Shop Windows to the Universe

The Universe at Your Fingertips 2.0 DVD from the Astronomical Society of the Pacific is in our online store, filled with Earth and space science resources.
This simple cartoon shows general similarities and differences between eukaryote and prokaryote cells.
Click on image for full size
Image courtesy of Windows to the Universe

Cells: The Building Blocks of Life!

The Cell Theory states that all living things are made of cells, which are the basic units of life, and that cells come from other cells.

Prokaryotic cells have no nucleus or organelles enclosed within membranes. Species in the domains Archaea and Eubacteria have prokaryotic cells.

Eukaryotic cells have a nucleus and organelles that are surrounded by membranes. Each organelle does a specific cell function. All species in the Eukaryota domain (protists, fungi, plants, and animals) have eukaryotic cells. Individual protists have only one cell, while plants and animals can have trillions of cells. Complex creatures like humans have special cells for special functions like carrying oxygen around the body, digesting food, or making bone.

Last modified October 15, 2011 by Jennifer Bergman.

Shop Windows to the Universe Science Store!

The Spring 2010 issue of The Earth Scientist, focuses on the ocean, including articles on polar research, coral reefs, ocean acidification, and climate. Includes a gorgeous full color poster!

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

The Domain Eubacteria

Eubacteria, also know as “true bacteria”, are microscopic prokaryotic cells. Cyanobacteria, also called blue-green algae, are Eubacteria that have been living on our planet for over 3 billion years. Blue-green...more

Meiosis: How Gametes Are Made

Plants, animals and many other species within the domain Eukaryota are able to make offspring, or young, by sexual reproduction. Their offspring are made from gametes. Gametes are special cells that have...more

Evidence of Evolution

Scientists use the word theory differently than nonscientists. "It’s just a theory," you hear people say. When speaking casually, people often use the word "theory" to mean a "guess" or a "feeling". In...more

Did Life First Develop in a Mica Sandwich at the Bottom of a Primordial Sea?

Earth's first life form may have developed between the layers of a chunk of mica sitting like a multilayered sandwich in primordial waters, according to a new hypothesis. The mica hypothesis, which was...more

Can living cells repair damage from radiation?

Whether or not a cell can repair itself after being damaged by radiation depends on the type of damage to the cell's DNA. Type of Damage Prospects for DNA Repair Single strand break in the DNA Can usually...more

How can radiation damage a living cell?

High frequency radiation or fast moving particles plow into a living cell with enough energy to knock electrons free from molecules that make up the cell. These molecules with missing electrons are called...more

Scientists Discover Fish that Talk

We used to think that only cartoon animated fish could talk. But now scientists have found that fish really do talk. It may not be the same sort of language that people use, but fish are able to hum and...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA