Reviewing Macromolecules

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

*Adapted from an activity presented by Dawn Tamarkin, Springfield Technical Community College at the National Association for Biology Teacher (NABT) Conference 2010.

Learning Outcomes:

– To review nomenclature related to macromolecules

– To practice organizing and making connections between concepts

Activity Description: Students are given a sheet of paper covered with words related to macromolecules. They will first cut the words out (like flashcards) and organize them into piles with a partner. Students are encouraged to discuss different ways to group the same set of words.

Time Needed: Approximately 25 minutes

Materials Needed: Worksheets and scissors for each group


  1. Have the students cut out the words.
  2. Let them organize them into piles without telling them how the organization should be done.
  3. Allow them time to see how other groups grouped their words. Allow time for questions and discussion about the different ways to group words.

Worksheet: Reviewing Macromolecules Worksheet

Appreciating the Diversity of Primary Sequences in Protein Structure

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

Learning Outcomes:

– To gain an appreciation for the diversity of proteins in amino acid sequence and length

– To examine an internet tool utilized by research scientists

– To appreciate quantitative biology

Activity Description: A classroom demonstration involving one student and multiple pairs of mittens of different colors is used as an analogy to the 20 amino acids that can be ordered in a multitude of ways in primary protein structure. Students can then use theNationalCenter for Biotechnology Information (NCBI) website to explore real proteins.

Time Needed: The activity should take approximately 15 minutes

Materials Needed: Multiple pairs of mittens or gloves

Activity Instructions:

One student comes to the front of the room in which there are two pairs of mittens (say a red and a blue pair). The student is allowed to choose one for each hand. Ask the audience, “How many possible combinations are there?” (Answer: 4)

Students won’t need a mathematical equation to figure this out:

Right – red, Left – red or Right – red, Left – blue or Right – blue, Left – blue or Right – blue, Left –red

Next put another pair of mittens on the table for your student to choose from (there are three pairs total at this point). Ask the audience, “How many combinations are now possible?” (Some students may start forming combinations of colors. Give them time to see how difficult this can be. Others may see the need for a calculation more quickly.) This is a good time to point out that biology is quantitative (many students will not recognize at the introductory level that as biology advances it intersects with mathematics more and more.)

The equation for the two hands and three pairs of gloves is: 32 = 9

Two hands and four pairs of gloves: 42 = 16

Next ask the audience, “How many amino acids exist?” (Answer: 20). Make the analogy clear by explaining that you could bring 20 pairs of mittens to your student. And ask them, “For a dipeptide sequence, how many different combinations would be possible?” (Answer: 202 = 400).

(Be sure to note that Ala-Leu is indeed different from Leu- Ala because polypeptides have directionality with an amino end and a carboxyl end.)

Lastly, ask students how long a typical polypeptide is. Let them take guesses and then explain the variation that exists. You can let them name a few proteins they know and go to:

to show them how many amino acids are in their named proteins. (This is a great site to show them as a collaborative tool that scientists use in the research.)

Ask them to calculate the number of combinations in a protein with say 125 amino acids:

Answer:  20125 = 4.25352959 × 10162

Note: You can bring in this same idea again when you discuss the triplet nature of the DNA code. With 4 nucleotides and a triplet sequence there are 43 = 64 combinations or codons.

A Student “Bully” Demonstrates the Polar Covalent Bond

Written by Jennifer Wiatrowski, Pasco-Hernando Community College

Learning Outcomes:

– To help students visualize the relationship that exists between atoms in a polar covalent bond

Activity Description: Three students use paper to demonstrate how electrons are equally shared in non-polar covalent bonds and unevenly shared in polar covalent bonds. This works well in a class of any size.

Time Needed: A few minutes

Materials Needed: Five pieces of paper and 3 students

Activity Instructions: I usually look for a large male student to be “oxygen” and then two smaller students to be “hydrogen.”  I have the students stand in a row with oxygen in the center. Between each hydrogen and the oxygen, I have them hold a piece of paper with two large dots on it. These represent the shared pairs of electrons. I have them start out holding the electron pairs at equal distance from one another (like in a non-polar relationship). But, then I tell oxygen to be the “bully” and pull those electrons closer to his body. I then hold signs over their heads indicating partial positive and partial negative charges. (A more creative person could probably come up with some funny hats representing the charges for the students to wear.)

Practicing the Scientific Method: Are Girls Better than Boys at Some Tasks?

