Irvington Middle School seventh graders, who have been exploring the role of cells in the growth and development of living organisms, conducted a laboratory experiment in teacher Nicole Arvanites’ class to solidify their knowledge.
Equipped with a microscope, the students observed and investigated the structures of a red onion tissue. They worked with a partner to create a wet mount slide of a piece of red onion skin. They used saltwater and plain water to cause observable changes in the cells and watched under the microscope what happens to the onion skin when they add water.
“We noticed that onion cells have a cell membrane, like other cells we have observed,” Arvanites said. “We also noticed a cell wall, which is a structure we did not see previously in blood, nerve, muscle or bone cells. This structure provides support for plant cells and is not found in animal cells. We used models to show that the cell membrane and cell wall allow water into and out of the cell. We used our observations as evidence to argue that the cell membrane and cell wall are structures that allow what the cell needs into the cell and allow whatever the cell does not need to leave the cell.”
Arvanites said the unit on cells has helped the seventh graders explore the role of cells in the growth and development of living organisms through pursuing questions and ideas for investigation.