Biology 131 – Chemistry & Biochemistry Vocabulary

Vocabulary flashcards covering key terms from the lecture notes.

Matter

Anything that takes up space and has mass.

Mass

A physical quantity representing the amount of matter in an object; measured in grams (g).

Element

The simplest type of matter with unique chemical properties; composed of atoms of only one kind.

Atom

Smallest particle of an element that has the chemical characteristics of that element.

Neutron

Electrically neutral subatomic particle; mass = 1.

Proton

Positively charged subatomic particle; mass = 1.

Electron

Negatively charged subatomic particle; mass ≈ 0.

Nucleus

Center of the atom that contains protons and neutrons.

Periodic Table

A chart of elements organized by properties.

Atomic Number

Number of protons in the nucleus of an atom.

Mass Number

Total number of protons and neutrons in an atom's nucleus.

Atomic Mass Unit (Dalton)

Unit used to express atomic and molecular masses; 1 Dalton is roughly the mass of a proton.

Isotope

Different atomic forms of the same element with varying numbers of neutrons; same number of protons.

Natural Abundance

Relative proportions of isotopes of an element found in nature.

Radioactive Isotope

Isotope that emits radiation and can be used for diagnosis, dating, and tracing.

Avogadro's Number

6.022 x 10^23; the number of particles in one mole.

Mole

Amount of substance that contains Avogadro's number of particles.

Molar Mass

Mass of one mole of a substance in grams; numerically equal to the molecular weight in amu.

Water as Solvent

Water is a major solvent in biology; high heat capacity; participates in reactions; cohesive and lubricating.

Solvent

The dissolving medium in a solution.

Solute

Substance dissolved in a solvent.

Solution

Uniform mixture of solute dissolved in solvent.

Suspension

Mixture in which particles settle out unless stirred.

Colloid

Mixture with dispersed particles that remain suspended in a medium.

Emulsion

Two liquids that do not mix; examples include milk.

Gel

A mixture with a solid-like network within a liquid.

Solubility

Ability of one substance to dissolve in another.

Dissociation

Ionic compounds separate into ions when dissolved in water.

Electrolyte

Substance that dissociates in water to conduct electricity (e.g., Na+ and Cl-).

Nonelectrolyte

Substance that dissolves but does not dissociate; does not conduct electricity (e.g., glucose).

pH

Scale of hydrogen ion concentration; neutral is 7; acids below 7; bases above 7.

Acid

Substance that releases H+ in solution.

Base

Substance that accepts H+.

Buffer

Substance that resists changes in pH; bicarbonate is an example.

Essential Elements

About 25 elements essential for life; C, H, O, N make up ~96% of living matter.

Trace Elements

Elements required in minute quantities.

Carbohydrates

Organic molecules made of carbon, hydrogen, and oxygen; monosaccharides, disaccharides, polysaccharides.

Monosaccharide

Simple sugar (e.g., glucose).

Disaccharide

Two simple sugars bound by dehydration synthesis (e.g., sucrose).

Polysaccharide

Long chains of monosaccharides (glycogen, starch, cellulose).

Glycogen

Animal storage polysaccharide.

Starch

Plant storage polysaccharide.

Cellulose

Plant structural polysaccharide; dietary fiber.

Lipids

Diverse group of molecules that are water-insoluble: fats, phospholipids, steroids, eicosanoids, and fat-soluble vitamins.

Fat (Triglyceride)

Glycerol with fatty acids; energy storage, protection, and insulation.

Phospholipid

Lipid with polar phosphate head and nonpolar tail; major membrane component.

Steroid

Lipid with four fused rings (e.g., cholesterol, hormones).

Eicosanoid

Regulatory molecules derived from fatty acids (prostaglandins, thromboxanes, leukotrienes).

Fat-Soluble Vitamins

Vitamins A, D, E, K; nonpolar and soluble in fats.

Protein

Macromolecule built from amino acids; functions include regulation and structure; formed by peptide bonds.

Amino Acid

Building block of protein; contains an amino group, carboxyl group, hydrogen, and a variable R group.

Peptide Bond

Covalent bond linking amino acids in a protein.

Protein Structure

Hierarchy: primary, secondary, tertiary, and quaternary structures.

Nucleic Acids

DNA and RNA; built from nucleotides; store and transfer genetic information.

DNA

Deoxyribonucleic acid; two strands with A-T and C-G base pairing; double helix; deoxyribose and phosphate backbone.

RNA

Ribonucleic acid; usually single-stranded; bases A, G, C, U (uracil replaces thymine).

Nucleotides

Monomer units of nucleic acids; sugar, base, and phosphate.

ATP

Adenosine triphosphate; energy currency of the cell; energy released on hydrolysis.

Activation Energy

Minimum energy reactants must have to start a chemical reaction.

Enzymes

Biological catalysts that lower activation energy; have an active site; may follow induced fit; many are proteins; often end with -ase.

Cofactors/Coenzymes

Non-protein helpers required for enzyme activity; organic cofactors are called coenzymes.

Organic Chemistry

Chemistry of carbon-containing substances; carbon-based molecules predominate in biology.

Inorganic Chemistry

Chemistry of substances that typically do not contain carbon.

Carbon Skeleton

The chain or ring of carbon atoms forming the backbone of organic molecules.

Isomer

Compounds with the same molecular formula but different structures.

Structural Isomer

Isomers with different connectivity of atoms.

Geometric Isomer

Isomers differing in spatial arrangement around a double bond (cis/trans).

Enantiomer

Molecule that is a non-superimposable mirror image of another.

Functional Groups

Specific groups of atoms (e.g., -OH, -C=O, -COOH, -NH2, -PO4) that confer characteristic chemical reactivity.

Hydroxyl (-OH)

Alcohol or sugar functional group.

Carbonyl (-C=O)

Functional group found in aldehydes and ketones.

Carboxyl (-COOH)

Acidic functional group found in carboxylic acids.

Amino (-NH2)

Functional group found in amino acids.

Phosphate (-PO4)

Functional group found in ATP and phospholipids.

Hydrogen Bond

Attraction between a positively charged H and a negatively charged O or N in another molecule.

Covalent Bond

Bond formed by sharing electrons between atoms.

Ionic Bond

Attraction between oppositely charged ions after electron transfer.

Polar Covalent Bond

Covalent bond with unequal sharing of electrons, creating partial charges.

Nonpolar Covalent Bond

Covalent bond with equal sharing of electrons.

Electronegativity

Tendency of an atom to attract electrons in a covalent bond; F, O, Cl, N are highly electronegative.

Hydrophilic

Molecule or portion that is water-loving and dissolves in water.

Hydrophobic

Molecule or portion that is water-fearing and does not dissolve in water.

pH Scale

Logarithmic scale of H+ concentration; 0–14; 7 is neutral;

Buffer (bicarbonate)

Substance that resists changes in pH; bicarbonate is a physiological example.

Osmolality/Osmolarity

Osmolality: particles per kilogram of solution; Osmolarity: particles per liter; 1 Osm = 6.022 x 10^23 particles.

Osmole (Osm)

6.022 x 10^23 particles in 1 liter of solution; used as a unit in physiology (often in mOsm).