The MAPK pathway typically involves the activation of the small G protein Ras downstream of the activated receptor. The activation of Ras is mediated by the two cytosolic proteins Grb-2 and Sos.  

What type of protein is Sos? 

A newborn presents with a cleft palate and associated craniofacial abnormalities. Genetic testing reveals a mutation affecting a receptor involved in craniofacial development. The mutation disrupts the normal function of this receptor, which is essential for regulating gene expression during embryogenesis. 

     Which single receptor dysfunction is most likely responsible for this presentation? 

 Erythropoietin is a hormone that is naturally made by your kidneys to stimulate the production of red blood cells.  

Which is the most likely character of its signaling pathway? 

A 19-year-old adolescent is brought to the endocrine clinic by his parents worried that he had never grown facial, axillary, or pubic hair, and his voice had not changed. Blood tests reveal low luteinizing hormone (LH) and follicular stimulating hormone (FSH). Which hormone is the single stimulator for the synthesis of these hormones?  

A 25-year-old woman is diagnosed with primary adrenal hyperfunction. 

        Which is the single most likely hormonal profile that confirmed this diagnosis? 

  What is the type of tissue noted in the microscopic image shown below?

 The muscle is a mixture of fast and slow twitch fibers.

Which of these exercises most likely increases the mass of the fast twitch fibers?

A 29 Year Old man is brought to the Emergency Department with a gunshot wound that injured the spinal cord at the L1 Level. Which deep tendon Reflex would be diminished in this patient?

.  A 6 year old boy is diagnosed with Duchenne Muscle Dystrophy. His muscle biopsy is shown below.

Which is the most prominent characteristic feature in this biopsy?

After falling on a slippery ground, a 12-year-old boy complains of severe pain in his right arm, X-ray shows fracture of surgical neck of humerus, followed by a flat shoulder & subsequent weak abduction of his arm.

Which nerve is most probably injured in this case?