High-density lipoproteins have the highest proportion of protein of the five classes of blood lipoproteins: chylomicrons, very-low-density lipoproteins, intermediate-density lipoproteins, low-density lipoproteins, and high-density lipoproteins. Chylomicrons have the lowest density of the five classes of lipoproteins. This is because the have the highest proportion of triglycerides and the least lowest proportion of protein. Very-low-density lipoproteins are a bit more dense than chylomicrons; however, the relative amount of triglycerides is still high. Intermediate-density lipoproteins which are formed from the very-low-density lipoproteins have a higher density than very-low-density lipoproteins due to the fact that they have less than half of the amount of triglycerides as very-low-density lipoproteins. Low-density lipoproteins have the highest amount of cholesterol and an even lesser amount of triglycerides than intermediate-density lipoproteins. Lastly, high-density lipoproteins are the densest of the lipoproteins due to the fact that they have the highest amount of protein in relation to the amount of triglycerides they contain.

Glutamine is one of two amino acids that are amides. The nitrogen bonded to a carbon-oxygen double bond makes it an amide.

Vitamin B12 is also known as cobalamin, and has cobalt at the center of a corrin ring. Cobalt is rarely found in biology, and the synthesis of cobalamin only naturally occurs in bacteria and archaea. For that reason, vitamin B12 has to be ingested in our diet; it is not synthesized in the human body. Iron is found, among other places, in hemoglobin; zinc, in carbonic anhydrase; magnesium, for example, in chlorophyll; and sulfur in iron-sulfur proteins.

Phenylalanine is a non-polar amino acid. The structure of this amino acid is literally alanine with a phenyl group attached.

An acidic amino acid must have a carboxyl moiety in its R-group. Because all amino acids contain a carboxyl moiety on the alpha carbon, that acidic group does not determine whether or not the amino acid is considered acidic.

Low-density lipoproteins have the highest content of cholesterol and cholesterol esters. There are essentially five classes of blood lipoproteins: chylomicrons, very-low-density lipoproteins, intermediate-density lipoproteins, low-density lipoproteins, and high-density lipoproteins. Chylomicrons have the lowest density of the five classes of lipoproteins. This is because the have the highest proportion of triglycerides and the least lowest proportion of protein. Very-low-density lipoproteins are a bit more dense than chylomicrons; however, the relative amount of triglycerides is still high. Intermediate-density lipoproteins which are formed from the very-low-density lipoproteins have a higher density than very-low-density lipoproteins due to the fact that they have less than half of the amount of triglycerides as very-low-density lipoproteins. Low-density lipoproteins have the highest amount of cholesterol and an even lesser amount of triglycerides than intermediate-density lipoproteins. Lastly, high-density lipoproteins are the densest of the lipoproteins due to the fact that they have the highest amount of protein in relation to the amount of triglycerides they contain.

Disulfide bonds are involved in the tertiary and quaternary structure of proteins, not the other structural levels. Primary structure consists of the amino acid sequence. Secondary structure consists of alpha helices and beta pleated sheets. Tertiary structure consists of bonds between hydrogen bonds between R-groups, nonpolar interactions, electrostatic interactions, and covalent bonds including disulfide bonds. Quaternary structure involves the arrangement of more than one polypeptide into a protein complex, and involves the same bonds as those in tertiary structure.

Bases, according to the Bronsted-Lowry definition, are substances that accept

There are essentially five classes of blood lipoproteins: chylomicrons, very-low-density lipoproteins, intermediate-density lipoproteins, low-density lipoproteins, and high-density lipoproteins. Chylomicrons have the lowest density of the five classes of lipoproteins. This is because the have the highest proportion of triglycerides and the least lowest proportion of protein. Very-low-density lipoproteins are a bit more dense than chylomicrons; however, the relative amount of triglycerides is still high. Intermediate-density lipoproteins which are formed from the very-low-density lipoproteins have a higher density than very-low-density lipoproteins due to the fact that they have less than half of the amount of triglycerides as very-low-density lipoproteins. Low-density lipoproteins have the highest amount of cholesterol and an even lesser amount of triglycerides than intermediate-density lipoproteins. Lastly, high-density lipoproteins are the densest of the lipoproteins due to the fact that they have the highest amount of protein in relation to the amount of triglycerides they contain.

Amino acids are classified based on their charged (polar groups) at neutral pH (pH=7).Lysine (Lys, K), arginine (Arg, R) and histidine (His, H) are positively charged at neutral ph (pH=7), while aspartate and glutamate are negatively charged.