Microbiology & Macromolecules – Exam 1 Vocabulary

Vocabulary flashcards covering domains of life, cell types, bacterial staining groups, and key macromolecule concepts for Test 1 review.

Three Domains of Life

Bacteria, Archaea, and Eukarya— the broadest taxonomic divisions of all organisms.

Prokaryote

A cell that lacks a true nucleus and membrane-bound organelles; generally small and simple in structure.

Eukaryote

An organism whose cells contain a membrane-bound nucleus and organelles; includes animals, plants, fungi, and protists.

Bacteria

One of the two prokaryotic domains; characterized by peptidoglycan cell walls and diverse metabolic types.

Archaea

Prokaryotic domain distinct from bacteria; cell walls lack peptidoglycan, membrane lipids are unique, often live in extreme environments, and share some genetic machinery with eukaryotes.

Gram-Positive Bacterium

Bacterium with a thick peptidoglycan cell wall that retains crystal-violet stain, appearing purple under the microscope.

Gram-Negative Bacterium

Bacterium with a thin peptidoglycan layer and an outer membrane containing lipopolysaccharide; loses crystal-violet and stains pink with safranin.

Four Major Macromolecules

Carbohydrates, lipids, proteins, and nucleic acids—large biomolecules essential to life.

Carbohydrate

Hydrophilic macromolecule used for energy and structural support; examples include glucose, starch, and cellulose.

Lipid

Generally hydrophobic macromolecule for energy storage and membrane structure; includes fats, oils, steroids, and waxes.

Protein

Nitrogen-containing macromolecule made of amino acids linked by peptide bonds; functions as enzymes, transporters, and structural components.

Nucleic Acid

Polymer of nucleotides (DNA or RNA) that stores and transmits genetic information.

Hydrophilic Molecule

Substance that is water-loving and readily dissolves in aqueous solutions due to polarity (e.g., most carbohydrates, some protein regions).

Hydrophobic Molecule

Water-fearing substance that does not dissolve well in water because it is non-polar (e.g., most lipids).

Amphipathic Lipid

Molecule possessing both hydrophilic and hydrophobic regions, enabling formation of biological membranes.

Phospholipid

Amphipathic lipid with a glycerol backbone, two fatty acid tails, and a phosphate head; primary component of cellular membranes.

Peptide Bond

Covalent bond formed between the nitrogen of one amino acid and the carbonyl carbon of another, linking amino acids into a protein chain.

Polymer

A long chain of repeating subunits (monomers); examples include polysaccharides, proteins, and nucleic acids.