Metabolism — Part 1 Vocabulary

Vocabulary flashcards defined verbatim from the Metabolism — Part 1 lecture materials covering enzymes, cellular systems, chemistry basics, and metabolic pathways.

Metabolism

The sum of all chemical reactions occurring in a cell or organism, forming a continuous network of thousands of simultaneous reactions that obtain, release, and use energy.

Enzyme

A specialised protein that acts as a biological catalyst inside living cells to speed up reactions without being permanently changed or consumed.

Catalyst

A substance that increases the rate of a chemical reaction and is not consumed in the process.

Substrate

A specific molecule that binds to an enzyme's active site to undergo a chemical reaction.

Active site

A region on an enzyme with a specific three-dimensional shape where a complementary substrate molecule binds.

Product

The substance or substances released from the active site of an enzyme after a chemical reaction occurs.

Enzyme-substrate complex

A temporary structure formed when a complementary substrate molecule enters and binds to an enzyme's active site.

Lock-and-Key Model

A simplified scientific model where the enzyme's active site acts as a fixed lock and only a substrate with a complementary shape acts as the matching key.

Anabolism

Metabolic processes that build larger, more complex molecules from smaller, simpler ones, requiring an input of energy.

Catabolism

Metabolic processes that break down larger, complex molecules into smaller components, releasing energy in the process.

Cell Membrane

The cellular structure that separates the cell's internal environment from its external surroundings and controls what enters and exits.

Nutrition

The intake of materials—such as nutrients, water, and oxygen—needed to fuel metabolic reactions inside a cell.

Excretion

The removal of waste products produced by metabolism to keep a cell's internal environment stable.

Element

A pure substance consisting of one type of atom only that cannot be broken down chemically into simpler substances.

Atom

The basic unit of matter, consisting of a central nucleus containing protons and neutrons, surrounded by electrons arranged in shells.

Ion

An atom that has gained or lost electrons, creating an imbalance between positive protons and negative electrons, giving it an overall charge.

Molecule

Two or more atoms joined together by chemical bonds.

Ionic Bond

A chemical bond formed when an electron is transferred from one atom to another, creating oppositely charged ions that attract electrostatically.

Covalent Bond

A stable chemical bond formed when two atoms share a pair of electrons.

Carbon

The backbone element of all biological molecules, containing 6 protons and 4 valence electrons that allow it to form four covalent bonds.

Structural formula

A diagrammatic representation of a molecule where lines represent shared electron pairs forming covalent bonds between atoms.

Molecular formula

A notation, such as $CH_4$, that shows the number and type of each atom present in a molecule but not their arrangement in space.

Justify

An MYP command term meaning to give valid reasons or evidence to support an answer or conclusion.

Describe

An MYP command term meaning to give a detailed account.

Explain

An MYP command term meaning to give a detailed account including reasons or causes.

Distinguish

An MYP command term meaning to give the differences between two or more items or concepts.