When used as a whole, this activity sequence ties together several
important topics foundational to molecular biology: embedded genes,
translation, mutations, and genetics and disease. The sequence allows
students to think through core concepts and investigate connections
using hands-on tasks and assignments that guide construction of
student understanding. While the sequence was designed to be implemented in its entirety, the various parts can be used separately if
Activity Sequence Overview
The sequence called “Introduction to Molecular Biology Activity” is
available for download in both Word and PDF formats (see below).
These activity handouts guide students through the four different parts
of the sequence. (For convenience, several of the important components of these handouts are also included as figures within this article.)
There are four main parts to this activity sequence that lead the
students through concepts related to the genetic code (part 1), use
of the genetic code (part 2), the effects of genetic mutations on the
code’s resulting protein product (part 3), and how this relates to
human disease (part 4). The activity is flexible to fit within various
course schedules, and portions of it can be assigned as homework.
We generally have our students complete parts 1 and 2 in class within
small groups of three or four students, with parts 3 and 4 done as
homework. The homework assignments are followed by extensive
discussion in class the next day. The understandings students gain
from this activity are then interwoven throughout the “molecular biology” unit and can be used to reorient students to these concepts
throughout the rest of the course.
• “Introduction to Molecular Biology Activity” handouts, available
for download in either Word doc or PDF format:
• Discussion slides, available for download in PowerPoint or PDF
• Guide to using the discussion slides (description of slides), available at
This activity sequence can be used at the beginning of a course’s
molecular biology unit to introduce key concepts, and then as a
foundation from which to draw as students further explore the central dogma of molecular biology and molecular genetics.
Teacher preparation prior to the activity sequence
1. Teachers should cut strips of colored paper using 10 standard
colors of construction paper (black, blue, brown, green, orange,
pink, purple, red, white, and yellow). By cutting the colored
strips of paper into long and short strips, 20 categories of paper
strips are made (10 colors of long strips and 10 colors of short
strips). The strips should be kept organized by category, and
each student or group of students should be given around five
of each length and color. This can be somewhat time consuming for the instructor. Thus, if time or resources are limiting,
the teacher can premake a few paper chains that can be displayed to the class during the activity (see notes/potential
modifications in the description for part 2 of the activity
below) and have the students simply write down the chain
sequences as they “translate” them. Teachers should also premake the short chain translated in part 3 of the activity and
at least one “mutated” chain based on the various mutations
identified in part 3 of the activity sequence. We suggest
making one of the chains that would result from an insertion
or deletion to demonstrate how dramatically the chain will
change when the reading frame is altered. These premade
chains can be stored and used in subsequent years to save
repeated preparation time.
2. Teachers should print the “Introduction to Molecular Biology
Activity” handout packet, with a copy for each student or
group of students.
3. Teachers should familiarize themselves with the discussion
slides and the key concepts that they address, adapting
the slides as appropriate to the teacher’s style and course
Part 1: Thinking about Codes
1. Students will devise a simple code using four shapes to convey complex information.
2. Students will be able to explain why three consecutive shapes
are required to adequately code for all 26 letters of the
English alphabet, and why this results in codon degeneracy.
3. Students will understand why other aspects beyond the letters
must be considered, such as where to start, punctuation, etc.
Classroom workflow and teaching instructions
Students should be given the entire “Introduction to Molecular Biology Activity” handout packet at the beginning of class and instructed
to work on part 1 (page 1) without progressing to part 2 until further
instructions are given. In part 1, students are asked to develop a code
that can be used to distribute secret messages. They must consider
how to code for letters of the English alphabet using only four distinct shapes (triangle, star, square, and circle; Figure 1) and consider
what other aspects beyond just the English letters might require coding in order to effectively communicate the secret message. Students
are not given any additional information and are instructed to work