The Cell Theory and Cell Structure - Vocabulary Flashcards

Vocabulary flashcards covering cell theory, key scientists, cell types (prokaryotic/eukaryotic), cell organelles, and bacterial cell features from the lecture notes.

Cell Theory

Three tenets: (1) new cells are produced from pre-existing cells, (2) cells are the basic unit of life, and (3) all living things are composed of one or more cells.

Schleiden

Matthias Jakob Schleiden, a German botanist, who concluded that all plant tissues are made of cells and that the cell is the basic building block of plant matter.

Schwann

Theodor Schwann, a German zoologist, who concluded that both plants and animals are composed of cells.

Virchow

Rudolf Virchow, a German pathologist, who stated that every cell stems from another cell.

Robert Hooke

English physicist who, while observing cork, described tiny boxlike cavities as cells, revealing plant cells and laying groundwork for cell theory.

Unicellular organism

An organism composed of a single cell; bacteria are examples.

Multicellular organism

An organism composed of many cells that live and work together; humans are multicellular.

Prokaryote

Cell type lacking a nucleus and membrane-bound organelles; DNA is in the cytoplasm; cell wall typically made of peptidoglycan.

Eukaryote

Cell type with a nucleus and membrane-bound organelles; generally larger (about 10–100 µm) than prokaryotes.

Nucleus

Control center of the cell that contains DNA and is bounded by a nuclear envelope with pores; present in eukaryotic cells.

Nucleolus

Region inside the nucleus responsible for ribosome production.

Chromatin

DNA associated with proteins inside the nucleus; condenses to form chromosomes during cell division.

Nuclear envelope

Double membrane surrounding the nucleus with nuclear pores, separating nucleus from cytoplasm.

Nuclear pore

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

Ribosome

Cellular organelle that manufactures proteins; can be free in cytoplasm or attached to rough endoplasmic reticulum.

Rough endoplasmic reticulum

ER studded with ribosomes; synthesizes and modifies proteins produced by ribosomes.

Smooth endoplasmic reticulum

ER lacking ribosomes; synthesizes lipids and carbohydrates and participates in detoxification.

Golgi apparatus

Packaging center that processes and ships proteins and lipids after synthesis.

Lysosome

Digestive organelle containing enzymes; breaks down waste, bacteria, and old cellular parts.

Mitochondrion

Powerhouse of the cell; produces ATP through cellular respiration.

Centrioles

Cylindrical structures found in animal cells that assist in organizing chromosomes during cell division; part of the centrosome.

Cytoskeleton

Network of filaments (microtubules, intermediate filaments, microfilaments) that gives the cell its shape and support.

Plasma membrane

Semi-permeable phospholipid bilayer surrounding the cytoplasm; controls what enters and exits the cell.

Cell wall

Rigid layer outside the plasma membrane found in plants and bacteria; provides support and maintains shape.

Vacuole

Membrane-bound sacs used for storage of water and other substances; plant cells have a large central vacuole, animals have smaller vacuoles.

Chloroplast

Plant cell organelle where photosynthesis occurs; contains chlorophyll and has inner/outer membranes and thylakoids (granum).

Granum

Stack of thylakoids within a chloroplast; site of light-dependent reactions.

Plasmodesmata

Channels through plant cell walls that connect adjacent plant cells for transport and communication.

Cytoplasm

Jelly-like substance inside the cell that holds organelles in place; present in all cells.

Capsule

Gelatinous layer around some bacteria that protects from desiccation and phagocytosis; a virulence factor.

Pili (Pilus)

Hairlike projections that help bacteria attach to surfaces and other cells.

Flagellum (Flagella)

Hairlike structure that enables locomotion in motile bacteria.

Nucleoid

Region in a bacterial cell where the chromosomal DNA is located; not enclosed by a nuclear membrane.

Plasmid

Small circular DNA molecule in bacteria that carries genes and can be transferred between bacteria; often carries antibiotic resistance.

Egg cell

Largest cell in the human body.

Sperm cell

Smallest cell in the human body; the only human cell that typically has a flagellum.

Plant cell (general)

Eukaryotic cell with a cell wall, chloroplasts, and a large central vacuole; typically rectangular in shape.

Animal cell (general)

Eukaryotic cell without a cell wall or chloroplasts; irregular shape; often contains centrioles.

Bacterial cell (general)

Prokaryotic cell; lacks a nucleus; DNA in a nucleoid; may have capsule and flagella; cell wall with peptidoglycan.

Endoplasmic reticulum (general)

Network of membranous tubules; rough ER has ribosomes and makes proteins; smooth ER makes lipids and detoxifies.

Centrosome

Organizing center for microtubules in animal cells, often containing a pair of centrioles.