Answer:A. The release of calcium ions causes myosin and actin to attach to each other.
The contraction of skeletal muscles takes place by induction of a nerve impulse, which produces a movement and the interaction of the filaments containing proteins named as actin and myosin. This interaction of filaments is regulated by proteins called tropomyosin and troponin present on the actin filaments. The motor nerve causes the depolarization of the muscle membrane sarcolemma. This triggers the sarcoplasmic reticulum to release calcium ions. This calcium binds to troponin and thus allows the tropomyosine strand on the actin filament to displace so that the part of the actin where myosine head needs to be attached remain uncovered. Binding of the actin myosine filament results in contraction.
Hence, the release of calcium ions causes myosin and actin to attach to each other causes muscle contraction.
An organelle is a specialized structure inside Eukaryotic cells.
Answer:
The third sentence is not correct. The correct statement would be as follows:
because the contents of the lumen of ER (or any other compartment) in the secretory or endocytic pathways never mix with the cytosol, Proteins that enter these pathways is never imported again.
Explanation:
During mitosis, specifically during prophase, when the nuclear envelope breaks down, or in other words, retracts from the chromatin, its content that is the membrane protein intermix with the ER membrane protein. However its content will always remain separated from that of the cytosol because of the presence of an intact membrane.
<span>The nurse should stand or sit within the line of vision for the patient, close the door to his/her room so minimize noise, reduce distractions by turning on televisions and removing visitors, ,be certain the clients hearing aid is working properly, and be sure to get the clients attention before beginning any discussions.</span>
I believe false but i’m not sure :)