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

Learning Outcomes:

– To practice the scientific method, beginning with an observation

– To appreciate that there are multiple ways to test a single hypothesis

Activity Description: Students are given information about females being better at articulation than males. They are asked to follow the steps of the scientific method and design their own experiment to test this statement. After class discussion about the weaknesses/strengths relative to their designs, the instructor introduces a planned experiment involving the students and tongue twisters. Class data is compiled and the instructor leads the class in a discussion about the results and how they compare to other results.

Time Needed: This activity takes about 30 minutes.

Materials Needed: If interested in compiling class data: a calculator, an Excel spreadsheet, or clickers.

Activity Instructions:

1. Engage your students with a fun survey. Ask them a few questions, “Who is better at ______, men or women?”

Fill in the blanks with these ideas, based on “Sex Differences in the Brain,” Scientific American,, Sept 1992 by Doreen Kimura:

a. Fine motor skills (putting pegs in small holes, needle-pointing, surgery)

b. Learning a new route from a map

c. Remembering landmarks on a new route

d. Matching items that are alike (among a sea of similar items)

e. Spatial ability (rotating pictures of 3D items visually)

f. Naming objects in a category (i.e. name all objects you can think of that are red)

g. Articulation of words

2. Explain that on average, men have been found to excel at b and e, and women excel at the other activities.

(Based on “Sex Differences in the Brain.” Scientific American, Sept 1992 by Doreen Kimura)

3. Ask students, “Is this real? How was it tested? What could account for these differences?”

The article referenced above will give you a brief review about what might account for these differences. “Differing patterns of ability between men and women most probably reflect different hormonal influences on their developing brains. Early in life the action of estrogens and androgens (male hormones chief of which is testosterone) establishes sexual differentiation.” -Doreen Kimura

4. Choose one of these topics to focus on. I have chosen articulation. Explain articulation difficulty by having the students repeat this statement several times.

“We surely shall see the sun shine soon.” The students will recognize that this is a tongue twister.

5. Instruct the students to do this activity: “Using critical thinking, design a scientific approach to see if there is evidence for this statement, ‘Females are better at articulating than males.’ In your answer, you should write out the steps of the scientific method.” (If students have not yet had a mini lecture on these steps, this would be the time to do this.)

6. Allow them time to share their ideas for an experiment with classmates. Allow other classmates to comment on their designs. (To encourage participation here, you might have the groups switch ideas and read each other’s ideas.)

7. After a discussion period, tell them you had an experiment already planned (It is possible that they have come up with something similar. Now is a great time to stress to them that there are often a myriad of experimental designs to answer the same question. Science is creative.)

8. Detail your experimental design to them:

Observation: Females articulate better than males.

Question: Are females better at articulating than males?

Hypothesis: Females perform better on tongue twister challenges than males.

Prediction: If told to repeat a tongue twister 5 times as quickly as possible, then females will successfully complete the task faster than males.

Experimental Design: Students will be asked to work in small groups to time members of their group. They will collect data for each female and male in their group. The tongue twister the students will repeat is “a box of mixed biscuits in a biscuit mixer.” Have each student repeat it 5 times without errors and record this time in seconds. This will likely lead to laughter and fun and a noisy room!

9. After the class completes their group tasks, if you can manage to do so quickly, the class data can be compiled and averaged. (If your class is large and you are using clickers, you might quickly collect the data from the class by setting up MC options for ranges and show a quick histogram or collect open-ended answers and quickly manipulate a spreadsheet. The majority of my class completed it in under 17 seconds, but there were many that reported over 23 seconds.)

10. Be sure to discuss any weakness of the design and sampling errors. Are there other ways to test this skill? Can we now call this a theory? (One example of something to point out is that the males and females would need to be similar in every aspect aside from sex; for example, their average age should be the same. Depict an obvious pitfall if the males were all under 6 years of age and the females were college-aged.)

11. Lastly, let them know that this was a real experiment; it was one task in a series of experiments performed by Doreen Kimura and Elizabeth Hampson of the University of Western Ontarioin Canada. On average, women were faster than men when asked to repeat the sentence 5 times; women averaged 17 seconds. (Interestingly, the scientists found that the women’s values varied depending on where they were in their menstrual cycle. At peak estrogen levels at mid cycle, the average was 14 seconds.) When my class data didn’t match the reported data, I used it as an opportunity to explore the weaknesses of our specific design (no official unbiased data collector, reporting on peers, noisy room, uneven number of males and females etc.) Additionally, I used it as an opportunity to explain how science needs to be repeatable and what it means when a scientist can’t repeat another scientist’s experiment.

