Lab 7: Cell Structure and Function

Cell Theory

The fundamental theory stating that all living organisms are composed of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells.

Surface Area to Volume Ratio

The ratio of a cell's outside surface area to its inner volume, which limits maximum cell size for efficient diffusion and exchange.

Unicellular Organism

An organism consisting of a single independent cell (e.g., Amoeba, Escherichia coli).

Colonial Organism

A collection of individual, independent single cells living closely together in a group or cluster (e.g., Volvox).

Multicellular Organism

An organism composed of many specialized cells working together (e.g., Humans, Oak Trees).

Prokaryotic Cell

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

Eukaryotic Cell

A complex cell containing a membrane-bound nucleus and specialized membrane-bound organelles.

Nucleoid

The irregular, non-membrane-bound region in a prokaryotic cell where genetic material (DNA) is located.

Plasmid

A small, circular, extra-chromosomal DNA molecule found in prokaryotes.

Bacterial Cell Wall

A rigid structure outside the plasma membrane in bacteria, primarily composed of peptidoglycan.

Peptidoglycan

A polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of most bacteria.

Flagellum

A long, whip-like appendage used by prokaryotic and eukaryotic cells for locomotion.

Pili / Fimbriae

Hair-like appendages on the surface of many bacteria used for attachment to surfaces or conjugation.

Ribosome

A cellular structure composed of RNA and protein responsible for synthesizing proteins.

Plasma Membrane

A selectively permeable phospholipid bilayer that encloses the cytoplasm of a cell.

Nucleus

A membrane-bound organelle in eukaryotic cells containing genetic material (DNA).

Nuclear Envelope

The double-membrane structure surrounding the nucleus of a eukaryotic cell.

Nucleolus

A dense region within the nucleus where ribosomal RNA (rRNA) is synthesized and ribosomes are assembled.

Cytoplasm

The entire contents within a cell, excluding the nucleus in eukaryotes, comprising cytosol and organelles.

Cytosol

The fluid portion of the cytoplasm surrounding the organelles.

Mitochondrion

A eukaryotic organelle bounded by a double membrane that generates ATP through cellular respiration.

Chloroplast

An organelle found in plant and algae cells where photosynthesis occurs; contains chlorophyll.

Central Vacuole

A large organelle found in plant cells that stores water, nutrients, and waste, providing turgor pressure.

Plant Cell Wall

A rigid outer structure surrounding plant cells, composed mainly of cellulose.

Cellulose

A complex structural polysaccharide made of glucose monomers that forms plant cell walls.

Lysosome

A eukaryotic organelle containing digestive enzymes that break down waste, debris, and foreign material.

Centriole

A cylindrical structure composed of microtubules involved in organizing spindle fibers during cell division in animal cells.

Protist

A diverse group of unicellular or simple multicellular eukaryotic organisms that are not plants, animals, or fungi.

Fungus (Fungi)

A eukaryotic organism (such as yeast or mold) with cell walls composed of chitin that absorbs nutrients from organic matter.

Chitin

A structural polysaccharide found in fungal cell walls and arthropod exoskeletons.