Protein Chemistry Quiz

Protein Chemistry

• Proteins are amino acid polymers
• There are 20 different amino acids, many combinations
• Proteins are made in the ribosome
• The L-Form Amino Acid Structure has a carboxyl group, amino group, and an R group attached to a central alpha carbon
• The general structural formula of an amino acid includes an amino group, carboxyl group, and an alpha carbon with an R group
• Amino acids can be classified based on the structure of the side chain (R), polarity of the side chain, nutritional requirement, and metabolic fate
• Amino acids can be classified based on the structure of the side chain (R) into Aliphatic, Aromatic, and Imino acids
• Aliphatic amino acids are further classified based on their R groups into simple, branched-chain, alcoholic, sulfur-containing, acidic, and basic amino acids
• Aromatic amino acids include phenylalanine, tyrosine, and tryptophan
• Imino acids include proline
• Amino acids can be classified by their nutritional requirement into essential and non-essential amino acids
• Essential amino acids cannot be synthesized by the body and must be obtained from dietary sources
• Non-essential amino acids can be synthesized by the body from intermediates of glycolysis or the TCA cycle
• There are eight essential amino acids; they are: Tryptophan, Threonine, Histidine, Valine, Isoleucine, Phenylalanine, Methionine, Leucine, Lysine
• Non-essential amino acids are: Alanine, Asparagine, Aspartate, Cysteine, Glutamate, Glutamine, Glycine, Proline, Serine, Tyrosine
• Proteins can be classified by their biological value (digestibility and essential amino acid content) into high and low biological value.
• Animal proteins tend to be high biological value, while plant proteins often have low biological value
• Protein supplementation or complementation can be used to improve the quality of partially incomplete proteins by supplying the deficient amino acid
• Amino acids can be classified by their metabolic fate, which is either ketogenic, glucogenic, or mixed
• Ketogenic amino acids are converted to acetyl-CoA or acetoacetate
• Glucogenic amino acids are converted to pyruvate, alpha-ketoglutarate, succinyl-CoA, fumarate, or oxaloacetate
• Amino acids with polar R-groups are generally hydrophilic (water-loving) and can be further classified as acidic, neutral, or basic
• Amino acids with non-polar R-groups are generally hydrophobic (water-fearing) and tend to bury themselves in the interior of proteins
• Amino acids have physical and chemical properties
• Amino acids are readily solvated by water and soluble in polar solvents, making them generally hydrophilic
• Amino acids are generally insoluble in non-polar solvents and precipitate from aqueous solutions by alcohol
• Amino acids have a high melting point due to the ionic forces that stabilize their crystal lattice
• Amino acids can have different tastes, with some being sweet, tasteless, bitter, or having flavoring properties
• The isoelectric point (pI) is the pH at which an amino acid is electrically neutral.
• At the isoelectric point, an amino acid has no net charge and has minimum solubility and buffering capacity

Amino Acid Chemistry

• Amino acids have a buffering effect due to the presence of both acidic (carboxyl) and basic (amino) groups
• The isoelectric point is the pH at which an amino acid will carry no net charge, as all groups are ionized but the charges cancel each other out
• At its isoelectric point, an amino acid will not move in an electric field.
• By adding HCl to an amino acid solution, the molecules become cationic in nature and solubility increases.
• By adding NaOH to an amino acid solution, molecules become anionic in nature.
• The isoelectric point for monoamino monocaboxylic amino acids (neutral) can be calculated as (pK1 + pK2)/2.

Test your knowledge on the fundamentals of protein chemistry, including the structure and classification of amino acids. Explore the various types of amino acids and their significance in protein synthesis. This quiz is designed for students studying biochemistry and protein biology.