymerase I that is absent from DNA polymerase III?

In prokaryotes, during DNA replication, which enzyme synthesizes the Okazaki fragments?

Cleavage of the nascent RNA from RNA Polymerase II is tightly coupled to recognition of an RNA sequence within the 3’ UTR. An enzyme among these proteins recognizing this sequence adds a poly-A tail to the RNA as soon as it comes free. What is this enzyme’s name?

What is one important feature of an eukaryotic mRNA that determines its half-life?

What RNA is produced by eukaryotic RNA polymerase III?

An important general transcription factor in eukaryotes is TBP. What is the function of TBP?

If a cell were to become deficient in the nuclear enzyme, guanine-7-methyltransferase, what problem would result?

What mediates the Rho-independent termination of transcription in bacteria?

What is the name for the GU site at 5’ end of an intron that is recognized by the U1 snRNP at the beginning of the RNA-splicing process?

Crucial to the expression of protein-encoding genes in a eukaryote is the complex set of steps that must be followed in order to process an RNA transcript into a mature functional mRNA. If a mutation knocked out the splice donor site for one or more introns. What would happen?

What is the specific term used to describe proteins from different species that have extremely similar structures and identical functions?

Antibody proteins have among the strongest known binding properties. Which of these values would describe the binding of a very high affinity antibody to its specific antigen?

Especially  important in extracellular and secreted proteins such as insulin, what is the most common type of covalent bond used to stabilize a protein’s tertiary structure?

Many proteins seem to be constructed from semi-independent modules that fold and function largely independent of the rest of the protein. These 3-D modules are termed:

Myoglobin, a globular heme-protein in muscle cells, is an important oxygen carrier. This protein greatly resembles one of the subunits found in hemoglobin. In each case, the overall globular shape is achieved by using rods to enclose and cradle a central portion that holds a heme group. These bendable rods represent a very important secondary structure known as: 

What type of an amino acid is valine considered to be?

Myoglobin, a globular heme-protein in muscle cells, is an important oxygen carrier. Which of the following amino acids would most likely be found in the interior of this protein?

Which factor causes translocation of the ribosome in eukaryotes?

Where is the first charged initiator tRNA placed by the initiation factor during initiation of translation?

Which post-translational modification acts as a signal to target a protein to be degraded by the proteasome?

How does puromycin work?

What is the name of the “ribosome recognition site” found in many prokaryotic mRNAs?

Eukaryotic cells typically use over 50 different tRNAs. How many aminoacyl-tRNA synthetases does a cell use?

Which prokaryotic initiation factor ushers in the aminoacyl-tRNA, acts as a GTPase, and seems to position the 50S subunit onto the 30S subunit?

What is the role of the signal sequence in precursor version of a protein?

To what does an amino-acyl tRNA Synthetase couple its adenylated-amino acid intermediate?

What factor brings a new charged tRNA into the A site of a prokaryotic ribosome?

What brings the new aminoacyl-tRNA into the A site of the eukaryotic ribosome?

  Which factor causes translocation of the ribosome in prokaryotes?

Which of these is an important protein modification that specifically causes plasma proteins to become involved with the endothelial lining of blood vessels as one of the first steps in blood clotting?

If an mRNA codon reads GAU, then what is the tRNA anticodon?

Transcription Factors bind to specific DNA sequences in the regulatory regions of the genes they regulate. How do most DNA-binding proteins recognize the specific DNA sequences to which they bind?

What mediates the interaction between an activator and a basal transcription factor?

Which of the following would occur in genomic regions that feature extensive deacetylation of histones?

In the regulation of the E. coli lac operon, the “operator” is … 

In the regulation of the E. coli lac operon, the CAP protein can only bind to the CAP site when…

In E. coli, cAMP is a ligand for the CAP transcription factor.  The CAP protein can only bind DNA when complexed with the cAMP ligand.  What is the term used to describe this type of ligand?

Which of the following would occur in genomic regions that feature extensive acetylation of histones?

What is one possible reason for diseases caused by malfunctions of the base-excision repair mechanism? 

c.734_735insGT is a …

What is the main cause for the autosomal dominant disease, hereditary nonpolyposis colorectal cancer? 

A 28-month old boy presented with unsteady gait, frequent falls and spidery veins in his eyes.  DNA sequencing revealed that the boy was homozygous for loss-of-function mutations in the ATM gene.  The most likely diagnosis for the boy is...

A newborn boy delivered using forceps suffered cephalohematoma.  Heavier than normal iatrogenic bleeding occurred after a heel stab to collect blood for prenatal testing, and again after an injection of vitamin K.  The OBGYN who delivered the boy suspects he may have Hemophilia A even though there was no family history of the disease.  Which of the following genetic tests would be most appropriate to use to detect the most common mutation causing the disease?

The following 6bp DNA-sequence (with blank spaces) represents a palindrome.  What is the full sequence?5'-A_C_C_-3'

When we use the analogy that we have protein ships floating around butter islands on an oil sea, what is the oil?

The LMNA gene encodes both lamin A and lamin C, the two crucial components of the intranuclear lining web of lamin intermediate filaments. All of the following disorders are associated with defects of lamin A/C, except:

What portion of the nucleoplasm is devoted to producing and maturing both the snoRNPs and the snRNPs?

All of the following statements about hereditary spherocytosis are correct, except:

Biological membrane feature a central structure that is a phospholipid bilayer. Glycolipids are similar, yet different, than the phospholipids. Which one of these important compounds is a glycolipid and not a phospholipid?

Which of the following statements is correct about membrane glycolipids?

