Download Activity: Can You Crack the Code

Name ____________________________________________
Date ______________
Activity: Can You Crack the Code?
Goals:
1. To form an operational definition of the word
“code.”
2. To understand what is meant by the term
“genetic code.”
Background Information:
Chromosomes are composed mostly of DNA. A DNA molecule is made up of four
different nitrogen bases – adenine (A), thymine (T), guanine (G), and cytosine
(C). These bases form the rungs of the DNA “ladder.” A single gene on a
chromosome may contain anywhere from several hundred to a million or more of
these bases. The bases are arranged in a specific order – for example,
ATGACGTAC – and are specific for each protein.
The order of the nitrogen bases along a gene forms the genetic code that
specifies what type of protein will be produced. In the genetic code, a group of
three bases codes for the attachment of a specific amino acid. Amino acids are
the building blocks of proteins. The order of the nitrogen bases determines in
which order the amino acids are put together to form a protein. You can think of
the bases as three-letter code words. The code words tell the cell which amino
acid to add to the growing protein chain. (This information is from page 102 of
Prentice Hall Science Explorer.)
Morse code is a telegraphic code in which the letters of the alphabet are
represented by combinations of long and short light or sound symbols. In our
case the dots and dashes will represent the twenty-six letters of the alphabet.
Materials: Morse Code chart, pencil, dictionary
Procedure:
1. What I Know: Write a sentence or two about what you already know
about inheritance and the DNA molecule.
2. What I Observed:
Use the Morse Code Chart provided to decode the question in the
message below. The letters are separated by slash marks. If you find
this difficult to read, refer to page 101 in your textbook.
.__ /.... /./._. / . / ._ / . _ . /./ __./ . / _. /
. /... /._ .. / ___ /_._. /._/ _ /. / -../
a. Decoded Message (the Morse code question above in English
words):
b. Your answer to the question in English words:
c. The answer to the question in Morse Code:
d. Your definition of the term code:
e. The dictionary definition of the word code:
3. What I Did: Write a short description of the procedure you used fro this
activity.
4. What I Learned: Write a description of what you learned about the term
genetic code from this activity.
5. What I Wonder: Pose a question you may still have concerning DNA or
the genetic code.
6. Question: Read the background information on this lab sheet and refer to
page 104 in your text book and complete the flowchart below that shows
how a cell produces a protein. A flowchart is a graphic organizer that
shows the chronological steps in a process. Include a heading for each
part and a short description (using your own words).
PROTEIN SYNTHESIS
1. Messenger RNA Production
The DNA in the nucleus serves as a pattern to create messenger
RNA.
3. Transfer RNA Attaches to Messenger RNA