Biological Specimens, Accuracy, Precision and Chromatography

This flashcard set covers key vocabulary and concepts from the lecture on metabolism, enzymes, biological specimens, chromatography, and the fundamentals of laboratory testing accuracy and precision.

Metabolism

A series of biochemical reactions occurring in a pathway, consisting of both anabolic and catabolic processes.

Anabolic pathways

Divergent metabolic pathways concerned with building larger molecules from smaller ones, which are reductive, require electrons, and require energy.

Catabolic pathways

Convergent metabolic pathways concerned with breaking molecules down, which are oxidative, donate electrons, and yield energy.

Dynamic steady state

A process in biological systems where a constant concentration of an intermediate is maintained through the balance of synthesis and degradation rates.

Enzymes

Essential biological catalysts, mostly proteins but sometimes RNA molecules, that speed up the rate of reactions without being consumed.

Catalyst

A substance that increases the rate of a chemical reaction by providing an alternative pathway with a lower free energy of activation, without being changed by the reaction.

Transition state

An unstable, high-energy state that a reactant must reach before it can be converted into the final product.

Free energy of activation

The amount of energy required to reach the transition state, which determines the rate of a chemical reaction.

Active site

A specific region of an enzyme, often formed by only a few amino acids, where the substrate binds to be converted into a product.

Substrate

The reactant or starting material that binds to the active site of an enzyme in a catalyzed reaction.

Michaelis Menten plot

A graph measuring the rate of an enzyme-catalyzed reaction relative to increasing substrate concentration.

Whole blood

A biological specimen consisting of cellular components (red cells, white cells, and platelets) suspended in the liquid component known as plasma.

Plasma

The liquid component of blood containing water, proteins (like human albumin and antibodies), electrolytes, glucose, and coagulation proteins.

Human albumin

A major protein found in the liquid component of human blood.

Serum

The liquid component of blood that remains after the blood has clotted, effectively consisting of plasma without the clotting proteins.

Coagulation proteins

Proteins dissolved in plasma, such as fibrinogen, that are essential for the blood clotting process.

Anticoagulant

A substance added to a blood sample to prevent coagulation, allowing for the collection of plasma or whole blood for testing.

EDTA ($\text{Ethylenediamide tetraacetic acid}$)

An anticoagulant that prevents blood from clotting by binding to or chelating divalent cations like calcium ($Ca^{2+}$).

Sodium citrate

A reversible anticoagulant that chelates calcium and is frequently used in the laboratory for conducting coagulation studies.

Sodium fluoride

An additive used in blood collection tubes to preserve glucose levels for accurate measurement.

Chromatography

A technique used to purify or analyze mixtures by distributing molecules between a stationary phase and a mobile phase.

Stationary phase

The part of a chromatography system that remains fixed in place, such as the beads in a column matrix.

Mobile phase

The part of a chromatography system, usually a buffer solution, that flows through the system carrying the sample molecules.

Ion exchange chromatography

A separation method where molecules are sorted based on their charge relative to a positively or negatively charged matrix.

Size exclusion chromatography

Also known as gel filtration, this method separates molecules by size and shape, allowing large molecules to elute first because they cannot enter the hollow beads of the stationary phase.

Affinity chromatography

A purification technique that uses a specific ligand attached to beads to bind a target molecule, which is later eluted by adding a free form of that ligand.

Accuracy

A measure of how close a measurement or experimental result is to the true value.

Precision

A measure of the reproducibility or repeatability of results, indicating how close multiple measurements are to each other.

Sensitivity

The ability of a test to detect very small amounts of an analyte or very small changes in its concentration.

Specificity

The degree to which a test can distinguish the target analyte from other interfering substances.