Fish and marine mammals sift out the salt from the water, then they drink it.
Answer:
Cross-bridges would form in the absence of an action potential from a motor neuron.
Explanation:
The injected calcium ions would bind to troponin. Troponin would make tropomyosin move away from the myosin-binding sites on actin. The presence of free binding sites on the actin would be followed by the contraction cycle. This would include hydrolysis of ATP to energize myosin heads and binding of these heads to actin to form cross-bridges. Therefore, cross-bridge formation would occur without any action potential if calcium ions are injected directly into the muscle.
Answer:
O The neuron has more potassium ions inside than outside.
Explanation:
The membrane resting potential is defined as the difference in electrical charge between the interior of neurons and their outer environment. In neurons, both sodium (Na+) and potassium (K+) pumps contribute to generating the resting potential. Neurons have a higher concentration of K+ inside than outside and a higher concentration of Na+ outside than inside. When a neuron is at its rest state, where the inside is negative with respect to the outside, its membrane is more permeable to K+ than Na+, and therefore the resting membrane potential is closer to the equilibrium potential of K+.
