Answer:
<u>d. Transport proteins within the membrane serve as a tunnel for molecules to enter the cell.
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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>.
Answer:
Inertia- the tendency of an object to resist a change in velocity
Explanation:
Say a car was going at 65 MPH, but suddenly stopped. For all of the people in that car, their bodies would keep moving forward at 65 MPH until stopped by an equal force (say, the thing right in front of each person) The seatbelt is there to protect you from your own inertia.
Genes and the environment
bring change in the genetic basis of a population
