Metabolism, Enzymes, and Biomolecules Review

Vocabulary flashcards covering foundational concepts of metabolism, enzyme structure, chemical reaction types, and biomolecule classifications.

Entropy

The natural tendency of everything in the universe towards disorder and falling apart.

Metabolism

The sum total of all biochemical reactions in the cell or body, including both building (anabolic) and breaking down (catabolic) processes.

Anabolism

The branch of metabolism involved in building complex molecules to create greater biological order.

Catabolism

The branch of metabolism involved in breaking down molecules with the intention of releasing energy.

Exergonic reaction

A spontaneous or downhill reaction that releases energy and has a negative change in free energy ($\Delta G$).

Endergonic reaction

A non-spontaneous or uphill reaction that requires an input of energy to proceed and has a positive change in free energy ($\Delta G$).

Coupled reaction

A process in which an exergonic reaction drives an endergonic reaction using an intermediate molecule rather than direct transfer.

Activation energy

The initial energy required to bring reactants to the transition state so a chemical reaction can occur.

Holoenzyme

The complete, active, and fully functional enzyme complex consisting of its protein portion alongside all necessary cofactors or coenzymes.

Apoprotein

The protein portion of an enzyme, which can function on its own or combine with coenzymes and cofactors.

Coenzyme

An organic molecule derived from vitamins that binds to an apoprotein to assist in enzyme function.

Cofactor

An inorganic mineral element, such as zinc or copper, that attaches to an apoprotein to help form an active enzyme.

Monosaccharide

The simplest structural unit of carbohydrates, consisting of a single sugar monomer typically containing three to seven carbon atoms.

Disaccharide

A sugar molecule composed of two monosaccharides linked together, such as sucrose, lactose, or maltose.

Polysaccharide

A complex carbohydrate consisting of ten to hundreds of monosaccharide units joined together.

Glycogen

The primary polysaccharide used for carbohydrate energy storage in animals, primarily located in the liver and muscles.

Cellulose

A structural polysaccharide made by plants that humans cannot digest, serving as dietary fiber in the human gut.

Dehydration synthesis

A chemical reaction that links monomers together by removing a hydroxyl group from one side and a hydrogen from another, releasing a molecule of water.

Hydrolysis

A chemical reaction that breaks down complex polymers into smaller units through the addition of a water molecule.

Triglyceride

A lipid composed of one glycerol molecule linked to three fatty acids by dehydration synthesis, stored in adipose tissue.

Saturated fatty acid

A fatty acid chain containing only single carbon-carbon bonds and maximum hydrogens, allowing tight packing into a solid form at room temperature.

Unsaturated fatty acid

A fatty acid containing one or more double bonds between carbon atoms, creating kinks in the chain that make it liquid at room temperature.

Amphipathic

Describing a molecule, such as a phospholipid, that possesses both hydrophilic (water-loving) and hydrophobic (water-fearing) regions.

Eicosanoids

Lipids derived from the 20-carbon fatty acid arachidonic acid, including prostaglandins and leukotrienes, which mediate immune, temperature, and inflammatory responses.

Amino acid

The monomer subunit of proteins, containing an amino group, a carboxyl group, a hydrogen atom, and a variable R group attached to a central chiral carbon.

Primary structure of a protein

The specific linear order or sequence of amino acids in a polypeptide chain.

Secondary structure of a protein

The regular, repeating spatial folding patterns of a polypeptide chain, such as an alpha helix or a beta pleated sheet.

Tertiary structure of a protein

The irregular, three-dimensional folding pattern of a single polypeptide chain, often stabilized by disulfide bonds.

Quaternary structure of a protein

The functional structural arrangement that results when two or more distinct polypeptide chains interact.

Law of mass action

The principle stating that a reversible chemical reaction is driven toward the side of the equation opposite to the side with the higher concentration of reactants or products.