I guess it is aluminium in cationic form
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>.
The answer is A. def- of a plant or animal) native or restricted to a certain country or area.
"a marsupial endemic to northeastern Australia"
It is thigmotropism because it is not affected by gravity or light.
<span>Ions are another name for charged atoms. Some elements are electropositive, and some are electronegative. Electropositive elements such as metals like to give up electrons, thus taking on a positive charge. Electronegative elements such as chlorine attract electrons, so they become negative. When electropositive and electronegative atoms meet and exchange ions, they take on opposite charges. Because positive and negative charges attract, these charged atoms become attracted to one another. This attraction forms an ionic bond that keeps the ions together.</span>
