Answer:
<u>d. Transport proteins within the membrane serve as a tunnel for molecules to enter the cell.
</u>
<u />
Explanation:
Solutes are typically moved across the cell through either passive or active transport. The cells, surrounded by a bilipid layer or plasma membrane is amphiphlic- its polar, hydrophilic lipid heads face outwards, while their non-polar hydrophobic lipid tails face inwards towards each other.
While lipid-soluble molecules move across the layer easily, it is also difficult for charged and also large molecules to move across its surface, into the cell. Transmembrane channels, <u>embedded within the membrane</u>, help to maintain selective permeability as transport proteins, pores and gated channels. Simple diffusion happens as a method of passive transport in cells through plasma membranes.
The solutes travel through the plasma membrane in the process of diffusion from regions of high concentration to regions of low concentration; this occurs without the use of energy. <u>Molecules moving against their concentration require active transport mechanism to cross the membrane</u>.
The specific volume will be different for various kinds of cells. The safe answer would be that the new cell will pretty much have the same volume as the one that it divided from. This is true for most eukaryotic cells unless other factors like epigenetics or mutations come into place.
One example of moments a cell would increase in volume is during hypertrophy. This simply means that the cell is increasing in size (compared to: hyperplasia -- which is an increase in number of the cells). Hypertrophy is definitely an increase in volume of the cell but this doesn't necessarily translate to cell division (i.e. just because the cell is big now, doesn't mean it will still be big when it divides).
Another moment of increasing volume of the cell and now also related to cell division would be during the two stages in the cell cycle (i.e., G1 and G2 phases). This is the growth phase of the cell preparing to divide. However when mitosis or division happens, the cells will normally end with the same volume as when it started.
This are safe generalizations referring to the human cells. It would help if a more specific kind of cell was given.
Answer:
Size of pot
Explanation:
The size of the pot is the only variable changed from the control group in this experiment.
Parasympathetic nerves govern involuntary actions such as pupil dilation, peristalsis, gland secretions, etc.
Stratum corneum is the answer
