Unit 2 Modules 3–6: Basic Chemistry and Biological Macromolecules

A comprehensive set of vocabulary flashcards covering the key terms from Unit 2 Modules 3–6 on atoms, chemical bonding, water properties, and biological macromolecules.

Atom

The basic unit of matter composed of protons, neutrons, and electrons.

Proton

Positively charged (+1) subatomic particle located in the nucleus.

Neutron

Neutral (0 charge) subatomic particle located in the nucleus.

Electron

Negatively charged (–1) subatomic particle found in orbitals around the nucleus.

Electron Shell

Energy level where electrons reside; first shell holds up to 2 electrons, second and third up to 8 each.

Atomic Number

The number of protons in an atom’s nucleus.

Mass Number

The total number of protons and neutrons in an atom’s nucleus.

Valence Electrons

Electrons in the outermost shell that influence chemical bonding.

Chemical Bonds

Attractive forces that hold atoms together by transferring or sharing electrons.

Ionic Bond

Bond created by transfer of electrons and attraction between oppositely charged ions.

Covalent Bond

Bond formed when atoms share electrons; may be polar or non-polar.

Electronegativity

An atom’s tendency to attract bonding electrons.

Hydrogen Bond

Weak attraction between a hydrogen covalently bonded to an electronegative atom and another electronegative atom.

Adhesion

Attraction between water molecules and other substances.

Cohesion

Attraction between water molecules due to hydrogen bonding.

Surface Tension

Film-like surface of water produced by cohesive hydrogen bonds.

Hydrophilic

Having an affinity for water; readily dissolves or interacts with it.

Hydrophobic

Repelled by water; lacking affinity for it.

Solute

Substance that is dissolved in a solution.

Solution

Homogeneous mixture of solute dispersed in a solvent.

Solvent (Water as Excellent Solvent)

Property of water that allows it to dissolve ionic and polar substances effectively.

Temperature Regulation (Water)

Water’s ability to absorb heat with minimal temperature change due to hydrogen bond dynamics.

Density Anomaly

Phenomenon where ice is less dense than liquid water because of stable hydrogen-bonded crystalline structure.

Organic Molecules

Compounds containing carbon-to-hydrogen covalent bonds that store significant chemical energy.

Inorganic Molecules

Compounds lacking carbon-hydrogen bonds and storing little chemical energy.

Polymer

Large molecule composed of repeating monomer subunits.

Monosaccharide

Single sugar unit; monomer of carbohydrates.

Polysaccharide

Carbohydrate polymer made of many monosaccharides.

Carbohydrates

Sugars and their polymers that provide short-term energy and structural support.

Glucose

Six-carbon monosaccharide serving as a primary energy source.

Lipids

Hydrophobic molecules such as fats, phospholipids, steroids, and waxes used for energy storage and barriers.

Fatty Acids

Hydrocarbon chains that are building blocks of many lipids.

Fats

Triglyceride lipids specialized for long-term energy storage.

Phospholipids

Lipids containing a phosphate group that form biological membranes.

Steroids

Lipids with four fused carbon rings that help regulate biological processes.

Waxes

Lipid type that provides waterproof protective coatings.

Proteins

Polymers of amino acids that perform most cellular functions.

Amino Acid

Protein monomer composed of an amino group, carboxyl group, and variable side chain.

Protein Folding

Process by which a protein assumes its functional three-dimensional shape.

Enzyme

Protein catalyst that speeds up chemical reactions by lowering activation energy.

Nucleic Acid

Polymer of nucleotides that stores and transmits genetic information.

Nucleotide

Monomer of nucleic acids consisting of a phosphate, sugar, and nitrogenous base.

DNA

Double-stranded nucleic acid that stores genetic information in the nucleus.

RNA

Single-stranded nucleic acid that participates in protein synthesis and can leave the nucleus.