To see a discussion of the research on articulation: “Women’s skills linked to estrogen levels.” Science News, Nov 26, 1988 by Rick Weiss.

Learning to Think Critically Like a Scientist

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

Learning Outcomes:

– To discover “bad” scienceStreaming and download Inferno (2016)

– To recognize how media reports of scientific papers can cause the spread of misinformation and fear

– To have students suggest studies that would produce convincing data

Activity Description: Students are shown a summary of an infamous scientific article related to the MMR vaccine and autism. They are asked to evaluate if this fits the guidelines of good science. The class should come to the conclusion that it does not fit the guidelines of good science by determining what data is lacking.

Time Needed: 30 minutes with discussion

Materials Needed: Copies of the worksheet below

Activity Instructions: Students are given a summary of a monumental paper linking the MMR vaccine and autism. Students discuss their reactions and then spend time determining why the study was flawed and what kind of studies would be better. Class discussions are followed by a presentation of real data from studies similar to those they may have suggested. Lastly, the instructor reveals that the paper was retracted. Nonetheless, public fear and misinformation remain despite no supporting evidence linking the MMR vaccine to autism. (There are numerous news articles on the paper’s retraction that you can reference.)

Worksheet: Thinking Critically Worksheet

Background/Follow-up for the Instructor:

The following are questions students may come up with on their own for question 3 of the worksheet. Below each question is a brief summary of what was found in various studies.

  • Did autism rates increase after the introduction of the MMR vaccine?

– No. Sweden and UK studies (see below) showed no difference in the rate of autism before and after the introduction of MMR to society

  • Does onset of autism correlate with time of vaccination?

– No. UK studies show that age of onset does not correlate with the timing of the MMR vaccine, if given at all. (Although autism symptoms frequently present around the age this shot is most commonly administered).

  • What is the normal rate of autism (control group vs. a MMR vaccinated group)?

– Denmark: study involved over 500,000 children. No difference in autism risk in those vaccinated vs. those not vaccinated.

More specific information originally published on in 2004):

The MMR-autism theory came to the forefront when, in 1998,Wakefield and colleagues reviewed reports of children with bowel disease and regressive developmental disorders, mostly autism. The researchers suggested that MMR vaccination led to intestinal abnormalities, resulting in impaired intestinal function and developmental regression within 24 hours to a few weeks of vaccination. This hypothesis was based on 12 children. In 9 of the cases, the child’s parents or pediatrician speculated that the MMR vaccine had contributed to the behavioral problems of the children in the study. There are a number of limitations in the Wakefield et al. (1998) study:

1. The study used too few cases to make any generalizations about the causes of autism; only 12 children were included in the study. Further, the cases were referred to the researchers and may not be a representative sample of cases of autism.

2. There were no healthy control children for comparison. As a result, it is difficult to determine whether the bowel changes seen in the 12 children included in the study were similar to changes in normal children, or to determine if the rate of vaccination in autistic children was higher than in the general population.

3. The study did not identify the time period during which the cases were identified.

4. In at least 4 of the 12 cases, behavioral problems appeared before the onset of symptoms of bowel disease; that is, the effect preceded the proposed cause. It is unlikely, therefore, that bowel disease or the MMR vaccine triggered the autism.

In 2004, 10 of the 13 authors of the study retracted the paper’s interpretation, stating that the data were insufficient to establish a causal link between MMR vaccine and autism (Murch et al., 2004) The paper was fully retracted from Lancet in Feb 2010.

Epidemiologic studies have shown no relationship between MMR vaccination in children and development of autism:

In 1997, the National Childhood Encephalopathy Study (NCES) was examined to see if there was any link between measles vaccine and neurological events. The researchers found no indication that measles vaccine contributes to the development of long-term neurological damage, including educational and behavioral deficits (Miller et al., 1997).

A study by Gillberg and Heijbel (1998) examined the prevalence of autism in children born inSwedenfrom 1975-1984. There was no difference in the prevalence of autism among children born before the introduction of the MMR vaccine inSwedenand those born after the vaccine was introduced.

In 1999, the British Committee on Safety of Medicines convened a “Working Party on MMR Vaccine” to conduct a systematic review of reports of autism, gastrointestinal disease, and similar disorders after receipt of MMR or measles/rubella vaccine. It was concluded that the available information did not support the posited associations between MMR and autism and other disorders.

