Download DNA Replication Modeling

DNA Structure +
Replication Modeling
CLASS COPY! Do not write on
or take this sheet!
On your own sheet of paper, answer the following questions in complete sentences. Be sure your answer is written in a way
that clearly indicates what the question was asking!
Part A: Structure of DNA – Using your pasta/pipe cleaner model of DNA.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
What is DNA? Who has it and where is it found?
What are the three components of a DNA nucleotide?
What are the four nitrogenous bases found in the DNA molecule?
Nitrogenous bases can be divided into two categories based on shape/structure. Describe the two different shapes. Of the
four bases, which other base does adenine most resemble in shape? Thymine most resemble in shape?
According to the materials you are using, how do you represent there are 4 different bases?
When DNA is flattened (straightened out) to look like a ladder, which two molecules of a nucleotide form the
sides of the ladder?
To which molecule does each base attach?
Sides
Name the molecules of the nucleotide that form the ladder’s rungs.
What is the sequence of bases on one side of your DNA model?
What is the sequence of bases on the other side of the DNA model?
In a real DNA molecule, what kinds of bonds hold the complementary nitrogenous bases together?
Why are they called “complementary?”
Only two combinations of base pairings are possible for the rungs. Name these molecule combinations.
Adenine and Guanine are known as what kind of nitrogenous bases?
Cytosine and Thymine are known as what kind of nitrogenous bases?
Rungs
The hydrogen bond always occurs between what two general kinds of bases? What would the DNA molecule
look like if this weren’t true?
If four guanine bases appear in a DNA model, how many cytosine bases should there be?
If the following are the bases on the left side of a DNA molecule, list the bases that would make up the right side of a DNA
molecule.
a. Thymine b. Adenine c. Guanine d. Cytosine -
Part B: DNA Replication
Separate your DNA model along the points of attachment between base pairs. This will separate the two ladder halves. One
partner gets the left half of the ladder and the other partner gets the right half. On your own, using your half as a pattern, add
new nucleotides to the original half of the model.
19.
20.
21.
22.
23.
24.
When a DNA molecule replicates what will be the first thing that needs to happen to it?
What enzyme does this?
Compare your model with your partner’s model. What do you notice about the sequence (order) of bases on each model?
Is this new molecule any different than the original?
How did the new nucleotides get added to the template strand? (What enzyme)
What is it called when the template strand is from the original DNA and the replicated strand is newly created? (In other
words, what is this model of replication called?)
Be prepared to bring your model to your teacher and answer, from memory, any
of the previous questions.