Download J) DNA_Workshop_webquest2

DNA Workshop
www.pbs.org/wgbh/aso/tryit/dna/#
This computer simulation allows you, as a student, the opportunity to watch
DNA as it unwinds and requires that you assemble a replicated DNA molecule.
After you have mastered DNA replication, and answered the corresponding
questions, move on to protein synthesis, a process which includes transcription and
translation. Follow all instructions, and answer all questions.
During this interactive lesson, you may press the “HELP” button at any time
to better understand the processes being illustrated.
1.
The first screen for the interactive “DNA Workshop” gives you the
choice of “DNA Replication” on the left, and “Protein Synthesis” on
the right. Before you click on DNA Replication, answer the following
questions:
a. What is the name of the molecule which holds the genetic
information? ________________
b. When does this molecule need to make an exact copy of itself?
____________________________
Click on DNA Replication.
Unzip the DNA.
c. In a real cell, the molecule ______________ from spools made of
protein, then ___________________.
d. Now, the molecule resembles a _______________.
e. The types of molecules which help break apart the rungs are called:
___________________.
2.
In the lower right corner the illustration says, “You are here.”
a.
Where is replication occurring? _________________.
Click and drag the nucleotides and base-pair according to each
complementary base.
b.
Using this pattern, cytosine always pairs with
_______________, and adenine always pairs with
___________________.
Be sure to make two new DNA molecules.
c.
How many base-pairs are found in each DNA molecules shown?
______________________
d.
Each human chromosome actually contains ___________ of
base-pairs. Humans actually have a total of _____________
chromosomes.
3.
Click on Protein Synthesis.
Unzip DNA.
Notice this time the DNA molecule is only partly unzipped.
When making a protein, a cell only needs to use a portion of the
DNA strand.
The first step in protein synthesis is called transcription.
a. In the lower right hand corner, where is transcription
occurring?_________________________________
Drag nucleotide bases to make a complementary of the DNA. This
time the nucleotides are actually RNA, rather than DNA.
b. Notice that all the bases are the same except ___________
substitutes for thymine.
c. The name of the type of RNA you have just created is called
_____________________ RNA, or ____________ for short.
d. The mRNA will now ______________ the nucleus and travel to
the ribosomes in the cytoplasm, or on the Rough Endoplasmic
Reticulum.
e. Notice the diagram in the lower right corner. Where are you now?
___________________________________.
f. Look carefully at the diagram. On the dark pink mRNA, a set of
three nucleotides is called a ____________________.
The first codon attaches to the ribosome which is also made of RNA.
g. The blue rectangular shapes represent _________________.
Examples are arginine, valine, and methionine.
h. These amino acids are attached to the light pink
______________.
i. The other side of the tRNA has three nucleotides that are called
the ___________________.
Using your mouse, match the anticodons with the codon moving in
order from left to right.
j. What is the name of the first amino acid to be made by this
sequence of mRNA? ________________________.
k. What happens to the ribosome after you bring the correct amino
acid to the growing polypeptide (protein)? ___________
________________________________.
l. After the amino acid is attached and the ribosome moves to the
right, what happens to the tRNA? ___________________
m. After the protein has been assembled, what causes protein
synthesis to stop? ___________________________________.
n. Name the order of the amino acids in your polypeptide chain from
left to right: _________________________________________.
If you have time, repeat the above processes and watch carefully!
Learn!