Download Transcription to Translation Scavenger Hunt

-
Professor Program
Activity: From DNA to Protein
Author/Creator: Robyn Kaake (2nd Year Graduate Student)
Created for: Bio 93
Activity Type
Small group activity, Small group model building
Time Needed in Discussion
30-35 minutes
Purpose
• To provide a hands-on learning experience that covers the topics of transcription and
translation, and also reviews material from before the midterm.
• To help students understand important differences between DNA, RNA and protein
molecules and synthesis.
Abstract
Pre-class prep (Day Before)
Pre-class prep (Day Of)
Teacher explains activity and discusses important points to
transcription and translation.
Students complete activity
Teacher summarizes activity and discusses topic further
60 min
10 min
5 min
20-25 min
5-10 min
Supplies
• 10 Plastic Bags (ziplock best). In each bag place:
o a blank strip of paper (For them to write “export signal”):
o 4 small stacks of different colored small post-its (RNA)
o 1 strip of paper with “group number” and “mRNA” written on it
o 1 strip of paper with “group number” and “protein” written on it:
Group Number X
mRNA
Group Number X
o 1 Card with “P”
o 1 Card with “OH”
P
•
OH
Tape
© 2007 by the HHMI-UCIrvine Professor Program. For non-commercial, educational use only.
protein
•
•
Professor Program
Regular sized post-its
10 DNA template strands (use about 18 bases). Put TAC (this will become AUG in
mRNA) about 3-4 bases into the strand (to imitate 5’UTR). Follow with 2 codons, then a
stop codon. End with a couple of bases to imitate 3’UTR.
5’
G A C T T A C A G A C A G A C T G G
3’
(example, with start/stop highlighted. Don’t highlight on student versions)
•
10 complementary DNA non-template (coding) strands. Make sure template and nontemplate strands are labeled properly (check twice!). Also label which end is 3’ and 5’
properly.
3’
C T G A A T G T C T G T C T G A C C
5’
(example, with start/stop highlighted. Don’t highlight on student versions)
•
•
•
Print-out of CODON code dictionary.
Candy prizes for winners.
Answer sheet (to make it easy to check their answers).
Pre-class prep
• Make all of the bags before hand.
• Make DNA template and non-template strands. (I made two different DNA sequences, all
the odd groups had one sequence and all the even groups had another sequence).
• Make answer sheet.
• Come early to class to tape DNA strands to walls OUTSIDE of class. Tape CODON code
dictionary somewhere in classroom.
In Class
1. (5 min) Introduce the day’s activity, example: “We will be working in groups of
three. Each group will be transcribing mRNA and then translating the mRNA into protein.”
You will need to explain that classroom is the cytosol and that outside the classroom is the
nucleus. You can then ask students questions, for example: “where is DNA located?” “Where
does transcription occur?” “Where does translation occur?” “What is the organelle
responsible for translation?” Just make sure you cover some of the basics to make sure
everyone is focused and understands the basics of transcription and translation. Here is a good
time to have them take out the two blank strips from the bag. Tell students that the door is the
nuclear pore complex and that to get back in they need to write down what is required to get
out of the nucleus on the paper strip provided.
Then give them a tiny lecture covering basic vocabulary and topics from class. For
example: Differences between DNA and RNA (this is a good time to have them take out their
post-its from their bags. Ask them the four bases in RNA and assign each colored post-it to a
base, you should write these assignments on the board. For example:
A=Pink
© 2007 by the HHMI-UCIrvine Professor Program. For non-commercial, educational use only.
-
Professor Program
G=Yellow
C=Green
U=Orange
You can also discuss how DNA is double standed and RNA is single stranded.
Define: Antipolar, Complementary, 5’, 3’. This is a good point to have the students take out
the 5’ phosphate [card with P] and tape to one end of the mRNA strip, then tape the 3’ OH to
the other end.
They should have everything they need to get started now. Tell them that this is a “scavenger
hunt” sort of activity and that the teams which come in first will “win”.
2. (2-5 min) Transcription: Instruct students that they will only be able to take their
mRNA strip, their nucleotides and their strip of paper into and out of the nucleus (hallway
outside of class). Instruct students NOT to write directly onto the mRNA and protein strips
(otherwise you will have to make more for following classes). Now tell them to write down
the letters on the post-its and begin the activity. It should take them about 2-5 minutes to write
down the letters and figure out that they need an “Export signal” to get back into the
classroom. Students can then go outside and start “transcribing their mRNA”.
3. (15-20 min) Translation: Once they are finished they can come back into the classroom if
they give you the “export signal”. Here you will give them a small stack of larger post-its and
let them know these are their amino acids. Tell them to write directly on the post-its and show
them to look in their notes for the CODON code, or show where you have posted one.
Students will have to remember what the start codon is, and also the stop codon. When they
are complete they can come to you and show you their mRNA and their protein. Make sure
they have both correct, give hints to students who need more help. First group with the correct
answer gets candy (optional, but they seem to like rewards for being first).
4. Teams which finish early should be assigned to “posts” in order to help teams which are
struggling. Have someone collect “export” signals for you. Have some outside to help
students transcribe the mRNA. Have others inside to help students translate their protein.
5. (5 min) Once all teams are finished, or time runs out, have everyone sit back down. Recap
the important points of the activity: which strand you should have copied from, which direction
RNA polymerase adds nucleotides, where to start translation and where to stop, what happens
to the protein if you miss a base in your mRNA (or add a base), what happens when you don’t
start at the AUG, explain the 3’UTR and 5’UTR. Also talk about some common problems: not
copying from correct DNA strand, copying in the wrong direction, not starting translation at
AUG, not stopping at Stop codon.
Things to Ask or Emphasize
• Emphasize polarity of DNA and RNA strands and what they mean (phosphate at one end,
OH at the other).
• Be sure to explain Complementary Bases and which strand the mRNA is complementary
to (template strand).
• You should REVIEW some things such as phosphodiester bonds, DNA is in the nucleus,
how things get in and out of the nucleus, what the ribosome does, where it is located.
© 2007 by the HHMI-UCIrvine Professor Program. For non-commercial, educational use only.
•
Professor Program
Be sure to talk about start and stop codons and how important these are. Also, the 3’UTR
and 5’UTR, where they were on the students mRNA.
Comments
Some students will finish much faster than others because they are quick to understand what
they should do. These students will get bored if they aren’t doing anything, so have them help
other students who are struggling.
If you have a second activity to complete after (I had an mRNA activity for them to do after),
you can have the students who are finished early help set up for your next activity, or start
reviewing their notes so they will be ready once the rest of the class is finished.
Reset for Next Discussion
After the class is over, you will need to set-up for your next class. Come prepared with new
sets of post-it note nucleic acids and blank strips for the import and export signal. Have
students in previous class remove all of their post-its and the phosphate and OH group.
© 2007 by the HHMI-UCIrvine Professor Program. For non-commercial, educational use only.