After a week of re-learning cell organelles and observing cells under the microscope, today students learned about how the cell membrane works. The primary focus of the lesson was to provide students with the vocabulary to explain the concepts of osmosis and transport of water across the membrane via the membrane protein channel aquaporin. Students should review the Membrane Functions PowerPoint slide deck and commit the vocabulary terms to memory. The aquaporin claymation video included in the slide deck is also provided below for easy access:
To support our school’s goal of improving the ability of students to use writing to explain, the science department gave the first of three “writing to explain” science prompts this school year. This first writing prompt serves as a baseline, with the next two prompts designed to assess growth in student ability to use writing to explain science. Although students had the entire class period to respond to the prompt, students who finished early had the remainder of the class period to complete unfinished work.
As promised, students were quizzed on their understanding of the content we covered on Monday’s lesson on Membrane Function. Specifically, students needed to apply their learning of several key vocabulary terms to an example of a plant in a solution analogous to an egg in corn syrup. Because the quiz was content-rich, students were allowed to use their written notes, as well as their phones to access the PowerPoint from Monday’s lesson. As we progress into the year, supports like using notes on quizzes will be removed, with students having to improve study habits in order to commit content to memory.
Every now and then we have to take a day of class to “sit and get” – a day of class where students learn and review important science concepts designed to help them make sense of their lab observations and use science to explain what they saw. Today was one of those days. Students learned about how the cell membrane works, focusing on the concepts of osmosis and transport. Students should review the Membrane Functions PowerPoint slide deck and commit the vocabulary terms to memory. The aquaporin claymation video included in the slide deck is also provided below for easy access:
Class began with students receiving their graded quizzes from Friday. We reviewed the correct responses and students learned that their lowest quiz score will be dropped each quarter. Make-up quizzes are not available, so student attendance on Fridays is very important. Students also learned about the weekly extra credit opportunity: read a scientific article (available in the classroom magazine collection or online) and write a paragraph explaining what was learned. The article must be related to the content covered in the most recent quiz, and the paragraph must be turned in prior to the next quiz in order to qualify for five extra credit points.
After the quiz review, we turned to the Egg Lab. In their lab notebooks, students wrote the steps of the procedure they followed on Friday to measure the starting mass of their eggs and immerse the eggs in vinegar to begin the process of dissolving the eggshell. Next, students made visual observations of their eggs before putting on gloves and handling their eggs while rinsing them. Eggs were then placed back in the cups with fresh vinegar, recovered with plastic wrap, and returned to the fume hood for another day. Students were encouraged to bring a school-appropriate liquid tomorrow as we continue our study of how cells interact with their environment by moving molecules across the cell membrane.
Egg Lab Procedure:
- Write name and class period on a cup with a Sharpie.
- Measure the mass of one egg with a scale while wearing gloves. This is the starting mass in grams.
- Place the egg in the cup and record the starting mass on the cup.
- Pour vinegar over the egg until it is completely covered.
- Cover the cup in plastic wrap.
- Place the cup inside a fume hood for three days.
- Wearing gloves, observe the egg and record observations.
- Gently pour vinegar solution into sink, carefully catching egg.
- Rinse egg and cup gently with room temperature tap water.
- Return egg to cup and repeat steps 4-5.
- Place the cup inside a fume hood for one more day.