Identifying Specific Protein Structures - Biochemistry

The amino acid's chiral carbon is connected to two methyl groups followed, by a sulfur, and finally another methyl group. Therefore, the amino acid is methionine (M).

The structure would most closely resembe tyrosine (pictured).

Alanine is the amino acid that would be formed by removing the phenyl group from phenylalanine (the pictured molecule).

Threonine (pictured here) would be formed.

Threonine is a polar uncharged amino acid with a R-group.

Arginine is a basic amino acid. The charge on the amine in the functional group makes this structure basic. While lysine is also a basic amino acid, it has a different R-group.

Methionine is a non-polar amino acid. It is one of two amino acids that contain sulfur, the other is cysteine.

Leucine is a non-polar amino acid with a R-group.

Cysteine is a polar amino acid with an R-group of . It is one of two amino acids with a sulfur in the R-group, the other is methionine.

The polarity of an amino acid is determined by the R-group. The electronegativity difference between oxygen and carbon creates a dipole with the partial positive being on carbon and the partial negative being on oxygen. The dipole makes the molecule polar.

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.

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

Aspartic acid is an acidic amino acid, meaning it contains in its R-group. The R-group of aspartic acid is .

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

Although tyrosine is hydrophobic, it is more soluble than phenylalanine. The only difference between the two amino acids is the hydroxyl group present on tyrosine. The hydroxyl is much more acidic than the hydrogen, and so it is more likely to ionize. The ability to ionize makes it more soluble (think electrolytes).

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.

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.

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.