So to sum up, when matter is transitioning from solid to liquid (melting) or liquid to solid (freezing<span>), its </span>temperature<span> is fixed at the </span>melting/freezing<span> point, which is the </span><span>same temperature</span>
Answer:
by looking at their physical features, the fossil record, and dna sequences
Answer:
Explanation:
DNA is deoxyribose nucleic acid. It is a double helical structure. It remains in the coiled form so as to make the information stored in the small region within the cell. The sequence of bases allows the information to be stored in the coded form so as to promote the synthesis of proteins. Complementary base pairing allows the DNA molecule to replicate itself.
Answer:
The prolonged electrical depolarization of cardiac muscle cells -that occurs during contraction- is due primarily to the persistent influx of calcium ion
Explanation:
The action potential of the heart muscle is longer with respect to skeletal muscle (around 300 milliseconds), and this is due to the activity of calcium (Ca⁺⁺ ) in the intracellular compartment.
The initial depolarization of cardiac muscle fiber depends on the entry of sodium (Na⁺) into the cell. However, for the action potential to occur and be maintained, Ca⁺⁺ must increase its cytoplasmic levels, which depends on:
- The increase in intracellular sodium induces the release of Ca⁺⁺ from the sarcoplasmic reticulum.
- Calcium entry from the extracellular space through the voltage dependent Ca⁺⁺ channels.
- The entry of extracellular Ca⁺⁺ causes the release of more Ca⁺⁺ ions by the sarcoplasmic reticulum, further increasing its intracellular concentration.
This is how the ion that guarantees the duration of the action potential of the cardiac muscle cell is the Ca⁺⁺.
Learn more:
Calcium, sodium and cardiac muscle cells brainly.com/question/4473795
