Chapter 4: Cell Structure

Cell Theory

The unifying foundation of biology that states all organisms are composed of cells, cells are the smallest living things, and cells arise only from pre-existing cells.

Diffusion

The process by which molecules move from an area of high concentration to an area of low concentration.

Surface Area-to-Volume Ratio

The ratio of the surface area of a cell to its volume, which affects the cell's ability to exchange materials with its environment.

Microscopes

Instruments used to magnify and visualize cells and other small structures.

Prokaryotic Cells

The simplest organisms that lack a membrane-bound nucleus and have no membrane-bound organelles.

Eukaryotic Cells

Cells that possess membrane-bound organelles and a nucleus, and are more complex than prokaryotic cells.

Nucleus

The repository of genetic information in eukaryotic cells, which contains DNA and is surrounded by a nuclear envelope.

Ribosomes

Cellular structures responsible for protein synthesis, found in all cell types.

Endomembrane System

A series of separate compartments formed by membrane-bound organelles, such as the endoplasmic reticulum, Golgi apparatus, and lysosomes.

Mitochondria

Organelles responsible for generating ATP through the metabolism of organic compounds, found in all types of eukaryotic cells.

Chloroplasts

Organelles present in plant cells and some other eukaryotes that use light to generate ATP and sugars through photosynthesis.

Cytoskeleton

A network of protein fibers found in all eukaryotic cells that supports the cell's shape and maintains cellular structure.

Cell Walls

Structures found in plants, fungi, and many protists that provide support, maintain shape, and prevent excessive uptake or loss of water.

Extracellular Matrix (ECM)

A mixture of glycoproteins secreted by animal cells that forms a protective layer and influences cell behavior.

Cell Connections

Various types of junctions that connect cells and allow for communication, adhesion, and tissue organization.