Answer:
B. The membrane lets certain substances move across it freely, while others must move through a “gate”.
Explanation:
Selective permeability is a property of cellular membranes that only allows certain molecules to enter or exit the cell. This is important for the cell to maintain its internal order irrespective of the changes to the environment. For example, water, ions, glucose and carbon dioxide may need to be imported or exported from the cell depending on its metabolic activity. Similarly, signaling molecules may need to enter the cell and proteins may need to be released into the extracellular matrix. The presence of a selectively permeable membrane allows the cell to exercise control over the quantum, timing and rate of movement of these molecules.
B) They maintain balance in the cell.
That mix of hydrophobic and hydrophilic, in other words, the mix of repelling and attraction maintains the aqueous balance in a cell and it's exterior.
Hope it helped,
BioTeacher101
Facilitated diffusion. It is a passive transport mechanism in which carrier proteins shuttle molecules across the cell membrane without using the cell’s energy supplies. Instead, the energy is provide by the concentration gradient, which means that molecules are transported from higher to lower concentrations, into or out of the cell. The carrier proteins bind to glucose, which causes them to change shape and translocate the glucose from one side of the membrane to the other. Red blood cells use facilitated diffusion to absorb glucose.
Answer:
I haven't really learned about cell types but I did find this information
Explanation:
How can epinephrine have different effects on different cells? Different cells have different receptors that bind epinephrine. Different cells activate different enzymes as a result of epinephrine binding.
epinephrine induces increased vascular smooth muscle contraction, pupillary dilator muscle contraction, and intestinal sphincter muscle contraction. Other significant effects include increased heart rate, myocardial contractility, and renin release
Hope it at least helps a little :)
I think it’s option B
I hope it helps you