The Central Dogma of Biology: DNA to Protein
Introduction:
You have already learned that you inherit half of your DNA from your mother and half of your
DNA from your father. But how is that DNA the instructional manual for your cells to maintain
homeostasis so that you survive?
Parts of that 3 billion base pair DNA holds the recipes to make thousands of proteins that are
needed everyday. But what happens if that recipe is illegible or the steps are scrambled? – we
develop some medical condition.
You will be given one small section of a human DNA sequence to analyze to figure out what
medical condition results when the instructions you are holding are incorrect.
Materials (per pair)
DNA sequence
Computer with internet
Procedure:
1. Obtain your DNA sequence from your teacher.
2. Find your partner for this activity by finding the student who has the same colored sequence
that is complimentary to your sequence to create a double stranded DNA molecule.
3. Place the two DNA sequences together to make a double stranded piece of DNA. The TOP
piece of DNA holds the message for making a protein.
4. Lay the bottom piece of DNA aside and transcribe your DNA sequence into the
complementary mRNA sequence and record it in the space below.
Note: Depending on what sequence you selected, you may not fill all the blanks below.
mRNA: [__ ___ ____] [___ ___ ___] [___ ___ ___] [___ ___ ___] [___ ___ ___]
[___ ___ ___] [___ ___ ___] [___ ___ ___] [___ ___ ___] [___ ___ ___]
[ ___ ___ ___] [___ ___ ___] [__ ___ ___] [___ ___ ___] [___ ___ ___]
5. Use the picture below to draw an arrow to where the process of transcription occurs in the
cell.
6. Why must transcription occur in this location in the cell? In other words, why can’t it occur
in other locations of the cell?
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
7. Translate the code into an amino sequence using the genetic code chart on the attached sheet.
Make sure you use the right 3 base sequences to determine each amino acid.
__________ __________ __________ __________ __________ __________ __________
__________ __________ __________ __________ __________ __________ __________
__________
8. How does each mRNA codon hold the message for a specific amino acid even though it is not
the molecule that brings the amino acid to the ribosome for polypeptide synthesis?
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
9. The BLAST program that you are about to use has a different code for the amino acids then
the 3 letter abbreviation you are used to. Use the attached chart to convert the amino acid
sequence into the one letter code for analysis by BLAST.
___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___
10. Check your above sequence with another group that had the same original DNA sequence as
you before moving onto the next step.
BLAST is an online database that stores all of the DNA, mRNA, or amino acid sequences ever
sequences for any organism. Scientists use this database to compare sequences they are studying
against the database to find similarities and differences. This sometimes can answer questions
the scientist has about the sequence they are studying. Also, the database can be used to identify
a sequence of DNA or amino acids. This is what you will be doing today.
11. Go to the website by clicking on the protein blast link on my moodle page under DNA and
Protein Synthesis resources.
12. Once the website pops up, choose Protein BLAST to run.
13. In the box below where it says ENTER accession number, type the one-letter abbreviations
from #7. BE SURE TO ENTER THEM IN THE CORRECT ORDER AND IN ALL
CAPS!
14. Below Choose Search Set, limit the search to only humans by typing in humans next to the
organism label. Choose Human (taxid 9606) from the list.
15. Scroll down and click on the BLAST button. It may take a few minutes to process your
request. The database is screening your amino acid sequences with known sequences to see if it
can find a match.
16. On the next page, scroll down to the list of proteins that matched your sequence. The
database has ordered them with the best match as the first match in the list. Choose the first gene
that matches one on the list of possible proteins attached to the back of the packet.
17. Click on the max score for the first entry to move to the part of the page showing how
closely the two sequences match. See below for what the website should take you to. This
section provides you with a wealth of information about your sequence.
18. Reference the data table of possible genes for this activity to answer questions 15-17.
19. What gene was your DNA sequence part of? (should be in the list on the attached sheet):
___________________________________
20. What is the name of the protein this gene produces?
___________________________________
21. The protein is involved in the following disease: ____________________
22. Open to the NCBI homepage link on moodle and select STRUCTURE from the dropdown
database menu. Type in the GENE NAME from #15 and hit enter.
23. Click the link titled view in CN3D below hit #1. This should open a program on the
computer that allows you to look at the 3-D structure of the entire protein. Remember your DNA
sequence only codes for a small portion of that protein. If you click on the protein and drag the
mouse, you can rotate the protein to see it from multiple angles.
24. Based on the image of the protein, what level of protein structure is being shown? Circle one:
primary
secondary
tertiary
quaternary
Explain: ______________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
25. Take a snapshot of the protein (open apple + shift + 4) and upload it to the dropbox under
the DNA and protein Synthesis Resource heading.
26. Now you are going to learn a little about the medical condition that can result when this
protein is not formed properly. Go to the Genetics Home Reference Website and click on the
medical conditions tab. Type in the disorder to fill in the data table on the next page. MAKE
SURE TO PUT THE INFORMATION INTO YOUR OWN WORDS!!!
Medical Condition
What is it?
How common is it?
Symptoms
What is the normal function of the gene?
*note: you will have to click on the gene name to open
another page
How does a mutation cause/ increase the risk
for the medical condition?
What is the cytogenetic location of the gene?
What is the molecular location of the gene?
How is it inherited?
AMINO ACID
Alanine (Ala)
Arginine (Arg)
Asparagine (Asn)
Aspartic acid (Asp)
Cysteine (Cys)
Glutamine (Gln)
Glutamic acid (Glu)
Glycine (Gly)
Histidine (His)
Isoleucine (Ile)
Leucine (Leu)
Lysine (Lys)
Methionine (Met)
Phenylalanine (Phe)
Proline (Pro)
Serine (Ser)
Threonine (Thr)
Tryptophan (Trp)
Tyrosine (Tyr)
Valine (Val)
Link to similar codon chart:
http://simplemoleculargenetics.weebly.com/uploads/1/8/3/4/18345767/5269678_orig.png
Link to similar amino acid chart:
http://patentimages.storage.googleapis.com/WO2010084157A2/imgf000015_0001.png
Possible genes sequenced:
Protein
Apoelipoprotein E
Presenilin 2
BRCA2
Presenilin 2
Synuclein
Gene
APOE
PS2
BRCA2
PS2
SNCA
Disease
Alzheimer’s
Alzheimer’s
Breast Cancer
Alzheimer’s
Parkinson’s
abbreviation
A
R
N
D
C
Q
E
G
H
I
L
K
M
F
P
S
T
W
Y
V
TEMPLATE
NUMBER
1A
1B
2A
2B
3A
3B
4A
4B
TEMPLATE DNA SEQUENCE
TACGAGTGTAAGTACCGGAGACTGTCGCTCCTTCTTCACACACTA
ATGCTCACATTCATGGCCTCTGACAGCGAGGAAGAAGAGAGAGAT
TACCTACATAAGTACTTTCCTGAAAGTTTCCGGTTCCTCCCTCAA
ATGGATGTATTCATGAAAGGACTTTCAAAGGCCAAGGAGGGAGTT
TACGGATAACCTAGGTTTCTCTCCGGTTGAAAAAACTTTAAA
ATGCCTATTGGATCCAAAGAGAGGCCAACTTTTTTGAAATTT
TACTTCCAAGACACCCGACGCAACGACCAGTGTAAGGACCGTCCT
ATGAAGGTTCTGTGGGCTGCGTTGCTGGTCACATTCCTGGCAGGA