Instructor Exchange

Speed Dating with Gene Testing

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

Learning Outcomes:

– Evaluate the strength of the scientific studies presented at direct to consumer personal genomic testing services.

– Practice science communication through a two-minute discussion several times with different partners.

Activity Description: Students (for a class of approximately 30) are assigned prior to the activity one genetic test.  They will use the 23andme website to find out information about the gene test for their assigned trait/disease. During the activity, students follow a sort of “speed dating” protocol in which each student will meet with four other students (5 min each). After the four 5-minute sessions, students will be given an opportunity to choose other students’ presentations they found especially engaging.

Time Needed: 30 minutes in class

Materials Needed: Speed Dating with Gene Testing Homework and DNA Cards Worksheet

Activity Instructions: A week prior to the activity, assign each student to a genetic test (see the list and the student assignment attached). On the day of the activity, set up the classroom– make an inner circle and an outer circle of students, with equal numbers in each circle.  Randomly give five students one of the DNA cards before the activity begins. Each student is initially paired with and talks to another student for a total of 5 minutes. During this time, they each get about 2 minutes to tell each other what they learned.

While talking, each pair should have the list of “question prompts,” but they should not have their own notes out. They can each talk for two minutes straight or they can go back and forth for the 5 minutes. They can decide as a pair initially.

When the buzzer sounds, students in the outer circle rotate and meet with the next student for another 5 minutes. Repeat two more times, such that each student has spoken with four students over the course of 20 minutes. (Rather than a circle, you might try two rows of students in which one of the two rows moves every 5 minutes).

After the four 5-minute sessions, each of the five students with a card chooses one person they found especially engaging by giving them their DNA (a picture card, analogous to a reality show and a rose; see attached). Ask them to explain why. This is meant to get the discussion started, but others might want to also tell what they found most engaging.

Print an image like this to make the DNA cards:








Q: If an Asian male wanted to be tested by 23andme, would the results be applicable to him? Explain why or why not.

A: Yes and no. Many of the tests have been validated by studies of specific ethnicities but the studies have not been replicated in all populations. This does not mean that the results won’t hold true in other ethnicities, but there are limitations to the current knowledge. Nonetheless, many tests have been validated in multiple ethnicities. The site clearly states this for each gene test, so he can look to see which have been specifically validated in Asians.

Vertebrate Phylogeny

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

Learning Outcomes:

– To describe how phylogenetic trees show evolutionary relationships

– To describe shared characteristics in vertebrate evolution

– To construct a simple phylogenetic tree for mammalian evolution

Activity Description: This activity can be used while teaching vertebrate evolution. It will also bring in phylogeny, as a way for students to see relationships rather than lists of characteristics to memorize about vertebrate. Students will explain phylogenetic trees, practice with the vertebrate phylogenetic tree they have seen in their textbook, and then construct their own tree to demonstrate their understanding of phylogeny. After the worksheet, an assessment question (see below) can be used b the instructor in various ways.

Time Needed: 15-20 minutes

Materials Needed: The activity worksheet can be printed for class time. A key is also attached. An optional “Guided Reading Questions” worksheet accompanies the activity for students to do on their own while reading to prepare for this day’s activity.

Vertebrate Phylogeny Worksheet

Vertebrate Phylogeny Worksheet KEY

Guided Readings Questions for Vertebrate Evolution

Activity Instructions: Students should read about vertebrate evolution before this activity. Students work through the worksheet and are then given the assessment below.

Assessment: The following assessment is adapted from an “Applying the Concepts” Question in Chapter 15 of Campbell Biology Concepts and Connections 7th Edition. It can easily be modified into a set of clicker or multiple choice exam questions.

Directions: Arrange the species on the phylogenetic tree below and indicate the derived character that defines each branch point.

Numerous questions can be made for clicker or test exams for students to make correct labels. Example:

What should be at label “Z”?