In this disease caused by a mutation in the LMNA gene, patients exhibit peripheral lipoatrophy with muscle prominence, but they accumulate adipose tissue on their faces and around their neck. What is the name of this disease?

When Ran GAP hydrolyzes the GTP of Ran-GTP in the cytoplasm which of the following happens next?

Vesicular trafficking is critical for intracellular function and all aspects of endocytosis, exocytosis and transcytosis. Vesicles are literally moved around the cell on microtubules by specific motor proteins. Vesicles almost miraculously deliver their cargoes to the correct location due to various molecular mechanisms that control the membrane they dock with and which membranes they can fuse with. The process of vesicle fusion is very similar throughout the cell and depends on the binding of complementary proteins. With all this in mind, when does Rab-GTP hydrolyze its GTP to GDP and become inactive?

How does an occupied M6P receptor interact with the clathrin coat of transport vesicles?

What type of lysosomal storage disease is Krabbe Disease?

Which one mucopolysaccharidoses is X-linked recessive rather than autosomal recessive in its inheritance pattern?

One of the most unique features of the mitochondria is the electron transport chain. All of the following are transmembrane enzymatic proteins that span the inner mitochondria membrane, except:

AZT (aka Zidovudine) is an antiretroviral drug used in HIV therapy.  It acts as an inhibitor of the viral reverse transcriptase. It has many negative side-effects including headaches, fever, and nausea, liver and muscle damage and lactic acidosis.  Which of the following actions of AZT explains the side-effects?

A 17-year-old female presents with progressively worsening myoclonic seizures.  A biopsy of her skeletal muscle reveals ragged red fibres and crystalline mitochondrial inclusions.  Her physician suspects her condition is caused by a mitochondrial DNA mutation.  Which mutation is most likely?

A 5-year-old boy presents with a blistering skin condition. The pediatrician diagnoses his condition as epidermolysis bullosa simplex after genetic analysis reveals a mutation in a gene that most likely encodes which group of proteins?

Extracellular matrix is generally composed of a ground substance embedded with various types of proteins and protein fibers. What is the most prevalent protein constituent of all basal laminae?

If your immune system attacks desmosomal cadherins (such as desmoglein or desmocollin) and destroys an area of desmosomes, cells in areas such as the epidermis become only weakly linked together. The epidermal cells sometimes come apart simply from friction or mild stress. The problems progress with age. What disease condition often develops by middle-age?

Your patient clearly has a severe disease where the skin literally seems to fall off certain parts of their body, particularly the hands and feet. Other parts of the body show subbasilar blisters. Two fingers and two toes are webbed together. You and your colleagues diagnose the patient with Dystrophic Epidermolysis Bullosa. What is the cause of this terrible disease?

A patient presents with hyperextendible skin and joint hypermobility. This is most likely the result of a defect in which of the following proteins?

Which of the following glycosaminoglycans forms the longest repeating disaccharide chains and does not covalently attach with core proteins to form proteoglycans?

The main difference between phase 2 and phase 3 in drug development is

What does DAG do?

How is Protein kinase C (PKC) activated?

A 6-month-old infant who is failing to thrive is brought to your clinic. Tests reveal hepatosplenomegaly, muscle weakness and atrophy, hypotonia, and decreased deep tendon reflexes. Blood tests reveal that the infant has normal glucose levels. Biopsy of the liver reveals initial stages of cirrhosis due to the accumulation of an abnormal glycogen with few branch points whose structure resembles amylopectin. The clinical and laboratory results presented are indicative of which GSD? 

You are studying the effects of a new drug on the activity of your favorite enzyme. The results of your assays indicate that the drug acts as a noncompetitive inhibitor. Which of the following changes to the Km and Vmax allowed that determination to be made regarding the drugs actions?

Regulation of glycogen metabolism is tightly controlled at the level of the activity of glycogen phosphorylase. Which of the following is known to act as a negative effector of glycogen phosphorylase? 

Which of the following intermediates of TCA cycle can be directly converted to phosphoenolpyruvate to trigger the pathway of gluconeogenesis? 

A 5-week-old girl, who appeared to be healthy at birth, develops vomiting a few days after birth. The baby was exclusively breast fed and no processed food was given. Your current examination reveals that she has hepatomegaly, jaundice, and early cataract formation and is not meeting developmental milestones. You suspect that she has which of the following conditions? 

Which of the following vitamins is needed for the synthesis of a cofactor required for the conversion of succinate to fumarate? 

The maximum capacity of the liver to carry out gluconeogenesis during starvation depends upon which of the following?

Treatment of maple syrup urine disease involves the dietary restriction of which amino acid(s)?

Which of the following mutations would be most likely to cause Type II Osteogenesis Imperfecta?

Loss-of-function mutations in the _____ gene are associated with campomelic dysplasia.

Which of the following describes DiGeorge Syndrome?

A study found 400 peoplewith heart failure had a mean serum cholesterol of 230 mg/dl with a standard deviation of 15mg/dl/ What is the best estimate of how many people in this study had a serum cholesterol <200 mg/dl?

Embryologicallly, the inner lining ad outer wall of the lung consist of which of the following?

A researcher is trying to determine if going to a tanning salon increases risk of skin related cancer. She enrolls 100 women whi regularly plan on going to a tanning salon at least twice a week throughout the upcoming year and 100 women who do not plan to use any tanning methods. What type of study is this?

What structure/chemicals are most responsible for the overall negative charge on the outer cell membrane of healthy cells?

A study compared new criteria for diagnosing gout to crystals found in the joint fluid (gold standard). 400 patients were evaluated with the new criteria and 60% had gout according to the gold standard. The sensitivity of the new criteria was 75% and the specificity was 95%. Which is the closest to the positive predictive value?