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Biochem-Amino Acids
Med’11 Biochemistry Proteins
Question | Answer |
---|---|
Proteins | Polymers of amino acids |
Amino acids | The basic building blocks of polymers |
List the biological functions of proteins. | 1. Catalytic Function 2. Transport and Storage 3. Coordinated Motion 4. Structural & Mechanical Support 5. Defense Function 6. Generation & Transmission of Nerve Impulses 7. Control of Growth & Differentiation |
What does each amino acid have? | An amino group, a carboxyl group, a hydrogen atom, and a side chain bonded to an alpha-carbon atom. |
Describe the amino acid at physiologic pH. | The carboxyl dissociates, forming the negatively charged ion. The amino group is protonated, forming the positively charged ion. |
How many acids make up the proteins in the body? | 20 |
How do different side chains vary from each other? | Size Shape Charge Hydrogen-bonding capacity Chemical reactivity |
What is the simplest amino acid? | Glycine (Gly - G) |
What are the polar, positively charged amino acids? | Lysine (Lys - K) Arginine (Arg - R) Histidine (His - H) |
What are the polar, negatively charged amino acids? | Aspartic Acid (Asp - D) Glutamic Acid (Glu - E) |
Which 2 amino acids have sulfur? | Methionine (Met - M) Cysteine (Cys - C) |
What are the amino acids with the aromatic R-groups? Which are nonpolar, and which are polar? | Nonpolar: Phenylalanine Trytophan Polar: Tyrosine (because it has a hydroxyl group) |
Give some examples of hydrophobic amino acids. | Glycine Methionine Proline |
Give an example of a polar, uncharged amino acid. | Cysteine |
Which amino acid has a nonpolar, aliphatic, cyclic R group? | Proline |
Which are the most hydrophilic R groups? | The amino acids that are either positively or negatively charged. +ve: Lys - His - Arg -ve: Asp - Glu |
What is the difference between essential and nonessential amino acids? | Essential: cannot be synthesized in the body and must be taken in the diet. Nonessential: can be synthesized in the body; not needed in the diet |
What is the difference between ketogenic, glucogenic, and mixed amino acids? | Ketogenic: give ketone bodies Glucogenic: give glucose Mixed: give both ketone bodies and glucose |
Which amino acid is both nonessential and ketogenic and glucogenic? | Tyrosine |
Which amino acids are both essential and ketogenic and glucogenic? | Phenylalanine Tryptophan Isoleucine |
Which amino acids are both essential and ketogenic? | Leucine Lysine |
What is the largest amino acid? | Tryptophan |
Which amino acid does not have a stereoisomer? | Glycine |
If the amino acid has a stereoisomer, the alpha-carbon is called _____. | asymmetric (chiral) |
What are the 2 possible forms of stereoisomers? Which one is found in amino acid residues? | L-form and D-form. L-form |
How does an amino acid behave in an acidic medium? Basic medium? What is this property called? | Acidic medium: proton acceptor Basic medium: proton donor This is an amphoteric property. |
What is the pI? | Isoelectric point: a specific pH where the amino acid is fully ionized but electrically neutral. |
What is the amino acid called at pI? | Zwitter ion |