Of the choices provided, only energy storage in the form of tricacylglycerols makes sense. Free fatty acids do not act as the main storage form for fats, but are used to create triacylglycerols.

Triacylglycerols (triglycerides) are composed of three fatty acids and a glycerol backbone. Their primary function is to store energy. As a secondary function they can also provide thermal insulation for an organism.

Phospholipids (glycerophospholipids) are primarily used in the cell membrane, but can also be involved in signaling. Sterol lipids (steroids) are primarily used as hormones, or involved in cell signaling. Eicosanoids are a family of fatty acid involved in signaling.

Glycogen is used to store energy, but it is a carbohydrate glucose polymer. The question specifies that the answer must be a lipid.

Steroids are a type of lipid. This means that steroids are nonpolar molecules, composed of primarily of hydrogen and carbon. Recall that the interior of the plasma membrane consists of the nonpolar tails of phospholipids. Since nonpolar molecules tend to dissolve in other nonpolar molecules, steroids will be able to traverse the interior (nonpolar phospholipid tail) of plasma membranes and cross into the cell.

类固醇是一种脂质分子,但书d extensively in living organisms. Recall that triglycerides are also a type of lipid; therefore, steroids and triglycerides are classified as the same type of macromolecule. One of the characteristics of steroids is that they have four cycloalkane rings. Three of the four rings are six-membered rings (cyclohexane) and one ring is a five-membered ring (cyclopentane). Steroids are found in several biomolecules, such as hormones. Some examples of steroid hormones include the sex hormones (estrogen, progesterone, and testosterone), aldosterone, and cortisol. Since they are nonpolar, steroid hormones can traverse the lipid bilayer and enter the cell; therefore, the steroid hormone receptors are found inside the cell (on the nuclear membrane).

A type of steroid, called cholesterol, can be found in plasma membranes but it is not the major component of the membrane. Recall that plasma membranes are primarily composed of a phospholipid bilayer; therefore, phospholipids (another type of lipid) are the major component of plasma membranes.

Steroids are a type of lipid that are characterized by their four-ring molecular structure. The four rings consist of three six-membered rings and one five-membered ring. Recall that six-membered rings are called cyclohexanes and five-membered rings are called cyclopentanes; therefore, you will most likely find a cyclohexane in a steroid.

Phosphate groups, pentose sugars, and nitrogenous bases are found in nucleotides, which are monomers that make up nucleic acids. Steroids are a type of lipid; therefore, you will most likely not find these substances in a steroid.

The correct answer issaturatedfat. Rather than attempting to draw each one of these macromolecules, one should view this conceptually. In a combustion reaction, heat is generated for every carbon-hydrogen bond that is oxidized. In other words, the higher the density of C-H bonds in a compound, the more potential energy it can store. Fats, which primarily consist of only carbon and hydrogen, will contain the most energy and subsequently generate the most heat when oxidized. This is the same reason why animals and plants store energy as fat molecules.

*Note:A polyunsaturated fat has more than one double bond between its carbons, which reduces the total number of C-H bonds.

Lipids are hydrocarbons, and are the most energy-rich biological macromolecules due to their heavily reduced state. This reduced state is a function of the roughly equal electronegativity between carbon and hydrogen atoms.

佤邦ter is able to solvatehydrophiliccompounds. Hydrophobic molecules, such as fatty acids, are typically aggregated together by water and can be separated.

Fats are less reactive, more reduced, and less acidic than proteins. They have much lower overall polarity, but do contain polar bonds, such as between C and O.

A molecule is solvated when it is surrounded by water molecules, and separated from the other molecules in the body. This separation is possible because of charge or polarity present in the molecule, which causes it to be attractive to water.

Lipids have very low solubility in water due to their nonpolarity. As a result, we conclude that lipids would not be properly solvated in the body, and would instead be clustered together by water molecules.