Matthews real amino acid cards

These flashcards cover key terms and concepts related to amino acids, protein structure, and biochemistry, aiding in exam preparation.

Amino Acid

Building blocks of proteins, consisting of an amino group, a carboxylic acid group, and a side chain (R group).

Zwitterion

A molecule that has both positive and negative charges, resulting in a net neutral charge, commonly found in amino acids at physiological pH.

Alpha Carbon (α-carbon)

The central carbon atom of an amino acid to which the amino group, carboxylic acid group, hydrogen atom, and R group are attached.

Chiral Center

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

Enantiomer

A type of stereoisomer that are mirror images of each other that cannot be superimposed.

L-amino Acid

The form of amino acids that is commonly found in proteins. They have an 'L' configuration at the α-carbon.

D-amino Acid

The form of amino acids that is not typically found in proteins; these have a 'D' configuration at the α-carbon.

Hydrophobic R groups

Amino acid side chains that are non-polar and repel water, often found buried within protein structures.

Polar R groups

Amino acid side chains that are hydrophilic and can form hydrogen bonds with water.

Ionic Bonds in Proteins

Attractions between positively and negatively charged side chains of amino acids, contributing to protein structure.

Hydrogen Bonds in Proteins

Weak interactions between the hydrogen atom of a polar group and an electronegative atom, stabilizing protein structure.

Secondary Structure

Local folding patterns within a protein, primarily alpha helices and beta sheets, stabilized by hydrogen bonds.

Alpha Helix

A coiled structure in proteins, formed by hydrogen bonds between every fourth amino acid.

Beta Sheet

A secondary structure formed by hydrogen bonding between segments of polypeptide chains lying side by side.

Peptide Bond

A covalent bond formed between the carboxyl group of one amino acid and the amino group of another amino acid.

Tertiary Structure

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

Quaternary Structure

The structure formed by the assembly of multiple polypeptide chains into a single functional protein.

Hydrophobic Interactions

The tendency of non-polar molecules to aggregate in aqueous solutions to minimize contact with water.

Disulfide Bond

A covalent bond formed between two cysteine residues, providing stability to protein structures.

Titration Curve

A graphical representation of the change in pH as an acid or base is added to a solution, illustrating ionization states.

Isoelectric Point (pI)

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

Peptide

A polymer of amino acids linked by peptide bonds, typically consisting of two or more amino acids.

Polypeptide

A long chain of amino acids containing more than fifty residues.

Dipeptide

A peptide formed from two amino acids.

Tripeptide

A peptide formed from three amino acids.

pKa

The pH at which half of the molecules of a given species are ionized.

Henderson-Hasselbalch Equation

An equation used to calculate the pH of a buffer solution from the concentration of the acid and its conjugate base.

Buffer

A solution that resists changes in pH upon the addition of small amounts of acid or base.

Titration

The process of gradually adding a solution of known concentration to a solution of unknown concentration to determine its concentration.

Protein Folding

The process by which a linear polypeptide chain folds into its biologically active three-dimensional structure.

Chaperone Proteins

Proteins that assist in the proper folding of other proteins.

Amyloids

Aggregates of misfolded proteins that can form fibrillary structures associated with diseases.

Phosphorylation

The addition of a phosphate group to a protein or molecule, potentially altering its function.

Denaturation

The process by which proteins lose their three-dimensional structure due to environmental factors like temperature or pH.

Hydrophobic Effect

A thermodynamic phenomenon where non-polar molecules aggregate to minimize their exposure to polar solvents.

Aggregation

The process by which proteins or biomolecules clump together, often leading to loss of function.

Molecular Chaperones

Proteins that assist in the folding of other proteins and prevent aggregation.

Translational Regulation

The control of the translation of mRNA into proteins, affecting protein synthesis and activity.

Covalent Modification

The process by which a molecule is chemically modified through covalent bonds, affecting its function.

Inhibitor

A molecule that binds to an enzyme and decreases its activity.

Substrate

The reactant in a chemical reaction upon which an enzyme acts.

Active Site

The specific region of an enzyme where the substrate binds and the reaction occurs.

Allosteric Regulation

The regulation of an enzyme's activity by the binding of an effector molecule at a site other than the active site.

Enzyme Kinetics

The study of the rates of enzyme-catalyzed reactions.

Feedback Inhibition

A regulatory mechanism in which the end product of a metabolic pathway inhibits an upstream process.

Amino Acid Composition

The specific sequence and types of amino acids that make up a protein.

Protein Database (PDB)

A repository of 3D structural data of proteins.

Protein Misfolding Diseases

Diseases caused by the misfolding of proteins leading to aggregates that disrupt cellular function.

Prion Disease

A type of infectious disease caused by misfolded proteins that induce other proteins to misfold.

Hydrogen Bonding

Forces that occur when a hydrogen atom covalently bonded to a highly electronegative atom is attracted to another electronegative atom.

Tertraprime Complex

A protein complex formed by multiple polypeptide chains, often found in multisubunit proteins.

Enzyme Substrate Complex

The intermediate formed when a substrate binds to the active site of an enzyme.

Binding Affinity

A measure of the strength of the interaction between an enzyme and its substrate.

Thermodynamics

The branch of physical science that deals with the relations between heat and other forms of energy.

Activation Energy

The minimum energy required for a chemical reaction to occur.

Transition State

A state during a chemical reaction at which the system is at maximum energy and most unstable.

Coiled Coil

A structural motif in proteins where two or more α-helices coil around each other.

Protein Domain

A distinct functional and structural unit within a protein, often capable of independent folding.

Motif

A recurring combination of secondary structure elements within proteins.

Aggregate

A clump or cluster of molecules, often referring to proteins that no longer function properly due to misfolding.

Functional Group

A specific group of atoms that confer characteristic properties to a molecule.

Structural Protein

Proteins that provide support, shape, and elasticity to tissues.

Cryo-Electron Microscopy

A method used to determine the structures of proteins at low temperatures.

Nuclear Magnetic Resonance (NMR) Spectroscopy

A technique used to determine the structure of proteins in solution.

X-ray Crystallography

A method for determining the atomic structure of a crystal by observing the diffraction of X-rays.

Protein Misfolding

The incorrect folding of a protein that can lead to aggregation and loss of function.

Hydrophobic Core

The inner region of a protein where non-polar side chains are clustered away from water.

Hydrophilic Surface

The outer region of a protein that interacts favorably with water.

Covalent Cross-Linking

Links established between polypeptide chains via covalent bonds to enhance structural integrity.

Intrinsic Disorder

Refers to regions of proteins that do not have a stable structure under physiological conditions.

Fibrous Protein

Proteins characterized by elongated shapes and roles in providing structural support.

Globular Protein

Proteins that are generally rounded in shape and often have functional roles.

Mechanical Properties of Proteins

Characteristics like elasticity, strength, and flexibility that determine how proteins respond to mechanical forces.

Average Molecular Mass of Amino Acids

The average mass of the 20 standard amino acids, important for calculating protein mass.

Protein Stabilization,

The processes and interactions that maintain the three-dimensional conformation of proteins.

Metastable State

A state of a protein that is stable but can be easily perturbed, leading to refolding.

Protein Modifications

Post-translational modifications that alter protein function, such as phosphorylation or glycosylation.

Biophysical Techniques

Methods used to study the physical properties of proteins, including their structure and dynamics.