Lecture Notes on Cell Structure (Prokaryotic and Eukaryotic Cells)

Vocabulary flashcards covering key terms and features of prokaryotic and eukaryotic cells, including organelles and plant/animal cell differences.

Prokaryotic cell

A cell lacking a distinct nucleus; genetic material is in a nucleoid and not enclosed by a nuclear membrane.

Nucleoid

Region in prokaryotes where chromosomal DNA localizes; not bounded by a membrane.

70S ribosomes

Ribosomes typical of prokaryotes (and organelles like chloroplasts and mitochondria in some contexts); smaller than eukaryotic 80S ribosomes.

Nuclear membrane

Membrane surrounding the nucleus; absent in prokaryotic cells.

Circular chromosome

Prokaryotic chromosome that is circular in shape.

Histones

Protein components around which eukaryotic DNA winds; prokaryotic DNA is not associated with histones.

Pili

Hair-like appendages on bacteria used for attachment or genetic transfer.

Capsule

Protective outer layer found in some bacteria, aiding protection and attachment.

Flagellum

Long, whip-like structure used for locomotion in some cells.

Eukaryotic cell

A cell with a true nucleus enclosed by a nuclear envelope and membrane-bound organelles.

Distinct nucleus

Nucleus is separate from the cytoplasm and enclosed by a nuclear envelope.

Double-membraned organelles

Organelles enclosed by two membranes (e.g., nucleus, mitochondria, chloroplasts).

80S ribosomes

Ribosomes found in the cytoplasm of most eukaryotic cells; larger than prokaryotic 70S ribosomes.

Nuclear pore

Protein channels in the nuclear envelope that regulate transport between nucleus and cytoplasm.

Plant cell

Eukaryotic cell type with cellulose cell wall, chloroplasts, and usually a large central vacuole.

Plastids

Plant organelles including chloroplasts and others involved in storage and photosynthesis.

Dictyosomes

Plant form of Golgi apparatus; stacked membrane-bound sacs involved in modification and sorting.

Centriole absent

Many plant cells lack centrioles.

Animal cell

Eukaryotic cell type lacking a cell wall; contains centrioles and microvilli.

Centrioles

Cylindrical organelles that organize spindle fibers during cell division in many animal cells.

Microvilli

Small, finger-like projections increasing surface area for absorption.

Lysosome

Organelle containing digestive enzymes for breakdown of waste materials.

Cytoplasm

Internal cellular region excluding the nucleus; contains cytosol and organelles.

Plasma membrane

Another term for the cell membrane; defines the boundary of the cell.

Centrosome

Microtubule-organizing center in animal cells, often associated with the organization of the spindle.

Plasmodesmata

Channels through plant cell walls that connect adjacent plant cells.