USABO Open Exam 2014 Questions And Answers

USABO Open Exam 2014 Questions And Answers Why is myelin important in the nervous system? A. It allows signals to travel faster along axons because depolarization occurs only at myelinated locations. B. It allows signals to travel faster along axons because depolarization occurs only at unmyelinated locations. C. It bundles the dendrites of adjacent neurons together. D. It increases capacitance across the cell membrane, which helps electrical signals to leave the axons. E. It traps neurotransmitters, increasing their concentrations in the synaptic cleft. - ANS B Which type of cytoskeletal fiber is the primary building block of eukaryotic cilia and flagella? A. Actin microfilaments. B. Intermediate filaments. C. Keratin. D. Microtubules. E. RNA. - ANS D. Microtubules. Which of the following human cell types contains the LEAST amount of RNA involved in splicing? A. Lymphocytes B. Lymphoblasts C. Erythrocytes D. Erythroblasts E. Hepatocytes - ANS C. Erythrocytes Antimicrobial drugs, also known as antibiotics, inhibit the growth of bacteria by targeting cellular components present in bacteria. Which of the following cellular components is NOT a valid antimicrobial drug target? A. Centrosome. B. Ribosome. C. Cell wall. D. RNA polymerase. E. DNA polymerase - ANS A. Centrosome.