Instructor Exchange

The Function of Antibodies and Complement Compared to Chocolate Chips

Written by Kelly A. Hogan, University of North Carolina at Chapel Hill

When explaining how complement or antibodies enhance the innate system’s phagocytes to engulf these coated pathogens, I explain my behavior at a buffet. I may see vanilla cake, plain ice cream, short bread cookies etc. and all of these might taste good if I chose them. However, if my eye catches something with chocolate chips on it, I am immediately drawn to it and choose this to eat.Movie Get Out (2017)

The Immune System as the Body’s Militia

Written by Gidi Shemer, University of North Carolina at Chapel Hill

When discussing the immune system in human physiology, the military is the star of the show. The first line defense (e.g. our skin) can be represented by the physical barriers we have in our borders, defending us from the enemy (e.g. bacteria). The second line of defense (e.g. the phagocytes of the innate immune system) is represented by the soldiers who are found at the front lines. The third defense, the adaptive immune system, our B and T cells, is represented by the elite forces. These elite forces are more expensive, hard to come by, and called to action by the plain soldiers, but they provide modern, selective, and sophisticated tactics to fight the enemy.

The Smell of Fresh Pizza and Cell Movement

Written by Sheri Kuslak, University of North Carolina at Chapel Hill

When discussing chemokines and chemotaxis of immune cells to an injury site I describe college students’ response to the smell of pizza. For example imagine a classroom containing a dozen freshly baked pizzas being similar to an injury site in the human body. As the smell of pizza (chemokines) wafts through the air into the hallways the students (immune cells) follow the smell to the source (chemotaxis). Once the students (immune cells) find the source they begin eating the pizza (healing the injury through specialized processes). Once the pizza is gone (injury is healed), the pizza smell (chemokines) subsides therefore not drawing in any more students to the classroom (the former injury site).

Article Alert: Can We “Level the Playing Field” with Active Learning?

Written by Kelly A. Hogan, University of North Carolina

We all intuitively know as instructors that the success of a student is tied to their high school preparation. Students coming from disadvantaged high schools will often struggle with the transition to college biology more so than other students. You know the type; they work hard and spin their wheels, only to feel frustrated with their ability to keep up and pass the tests. How do we reach these students and “level the playing field”?

David Glenn writes a summary of two studies examining the effect on the achievement gap when a large introductory biology class is redesigned into an active learning environment. The article, “Low-Cost Instructional Changes Can Cut Achievement Gap in Intro Biology,” is a quick summary with links to the Science and Life Sciences CBE Education journal articles. The study was led by Scott Freeman at the University of Washington and concludes that active learning in this study cut the achievement gap by almost half. The study discusses some simple ideas like randomly calling on students in the large lecture class, having students write minute papers in class, and being quizzed on the reading.

What kinds of simple things have you done to improve the active learning environment of your class?

How Does a Tree Grow? Which Four Year Old Do You Agree With?

Written by Kelly A. Hogan, University of North Carolina at Chapel Hill

Learning Outcomes:

– To correct a misconception about how trees grow

– To describe primary growth in plants

Activity Description: A video is shown of two four-year-old boys who are asked what would happen to a basketball hoop nailed into a tree after many years of tree growth. Students must decide which boy they agree with. After answering on their own, they must then discuss and answer again.

Time Needed: 10 minutes

Materials Needed: Link to this video:

Activity Instructions: Show the video above. Using the PowerPoint linked, poll the students, preferably through clickers, to find out what students think. My class was close to a 50/50 split without much introduction to the topic. This is a great question to have them find someone with a different answer and try to convince the other that they are correct. This generates a lot of discussion. In their discussion, I will often show them the two models of growth we are comparing with the question (see PowerPoint.)

In the end, I explain how Jake was correct (my son!). I use this as a launch into a discussion about primary growth from apical meristems.

PowerPoint Presentation: How Does a Tree Grow PowerPoint