DNA Structure and Replication POGIL
What parts of the nucleotides make up the sides (backbone) of the "ladder"?
Sugar and phosphate
Examine Model 2. Number the steps below in order to describe the replication of DNA in a cell.
1.)Hydrogen bonds between nucleotides break. 2.) Strands of DNA separate. 3.)Free nucleotides are attracted to exposed bases on the loose strands of DNA. 4.)Hydrogen bonds between nucleotides form.
Name the four nitrogen bases shown in Model 1
Adenine, thymine, guanine, cytosine
According to Model 3, what term refers to loose DNA inside of a nucleus?
Chromatin
Look at the bottom and top of the "ladder" in Model 1. Are the rungs parallel (the ends of the strands match) or antiparallel (the ends of the strands are opposites)?
Antiparallel
explain why DNA replication is called semi-conservative.
Because half of it is original and half of it is new
What structure holds the two sister chromatids together as they prepare for cell division?
Centromere
What rule is used to join the free nucleotides to the exposed bases of the DNA?
Complementary base pair rule; Chargaff's rule
What kind of sugar is found in a nucleotide?
Deoxyribose sugar
What are the three parts of a nucleotide?
Deoxyribose sugar, phosphate, and nitrogen containing base
What type of biological molecule is DNA helicase?
Enzyme
Refer to Model 1. When one nucleotide contains cytosine, what type of base is the cytosine attached to on the opposite nucleotide strand?
Guanine
Refer to the double helix diagram in Model 1 and describe its shape using a complete sentence.
It is a twisted ladder
During what part of the cell cycle is the DNA in a cell condensed into chromosomes?
M-phase
What part(s) of the nucleotides make up the rungs of the "ladder"?
Nitrogen bases
Which nucleotide component contains nitrogen?
Nitrogen containing base
During what part of the cell cycle is the DNA in a cell's nucleus replicated?
S-phase
Fill in the complementary bases on the strand below according to the base-pair rule. A T C C A G
T A G G T C
. With your group, use a complete sentence to write a rule for how the bases are arranged in the ladder model of DNA.
The bases are all always going to be to paired with the base that resembles the base the most. Like for example, Adenine will always be paired with Thymine and Cytosine will always be paired with Guamine
How does semi-conservative replication help prevent mutations during DNA replication?
There is a better chance of correct copying if one half is the original
How many hydrogen bonds connect the two bases from Question 6?
Three
Refer to Model 1. When one nucleotide contains adenine, what type of base is the adenine attached to on the opposite nucleotide strand?
Thymine
The two strands of DNA are held together with hydrogen bonds between the nitrogen bases. These are weak bonds between polar molecules. How many hydrogen bonds connect the two bases from Question 4?
Two
What is the role of DNA helicase in the replication of DNA?
Unzips the DNA molecule
