Molecular Genetics 2024 Flashcards
The molecule of DNA is ______. The top strand of DNA is in the _____ direction and the bottom strand is in the _____ direction.
Antiparallel, 5-3, 3-5
DNA replicates semi-__________. That means that ______ of the original strand will be a part of each of the ____ strands.
Conservatively, half, two
Replication starts at ________ locations all at once and occurs in both ________ creating replication ______. One replication _______ is two replication ________ moving in opposite directions.
Multiple, directions, bubble, bubble, forks
What are topioisomerases? Give 2 examples.
Enzymes that work together to open up the DNA molecule so it can be replicated. Gyrase and helicase are examples.
What does DNA gyrase do?
DNA gyrase attaches to the DNA molecule and disrupts the hydrogen bonds in the backbone of the molecule that maintain its double-helix shape.
To prevent the complementary bases from ___________, ______ _______ ______ ________ attach to the open strands and block the attraction.
Re-annealing, single-stranded binding proteins.
Once the DNA has been ________, the next enzyme involved is RNA primase. RNA primase carries a ___ ________ and attaches it to the newly opened end of the _____. The job of the RNA primer is to tell the _____ _____________ _______ where to start adding _________ and therefore building the new DNA strands.
Unzipped, RNA primer, DNA, DNA polymerase enzymes, nucleotides.
DNA polymerase III is the enzyme that is responsible for finding the __________ and then bringing the complementary ___________ (one at a time). DNA polymerase III builds the new strand of DNA in the ______ direction.
RNA primer, nucleotides, 5-3.
RNA primase is required by the ______ strand to place multiple ____ _________ as DNA _______ opens up the strands. This strand requires multiple _____ __________ ____ enzymes each building separate sections of the DNA in chunks called ________ _________.
Lagging, RNA primers, helicase, DNA polymerase III, Okazaki fragments.
DNA polymerase I acts by removing the ___ ________ and replace them with the proper complementary DNA _________. DNA _______ also helps secure the new __________ by helping to create their _______________ bonds.
RNA primers, nucleotides, ligase, nucleotides, phosphodiester
Exonucleases are a group of _________ that attach to the DNA, move along it and look for ________. What are two examples of exonucleases? What does DNA polymerase II do?
Enzymes, mistakes. DNA polymerase I and III. DNA polymerase II looks for errors in DNA during the rest of a cell’s life. Correcting errors that may have been caused by things like X-rays or ultraviolet light.
Restriction endonucleases or restriction _________ are molecular _______ that can cut double stranded DNA at specific _____ ______ ___________. Each type of restriction enzyme recognizes a characteristic sequence of ________ that is known as a _________ _______.
Restriction enzymes, scissors, base pair sequences, nucleotides, recognition site.
What does methylase do during DNA electrophoresis?
A methylase (a methyl group) is added to a recognition site to protect an undesired gene fragment from being cut.
What is DNA ligase and what does it do?
In DNA replication, DNA ligase is the “glue” that joins together fragments of DNA to form a seamless strand.
How does gene therapy work? How does it utilize viruses?
Gene therapy is the process of changing genes using genetic material. This changes the instructions of a protein that is synthesized to ideally target and eliminate specific diseases. Transported through a virus because of how effective they have become at getting into cells. The viral genes are removed from the virus, so that it might be used only for delivery of DNA or RNA. Done in or ex-vivo.
