Retention is the act or condition of keeping or containing something.
1.An example of retention is a dam holding back a river.
2.An example of retention is someone being held in a rehabilitation center.
3.An example of retention is memory
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1.The act of retaining or the condition of being retained: the retention of nutrients in the soil; the retention of jobs in the city.
2.The practice of requiring a student to repeat a class or a year of school because of insufficient educational progress to advance.
3.The ability to recall or recognize what has been learned or experienced; memory.
4.The inability of a person or animal to eliminate a bodily waste.
The double layered sac surrounding the heart is the pericardium
Answer:
Transporters are the integral membrane proteins that serve to move the substances across the membrane.
Explanation:
Transporters are the membrane proteins that serve to move specific ions or molecules across the lipid bilayer. These are the integral membrane proteins. Transporters include carriers, channels, pumps, etc. Channels are the integral membrane proteins that serve to provide a pathway for transport of charged and/or polar substances that otherwise can not cross the non-polar core of the lipid bilayer.
Pumps are involved in the active transport of substances against the concentration gradient and use the energy of ATP hydrolysis. Some of the examples of transporters are voltage-gated ion channels, GLUT1 glucose transporter, F₀F₁ ATPase proton pump, etc.