A)    Fur

B)     Green Skin

C)    Bleeker

D)    Suction Cup Feet

E)     Giant Eyes

Answer: D

Key: for all labels:

W – Green Skin

X – Giant Eyes

Y – Fur

Z – Suction Cup Feet

1- Bleeker

2- Floof

3- Snoozle

4- LooHoo

Using Analogies in Microbiology: The Bacterial Cell as an Entertainment Venue to Illustrate the ATP-binding Cassette (ABC) Transport System

Written by Kristen Z. Swider, Capital Community College

Students in my microbiology class are relatively unfamiliar with the scientific concepts involved in the course and will often attempt to rely on memorization. However, due to the complex nature of the material, it is difficult to access information from the perspective of pure recall. As abstract concepts are discussed throughout a science course, many learners still operating in the concrete stage of development may be lost by a failure to attach understanding to anything of substance. As a result, the concepts are often missed during examinations. There is no requirement that an instructor complicate the approach in order to communicate scientific principles. For these reasons, the use of analogies to illustrate complex processes can enhance a student’s comprehension of the material and make connections that promote lifelong learning. Analogies may be presented to the learner as prepared elements of a lecture or they may be generated by the learners themselves. Self-generated analogies can and do occur spontaneously in discussion. Students are encouraged to develop and present analogies to the class. In either case, the interactive, social process of exploring analogies, whatever their source, contributes to the learning process.

How the ATP-binding Cassette (ABC) Transport System Works

– ATP-binding cassette (ABC) system: This involves substrate-specific binding proteins located in the bacterial periplasm, the gel-like substance between the bacterial cell wall and cytoplasmic membrane.

– The periplasmic-binding protein attaches temporarily to the substance to be transported and carries it to

– Meanwhile, ATP gets broken down into ADP, and phosphate, releasing energy. It is this energy that powers the transport of the substrate, by way of the membrane-binding transporter, across the membrane and into the cytoplasm.

– Examples of active transport by means of ABC systems include the transport of certain sugars and amino acids. There are hundreds of different ABC transport systems in bacteria.


The Bacterial Cell as an Entertainment Venue to Illustrate the ATP-Binding Cassette (ABC) Transport System

The players:

Bacterial cell: Entertainment Venue

Substrate: Patron

Periplasm: Outer arena area

Substrate-specific binding protein: Event ticket

Cytoplasmic membrane: Inner arena barrier with turnstiles

Membrane-spanning transport protein: Turnstile

Cytoplasm: Event location (inner arena)

ATP: energy needed to move the turn-stile and allow entry of the substrate (Patron)

– The bacterial cell is the entertainment venue, with the cell wall being the outer boundary of the arena property. Once the patron reaches the arena, he/she can easily migrate through the cell wall to the inner arena (periplasm) since a “ticket” is not yet needed.

– In order for the patron to gain entry into the main arena area of the venue (cytoplasm), he/she must pick up a ticket at a will call/box office. Here in the periplasm, a patron will pick up a pre-prepared ticket (periplasmic binding protein) just before the entering the event.

– Before entering the main arena area, the patron with the ticket (transportable substance and periplasmic binding protein complex) must enter the arena through the turnstile (membrane-spanning transport protein). A turnstile is a form of gate which allows one person to pass at a time. A turnstile can restrict passage only to patrons who provide a coin or a ticket. It can also be made so as to enforce one-way traffic of people.

– Once at the turnstile, the ticket (periplasmic binding protein) gets left behind, and the transportable substrate (patron) can enter the cell via a turnstile.

– As the substrate (patron) moves through the turnstile, energy is required, and ATP is broken down. The patron (substrate) is now in the arena and can be used by the cell.

Media Review: Grade Reader created by Jeremy Petranka, Department of Economics, University of North Carolina at Chapel Hill

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

Are you almost done with the semester, but still need to submit grades? Maybe your institution has you submit them electronically, directly from a spreadsheet? If so, kudos to your university! If this isn’t your situation, keep reading, as you may find this website really useful. Grade Reader reads grades from your Excel file aloud, so you can enter them electronically or write them on the official grade roll documents. I have been using my spouse for years to enter grades for over 600 students per semester. Now Grade Reader can replace my husband!

At the site below, the creator of the program, Jeremy Petranka, has a tutorial explaining the program and why it’s better than simply using Excel’s cell reading function. While he details the reasons UNC faculty will find utility in it for our specific grading management system, the function translates to any institution where instructors have to enter grades manually in some way. The program (Windows only) can be downloaded here too. It is easily edited to grades that fit your institution, and Jeremy shows this in the tutorial.

