Protein Structure and Function Lecture Flashcards

Vocabulary practice flashcards covering protein structures (primary, secondary, tertiary, quaternary), bonding types, denaturation, clinical examples (sickle cell disease and hemoglobin), and analytical methods based on the lecture.

Dehydration reaction

A chemical reaction in which two molecules are combined to form one molecule with the loss of one water molecule, such as during the formation of a peptide bond.

Hydrolysis reaction

The reverse of a dehydration reaction, where one water molecule is used to split one molecule into two molecules.

Peptide bond

A covalent bond formed via a single dehydration reaction that connects neighboring amino acids together in a polypeptide chain.

Space filling model

A structural representation where individual atoms or amino acids of a protein are depicted as balls to show its three-dimensional structure.

Ribbon model

A visual representation designed to showcase the three-dimensional architecture of a protein that appears like a ribbon.

Wireframe model

A visual representation of a protein's three-dimensional structure that resembles a collection of barbed wire.

Transport protein

A protein responsible for moving substances either into or out of a cell.

Enzyme

A specialized protein that accelerates or speeds up the rate of a chemical reaction.

Substrates

The reactant molecules that bind to an enzyme so it can accelerate the chemical reaction to form products.

Insulin

A protein hormone synthesized by pancreatic beta cells that regulates blood sugar by signaling cells to absorb excess glucose.

Antibody protein

An immune system protein circulating in the blood that acts like a heat-seeking missile, specifically binding to foreign invaders such as flu viruses or bacteria to facilitate their destruction.

Polypeptide backbone

The repeating structural chain of a protein formed by the amino and carboxyl functional groups of its constituent amino acids.

Primary structure

The unique sequence or linear order of amino acids within a polypeptide chain, determined by genetic information.

Secondary protein structure

Localized coils or folds in a polypeptide formed by hydrogen bonding between the amino and carboxyl functional groups of the polypeptide backbone.

Alpha helix

A coiled secondary structure within a protein that resembles a spiral staircase, formed through hydrogen bonding in the polypeptide backbone.

Beta pleated sheet

A folded, sheet-like secondary structure within a protein that creates a flat surface through hydrogen bonding in the polypeptide backbone.

Tertiary protein structure

The overall three-dimensional shape of a polypeptide chain determined by interactions among the R groups (side chains) of the various amino acids.

Disulfide bridge

A covalent bond containing two sulfur atoms in a row that bridges and connects two neighboring R groups in tertiary protein structure.

Van der Waals interactions

Interactions between neighboring R groups where opposing charges or partial charges balance out to distribute charge evenly.

Quaternary protein structure

The overall protein structure resulting from the connection and aggregation of two or more individual polypeptide chains.

Collagen

A fibrous, rope-like structural protein composed of three intertwined polypeptide chains wrapped around one another.

Hemoglobin

A globular transport protein possessing quaternary structure composed of four polypeptide subunits (two alpha and two beta) that carries $O_2$ and $CO_2$ on red blood cells.

Sickle cell disease

A genetic blood disorder caused by an amino acid substitution of valine for glutamate at position $6$ of hemoglobin, deforming red blood cells into a crescent or sickle shape.

Native structure

The correct, natural, and biologically functional three-dimensional conformation of a protein.

Denaturation

A process in which a protein unravels and loses its three-dimensional shape and biological function due to extreme environmental factors such as changes in pH, salt concentration, or temperature.

Renaturation

The process by which a denatured protein regains its correct three-dimensional shape and biological function when the denaturing agent is removed.

X-ray crystallography

A laboratory method used to determine the three-dimensional structure of a protein by directing an X-ray beam at a crystallized protein and analyzing the resulting diffraction pattern.

Cryogenic electron microscopy (cryo-EM)

A technique to elucidate protein three-dimensional structure by flash-freezing samples and passing beams of electrons through them without requiring the protein to be crystallized.

Bioinformatics

An approach that uses computational methods and computer-based data to predict and determine the three-dimensional structure of proteins from amino acid sequences.

Transcription

The biological process in which DNA directs the synthesis of messenger RNA (mRNA).

Translation

The biological process, also known as protein synthesis, in which messenger RNA (mRNA) is used to produce a polypeptide chain.

Gene expression

The complete pathway from DNA to messenger RNA through transcription and from messenger RNA to protein through translation.