Chapter 4: Cells: The Basic Unit of Life

Ribosomes

A cell organelle composed of RNA and protein; the site of protein synthesis.

Lysosomes

A cell organelle that contains digestive enzymes.

Golgi Complex

A cell organelle that helps makes and package materials to be transported out of the cell.

Organ

A collection of tissues that carry out a specialized function of the body.

Organ System

A group of organs that work together to perform body functions.

Tissue

A group of similar cells that perform a common function.

Organism

A living thing; anything that can carry out life processes independently.

Cell Membrane

A phospholipid layer that covers a cell's surface and acts as a barrier between the inside of a cell and the cell's environment.

Cell Wall

A rigid structure that surrounds the cell membrane and provides support to the cell.

Prokaryotes

A single-celled organism that does not have a nucleus or membrane-bound organelles; examples are archaea and bacteria.

Vesicle

A small cavity or sac that contains materials in a eukaryotic cell; forms when part of the cell membrane surrounds the materials to be taken into the cell or transported within the cell.

Endoplasmic Reticulum

A system of membranes that is found in a cell's cytoplasm and that assists in the production, processing, and transport of proteins and in the production of lipids.

Chloroplasts

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

Eukaryotes

An organism made up of cells that have a nucleus enclosed by a membrane; eukaryotes include protists, animals, plants, fungi but not archaea or bacteria.

Structure

The arrangement of parts in an organism.

Nucleus

In a eukaryotic cell, a membrane-bound organelle that contains the cell's DNA and that has a role in processes such as growth, metabolism, and reproduction.

Mitochondrion

In eukaryotic cells, the cell organelle that is surrounded by two membranes and that is the site of cellular respiration.

Cytoskeleton

The cytoplasmic network of protein filaments that plays an essential role in cell movement, shape, and division.

Organelles

One of the small bodies in a cell's cytoplasm that are specialized to perform a specific function.

Cell

The smallest functional and structural unit of all living organisms; usually consists of a nucleus, cytoplasm, and a membrane.

Function

The special, normal, or proper activity of an organ or part.