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Biology Quiz: DNA Structure, Function, and Replication
Terms in this set (35)
A monomer that consists of a phosphate, a sugar, and a base molecule
The 4 base molecules are:
- Adenine (A)
- Guanine (G)
- Cytosine (C)
- Thymine (T)
A single unit of a small molecule; building blocks of polymer (Ex: a nucleotide)
Chains of monomers linked together (Ex: nucleotides linked together)
Deoxyribonucleic Acid; Stores and provides genetic info and instructions; found within the nucleus of a cell; divides during interphase (before cell division); condenses into chromosomes during cell division
The form of DNA. A twisted ladder
Base pairing rules
A - T
T - A
C - G
G - C
Bases with 1 ring; syngle ring
Bases with 2 rings (Adenine and Guanine)
The strongest bond; a bond that links the components in a nucleotide (1 sugar, 1 phosphate, and 1 base) and that links nucleotides of the same sugar-phosphate backbone together
A very weak bond; A bond that links bases that are across from each other together
S phase of interphase
The phase in interphase before DNA replication in which DNA replication takes place
The process by which DNA creates an identical copy of itself; occurs in the nucleus during S phase of interphase
The enzyme that unzips the double helix by breaking hydrogen bonds (step 1)
Builds new strand of DNA by placing nucleotides in an arrangement complementary to the template using the base pairing rules. Also, DNA polymerase forms covalent bonds between the nucleotides that it organizes (Step 3-4)
Builds covalent bonds on the sugar-phosphate backbone that were not made by DNA polymerase; The gluer (step 4)
Single strand binding protein; prevents separated strands from bonding again to reform the double helix
Places RNA primer to tell DNA polymerase where to start placing nucleotides; DNA starts placing nucleotides after the primer. Later, the primer is taken off by RNAse H and DNA polymerase goes back to fill in the missing nucleotides
Sliding clamp protein
A protein that holds DNA polymerase while DNA polymerase replace gaps with nucleotides
Removes RNA primer so that DNA polymerase can go back and replace the missing gaps where the primer was before it was removed
Segments of DNA on the lagging strand (strand going towards the origin where DNA polymerase needs to build in chunks)
A protein that aids in chemical reactions
The daughter strand of DNA replication is complementary to the template/parent strand
Semiconservative DNA replication
DNA replication is semiconservative because the new copies of DNA contain one original strand and one new daughter strand. The original strand is not destroyed or disturbed
The process of DNA replication in which the original DNA strand acts as a template to form a complementary strand
The original strand that came from ½ of the double helix; serves as a template in DNA replication
The strand formed to be complementary to its parent strand
Label three parts of a nucleotide
Base: the thing that is covalently bonded to the sugar molecule and hydrogen bonded to the other base (H bond - dotted line)
Given a picture, how would you identify a pyrimidine vs. a purine? Explain.
Pyrimidine: 1 shape base
Purine: 2 shape base
On ONE strand of DNA, nucleotides are held together by which type of bond to form a polymer?
When TWO strands of DNA are needed to form the double helix, which type of bond holds the two strands together to form the double helix?
Which has a stronger bond: A = T or C ≡ G? Why?
C - G has a stronger bond because it has 3 hydrogen bonds that link the 2 bases. A - has a weaker bond because it only has 2 hydrogen bonds that bond them together. Therefore, C - G would be harder to pull apart because it has more hydrogen bonds that bonds the base pair.
Why is DNA replication considered semiconservative?
The original DNA strand is not destroyed or messed with during replication. In the daughter strands of replication, it contains 1 old strand and 1 daughter strand (new strand).
When and where does DNA replication take place? Explain.
When: During the S phase of interphase
Where: In the nucleus
Why do cells replicate their DNA, regardless of whether they become diploid or haploid cells?
Regardless of whether a cell becomes a diploid or haploid, the cell will be forming 2+ copies of itself. The 2+ copies each need their own complete set of DNA. So, DNA replication has the job of providing all of the daughter cells with a full set of DNA.
Explain how DNA polymerase, the double helix structure of DNA, and the base-pairing rules work together to produce two identical copies of the original DNA molecule during DNA replication in S phase of interphase. (3-4 big picture steps)
The double helix structure splits apart to form a replication bubble. This creates space for DNA polymerase to make complementary daughter strands from the 2 templates provided from the splitting of the DNA double helix. When DNA polymerase starts making the complementary strand, it uses the base pairing rules to determine what type of nucleotide it should pair up with a certain nucleotide from the parent strand. For example, if polymerase comes across an adenine nucleotide on the parent strand, DNA polymerase will place a thymine nucleotide to pair with the adenine, assuming that it is forming a completely new set of DNA, rather than mRNA.