Principles of Chemistry

Vocabulary flashcards covering key chemistry and biochemistry concepts from the lecture notes.

States of matter

The forms matter takes: solid, liquid, and gas.

Matter

Anything that occupies space and has mass; it can be seen, smelled, and felt.

Element

A substance that cannot be broken down into simpler substances by ordinary chemical means; represented by one- or two-letter symbols.

Atom

The smallest unit of an element that retains its properties; consists of a nucleus with protons and neutrons and surrounding electrons.

Nucleus

Central part of an atom containing protons and neutrons.

Proton

Positively charged particle in the atomic nucleus.

Neutron

Electrically neutral particle in the atomic nucleus.

Electron

Negatively charged particle surrounding the nucleus in electron shells.

Electron shell

Regions around the nucleus where electrons are located.

Atomic symbol

One- or two-letter abbreviation representing an element (e.g., H, Na, Fe).

Compound

A substance formed from two or more different elements with properties distinct from those elements.

Molecule

Two or more atoms bound together by chemical bonds.

Mixture

Matter composed of two or more substances not chemically bonded.

Chemical bonds

Forces that hold atoms together in molecules.

Ionic bond

Bond formed by transfer of electrons, creating oppositely charged ions that attract.

Cation

Positively charged ion.

Anion

Negatively charged ion.

Sodium ion (Na+)

Sodium atom that has lost one electron, forming Na+.

Chloride ion (Cl-)

Chlorine atom that has gained one electron, forming Cl-.

Sodium chloride (NaCl)

Compound formed by Na+ and Cl- (table salt).

Hydrogen bond

A weak bond between hydrogen and a highly electronegative atom (e.g., as in base pairing).

Synthesis

A+B → AB; chemical reaction where components combine to form a larger molecule.

Decomposition

AB → A+B; chemical reaction where a compound breaks into simpler substances.

Displacement reaction

A reaction where an element replaces another in a compound (e.g., AB+CD → AD+CB).

Energy

The ability to do work or move matter; energy does not have mass.

Chemical energy

Stored energy in chemical bonds; released when bonds are broken.

Electrical energy

Energy from the movement of charged particles (electrons).

Mechanical energy

Energy involved in moving matter.

Radiant energy

Energy carried by electromagnetic waves (visible light, UV, X-rays).

Monosaccharide

Simple sugar; the basic unit of carbohydrates (e.g., glucose, fructose, galactose).

Glucose

A six-carbon monosaccharide; primary energy source for cells; stored as glycogen.

Fructose

A monosaccharide found in fruits; sweeter than glucose.

Galactose

A monosaccharide that combines with glucose to form lactose.

Disaccharide

Carbohydrate formed from two monosaccharides (e.g., sucrose, lactose).

Sucrose

Disaccharide: glucose + fructose; common table sugar.

Lactose

Disaccharide: glucose + galactose; sugar in milk.

Polysaccharide

Large carbohydrate polymers; e.g., glycogen, starch, cellulose.

Glycogen

Storage form of glucose in liver and skeletal muscle.

Lipid

Hydrophobic organic compounds (fats, oils, cholesterol) insoluble in water; energy storage and membranes.

Triglyceride

Three fatty acids bound to a glycerol backbone; main form of stored fat.

Glycerol

Three-carbon backbone of triglycerides; modified simple sugar used in fat synthesis.

Fatty acid

Linear hydrocarbon chain with carboxyl group (-COOH); building block of lipids.

Saturated fatty acid

Fatty acids with only single bonds between carbon atoms; typically solid at room temp.

Unsaturated fatty acid

Fatty acids with one or more double bonds between carbons; typically liquid at room temp.

Monounsaturated fatty acid

Unsaturated fatty acid with one double bond.

Polyunsaturated fatty acid

Unsaturated fatty acid with two or more double bonds.

Phospholipid

Modified triglyceride with two fatty acids and a phosphate group; major component of cell membranes.

Polar head

Hydrophilic (water-loving) region of a phospholipid.

Nonpolar tail

Hydrophobic (water-repelling) region of a phospholipid.

Steroid

Flat molecules with four interlocking hydrocarbon rings; cholesterol is a key example.

Cholesterol

Steroid molecule formed in the liver; precursor for all body steroids; component of cell membranes.

Lipoprotein

Particles that transport fatty acids and cholesterol in the bloodstream (e.g., LDL, HDL).

Protein

Macromolecule composed of amino acids; essential structural and functional component of cells.

Amino acid

Building blocks of proteins; 20 types; some are essential (must be obtained from diet).

Essential amino acid

Amino acids that cannot be synthesized by the body and must be ingested.

Globular protein

Functional, compact, spherical proteins (e.g., antibodies, hormones, enzymes).

Fibrous protein

Structural proteins with extended, strand-like shapes (e.g., keratin, collagen).

Denaturation

Unfolding of proteins due to changes in pH or temperature; often reversible or irreversible.

Nucleic acid

Large polymers (DNA and RNA) made of nucleotides; store and express genetic information.

DNA

Deoxyribonucleic acid; genetic material of cells; double helix; replicates before cell division.

RNA

Ribonucleic acid; usually single-stranded; types include mRNA, tRNA, rRNA; uracil replaces thymine.

Nucleotide

Building block of nucleic acids; consists of a sugar, phosphate, and base.

Deoxyribose

Five-carbon sugar in DNA's backbone.

Phosphate

Phosphate group forming part of the nucleic acid backbone.

Adenine

Purine base; pairs with thymine in DNA and with uracil in RNA.

Thymine

Pyrimidine base in DNA; pairs with adenine.

Cytosine

Pyrimidine base; pairs with guanine.

Guanine

Purine base; pairs with cytosine.

Uracil

Pyrimidine base in RNA; replaces thymine.

mRNA

Messenger RNA; copies genetic code from DNA and carries it to ribosomes.

tRNA

Transfer RNA; brings amino acids to ribosomes during protein synthesis.

rRNA

Ribosomal RNA; component of ribosomes and facilitates protein synthesis.

ATP

Adenosine triphosphate; high-energy molecule with three phosphate groups; produced in mitochondria.

ADP

Adenosine diphosphate; formed when ATP loses a phosphate group and energy is released.