Answer:
It means that the cell membrane allows certain substances to pass through and not others. As the cell membrane consists of a phospholipid bilayer with a hydrophobic core, only small uncharged hydrophobic molecules can pass through the cell membrane e.g. glucocorticoid and other larger charged particles require transporters or channel proteins to pass through the cell membrane, e.g. glucose.
Answer :
B
Explanation:
Photosynthesis is the process of converting light energy into chemical energy in the form of glucose, in small structures called chloroplasts. ... In cellular respiration, the energy stored in the bonds of the glucose molecule is broken down and transformed to another type of energy
Answer:
D. Molecules called pumps function to control active transport.
Explanation:
Active transport is one of the two types of transport (the other being passive transport). It is the type of transport in which substances move against their concentration gradient i.e. from a lower concentration to a higher concentration. Hence, due to this, energy input in form of ATP is required by the cell.
However, the process of active transport makes use of certain molecules called PUMPS to control it. The pumps moves ions/molecules against their concentration gradient. An example is the sodium-pottasium pump which moves sodium ions from a region of low conc. to a region of high conc.
The horsehoe crab because it was one of the first animals to ever live on earth
