Answer:
"As a molecule moves through the plasma membrane it passes through <em>a hydrophilic layer of phospholipid heads then a hydrophobic layer of phospholipid tails and then another hydrophilic layer of phospholipid heads".</em>
Explanation:
Biological membranes are formed by two lipidic layers, proteins, and glucans.
Lipids characterize for being amphipathic molecules, which means that they have both a hydrophilic portion and a hydrophobic portion at the same time. These molecules have a lipidic head that corresponds to a negatively charged phosphate group, which is the polar and hydrophilic portion. They also have two lipidic tails that correspond to the hydrocarbon chains -the apolar and hydrophobic portion- of the fatty acids that esterify glycerol.
Membrane lipids are arranged with their hydrophilic polar heads facing the exterior and the interior of the cells, while their hydrophobic tails are against each other, constituting the internal part of the membrane.
Through this lipidic bilayer, some molecules can move from one side of the cell to the other, which happens because of concentration differences. When this occurs, molecules must pass through the hydrophilic layer of phospholipid heads then through the hydrophobic layer of phospholipid tails and then again through another hydrophilic layer of phospholipid heads.
I would think that it is B or C
Your aging aunt luella has has a series of small strokes. these strokes can progressively damage her brain and are most likely to produce dementia
In the
process of the nitrogen cycle.
<span>
The nitrogen cycle is a
biogeochemical succession process of nitrogen that involves: fixation,
ammonification, nitrification, and denitrification. Like any other
biogeochemical cycles. This process undergoes and affects the biological, geometrical
and chemical aspects in the ecosystem and the abiotic and biotic community. Hence,
the nitrogen cycle leads the abiotic component –nitrogen- to contribute to the
biotic community, decomposition and primal production. Further, it becomes an
essential part of the environment because some life components are contains it,
similarly, amino acids, nucleic acids in RNA and DNA. </span>
