Which event occurs first in an action potential?
Answer and explanation
Correct answer: C. Sodium channels open and the membrane depolarizes
- Step 1: Threshold opens voltage-gated sodium channels. Answer: Sodium channels open and the membrane depolarizes. Why not the others: Potassium channels open during repolarization and the pump restores gradients afterward.
Practise more Cell Biology, Genetics and Physiology.
Free questions with an explanation for every one, and full timed MCAT (Medical College Admission Test) mock tests.
More Cell Biology, Genetics and Physiology questions
- Which organelle contains hydrolytic enzymes for intracellular digestion?
- Which organelle is mainly responsible for modifying, sorting and packaging proteins for secretion?
- During which phase of mitosis do the sister chromatids separate and move to opposite poles?
- In which phase of meiosis does crossing over between homologous chromosomes occur?
- In a population in Hardy-Weinberg equilibrium, 4% of people have a recessive condition. What is the frequency of carriers?
- A woman who is a carrier of an X-linked recessive disease has children with an unaffected man. What proportion of their sons are expected to…