Unit 5: DNA Replication Flashcards
What is a Nucleic Acid?
marcomolecules that contain genetic information which included DNA and RNA
What is a nucleotide?
monomers that make up nucleic acids (DNA)
What is the name for DNA?
deoxyribonucleic acid
What consists of a nucleotide? (DNA Structure)
Phosphate group, Sugar (deoxyribose), nitrogenous base
What is considered the “backbone” of DNA?
Phosphate group and Sugar base
What nitrogenous bases have two rings?
the type! not actual bases
Purines
What nitrogenous bases have a single ring?
the type, not the actual base!!
Pyrimidines
What bases are purines?
Adenine and Guanine
What bases are pyrimidines?
Cytosine and Thymine
What matches with Adenine? How many hydrogen bonds?
Thymine and two
What matches with Cytosine? How many hydrogen bonds?
Guanine and three
Which macromolecule is DNA?
nucleic acid
How many rings do the purine nitrogenous bases have?
2
How many rings do the pyrimidine nitrogenous bases have?
1
What type of bonding occurs between complementary bases in a DNA molecule?
hydrogen bond
what type of bonding occurs between sugar and phosphate groups?
covalent bond
When and where does replication occur?
during interphase, in the nucleus of a cell
Why does replication occur?
If a cell is going to split it will need two copies of DNA to send to each new cell
What does semiconservative replication mean?
DNA strands separate, serve as templates and produce with one old strand (parent) and one new strand of DNA.
What is the “direction” of the molecule?
5’ to 3’ direction
What is the normal “direction” of ribose sugar?
5’ to 3’ direction
Do the two strands run in opposite directions?
yes
What is the Helicase, what does it do?
a enzyme, Breaks/Unzips hydrogen bonds and separates strands of DNA, proteins attached to keep them separated.
What is the DNA polymerase, what does it do?
Starts adding nucleotides to each unzipped strand (base pairing rules followed).
What can a DNA polymerase only do? Which direction?
5’ to 3’ direction
What is a “leading strand”?
adds continuous b/c poly can follow it easily. 5’ to 3’ direction
What is a “lagging strand”?
goes 3’ to 5’ direction, so they have to add lots of primers to continue building b/c helicase keeps opening up
What does a lagging strand cause?
Okazaki Fragments
What are Okazaki Fragments?
discontnious base pairing
What is the primase, what does it do?
lays out primers (flags basically) on the DNA strand which tell the DNA polymerase where to start (signal).
What is the ligase, what does it do?
The “gluer”, hooks Okazaki Fragments together, hooks two strands together as well.
What are the rungs of the ladder called?
nitrogenous bases (base pairing)
