Chapter 4–5: Carbon and the Molecular Diversity of Life; Macromolecules and Genomics/Proteomics

Vocabulary flashcards covering key concepts, terms, and definitions from Chapter 4–5 lectures on carbon, organic molecules, macromolecules, and genomics.

Carbon backbone

The framework of most organic molecules built from carbon atoms; carbon’s versatility enables vast molecular diversity in life.

Organic chemistry

The study of carbon-containing compounds, ranging from simple molecules like CH4 to complex biomolecules like proteins.

Carbons’ common partners

Hydrogen, oxygen, nitrogen, sulfur, and phosphorus often bond with carbon to form organic compounds.

Hydrocarbons

Organic molecules consisting only of carbon and hydrogen; nonpolar and hydrophobic; major component of fats and petroleum.

Functional group

Specific atom groups that determine a molecule’s chemistry and properties; examples include hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, and methyl.

Hydroxyl group

–OH; increases solubility in water; found in alcohols; makes compounds polar.

Carbonyl group

C=O; determines whether a sugar is an aldose (end) or a ketose (within); influences reactivity.

Aldehyde

A carbonyl group at the end of a carbon skeleton.

Ketone

A carbonyl group within the carbon skeleton.

Carboxyl group

–COOH; acts as an acid; found in carboxylic acids and contributes acidic properties.

Amino group

–NH2; acts as a base; found in amines and amino acids.

Sulfhydryl group

–SH; forms thiols; can stabilize protein structure via disulfide bonds.

Phosphate group

–OPO3^2−; energy-transfer role (e.g., in ATP); negatively charged.

Methyl group

–CH3; nonreactive; often serves as a marker in organic molecules.

ATP (adenosine triphosphate)

Primary energy transfer molecule in cells; hydrolysis to ADP releases energy.

ADP (adenosine diphosphate)

Product of ATP hydrolysis when one phosphate is removed; stores usable energy.

Monomer

Small molecule that can join with others to form a polymer.

Polymer

Large molecule consisting of repeating monomer units; includes carbohydrates, proteins, and nucleic acids.

Dehydration reaction

Bond formation between monomers with loss of a water molecule; requires energy.

Hydrolysis

Bond cleavage of polymers by adding water; monomers are released.

Glycosidic linkage

Bond that connects monosaccharides to form disaccharides or polysaccharides.

Monosaccharide

Simple sugar; general formula a multiple of CH2O; can be aldose or ketose.

Glucose

Hexose sugar (C6H12O6); aldose; energy source; commonly forms rings in solution.

Disaccharide

Two monosaccharides joined by a glycosidic linkage (e.g., maltose, sucrose, lactose).

Polysaccharide

Polymers of sugars; storage or structural roles (e.g., starch, glycogen, cellulose, chitin).

Starch

Storage polysaccharide in plants; composed of α-glucose; energy reserve.

Amylose

Unbranched component of starch.

Amylopectin

Branched component of starch; more complex than amylose.

Glycogen

Animal storage polysaccharide; highly branched; stored in liver and muscles.

Cellulose

Structural polysaccharide in plant cell walls; made of β-glucose; forms microfibrils; indigestible for humans.

α (alpha) glucose

Glucose form that forms starch; glycosidic linkages lead to helical structures.

β (beta) glucose

Glucose form that forms cellulose; straight, unbranched chains; hydrogen-bonded microfibrils.

Chitin

Structural polysaccharide in arthropods and fungi; similar to cellulose but with nitrogen-containing groups.

Lipids

Hydrophobic, nonpolar molecules not forming polymers; include fats, phospholipids, and steroids.

Fat/triglyceride

Glycerol + three fatty acids via ester linkages; energy storage; can be saturated or unsaturated.

Glycerol

Three-carbon alcohol that forms the backbone of fats.

Fatty acid

Carboxyl group attached to a long hydrocarbon chain; saturation affects structure.

Saturated fatty acid

No carbon–carbon double bonds; straight chain; typically solid at room temperature.

Unsaturated fatty acid

One or more double bonds; cis double bonds create kinks; typically liquid at room temperature.

Hydrogenation

Addition of hydrogen to unsaturated fats; converts to saturated fats; can create trans fats.

Phospholipids

Two fatty acids + glycerol + phosphate group; major component of cell membranes; forms bilayer.

Steroids

Lipids with four fused carbon rings; cholesterol is a common example and a membrane component.

Cholesterol

Steroid component of animal membranes; precursor to other steroids; excess linked to heart disease.

Proteins

Macromolecules with diverse structures and functions; mostly enzymes; built from amino acids.

Amino acids

Monomers of proteins; have amino group, carboxyl group, an α-carbon, and an R group.

Peptide bond

Covalent bond formed between the carboxyl carbon of one amino acid and the amino nitrogen of the next.

Polypeptide

Chain of amino acids; protein precursor.

Primary structure

Linear sequence of amino acids in a protein.

Secondary structure

Local folding patterns (α-helix and β-pleated sheet) stabilized by hydrogen bonds.

Tertiary structure

Overall three-dimensional shape of a protein due to R-group interactions (H-bonds, ionic, hydrophobic, disulfide bridges).

Quaternary structure

Association of two or more polypeptide subunits (e.g., hemoglobin, collagen).

Chaperonins

Proteins that assist the folding of other proteins by providing an isolated environment.

Nucleic acids

Polymers of nucleotides; store and transmit hereditary information; include DNA and RNA.

Nucleotide

Nucleoside with one or more phosphate groups; building block of nucleic acids.

Nucleoside

Sugar + nitrogenous base; nucleotide without the phosphate.

Purine

Two-ring nitrogenous bases (Adenine and Guanine).

Pyrimidine

One-ring bases (Cytosine, Thymine, Uracil).

Ribose

Five-carbon sugar in RNA.

Deoxyribose

Five-carbon sugar in DNA lacking an oxygen on C2.

DNA

Double-stranded, anti-parallel nucleic acid; stores hereditary information; A–T and G–C pairing.

RNA

Typically single-stranded nucleic acid; uses uracil instead of thymine; ribose sugar.

Phosphodiester bond (nucleic acids)

Bond linking nucleotides via the sugar-phosphate backbone.

Antiparallel

Two DNA strands run in opposite 5' to 3' directions.

Complementary base pairing

A with T (DNA) or A with U (RNA); G with C; ensures accurate replication and transcription.

Genomics

Study of entire genomes; large-scale analysis of genes and their relationships.

Proteomics

Study of the full set of proteins in a cell or organism; large-scale protein analysis.

Gene

Unit of inheritance; DNA sequence that encodes a product (polypeptide or RNA).

Gene expression

Process by which information from a gene is used to synthesize a functional product (RNA or protein).

Transcription

Synthesis of RNA from a DNA template.

Translation

Synthesis of a polypeptide on a ribosome using mRNA as a template.

mRNA

Messenger RNA; carries genetic instructions from DNA to the ribosome for protein synthesis.

Ribonucleic acid (RNA)

Nucleic acid used in transcription and translation; contains uracil and ribose.

Complementary base pairing (summary)

Principle that bases pair specifically (A–T, G–C in DNA; A–U in RNA) enabling accurate information transfer.

Double helix

Three-dimensional structure of DNA with two antiparallel polynucleotide strands wound around an axis.