Inside the DNA
Two false color scanning electron microscope images of pollen particles. Scientists use gel electrophoresis to separate pieces of DNA. The bright "bands" on this gel are DNA fragments; the bands on the far sides are DNA-size markers.Copyright (top left) Charles Daghlian, Dartmouth College via NASA, (top right), Sophie Warny and Kate Griener, Louisiana State University, Baton Rouge via NASA, (bottom) NOAA http://www.nasa.gov/connect/chat/sickness_from_space_chat_prt.htm
http://www.nasa.gov/topics/earth/features/beechpollen.html
http://oceanexplorer.noaa.gov/explorations/03bio/logs/sept10/media/lasonolide3.html
Students conduct their own research to discover and understand the methods designed by engineers and used by scientists to analyze or validate the molecular structure of DNA, proteins and enzymes, as well as basic information about gel electrophoresis and DNA identification. In this computer-based activity, students investigate particular molecular imaging technologies, such as x-ray, atomic force microscopy, transmission electron microscopy, and create short PowerPoint presentations that address key points. The presentations include their own explanations of the difference between molecular imaging and gel electrophoresis.
Visualization of small structures such as molecular structures of complex proteins and genetic material (DNA) is based on engineering discoveries and breakthroughs in physics at small scales. Imaging technologies such as x-ray and scanning electron microscopy—used in by scientists and engineers to image microscopic structures—are also used by biomedical engineers and biologists to study biomolecules, cells and tissue samples.
After this activity, students should be able to:
- Enumerate some of the imaging technologies used for atomic scale microscopy.
- List the basic, underlying principles of the researched microscopy method.
- Describe how the microscopy method helped scientists to discover the structure of biomolecules.
- Explain the difference between molecular imaging and DNA gel electrophoresis.
- Explain that certain nucleotide base sequences in the DNA encode for proteins/enzymes whereas the molecular shape of protein/enzyme determines their function.