Do you have any ways that make you more efficient at the beginning or end of the semester? Please share in the comments!

Video Review: YouTube – Bang Goes the Theory: Evolution Made Simple

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

From a BBC show called Bang Goes the Theory ( and shown on YouTube at

5 min and 28 seconds

A clever and simple analogy is made by Dr. Yan to show how evolution produces large scale diversity. Dr. Yan draws a perfectly straight line on a tablet computer. He then asks people at a large fair to trace the line with the computer pen. Each person that traces only sees the line that the previous person traced. Over time, the original straight line looks less like a line. He also shows how different branches of an evolutionary tree arise with the same line analogy.

I found Dr. Yan’s personality and entire video really engaging. The simple demonstration will stick with your students because it is a memorable analogy that is easily understood. This would make an excellent in-class activity too with stacks of tracing paper!

Do you think this is a useful analogy and would you show it to your students?

The Genome as the Harry Potter Series

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

The genetic code is often described as being analogous to the written language. I expand this analogy to help students understand the hierarchy that exists in genetics, since I find many students don’t understand the relationship between a gene and a chromosome. Imagine a set of books, perhaps the Harry Potter series. The entire series on the shelf is analogous to the genome. Each book can be thought of as a chromosome. Within each book are chapters, these can be thought of as genes. Lastly, the 26 letters of the alphabet are arranged to make the variation of words within the genes. The genetic code has 4 letters to make unique arrangements/sequences. What would be the consequence if a few sentences or a chapter or an entire book was lost from the series? Would the story still make sense? (This would be analogous to mutations and chromosomal abnormalities.)

Pairs of Shoes and Pairs of Chromosomes

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

When discussing homologous chromosomes and sister chromatids, I often use analogies to shoes or socks. For example, I may have two pairs of the same cute flats, one pair in yellow and one in turquoise. These flats are the same size, same brand, exact same style. The yellow shoes are like sister chromatids to each other, just as the turquoise shoes are sister chomatids with each other. The yellow and turquoise are like homologs to each other. To carry the analogy further, I ask them what a pair of running sneakers might be analogous to. (These would be a completely different chromosome.)

Losing Control of a Car Relates to Unregulated Cell Division

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

When discussing the cell cycle and cancer causing genes, I often use an analogy to cars. There are two ways to lose control of a car: the gas pedal can get stuck down or the brakes will not work when engaged. In either case, the car speeds along without driver control. In this anology, tumor supressors are like brakes, which normally prevent the cell cycle from losing control (preventing cancer). When mutated, the brakes are lost and the cell divides out of control. Proto-oncogenes are like the gas pedal, in that they promote cell division. When mutated, like a gas pedal stuck down, they cause unregulated cell division.

Babysitting Gives Students Experience with Interspecific Competition

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

When discussing interspecific competition I always get students to think about a sitiation in which they are babysitting two kids. I make up different scenarios to illustrate ideas of competition. For example, I might tell them that there are two brothers (age 8 and 4) and only one remote control for the video game. What do they predict would happen with the brothers? If the big brother pushes the little brother out of the way and takes the control for himself, I explain Gause’s competitive exclusion principle. If I ask them what they might suggest as the babysitter, and they usually come to the conclusion quickly that the boys must share the remote. The little brother may “adapt” to his big brother by using it only when the big brother goes to eat a snack. Sharing the remote, illustrates resource partitioning as a way of differentiating niches, in this case temporal differentiation.

Using Waves at the Beach to Describe Concentration Gradients

Written by Jennifer A. Metzler, Ball State University

When discussing passive versus active transport and the difference between an input of cellular energy, I ask students to imagine they are at the beach or at a wave pool. Since passive transport is going down a concentration gradient, I tell them to liken it to having the waves at their back and moving into shore. It is not a problem for them at all and they do not need to expend any energy as they are going with the flow. With active transport going against the concentration gradient, I tell them to imagine turning around and having the waves hit their chest and try to move away from shore. In this case they must expend energy as they are going against the flow of the waves.