Question 1

A patient who had surgery for ovarian cancer is placed on a combination of cisplatin and taxol therapy. Taxol is an antimitotic agent that

Accepted Answer

Taxol stabilizes microtubules, preventing depolymerization and disrupting the normal cycling of microtubule assembly and disassembly during cell division. This ultimately leads to cell death.

Question 2

Dynein arms are always attached to one of the following. Which one is that structure?

Accepted Answer

Dynein arms are always attached to subunit A of the outer dynein arm.

Question 3

A two-week-old infant was seen by her pediatrician because of blistering of the fingers and the back of her hands. The blisters were quite large and the results of the biopsy indicated that blistering occurred in the basal layer of the epidermis. The diagnosis was epidermolysis bullosa simplex. This disease is caused by mutations in the

Accepted Answer

Epidermolysis bullosa simplex is a disorder caused by mutations in the genes that encode keratins, which are intermediate filaments that provide structural support to epithelial cells, including those of the skin. When these keratins are defective, the skin and other epithelial tissues are easily damaged, leading to blistering and erosion. The other choices (tubulins, neurofilaments, G actins, and chondroitins) are not associated with this disorder.

Question 4

The component of the erythrocyte cell membrane that is the most essential in maintaining its biconcave disc shape is

Accepted Answer

Spectrin is a fibrous protein that makes up the cytoskeleton of erythrocytes and is responsible for the cell's biconcave disc shape. Spectrin forms a network of interconnected fibers that maintain the membrane's integrity and flexibility. Glycophorin is a transmembrane protein that is responsible for the erythrocyte's blood type antigens. Ankyrin and band 3 protein are also important erythrocyte membrane proteins that help maintain the membrane's structure and function, but they are not as critical as spectrin. Actin is not a significant component of erythrocyte cell membranes.

Question 5

A six-month-old baby boy, when seen by his pediatrician,, exhibits an enlarged tongue and an enlarged liver. Additionally, the baby has problems with swallowing. The pediatrician should suspect that the child is suffering from

Accepted Answer

The symptoms of an enlarged tongue, an enlarged liver, and difficulty with swallowing are indicative of Pompe's disease, a rare genetic disorder that results in the buildup of glycogen in muscles and other tissues. It is caused by a deficiency in the enzyme alpha-glucosidase, which is responsible for breaking down glycogen. This can lead to muscle weakness, respiratory problems, and heart failure. It is important for a healthcare provider to consider Pompe's disease as a possibility in this scenario and conduct further testing to confirm the diagnosis.

Question 6

Which of the following refers to cadherins?

Accepted Answer

Cadherins are a type of transmembrane protein that is involved in cell-cell adhesion. They help to hold cells together by binding to other cadherins on neighboring cells.

Question 7

A 20-year-old male seeking help from his ophthalmologist presents with deteriorating vision in both eyes, especially his central vision. The patient also evidences cardiac dysrythmia and an apparent demyelination of the optic nerve. The ophthalmologist suspects Leber's hereditary optic neuropathy, a condition caused by a point mutation that is not X-linked but is transmitted only by females. This condition is due to problems with which of the following?

Accepted Answer

Leber's hereditary optic neuropathy is due to problems with the mitochondria, specifically a point mutation in the mitochondrial DNA. Mitochondria are responsible for producing energy in cells, and mutations in mitochondrial DNA can affect the function of cells that require a lot of energy, such as the optic nerve and cardiac muscle.

Question 8

Early in the morning, a male patient sees his physician because he and his wife have been trying to start a family. According to the patient, his wife was told that she is able to become pregnant, and he wants to have the physician check him for sterility. The physician notices that the patient has a heavy cough. Upon questioning, the patient reveals that he also coughs in the evening, produces a lot of sputum, and has had numerous colds and even occasional pneumonia. The doctor asks for a sperm sample but already is thinking of a possible diagnosis of Kartagener's syndrome, a genetic disorder that affects

Accepted Answer

Kartagener's syndrome is caused by defects in the microtubule-associated protein dynein, which affects cilia and flagella function. This results in respiratory issues, such as chronic cough and frequent infections, as well as male infertility due to abnormal sperm motility. Choice A, C, D, and E are not related to Kartagener's syndrome.

Question 9

A 77-year-old female is having problems sleeping, and her physician prescribed flurazepam, a sleep aid. The patient reports that she feels "groggy" for about 2 days after having taken the drug. Flurazepam is

Accepted Answer

Flurazepam is metabolized by the P-450 enzyme system in the liver. The fact that the patient feels groggy for 2 days after taking the drug suggests that it has a long half-life, which is consistent with being metabolized by the liver rather than being destroyed or inactivated in the stomach or intestines.

