USABO Open Exam 2025 QUESTIONS AND ANSWERS WITH CORRECT AND VERIFIED
ANSWERS
Integrins -CORRECT ANSWER-Cell surface receptors for extracellular matrix proteins.
Actin -CORRECT ANSWER-Protein involved in cell motility and muscle contraction.
Myosin -CORRECT ANSWER-Motor protein involved in muscle contraction and cytokinesis.
Dynein -CORRECT ANSWER-Motor protein involved in intracellular transport and
ciliary/flagellar movement.
Kinesin -CORRECT ANSWER-Motor protein involved in intracellular transport and mitotic
spindle formation.
Cyclin -CORRECT ANSWER-Regulatory protein involved in cell cycle control.
Extracellular matrix -CORRECT ANSWER-Non-cellular component providing structural
support and biochemical signaling to surrounding cells.
Cytokinesis -CORRECT ANSWER-Division of the cytoplasm following nuclear division.
pKa -CORRECT ANSWER-Negative base-10 logarithm of the acid dissociation constant.
Oxidative phosphorylation -CORRECT ANSWER-Process of ATP synthesis in mitochondria
using oxygen as the final electron acceptor.
, Frederick Griffith -CORRECT ANSWER-Discovered transformation through pneumococcal
bacteria.
Hershey and Chase -CORRECT ANSWER-Confirmed DNA as the hereditary material using
bacteriophages.
Chargaff -CORRECT ANSWER-Discovered the complementary base pairing in DNA.
Watson and Crick -CORRECT ANSWER-Proposed the double-helix structure of DNA.
Meselson and Stahl -CORRECT ANSWER-Demonstrated semi-conservative replication of
DNA.
Transmembrane protein -CORRECT ANSWER-Protein spanning the cell membrane and
facilitating molecular transport.
Transmembrane domain -CORRECT ANSWER-Region of a transmembrane protein that
crosses the lipid bilayer.
Alpha helices -CORRECT ANSWER-Secondary structure of proteins characterized by right-
handed coiled segments.
Electron transport chain -CORRECT ANSWER-Series of protein complexes and cytochromes
facilitating electron transfer to generate ATP.
Ubiquinone -CORRECT ANSWER-Coenzyme involved in electron transport and ATP synthesis.
FADH2 -CORRECT ANSWER-Reduced form of flavin adenine dinucleotide, donates electrons
to the electron transport chain.
ANSWERS
Integrins -CORRECT ANSWER-Cell surface receptors for extracellular matrix proteins.
Actin -CORRECT ANSWER-Protein involved in cell motility and muscle contraction.
Myosin -CORRECT ANSWER-Motor protein involved in muscle contraction and cytokinesis.
Dynein -CORRECT ANSWER-Motor protein involved in intracellular transport and
ciliary/flagellar movement.
Kinesin -CORRECT ANSWER-Motor protein involved in intracellular transport and mitotic
spindle formation.
Cyclin -CORRECT ANSWER-Regulatory protein involved in cell cycle control.
Extracellular matrix -CORRECT ANSWER-Non-cellular component providing structural
support and biochemical signaling to surrounding cells.
Cytokinesis -CORRECT ANSWER-Division of the cytoplasm following nuclear division.
pKa -CORRECT ANSWER-Negative base-10 logarithm of the acid dissociation constant.
Oxidative phosphorylation -CORRECT ANSWER-Process of ATP synthesis in mitochondria
using oxygen as the final electron acceptor.
, Frederick Griffith -CORRECT ANSWER-Discovered transformation through pneumococcal
bacteria.
Hershey and Chase -CORRECT ANSWER-Confirmed DNA as the hereditary material using
bacteriophages.
Chargaff -CORRECT ANSWER-Discovered the complementary base pairing in DNA.
Watson and Crick -CORRECT ANSWER-Proposed the double-helix structure of DNA.
Meselson and Stahl -CORRECT ANSWER-Demonstrated semi-conservative replication of
DNA.
Transmembrane protein -CORRECT ANSWER-Protein spanning the cell membrane and
facilitating molecular transport.
Transmembrane domain -CORRECT ANSWER-Region of a transmembrane protein that
crosses the lipid bilayer.
Alpha helices -CORRECT ANSWER-Secondary structure of proteins characterized by right-
handed coiled segments.
Electron transport chain -CORRECT ANSWER-Series of protein complexes and cytochromes
facilitating electron transfer to generate ATP.
Ubiquinone -CORRECT ANSWER-Coenzyme involved in electron transport and ATP synthesis.
FADH2 -CORRECT ANSWER-Reduced form of flavin adenine dinucleotide, donates electrons
to the electron transport chain.
