Prokaryotic vs. Eukaryotic Cells

Vocabulary flashcards covering key terms and concepts from the notes on prokaryotic and eukaryotic cells.

Prokaryotic cell

A simple, small cell lacking a well-defined nucleus; DNA is located in the nucleoid and the cell usually lacks membrane-bound organelles.

Eukaryotic cell

A complex, larger cell with a well-defined nucleus and membrane-bound organelles; found in plants, animals, fungi; can be single-celled, colonial, or multicellular.

Nucleoid

Region in prokaryotes where DNA is located; not surrounded by a membrane.

Nucleus

Membrane-bound organelle in eukaryotes that stores genetic material and governs transcription; enclosed by a nuclear envelope.

Glycocalyx

Receptor/adhesive outer layer of many prokaryotes that helps protection and attachment to surfaces.

Cell membrane (plasma membrane)

Thin semipermeable barrier surrounding the cytoplasm; phospholipid bilayer with embedded proteins; in plants lies beneath the cell wall; in animals is the outermost layer.

Cell wall

Rigid layer that provides shape and protection; composition varies (cellulose, pectin, chitin, or peptidoglycan) depending on organism.

Ribosome

Tiny particles that synthesize proteins; in eukaryotes, ribosomes are 80S composed of 40S and 60S subunits.

Pilus

Hair-like hollow attachment on the surface of bacteria used to transfer DNA during cell-cell adhesion.

Mesosome

Extension of the cell membrane into the cytoplasm; role in cellular respiration.

Flagellum

Long, whip-like structure that enables movement; attached to the basal body of the cell.

Fimbriae

Hair-like structures that help bacteria attach to surfaces and other cells; involved in mating.

Inclusion/Granules

Storage bodies for carbohydrates (glycogen), phosphate, fats.

Endospore

A tough, dormant structure that allows bacteria to survive harsh conditions.

Endoplasmic Reticulum

Network of membranes that transports lipids and proteins; two types: smooth and rough.

Golgi apparatus

Stack of flattened sacs (cisternae) that packages materials and secretes them.

Lysosome

Organelle with enzymes that digest intracellular molecules.

Vacuole

Membrane-bound cavity containing fluid or materials; can engulf substances via endocytosis.

Mitochondrion

Powerhouse of the cell; generates ATP; contains its own DNA and ribosomes.

Chloroplast

Organelle in algae and plants; site of photosynthesis converting light energy into chemical energy.

Cytoplasm

Interior of the cell where organelles reside and metabolic activities occur.

Nuclear envelope

Double membrane surrounding the nucleus that controls passage of ions and molecules.

Chromosome

Structure carrying genetic material; located inside the nucleus in eukaryotes.

Cytoskeleton

Support framework of the cell; includes microtubules (∼24 nm) and microfilaments (∼6 nm) made of tubulin and actin.

Cilia

Short, numerous locomotor appendages that help move the cell in response to stimuli.

80S ribosome

Eukaryotic ribosome size (80S), consisting of 40S and 60S subunits.

Prokaryotic DNA

DNA that is circular and double-stranded and located in the nucleoid.

Eukaryotic DNA

DNA that is linear and double-stranded and located in the nucleus.

Origin of replication (prokaryotes)

Single origin of replication.

Origin of replication (eukaryotes)

Multiple origins of replication.

Transcription and translation in prokaryotes

Transcription and translation occur simultaneously in the cytosol.

Transcription and translation in eukaryotes

Transcription occurs in the nucleus; translation occurs in the cytosol.

Prokaryotic reproduction

Prokaryotes reproduce asexually and may transfer genes via conjugation, transformation, and transduction.

Eukaryotic reproduction

Eukaryotes often reproduce sexually; many also divide via mitosis/meiosis.

Prokaryote size range

About 0.5–3 μm in length.

Eukaryote size range

About 2–100 μm in length.

Evolution age of prokaryotes

Prokaryotic cells evolved at least about 3.5 billion years ago.

Etymology: prokaryotic

‘Pro’ means old and ‘karyon’ means nucleus.

Etymology: eukaryotic

‘Eu’ means new and ‘karyon’ means nucleus.