Biomedical Sciences Flashcards
6 cards from real COMLEX-USA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Biomedical Sciences flashcards as text
Which enzyme is deficient in Tay-Sachs disease, leading to accumulation of GM2 ganglioside?
Answer: Hexosaminidase A
Tay-Sachs disease results from deficiency of hexosaminidase A, causing GM2 ganglioside accumulation in lysosomes.
A mutation in which gene is most commonly associated with hereditary breast and ovarian cancer syndrome?
Answer: BRCA1/2
BRCA1 and BRCA2 mutations are the most common inherited cause of breast and ovarian cancer syndrome.
The 'watershed' area between the superior and inferior mesenteric artery territories, most vulnerable to ischemia, is located at:
Answer: Splenic flexure
The splenic flexure of the colon is a watershed zone between SMA and IMA territories and is most vulnerable to ischemic colitis.
Which complement pathway is activated by antibody-antigen complexes and begins with C1q binding?
Answer: Classical pathway
The classical complement pathway is activated when C1q binds to antibody-antigen complexes, initiating the complement cascade.
During which phase of the cell cycle does DNA replication occur?
Answer: S phase
DNA synthesis and replication occur during S (synthesis) phase of the cell cycle.
The sliding filament theory of muscle contraction states that sarcomere shortening results from:
Answer: Myosin heads pulling actin toward the M line
During muscle contraction, myosin heads bind actin and pull the thin filaments toward the center (M line), shortening the sarcomere without changing filament length.