Do sports drinks lie about their sugar content?
In biology 105, HSU oceanography major Courtney Dressler and her classmates tried to answer this question.
“We are adding dinitrosalicylic acid into solutions of Gatorade and Vitamin Water Zero,” Dressler said. “The acid helps us identify how much sugar is in these drinks.”
Dinitrosalicylic acid, or DNS, binds to sugar molecules in a solution. When this binding occurs, the solution’s color can transform into a shade between orange and red.
Wesley Warren, also an oceanography major at HSU, explains how these color changes are detected.
“We put the solutions into a spectrophotometer, which tells us how much light they absorb,” Warren said.
Orange solutions absorb a different amount of light than red solutions. By comparing the sports drinks’ light absorbance values to those of the standards, or solutions with known sugar content, the drinks’ actual sugar concentrations can be determined.
Dr. John Steele, one of the instructors for biology 105, elaborated on how this experiment fits into the course’s schematic.
“Biology 105 provides an introduction to topics that a cell/molecular biology, microbiology and general biology major would encounter in their undergraduate studies,” Steele said. “[The experiment] is used to teach students how to make diluted solutions from a stock solution and how to determine the concentration of [molecules] in a given solution.”
In prior semesters, two laboratory periods were given for students to complete the experiment and learn these essential techniques. Now, students are allowed three periods to conduct the experiment.
A few other labs in biology 105 were also modified to include more time.
Video by Linh Pham and Surya Gopalan.
Dr. Brigitte Blackman, who teaches a section of biology 105, explained the factor that prompted these changes.
“We try to take feedback from students every semester and change the course based on their comments,” Blackman said. “In past semesters, some students have felt the labs were too long and covered too much in one period.”
“By spreading out the labs, we hope that students will be able to better understand the principles covered in lab and apply these principles to test a scientific hypothesis,” Steele said.
For Marjani Ellison, an environmental science major who’s retaking biology 105, the order in which the experiments are conducted also seemed to change.
“Last semester, the labs and lectures materials did not coordinate. I felt as if the two were separate classes,” Ellison said. “This semester, the labs follow the lectures. I feel that I’m actually learning this time.”
In addition to student feedback, current trends and issues in biology also determine the necessary changes for the class.
“Last semester, we incorporated the Small World Initiative into our laboratory curriculum,” Blackman said. “The initiative was introduced to the course by [professor] Mark Wilson. As part of this initiative, students sampled and grew bacteria from the local environment, such as the Arcata Marsh, then searched for bacteria that were producing antibiotics.”
This semester, biology 105 replaced the Small World Initiative with gene-editing using CRISPR as the current topic in biotechnology.
“CRISPR is a gene editing system made by two scientists named Jennifer Doudna and Emmanuelle Chapentier. To use this tool, all you need to know is the DNA sequence where you would like to make an edit,” Steele said. “Because of its versatility and popularity in biotechnology, bio 105 students need to learn the basics of this tool and the first step of building it.”
Learning CRISPR at the introductory biology level could increase the horizon of opportunities for HSU students.
“This topic has grown from being a sentence in a textbook to a paragraph, and soon, probably full sections of a chapter,” Steele said. “Biotech companies are looking for people who know how to use CRISPR and gene editing technologies. Learning this technique early could really put HSU students ahead of the competition.”
Steele also claimed a selfish reason for teaching students CRISPR.
“If more students know how to use this tool, then more students will be able to work for my lab,” Steele said. “My lab uses this tool everyday!”
