Prokaryotic & Eukaryotic Cells – Key Vocabulary

A comprehensive set of vocabulary flashcards covering key terms, structures, and processes discussed in the lecture on prokaryotic and eukaryotic cells.

Prokaryote

A cell lacking a membrane-bound nucleus and other membrane-bound organelles.

Eukaryote

A cell that possesses a membrane-bound nucleus and membrane-bound organelles.

Endosymbiotic theory

Idea that mitochondria and chloroplasts originated from once-free prokaryotic cells that lived inside an ancestral host cell.

Bacteria

One domain of prokaryotes whose cell walls contain peptidoglycan and membranes use ester-linked lipids.

Archaea

One domain of prokaryotes that lacks peptidoglycan in the wall and uses ether-linked membrane lipids; more closely related to Eukarya than to Bacteria.

Cell envelope

Collective term for the cell wall plus the cell (plasma) membrane of a prokaryote.

Cell wall

Rigid outer layer that provides shape and protection; in bacteria it is made of peptidoglycan.

Plasma membrane

Phospholipid bilayer that surrounds every cell and controls substance movement in and out.

Peptidoglycan

Protein–sugar polymer (murein) that forms the bacterial cell wall.

Ester-linked lipid

Type of lipid linkage found in bacterial cell membranes.

Ether-linked lipid

Type of lipid linkage found in archaeal cell membranes.

Nucleoid

Region in a prokaryote where the single circular chromosome is located.

Flagellum

Whip-like structure that propels a cell through a watery medium.

Pilus

Short hair-like projection on many prokaryotes used for adhesion to surfaces.

Plasmid

Small, circular piece of DNA separate from the main chromosome in many prokaryotes.

Capsule

Protective polysaccharide layer outside some bacterial cell walls.

Gram-negative bacterium

Bacterium with a thin peptidoglycan layer plus an outer lipid membrane.

Coccus

Spherical bacterium.

Bacillus

Rod-shaped bacterium.

Vibrio

Comma-shaped bacterium.

Spirochaete

Corkscrew-shaped bacterium.

Diplo-

Prefix indicating bacteria occurring in pairs.

Strepto-

Prefix indicating bacteria occurring in chains.

Staphylo-

Prefix indicating bacteria occurring in grape-like clusters.

Organelle

Specialised cellular compartment; often membrane-bound in eukaryotes.

Nucleus

Large double-membrane organelle that houses most of a cell’s DNA; the control centre.

Nucleolus

Dense region inside the nucleus where ribosomes are assembled.

Ribosome

Non-membrane structure made of rRNA and protein where proteins are synthesised.

rRNA

Ribosomal RNA; structural and catalytic component of ribosomes.

Rough endoplasmic reticulum

ER studded with ribosomes; transports and folds proteins.

Smooth endoplasmic reticulum

ER lacking ribosomes; involved in lipid synthesis and detoxification.

Reticulated

Divided so as to resemble a net; descriptive of ER appearance.

Mitochondrion

Double-membrane organelle, site of aerobic cellular respiration and ATP production; contains its own DNA.

Aerobic cellular respiration

Process in mitochondria that releases energy from glucose using oxygen to produce ATP.

ATP

Adenosine triphosphate; the main energy currency of the cell.

Golgi apparatus

Stack of flattened membranes that modifies and packages proteins for export.

Lysosome

Membrane-bound vesicle containing digestive enzymes for intracellular digestion.

Vesicle

Small fluid-filled membrane sac used for storage or transport in cells.

Sac

Membrane-enclosed cavity containing fluid; descriptive term used for Golgi cisternae.

Centriole

Cylindrical structure of microtubules that helps organise spindle fibres during cell division.

Chloroplast

Large double-membrane organelle in plants; site of photosynthesis and contains chlorophyll.

Thylakoid

Flattened membrane sac inside a chloroplast where light-dependent reactions occur.

Grana

Stacks of thylakoids within a chloroplast.

Stroma

Fluid matrix surrounding thylakoids inside a chloroplast; site of Calvin cycle.

Photosynthesis

Process by which plants convert CO₂ and H₂O into glucose and O₂ using light energy.

Large vacuole

Huge membrane-bound sac in plant cells that stores water, ions, and wastes and provides turgor.

Turgor pressure

Internal pressure from water inside a plant cell’s vacuole that helps maintain structure.

Cytoplasm

All cellular contents between the nuclear envelope and plasma membrane, excluding the nucleus.

Cytosol

Fluid portion of the cytoplasm in which organelles are suspended.

Synthesise

To build or assemble complex molecules from simpler components.

Protein

Biomacromolecule composed of one or more polypeptide chains of amino acids.