Bacterial cell wall comparison. Computer artwork comparing the structure of the cell wall from a gram-negative bacterium (left) with that of a gram-positive bacterium (right). Both forms have a cell membrane consisting of a phospholipid bilayer (blue), and then a layer of peptidoglycan (murein, orange) on the outside of this. The gram-negative cell wall has a thin peptidoglycan layer and then a second membrane (yellow), whereas the gram-positive one lacks the second membrane but has a much thicker peptidoglycan layer.
Science Photo Library was founded in 1981 by Michael Marten, one of the authors of "Worlds Within Worlds", a book exploring different ways to observe the universe - from electron micrographs, to images of earthrise taken from the Apollo spacecraft. When Marten started receiving requests for the beautiful images in the book, he had an idea of setting up Science Photo Library.
Since then, Science Photo Library has continued to work alongside world acclaimed photographers and the leading science and medical experts to provide a central source of the best science and specialist imagery available. Although the collection started with scientific images, it has grown to encompass all aspects of science and their impact on everyday life.
Shop with Confidence (Fine Art America Return Policy)
Our return policy is very simple:
If you're not happy with a purchase that you made on FineArtAmerica.com, for any reason, you can return it to us within 30 days of the order date. As soon as it arrives, we'll issue a full refund for the entire purchase price. Please note - Fine Art America does not reimburse the outgoing or return shipping charges unless the return is due to a defect in quality.