Taylor and colleagues (1999) studied 498 children with autism in theUKand found the age at which they were diagnosed was the same regardless of whether they received the MMR vaccine before or after 18 months of age or whether they were never vaccinated. Importantly, the first signs or diagnoses of autism were not more likely to occur within time periods following MMR vaccination than during other time periods. Also, there was no sudden increase in cases of autism after the introduction of MMR vaccine in theUK. Such a jump would have been expected if MMR vaccine was causing a substantial increase in autism.

Kaye and colleagues (2001) assessed the relationship between the risk of autism among children in theUKand MMR vaccine. Among a subgroup of boys aged 2-5 years, the risk of autism increased almost 4 fold from 1988 to 1993, while MMR vaccination coverage remained constant at approximately 95% over these same years.

Researchers in theU.S.found that among children born between 1980 and 1994 and enrolled inCaliforniakindergartens, there was a 373% relative increase in autism cases, though the relative increase in MMR vaccine coverage by the age of 24 months was only 14% (Dales et al., 2001). For more on this study, see California Data on Theory of Autism and MMR Immunization.

Researchers in theUK(Frombonne & Chakrabarti, 2001) conducted a study to test the idea that a new form, or “new variant,” of Inflammatory Bowel Disease (IBD) exists. This new variant IBD has been described as a combination of developmental regression and gastrointestinal symptoms occurring shortly after MMR immunization. Information on 96 children (95 immunized with MMR) who were born between 1992 and 1995 and were diagnosed with pervasive developmental disorder were compared with data from 2 groups of autistic patients (one group of 98 born before MMR was ever used and one group of 68 who were likely to have received MMR vaccine). No evidence was found to support a new syndrome of MMR-induced IBD/autism. For instance, the researchers found that there were no differences between vaccinated and unvaccinated groups with regard to when their parents first became concerned about their child’s development. Similarly, the rate of developmental regression reported in the vaccinated and unvaccinated groups was not different; therefore, there was no suggestion that developmental regression had increased in frequency since MMR was introduced. Of the 96 children in the first group, no inflammatory bowel disorder was reported. Furthermore, there was no association found between developmental regression and gastrointestinal symptoms.

Another group of researchers in theUK(Taylor et al., 2002) also examined whether MMR vaccination is associated with bowel problems and developmental regression in children with autism, looking for evidence of a “new variant” form of IBD/autism. The study included 278 cases of children with autism and 195 with atypical autism (cases with many of the features of childhood autism but not quite meeting the required criteria for that diagnosis, or with atypical features such as onset of symptoms after the age of 3 years). The cases included in this study were born between 1979 and 1998. The proportion of children with developmental regression or bowel symptoms did not change significantly from 1979 to 1988, a period which included the introduction of MMR vaccination in theUKin 1988. No significant difference was found in rates of bowel problems or regression in children who received the MMR vaccine before their parents became concerned about their development, compared with those who received it only after such concern and those who had not received the MMR vaccine. The findings provide no support for an MMR associated “new variant” form of autism and further evidence against involvement of MMR vaccine in autism.

Madsen et al. (2002) conducted a study of all children born inDenmarkfrom January 1991 through December 1998. There were a total of 537,303 children in the study; 440,655 of the children were vaccinated with MMR and 96,648 were not. The researchers did not find a higher risk of autism in the vaccinated than in the unvaccinated group of children. Furthermore, there was no association between the age at time of vaccination, the amount of time that had passed since vaccination, or the date of vaccination and the development of any autistic disorder. Though there were many more vaccinated than unvaccinated children in the study group, the sample was large enough to contain more statistical power than other MMR and autism studies. Therefore, this study provides strong evidence against the hypothesis that MMR vaccination causes autism.

DeStefano et al. (2004) conducted a study to see if there was a difference in the age at which children with autism and without autism received their first MMR vaccination. The study’s findings showed that children with autism received their first MMR vaccination at similar ages as children without autism.

So You Think You Are an Effective Multitasker?

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

Learning Outcomes:

– To point out that all humans are less effective at tasks as we juggle more and more at the same time

– To demonstrate an inverse relationship between multitasking during class and student learning

Activity Description: Students collect data about their own multitasking ability. The effectiveness of each single activity decreases as two tasks are performed simultaneously.

Time Needed: The worksheet will take approximately 5 minutes followed by discussion.

Materials Needed: Photocopies of the worksheets and student watches to measure seconds (or a classroom display of a computerized clock in a large classroom)

Activity Instructions: Hand out the worksheet and have the students work in pairs to record each other’s time. After the students have completed it, ask them what they think it demonstrates relative to the classroom. Encourage your students to see how switching between a quick text or email or website while trying to take notes in class could be more detrimental than they realize. Have a discussion about laptops in the classroom. This might be an opportunity to get their opinions and share your philosophy.