Question 10

Patients with sickle cell anemia possess hemoglobin-s, a mutated form of hemoglobin. Hemoglobin-s is

Accepted Answer

Hemoglobin, including its mutated form hemoglobin-s, is synthesized on free ribosomes because it is a cytoplasmic protein, not a secretory or membrane-bound protein.

Question 11

A 9-month-old female Jewish baby, whose parents were born in Poland, is seen by her pediatrician because of neurologic problems, including generalized paralysis and blindness. The pediatrician should suspect that the child is suffering from

Accepted Answer

The neurologic symptoms of generalized paralysis and blindness in a 9-month-old Jewish baby with parents of Polish descent are classic signs of Tay-Sachs disease, a genetic disorder that affects the nervous system. Spina bifida is a congenital disorder involving the spinal cord, not the brain. Cranial nerve X disorder refers to a specific nerve involved in controlling the heart, lungs, and digestive system, and would not explain the other symptoms. Fabry's disease and Refsum's disease are rare genetic disorders that can cause neurological symptoms, but they are not commonly associated with paralysis and blindness in infants.

Question 12

A patient suffering from asthma has difficulty breathing and is treated with albuterol and ipratropium, drugs that relax bronchiolar smooth muscles. Ipratropium acts as a(n)

Accepted Answer

Ipratropium is an anticholinergic drug that acts by blocking acetylcholine receptors, thus reducing bronchoconstriction and increasing airflow. Albuterol, on the other hand, is a beta-2 adrenergic receptor agonist that relaxes the smooth muscles of the bronchioles by increasing cAMP levels.

Question 13

In Fig. Img_001, the region at the arrow tip is the place where

Accepted Answer

The answer of In Fig. Img_001, the region at the...

Question 14

Acid hydrolases are synthesized on the rough endoplasmic reticulum and are delivered to the Golgi complex to be packaged and distributed to their final destination. In patients whose protooncogenes have mutated to form ras protein-related products known as ADP-ribosylation factor (ARF), this factor may interfere with

Accepted Answer

ADP-ribosylation factor (ARF) is involved in vesicle formation, particularly in the assembly of coat proteins on vesicles, such as coatomer protein complex II (COPII). ARF can interfere with the assembly of these coat proteins, affecting the transport of proteins from the endoplasmic reticulum to the Golgi apparatus.

Question 15

A neonatal baby boy is observed to have malformed hands, feet, and skull. Additional examination displays jaundice, hepatomegaly, and hypotonic muscles with psychomotor retardation. The pediatrician diagnoses the disorder as cerebrohepatorenal syndrome (Zellweger's syndrome). This condition is due to problems with which of the following organelles?

Accepted Answer

Cerebrohepatorenal syndrome (Zellweger's syndrome) is a peroxisomal disorder that results from mutation of genes encoding for peroxins. This leads to the absence or malfunctioning of peroxisomes in the affected individual, which leads to the accumulation of very-long-chain fatty acids and other metabolic products, causing the symptoms observed in the neonatal baby boy.

Question 16

A patient with lymphoma that involves his small intestines is treated with a various chemotherapeutic agents, including vincristine. This antimitotic substance acts on

Accepted Answer

Vincristine is an antimitotic substance that inhibits microtubule formation by binding to tubulin, preventing its polymerization and disrupting the mitotic spindle assembly. This mechanism of action ultimately leads to cell cycle arrest and apoptosis in rapidly dividing cells, such as cancer cells.

Question 17

A 55-year-old patient was placed on tetracycline therapy and a week later returns to the physician, indicating that the antibiotic did not alleviate his symptoms. During their conversation the physician determines that the patient took the tetracycline capsules with milk. Which of the following components of milk interfered with theaction of the drug?

Accepted Answer

Calcium in milk forms a complex with tetracycline, reducing its absorption and effectiveness. It is recommended to take tetracycline on an empty stomach, with water, and avoid milk or other dairy products for at least 2 hours after taking the medication.

Question 18

A patient with Kartagener's syndrome has a genetic disorder that is known to

Accepted Answer

Kartagener's syndrome is a genetic disorder that affects cilia motility due to defective dynein, which is responsible for the sliding movement of microtubules in cilium. Therefore, the best choice is C.

Question 19

A patient suffering from asthma has difficulty breathing and is treated with albuterol, a drug that relaxes bronchiolar smooth muscles. Albuterol acts as a(n)

Accepted Answer

Albuterol is a bronchodilator that works as an adrenergic receptor agonist, specifically a beta-2 adrenergic receptor agonist. It binds to the beta-2 adrenergic receptor and activates it, resulting in smooth muscle relaxation in the bronchioles and dilation of the airways, making it easier to breathe.

Question 20

The fluidity of the plasmalemma has well-established clinical significance. Which of the following molecules decreases the cell membrane fluidity?

Accepted Answer

Cholesterol decreases the fluidity of the cell membrane by reducing the movement of the fatty acid chains in the phospholipid bilayer.

Quiz 1: Cytoplasm