USABO Open Exam 2024 with 100% complete solutions

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 nonmyelinated 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. correct answersB 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. correct answersD. 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 correct answersC. Erythrocytes