Scientific Knowledge Flashcards
7 cards from real Physician Assistant practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Scientific Knowledge flashcards as text
Which enzyme is responsible for the rate-limiting step in cholesterol biosynthesis?
Answer: HMG-CoA reductase
HMG-CoA reductase catalyzes the conversion of HMG-CoA to mevalonate, the committed and rate-limiting step in cholesterol synthesis, and is the target of statins.
The Fick principle is used to calculate cardiac output. Which formula correctly represents it?
Answer: CO = VO2 / (CaO2 - CvO2)
The Fick principle states cardiac output equals oxygen consumption divided by the arteriovenous oxygen content difference.
Which cell type produces surfactant in the lung?
Answer: Type II pneumocytes
Type II pneumocytes synthesize and secrete pulmonary surfactant, which reduces alveolar surface tension and prevents collapse.
During oxidative phosphorylation, the chemiosmotic gradient drives ATP synthesis through which complex?
Answer: Complex V (ATP synthase)
Complex V (ATP synthase) uses the proton-motive force generated by the electron transport chain to synthesize ATP from ADP and inorganic phosphate.
Which blood group system determines the Rh factor, and what antigen is most clinically significant?
Answer: Rh system; D antigen
The Rh blood group system's D antigen is the most immunogenic and clinically important, particularly in hemolytic disease of the newborn.
In the cell cycle, at which checkpoint is DNA integrity assessed before the cell commits to DNA replication?
Answer: G1/S checkpoint
The G1/S checkpoint (restriction point) assesses DNA integrity and cell size before the cell commits to S phase DNA replication.
Which immunoglobulin class is the first to be produced during a primary immune response?
Answer: IgM
IgM is the predominant antibody produced early in a primary immune response and is the most efficient complement activator.