Bioquímica

Cards · 36

Enzyme

A biological catalyst, usually a protein, that speeds up chemical reactions by lowering the activation energy.

Substrate

The specific molecule upon which an enzyme acts during a chemical reaction.

Active Site

The region of an enzyme where the substrate binds and the chemical reaction is catalyzed.

ATP (Adenosine Triphosphate)

The primary energy currency of the cell, storing energy in its high-energy phosphate bonds.

Allosteric Site

A binding site on an enzyme other than the active site, where a regulatory molecule can bind and alter enzyme activity.

Glycolysis

A metabolic pathway that breaks down glucose into pyruvate, producing a net gain of 2 ATP and 2 NADH molecules.

Gluconeogenesis

The metabolic process of synthesizing glucose from non-carbohydrate precursors such as pyruvate, lactate, or glycerol.

Citric Acid Cycle

A series of chemical reactions in the mitochondrial matrix that oxidizes acetyl-CoA to CO2, generating NADH, FADH2, and ATP.

Oxidative Phosphorylation

The synthesis of ATP using energy derived from the electron transport chain and chemiosmosis in the mitochondria.

Electron Transport Chain

A series of protein complexes in the inner mitochondrial membrane that transfer electrons and pump protons to form a gradient.

ATP Synthase

An enzyme enzyme complex that utilizes the proton motive force to synthesize ATP from ADP and inorganic phosphate.

Amino Acid

The monomeric building block of proteins, consisting of an amino group, a carboxyl group, a hydrogen atom, and a variable R group.

Peptide Bond

A covalent amide linkage formed between the carboxyl group of one amino acid and the amino group of another via dehydration synthesis.

Primary Structure

The linear sequence of amino acids in a polypeptide chain.

Secondary Structure

Local folding patterns of a polypeptide chain, primarily alpha-helices and beta-sheets, stabilized by hydrogen bonds.

Tertiary Structure

The overall three-dimensional shape of a single polypeptide chain, stabilized by hydrophobic interactions, ionic bonds, and disulfide bridges.

Quaternary Structure

The structural arrangement resulting from the assembly of two or more polypeptide subunits into a functional protein complex.

Denaturation

The loss of a protein's native three-dimensional structure and biological function without breaking peptide bonds.

DNA (Deoxyribonucleic Acid)

A double-stranded nucleic acid carrying genetic instructions, composed of deoxyribose sugars, phosphate groups, and nitrogenous bases.

RNA (Ribonucleic Acid)

A single-stranded nucleic acid involved in protein synthesis and gene regulation, containing ribose sugar and uracil instead of thymine.

Nucleotide

The monomer of nucleic acids, consisting of a nitrogenous base, a five-carbon sugar, and one or more phosphate groups.

Transcription

The enzymatic process of copying a specific segment of DNA into messenger RNA (mRNA).

Translation

The process by which ribosomes synthesize proteins using the genetic code carried by mRNA.

Competitive Inhibition

Inhibition where an inhibitor molecule directly competes with the substrate for binding to the active site of an enzyme.

Non-competitive Inhibition

Inhibition where an inhibitor binds to an allosteric site, altering enzyme conformation so that substrate binding or catalysis is reduced.

Feedback Inhibition

A regulatory mechanism where the end product of a metabolic pathway inhibits an upstream enzyme to prevent overproduction.

Lipid

A diverse group of hydrophobic organic molecules, including fats, phospholipids, and steroids, insoluble in water.

Phospholipid

An amphipathic lipid consisting of glycerol attached to two fatty acids and a phosphate group, forming cellular membranes.

Zwitterion

A molecule containing both positive and negative functional groups, resulting in a net neutral electrical charge.

Coenzyme

An organic non-protein helper molecule, often derived from vitamins, required for an enzyme to catalyze a reaction.

Cofactor

A non-protein chemical compound or metallic ion required for an enzyme's biological activity.

Isoelectric Point (pI)

The specific pH at which a molecule, such as an amino acid or protein, carries no net electrical charge.

Catabolism

The metabolic breakdown of complex molecules into simpler ones, releasing energy.

Anabolism

The metabolic synthesis of complex molecules from simpler ones, requiring an input of energy.

Km (Michaelis Constant)

The substrate concentration at which an enzyme-catalyzed reaction reaches half of its maximum velocity (Vmax).

Vmax

The maximum rate of an enzyme-catalyzed reaction when the enzyme is fully saturated with substrate.