Unit 2.1: DNA Replication Flashcards
What are the three steps in the central dogma of life?
- Replication
- Transcription
- Translation
In this stage, cells prepare to divide and grow.
DNA Replication
True or False: When DNA is replicated, it is replicated in all of its entirety.
True
True or False: Neurons can divide.
False
What is the AT and GC that makes up the cell.
Genome
What phase does DNA replication occur?
a. G1 Phase
b. G2 Phase
c. S Phase
d. M Phase
c. S Phase
This refers to the phenomenon wherein the parent strand will be retained while a new strand is created.
Semi-conservative
DNA Polymerase acts on what direction?
3’ to 5’
Synthesis of new DNA strand occurs in what direction?
5’ to 3’
DNA Replication occurs bidirectionally from what point?
Origin of Replication/Replication Fork
True or False: Our objective to create a cell that looks a little bit like the parent cell (not exact replica)
False
(exact replica)
One strand of the DNA goes in the 5’ to 3’ direction while another goes in the 3’ to 5’ direction. This phenomenon is known as…
Antiparallel
Opening up of the DNA strands is called…
Denaturation of the Hydrogen Bonds
What group is found in the 5’ end of the DNA?
Phosphate Group
What group is found in the 3’ end of the DNA?
Hydroxyl Group
This is the strand that goes from 3’ to 5’. It is also how the enzyme (DNA Polymerase) reads the strand.
Leading Strand
This is the strand that goes from 5’ to 3’. This is also how the new strands are added.
Lagging Strand
The nitrogenous bases of the DNA are connected by what bond?
Hydrogen Bond
The Carbons 3 and 5 are connected by what bond?
Phosphodiester Bonds
After separating the two strands, we would be able to create ends called….
Replication Fork
What enzyme is responsible for unwinding the DNA in both direction?
Helicase
This is the building block of DNA and RNA.
Nucleoside
The bond among nucleosides is called…
Glycosidic Bonds
If the structure’s C2 has a hydrogen (H+) attached to it, this is a…
Deoxyribonucleic Acid
If the structure’s C2 has a hydroxyl (OH-) attached to it, this is a…
Ribonucleic Acid
The phosphodiester bond is formed by what direction?
3’ to 5’
Glycosidic Bonds are found in what carbon?
C1
Enumerate the 3 stages of DNA replication.
Initiation
Elongation
Termination
This is the area we want to open so that we could have two (2) parental strands where we can synthesize new DNA strands.
Origin of Replication
The Origin of Replication is an area concentrated with what nitrogenous bases? (2)
Adenine
Thymine
How many hydrogen bonds hold Adenine and Thymine?
2
How many hydrogen bonds hold Cytosine and Guanine?
3
What are the most dominant nitrogenous bases?
Adenine
Thymine
The protein responsible for destroying hydrogen bonds. These cells simply break down the H bonds in the Replication Fork.
Pre-Replication Protein Complex (PRPC)
True or False: Multiple origins of replication can occur in one strand of DNA (in Eukaryotic cells).
True
True or False: PRPC is responsible for breaking the bonds between what nitrogenous bases?
True or False: PRPC is responsible for breaking the bonds between what nitrogenous bases?
True or False: Once the PRCP opens the DNA up, it will no longer re-anneal.
False
The protection of the single strand of DNA against nucleases is done by what protein?
Single-Stranded Binding Protein
This is the protein that prevents reannealing of the origins of replication.
Single Stranded Binding Protein (SSB Proteins)
These act as primitive immune system that want to destroy the single-stranded DNA.
Nucleases
The nucleases work by destroying what bonds?
Phosphodiester Bonds
What enzyme hops into the exposed parental strands and unwinds the DNA in both directions?
Helicase
True or False: Nucleases and Ligases are opposite of each other
True
True or False: Helicase uses ATP in unwinding the DNA.
True
True or False: PRPC and Helicase both break Hydrogen bonds between nitrogenous bases. Helicases, however, are motile enzymes.
True
True or False: Helicases move unidirectionally.
False
True or False: Supercoiling is explained by the concept of Torsional Stress.
True
True or False: Helicase is capable of unwinding supercoils.
False
The enzyme responsible for fixing the supercoiling or torsional stress.The enzyme responsible for fixing the supercoiling or torsional stress.
Gyrase
Gyrases belong to what family?
Topoisomerase
This is a “2-in-1” enzyme; it can act both as a nuclease and a ligase
Gyrases
True or False: For gyrases, breaking the phosphodiester bonds allow the DNA to unravel, but continuous cutting would only lead them to fragment. That is why forming the phosphodiester bonds alleviate the cutting done
True
What topoisomerases are possessed by eukaryotes?
I, II
What is the only topoisomerase that does not need ATP?
I
This is a family of enzymes that can untangle supercoils in the DNA.
Topoisomerase
This group of enzymes can alleviate the supercoiling by chopping and re stitching the DNA strand to be replicated.
Topoisomerase
What are two enzymes involved in elongation?
Primase
Ligase
This is the enzyme that looks for a certain sequence where it will put in a primer.
Primase
The primer is made up of?
RNA Oligonucleotides
The primer is made up of short sequences of RNA Oligonucleotides running in what direction?
5’ to 3’
True or False: The primer is complementary to the DNA strand.
True
The _____________________ is enabled by providing a 3’ hydroxyl functional group that will be recognized by the DNA Polymerase where to start the synthesis of the new strand.
DNA Polymerase III
This substance serves as the guide of the polymerase molecule to start elongation.
Primers
The creation of the new strand starts from…
5’ to 3’
This needs the 3’ hydroxyl functional group provided by the primase.
DNA Polymerase III
In the 5’ to 3’ strand, the C5 is pointing to the ________, while the C3 is pointing to the __________.
left; right
DNA Polymerase III has a __________ exonuclease activity.
3’ to 5’
DNA Polymerase I has a ___________ exonuclease activity.
5’ to 3’
It hates primers but can do anything that the DNA Polymerase III does.
DNA Polymerase I
The enzyme responsible for connecting Okazaki Fragments and forming phosphodiester bonds.
Ligase
These enzymes fuse the DNA fragments together, forms the phosphodiester bonds (covalent bonds formed between the carbon 5 and carbon 3 of succeeding nucleotides that make up the DNA strand)..
Ligase
True or False: Didanosine and Zidovudine will not be recognized by DNA polymerase so termination occurs because of the lack of hydroxyl group. It prevents the DNA strand from further elongation. The DNA HIV virus would therefore not be able to form complete strands.
True
What phenomenon signals termination?
Meeting of Helicase
The strand where multiple primers are being made.
Lagging Strand
Once the primers are removed, what will be formed in the lagging strand?
Okazaki Fragments
What is responsible for removing the primers in the lagging strand?
DNA Polymerase I
The condition wherein the telomeres get too short to the point that it affects genes.
Hayflick Limit
What is the sequence of ribonuclotides that are complementary to the last sequence of nucleotides on 3’?
5’-TTAGGTG-3’
Where can we find cells that contain high levels of telomerase activity? (3)
Stem Cells
Cancer Cells
Epithelial Cells