Biology: Chapter 3 - The Chemistry of Organic Molecules

A complete set of vocabulary flashcards based on the Chapter 3 lecture covering organic molecules, biomolecules, and cellular chemical reactions.

Organic molecules

Molecules that contain both carbon and hydrogen atoms.

Four classes of biomolecules

Carbohydrates, lipids, proteins, and nucleic acids.

Functional groups

Clusters of specific atoms bonded to the carbon skeleton that determine the chemical reactivity and polarity of organic molecules.

Isomers

Organic molecules with identical molecular formulas but different arrangements of atoms.

Polymer

A molecule composed of many repeating units called monomers.

Dehydration reaction

A chemical reaction used to connect monomers into polymers by forming a covalent bond and producing water.

Hydrolysis reaction

A chemical reaction in which a water molecule is added to break a covalent bond, used to degrade polymers into monomers.

Enzymes

Molecules that act as catalysts to speed up chemical reactions without being consumed or changed themselves.

Carbohydrates

Biomolecules used as an energy source and structural material, containing carbon, hydrogen, and oxygen atoms in a $1:2:1$ ratio.

Monosaccharide

A single sugar molecule, also called a simple sugar, with a backbone of $3$ to $7$ carbon atoms.

Disaccharide

A molecule containing two monosaccharides joined together by dehydration synthesis, such as lactose, sucrose, or maltose.

Polysaccharide

A polymer of monosaccharides used for energy storage (e.g., starch, glycogen) or structural support (e.g., cellulose, chitin, peptidoglycan).

Lipids

Large, nonpolar biomolecules that are insoluble in water, including fats, oils, phospholipids, steroids, and waxes.

Triglycerides

Also known as fats and oils, these molecules consist of one glycerol molecule linked to three fatty acids.

Unsaturated fatty acids

Fatty acids containing one or more double bonds between carbons; they tend to be liquid at room temperature.

Saturated fatty acids

Fatty acids with no double bonds between carbons; they tend to be solid at room temperature.

Phospholipids

Membrane components consisting of one glycerol linked to two nonpolar fatty acid tails and a polar modified phosphate group head.

Steroids

Lipids composed of four fused carbon rings, such as cholesterol, testosterone, and estrogen.

Waxes

Long-chain fatty acids connected to carbon chains containing alcohol functional groups, providing waterproof protection.

Proteins

Polymers of amino acids linked together by peptide bonds.

Peptide bond

A covalent bond between amino acids.

Denatured

The state of a protein that has lost its proper shape due to exposure to certain chemicals, pH changes, or high temperature.

Primary structure

The linear sequence of amino acids in a polypeptide.

Secondary structure

Protein level characterized by alpha helices and beta sheets held by hydrogen bonds.

Tertiary structure

The overall three-dimensional shape of a polypeptide, stabilized by various interactions like hydrophobic bonding and disulfide bridges.

Quaternary structure

Protein level consisting of more than one folded polypeptide interacting to perform a biological function.

Chaperone proteins

Proteins that help other proteins fold into their normal shapes and may correct misfolding.

Prions

Misfolded proteins implicated in fatal brain diseases known as TSEs, such as Mad cow disease.

Nucleic acids

Polymers of nucleotides, namely DNA and RNA.

Nucleotide

A monomer of nucleic acids composed of a phosphate group, a pentose sugar, and a nitrogen-containing base.

DNA (deoxyribonucleic acid)

Genetic material that stores information for its own replication and for the sequence of amino acids in proteins.

RNA (ribonucleic acid)

A nucleic acid that performs functions including protein synthesis and regulation of gene expression.

Complementary base pairing

Specific hydrogen bonding between nitrogen-containing bases in DNA where adenine pairs with thymine ($A-T$) and cytosine pairs with guanine ($C-G$).

ATP (adenosine triphosphate)

The energy currency of the cell, composed of adenine, ribose, and three phosphate groups.