FINALS CHAPTER 13: DNA REPLICATION Flashcards
(18 cards)
What parts make up a nucleotide? (3)
Phosphate group
5-carbon sugar
Nitrogen base
What parts make up a DNA molecule?
Phosphate group
Deoxyribose
Nitrogen base (A, C, T, G)
What types of bonds hold DNA molecules together? Where is each type found?
Covalent - between nucleotides
Hydrogen - between nitrogen bases
What is base pairing?
Which nitrogen bases are connected to which other nitrogen basses by hydrogen bonds
What are the four nitrogen bases found in DNA?
Adenine
Cytosine
Thymine
Guanine
Which of DNA’s nitrogen bases pair with which other nitrogen bases? How many hydrogen bonds are used for each pairing?
Adenine pairs with thymine (2 bonds)
Cytosine pairs with guanine (3 bonds)
What is Chargaff’s rule?
In one strand of DNA, 20% of the nitrogen bases are adenine, 20% are thymine, 30% are cytosine, and 30% are guamine
What are antiparallel strands in DNA?
Two DNA strands run parallel to each other, but due to base pairing they run in opposite directions
What type of replication does DNA perform? Define it
Semi-conservative replication
One strand of the double helix is from the original DNA and the other strand is newly made
What enzymes are used in DNA replication? (5)
Topoisomerase
Helicase
DNA primase
DNA polymerase
DNA ligase
What does the topoisomerase do?
Unwinds the DNA double helix
What does the helicase do?
Unzips the DNA strands by breaking the hydrogen bonds between the nitrogen bases
What does the DNA primase do?
Adds RNA primers to the new DNA strand so the DNA polymerase knows where to start
What does the DNA polymerase do?
Attaches the nucleotides to the new DNA strand
What does the DNA ligase do?
Glues Okazaki Fragments together by creating a molecule-joining covalent bond and replaces RNA primers with DNA
What is the leading strand of DNA? How does the DNA polymerase work on this strand?
The strand that runs in a 3’ to 5’ direction
DNA polymerase moves up the strand toward the helicase, keeping up with the speed of the helicase unzipping the DNA
What is the lagging strand of DNA? How does the DNA polymerase work on this strand?
The strand that runs in a 5’ to 3’ direction
DNA polymerase moves down the strand away from the helicase, constantly having to jump back towards the helicase to continue working on new sections of DNA
What are Okazaki Fragments?
Sections of DNA the DNA polymerase breaks apart to work on on the lagging strand due to the polymerase having to work backwards
