Biology and Microbiology Vocabulary: Cells, Organisms, and Microbiomes

A set of vocabulary flashcards covering key terms related to cells, organelles, microbes, and symbiotic relationships from the lecture notes.

Isomer

Molecules with the same molecular formula but different structural arrangement.

Functional group

A specific group of atoms within a molecule responsible for characteristic reactions.

Monosaccharide

A simple sugar; the basic building block of carbohydrates (e.g., glucose, fructose).

Polysaccharide

A carbohydrate polymer composed of many monosaccharide units (e.g., starch, cellulose).

Lipid

A diverse group of hydrophobic molecules including fats, oils, phospholipids, and steroids; not polymers.

Triglyceride

A lipid formed from glycerol esterified with three fatty acids; main energy storage molecule.

Phospholipid

Amphipathic lipid with two fatty acids and a phosphate group; major component of cell membranes.

Endosymbiotic theory

Idea that mitochondria and chloroplasts originated from free-living bacteria taken up by ancestral cells.

Nucleoid

Region in prokaryotes where the chromosome resides; not membrane-bound.

Capsule (glycocalyx)

Organized polysaccharide layer outside the cell wall that aids defense and attachment.

Peptidoglycan

Bacterial cell wall polymer of NAM and NAG cross-linked by peptide bridges.

Gram-positive cell wall

Thick peptidoglycan layer with teichoic acids; no outer membrane.

Gram-negative cell wall

Thin peptidoglycan layer plus outer membrane containing LPS; periplasmic space present.

Pili

Hair-like appendages for attachment and, in some species, genetic exchange (conjugation).

Flagellum

Whip-like organelle enabling bacterial motility; composed of basal body, hook, and filament.

Chemotaxis

Movement toward or away from chemical stimuli; runs and tumbles adjust with gradients.

Nucleolus

Nuclear substructure where ribosomal RNA (rRNA) is synthesized.

Peroxisome

Organelle involved in lipid metabolism and detoxification of harmful compounds.

Endomembrane system

Interconnected membrane compartments (ER, Golgi, lysosomes) that traffic and modify materials.

Mitochondrion

Organelle that generates ATP through cellular respiration; contains cristae and matrix.

Chloroplast

Organelle for photosynthesis in plants/algae; contains thylakoids, grana, and stroma.

Endocytosis

Cellular intake of extracellular material via vesicle formation; includes phagocytosis, pinocytosis, receptor-mediated endocytosis.

Microbiome

All microorganisms and their genetic material associated with a host or environment.

Protist

Unicellular or simple multicellular eukaryotic organisms; diverse lifestyles including protozoa and algae.

Lichen

Symbiotic association between a fungus and a photosynthetic partner (alga or cyanobacterium).