Matthew amino stuff

This set of flashcards covers key vocabulary and concepts related to amino acids, protein structure, and related biochemical processes for exam preparation.

Amino Acid

Organic compounds that combine to form proteins; they contain an amino group, a carboxyl group, and a unique side chain (R group).

Zwitterion

A molecule that has both a positive and a negative charge, but is overall neutral; common state of amino acids at physiological pH.

Chiral Centre

A carbon atom that has four different substituents, resulting in non-superimposable mirror images (enantiomers).

α-Carbon

The central carbon atom in an amino acid that is attached to an amino group, a carboxyl group, a hydrogen atom, and a variable side chain (R group).

Hydrophobic Interaction

The tendency of nonpolar substances to aggregate in aqueous solutions to minimize their contact with water.

Disulfide Bond

A covalent bond formed between the sulfur atoms of two cysteine residues, important for stabilizing protein structure.

Polar Amino Acids

Amino acids that have side chains with polar functional groups, allowing them to form hydrogen bonds with water.

Nonpolar Amino Acids

Amino acids with side chains that are hydrophobic and do not interact well with water.

Peptide Bond

The covalent bond formed between the carboxyl group of one amino acid and the amino group of another, releasing water.

Secondary Structure

Local folded structures that form within a polypeptide due to interactions between backbone atoms, commonly α-helices and β-sheets.

α-Helix

A right-handed coil formed by hydrogen bonds between amino acids in a polypeptide chain, resulting in a helical structure.

β-Sheet

A secondary structure formed when hydrogen bonds link two or more segments of a polypeptide, creating a sheet-like formation.

Tertiary Structure

The overall three-dimensional shape of a polypeptide, determined by interactions among various side chains.

Quaternary Structure

The structure formed by the interaction of multiple polypeptide subunits in a protein.

Ramachandran Plot

A graphical representation of the dihedral angles (phi and psi) of amino acid residues in protein structures.

Titration Curve

A graph that shows the change in pH as a function of the amount of titrant added, useful for understanding the ionizable groups in amino acids.

Isoelectric Point (pI)

The pH at which an amino acid or protein has no net charge.

Hydrogen Bond

A weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in another.

Ionizable Groups

Functional groups in amino acids and proteins that can gain or lose protons depending on the pH of the environment.

pKa

The negative logarithm of the acid dissociation constant (Ka), a measure of the strength of an acid in solution.

Conjugate Acid-Base Pair

An acid and its corresponding base; the acid donates a proton to form the base.

Alpha-Keratin

A fibrous protein that forms the structural component of hair, nails, and the outer layer of skin.

Fibroin

A protein that makes up silk, characterized by a predominance of β-sheets.

Collagen

The most abundant protein in the body, providing structural support in connective tissues; characterized by a triple helix structure.

Hydrophobic Effect

The phenomenon where nonpolar molecules aggregate in aqueous solutions to minimize their contact with water.

Protein Denaturation

The process by which a protein loses its native conformation and biological activity due to environmental conditions like heat or pH.

Chaperones

Proteins that assist in the proper folding of other proteins, preventing misfolding and aggregation.

Prions

Infectious proteins that can cause misfolding of other proteins, often leading to disease.

Cysteine

An amino acid that can form disulfide bonds, crucial for stabilizing protein structures.

Hydroxyl Group

A functional group (-OH) that classifies an amino acid as polar and can participate in hydrogen bonding.

Amino Group

The -NH2 group in amino acids, which acts as a base and can accept protons.

Carboxyl Group

The -COOH group in amino acids, which serves as an acid and can donate protons.

Hydrophobic Amino Acids

Amino acids that contain nonpolar side chains, typically found in the interior of proteins.

Peptide Sequence

The linear sequence of amino acids in a peptide or protein, determined by the corresponding mRNA.

Native State

The correctly folded and functional form of a protein that is biologically active.

Denatured Protein

A protein that has lost its native structure and, consequently, its functional properties.

Binding Affinity

The strength of the interaction between a protein and its ligand, often influenced by the protein's structure.

Mutations

Changes in the DNA sequence that can affect protein structure and function by altering amino acid sequences.

Epitopes

Specific parts of an antigen recognized by the immune system, particularly by antibodies.

Enantiomers

Stereoisomers that are non-superimposable mirror images of each other, important in amino acid chirality.

Mutant Proteins

Proteins that have undergone mutations, possibly leading to alterations in their function or stability.

Amino Acid Groups

Categories of amino acids based on their side chain properties, such as polar, nonpolar, acidic, or basic.

Biological Macromolecules

Large complex molecules essential for life, including proteins, nucleic acids, carbohydrates, and lipids.

Hydrogen Bonding Capacity

The ability of a functional group to donate or accept hydrogen bonds affecting protein structure.

Folding Pathways

The specific routes and intermediates through which a polypeptide chains folds into its functional tertiary structure.

Thermodynamic Stability

The tendency of a protein to maintain its folded state due to favorable interactions at a given temperature.

Structural Domains

Distinct functional and structural units within a protein that can evolve, function, and exist independently.

Oligomeric Proteins

Proteins composed of multiple subunits, which can be identical (homomers) or different (heteromers).

Peptide Bonds

Covalent chemical bonds formed by a condensation reaction between two amino acids.

Rate of Denaturation

The speed at which proteins lose their native structure, often influenced by temperature, pH, and chemicals.

Polarity in Amino Acids

The distribution of charges within the side chains of amino acids that affects their interactions and solubility.