Cell Structures & Evolutio

Cytoskeleton

A network of protein fibers that maintains cell shape and helps with movement.

Microtubules

Hollow protein structures involved in cell shape, transport, and chromosome movement.

Actin Filaments

Thin protein fibers that help cells maintain shape and move.

Centriole

A structure that helps organize microtubules during cell division in many animal cells.

Spindle Fibers

Microtubules that separate chromosomes during cell division.

Cilia

Short hairlike structures used for movement.

Flagellum

A long structure used for cell movement.

Hydrolytic Enzyme

An enzyme that breaks chemical bonds by adding water.

Peroxisome

An organelle that breaks down certain fatty acids and detoxifies harmful substances.

Catalase

An enzyme that breaks hydrogen peroxide into water and oxygen.

Microvilli

Small cell surface projections that increase surface area for absorption.

Compartmentalization

The separation of cellular processes into specialized regions.

Endosymbiotic Theory

The theory that mitochondria and chloroplasts evolved from once-free-living prokaryotes incorporated into host cells.

Endosymbiosis

A relationship in which one organism lives inside another.

Primary Endosymbiosis

The incorporation of a prokaryote into a eukaryotic host, eventually producing an organelle.

Secondary Endosymbiosis

The incorporation of a photosynthetic eukaryote containing a chloroplast into another eukaryotic host.

Cyanobacteria

Photosynthetic prokaryotes related to the ancestors of chloroplasts.

Binary Fission

Cell division in which one cell divides into two daughter cells.