Fun background relative to this activity:

  1. This activity is based on demonstrations that David E. Meyer, a professor of psychology at the Universityof Michiganat Ann Arbordoes in his class. A typical student can do the individual tasks in about 2 seconds. You might guess that it should take about 4 seconds to combine the tasks, but it usually takes 15-20 seconds and usually includes mistakes. Meyer explains this is because there is a switching time cost. Additionally, studies have shown that people who consider themselves effective multitaskers performed worse on tasks that involved distraction, compared to people who considered themselves better at monotasking. (For more information about multitasking relative to the classroom, see “Divided Attention,” The Chronicle Review, Feb 28, 2010 by David Glenn.)
  2. Rigging a car with a red light to alert drivers when to brake, Car and Driver Magazine demonstrated how dangerous mutitasking can be when driving. Texting while driving is more dangerous than being legally drunk!

The magazine tested how long it takes a driver to hit the brake when sober, when legally drunk at .08, when reading an e-mail, and when sending a text. The driver drove 70 mph on a deserted air strip under different conditions. The results:

Unimpaired: .54 seconds to brake

Legally drunk: add 4 feet

Reading e-mail: add 36 feet

Sending a text: add 70 feet

Makes you wonder what texting during biology class does to exam scores!

Worksheet: Effective Multitasker Worksheet

Creating a Community for Active Learning on the First Day of Class

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

Learning Outcomes:

– To make students feel more comfortable sharing during class discussion

– To demonstrate to students that active learning involves every person in the class

Activity Description: Students are asked to complete a few small tasks that involve meeting their classmates and practicing a few active learning techniques. These are designed for the first day of class as an icebreaker and introduction to an active classroom.

Time Needed: 20 minutes

Materials Needed: Students will need plain paper or 3 x 5 notecards they can pass to each other.

Activity Instructions:

  1. Have the students introduce themselves to their classmates. Encourage them to meet people beside them, behind them, and in front of them. In a smaller class, you might have them introduce each other. This is also a good time to introduce yourself and share personal information and maybe funny photos of yourself to the class.
  2. Ask students to write down the answer to the following question on their blank paper (without putting their name on it): “What would encourage you to participate in class discussions? Are there rules that I and your classmates should follow that ensure everyone feels comfortable? What would they be?” You may have an alternative question you would find more useful in your class on day one. The two techniques below work well with any question.
  3. Call on a reporter: After students have had time to complete the question, call on one person to share. Inevitably that person will feel uncomfortable as will the whole class. Now, let that person know they are not going to share their answer. They have a few minutes to gather group answers. They will simply become a “reporter” for surrounding students. This should take the pressure off the student. In the meantime, have the other students discuss with their group, explaining you might call on some of them too.
  4. Pass the Paper: After you discuss a few of the student answers, try another technique. Have the students pass their notecards randomly to a neighbor. Each student should exchange a notecard with neighbors several more times until the class responses are well shuffled. Now, ask if some students will volunteer to read an interesting answer on the card they have in front of them. Let students know that if they are comfortable, they can always share their own ideas. Shuffling is one way to make people less self-conscious about sharing.


Dear Instructors,

I am excited to share with you my collection of activities for introductory biology students that will facilitate an instructor to create a more student-centered classroom. Several years ago, I only did one or two activities per semester. Now, I can’t imagine planning a 50 minute class phentermine meeting in which I lecture the whole time. I encourage you to scroll through the activities the way you might flip through a recipe book to get ideas. In some activities, you may decide you like an activity as is. And if the content does not interest you in some activities, skim it anyway, because the technique might spark an idea for your classroom. I have tried to vary the activities by content and also by technique (such as role plays, inquiry-base activities, jigsaw discussion groups, learning to study activities, etc.).

I hope you will find this to be a good resource. However, this will only be a GREAT resource when great instructors like yourself add your own ideas to this collection. I hope when you scroll through the current activities you will recognize that the possibilities are endless and no contribution is too small.

A good recipe only gets better when others comment and tweak it. My hope is that these activities will continuously evolve as more people use them for different audiences and share their comments. As a university instructor, I have not found a reliable, organized resource for sharing ideas like these. My vision is to have this be the first step in creating a community of instructors to share ideas in numerous, flexible formats. I hope this is a site you find well-organized and would like to contribute to.

I welcome your thoughts about the project and look forward to your submissions and comments.


Kelly A. Hogan

Biology Department, University of North Carolina at Chapel Hill

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