Answer:B). Cell membranes are composed of a lipid bilayer.
Explanation: A membrane is a lipid bilayer that surrounds the cell. Lipids have two parts: the fatty acid chain (the tail) and the phosphate group (the head).
The phosphate head groups are polar, face outward and interact with the outside environment of the cell. The fatty acid chain is hydrophobic and nonpolar, face each other in the bilayer thus forming a hydrophobic fluid interior.
The hydrophobic nature of the bilayer interior makes the membrane to permit only nonpolar and hydrophobic molecules to pass through the cell membrane. This is the reason the membrane allows only molecules that dissolve in the lipid bilayer to pass through to enter or leave the cell.
Answer: Water molecules are strongly attracted to each other, so they remain condensed (that is, a liquid, and not a gas) at higher temperatures. Dihydrogen and dioxygen have no strong attractive forces to hold the molecules together, so they exist as gases at room temperature and pressure (that is, in our everyday lives).
Explanation:
C) blood, blood vessels, and heart.
Answer:
<em>It acts as a catalyst, lowing the activation energy and speeding up a reaction.</em>
Explanation:
The acetaldehyde alcohol dehydrogenase is used to turn acetaldehyde to ethanol.
In the end it releases 2ATP. Yet it has not given energy in the reaction under any conditions to carry it to fruition.
This merely decreases the reaction's activation energy and favors its operation within physiological circumstances.
