Muscular dystrophy is a result of an abnormality of the muscle protein:
- A. glycoprotein
- B. dystrophin
- C. troponin
- D. actinomyosin
Correct Answer: B
Rationale: Muscular dystrophy is primarily caused by mutations in the gene that provides instructions for making the protein dystrophin. Dystrophin plays a crucial role in maintaining the structure of muscle fibers. Glycoprotein is a general term for proteins with sugar molecules attached, not specifically related to muscular dystrophy. Troponin is a protein involved in muscle contraction regulation, and actinomyosin is not a specific muscle protein but a complex formed during muscle contraction. Therefore, the correct answer is dystrophin.
You may also like to solve these questions
A 30-year-old has poorly controlled asthma and is taking prednisone 10 mg by mouth once a day. He has been on this regimen for 6 weeks. Abrupt withdrawal or discontinuation of this medication can cause:
- A. adrenal crisis
- B. hypercortisolism
- C. ACTH stimulation
- D. thyroid crisis
Correct Answer: A
Rationale: Abrupt withdrawal or discontinuation of prednisone, a corticosteroid, can lead to adrenal crisis. This occurs due to the suppression of the adrenal glands' natural cortisol production caused by prolonged exogenous steroid administration. Adrenal crisis presents with symptoms such as weakness, fatigue, abdominal pain, and hypotension. Hypercortisolism (Cushing syndrome) results from chronic excessive exposure to cortisol, not abrupt withdrawal. ACTH stimulation would be expected in response to low cortisol levels, not as a direct consequence of prednisone withdrawal. Thyroid crisis (thyroid storm) is associated with severe hyperthyroidism and is not directly related to corticosteroid withdrawal.
Which of the following patients are at higher risk for developing oral cancer?
- A. A female who has taken oral contraceptives for the last 4 years
- B. Both an adult male with a history of alcoholism and a middle-aged male who smokes a pipe
- C. An adult female who eats spicy foods regularly
- D. An older adult female who chews gum frequently
Correct Answer: B
Rationale: The correct answer is 'Both an adult male with a history of alcoholism and a middle-aged male who smokes a pipe.' Alcohol consumption and tobacco use, such as smoking a pipe, are well-known risk factors for developing oral cancer. These two factors significantly increase the likelihood of developing oral cancer compared to the other choices. Taking oral contraceptives, eating spicy foods regularly, and chewing gum frequently are not established risk factors for oral cancer, making them less likely to lead to the development of this type of cancer.
Which of the following types of vitamin or mineral deficiency can cause megaloblastic anemia and is associated with lower extremity paresthesias?
- A. Vitamin B12
- B. Folate
- C. Iron
- D. Vitamin K
Correct Answer: A
Rationale: The correct answer is Vitamin B12. Vitamin B12 deficiency can lead to megaloblastic anemia, a condition characterized by the production of abnormally large and immature red blood cells. Lower extremity paresthesias, such as tingling or numbness, are common neurological symptoms associated with vitamin B12 deficiency. Folate deficiency can also cause megaloblastic anemia but is not typically linked to lower extremity paresthesias. Iron deficiency leads to microcytic anemia, not megaloblastic anemia. Vitamin K deficiency is associated with bleeding tendencies, not megaloblastic anemia or paresthesias.
Which of the following statements describes an active cellular membrane exchange process?
- A. Sodium moving out of cells and potassium moving into cells
- B. The movement of water from an area of low solute concentration to an area of high solute concentration
- C. The movement of insulin using a protein to travel across the cell membrane
- D. Oxygen moving across the pulmonary capillaries to an area of high carbon dioxide
Correct Answer: A
Rationale: The correct answer is A. In active transport, energy is expended to move substances against their concentration gradient. Sodium moving out of cells and potassium moving into cells is an example of active transport because it requires energy to pump these ions across the cell membrane against their concentration gradients. Choices B, C, and D describe passive processes where substances move along their concentration gradients without the input of energy.
In a patient with a subconjunctival hemorrhage due to allergic rhinitis, which statement is accurate?
- A. The hemorrhage will resolve without treatment within 2 weeks.
- B. The patient should be referred for immediate ophthalmologic examination.
- C. Oral antihistamines should be started to prevent further complications.
- D. Topical corticosteroids may be considered to reduce inflammation.
Correct Answer: A
Rationale: In a patient with a subconjunctival hemorrhage secondary to allergic rhinitis, the hemorrhage is typically self-limiting and will resolve on its own within 2 weeks without the need for specific treatment. Referring the patient for immediate ophthalmologic examination is not necessary unless there are other concerning symptoms. Starting oral antihistamines may help manage the underlying allergic rhinitis but is not specifically indicated for the hemorrhage. Topical corticosteroids are not routinely prescribed for subconjunctival hemorrhage as they may have limited benefit and could potentially cause complications.