Answer:
Amino acids with non-polar side chains.
Explanation:
The class of proteins that is unable to form hydrogen bonds with water are the amino acids with non- polar side chains. This class includes the amino acids
Alanine
Valine
Leucine
Isoleucine
Proline
Phenylalanine
Cysteine
Methionine
Tryptophan
These are the nine proteins which are considered to be strongly hydrophobic. All these amino acids are hydrophobic in nature due to their side chains. Glycine is not added to this list as it does not have a side chain.
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
ANSWER:
Needed to form cell membranes
I hope I was of help to you :)
