Course hooks students' interest with hands-on, 'real world' lab work
DANVILLE — It looks like chicken and tastes like chicken.
Now Danville High School sophomore Chavontaye Bush is on a scientific quest to discover whether the meat in her school's chicken quesadillas is, in fact, chicken.
"I hope it's not something else," Bush said with a smile, as she prepared a small tissue sample for DNA purification in her New Tech biology class this week.
The six-day lab is giving these students a hands-on lesson in DNA purification and bar coding. It's part of a science course that's being piloted in six classrooms in the United States this year.
The course was developed by Educurious, a Seattle-based nonprofit organization that creates high school curriculums designed "to capture students' interest and imagination and equip them for success in the real world," and is funded by the Bill & Melinda Gates Foundation.
In addition to providing microscopes, a scanning microscope, a polymerase chain reaction thermal cycler, two centrifuges, and other materials and equipment, the course gives students a chance to collaborate with geneticists at Duke University, University of Southern California and other universities and to publish a scientific abstract.
"It's a very advanced course," said New Tech biology teacher Doug Mathias, who attended an intensive, weeklong training in Seattle over the summer to prepare to facilitate the course. "Our students are conducting labs that typically are done at the college level."
Like the New Tech program, the course uses a project-based learning approach, in which students gain knowledge and 21st-century skills by engaging in multilayered "real world" projects.
"Instead of learning about cells, meiosis, mitosis and DNA in separate units it's one big unit, and they're doing these hands-on projects that are showing them how everything correlates and works together. It's rigorous, and it's relevant. And that's where the new Common Core standards are heading," Mathias said.
For the lab, students in three biology classes set out to identify the DNA of several animal products including Spam, imitation crab meat and dog food that claims it's lamb and rice although the first ingredient on the label is chicken. Students with stronger stomachs are testing earthworms, feathers of some type of bird that was feasting on something in a school courtyard and that something the bird was eating.
"We call that an unknown," Mathias said, adding "that's one of the grosser things they're identifying. It could be a rat. It could be another bird. We don't know yet."
At one table, Dylan Nelson and Damajai Finch Jr. cut bologna and "crab" into tiny pieces, put them into microfuge tubes and diluted their samples with a small amount of water and "digestion buffer." They tapped on their tubes to help break apart the cell and start the purification process so they can extract the DNA.
Then they placed their tubes into a hot bath overnight to help speed up the lysing process (disintegrating cells) and discussed what their samples might reveal.
"I think I'm going to be surprised," Finch said.
On Tuesday, students placed their tubes in a centrifuge, which "spun" them at 10,000 revolutions per minute to separate the DNA from other cell parts and to purify it. Later this week, they will put them in the PCR thermal cycler to amplify the sections of the DNA necessary for bar coding.
"It will go from one DNA strand to about 1.3 million in two or three hours," Mathias told students.
Finally, they will put the DNA through a process called agarose gel electrophoresis, which Mathias explained, will separate the DNA "so you can see actual bars." After that's done, students will package their samples and send them off to a company for sequencing. Once students receive the sequencing results, or DNA code, they will use a computer program called BLAST to analyze the results and learn what their organism is.
Through Educurious, students will work with geneticists, who are volunteering their time, to write scientific abstracts on their labs and findings, which will be published.
Bush believes it's easier to grasp the sometimes complex genetics concepts through hands-on projects like these rather than reading about them from a book or listening to a lecture.
"We get to find out things for ourselves. That makes it more interesting," she said.
During the course, students also have extracted DNA from a strawberry and made a candy model of its life code and tested water for different nitrates, copper, zinc and other chemicals and applied them to plants to see how they would affect their growth. Later on, they will study fossils from the Badlands and infectious diseases.