Unit 10: DNA (CHAPTER 1`3 ONLY) Flashcards
What 3 sections make up a Nucleotide?
- Deoxyribose Sugar
- Phosphate Group
- Nitrogenous Base
What bond forms between Nitrogenous Bases?
A Hydrogen Bond.
What bond forms between the Deoxyribose Sugar & the Phosphate Group?
A Phosphodiester Bond.
What are the Purines?
Adenine and Guanine.
What are the Pyrimidines?
Thymine and Cytosine.
What is the Base-Pairing Rule?
Adenine (A) always pairs with Thymine (T), while Guanine (G) always pairs with Cytosine (C).
What sets Prokaryotes apart from Eukaryotes?
Prokaryotes have circular, free-floating DNA in the cytoplasm without a nucleus or membrane-bound organelles.
Eukaryotes have linear DNA found in the nucleus with membrane-bound organelles (Ex: Mitochondria, Golgi, etc.).
Single Stranded Binding Proteins
Keeps DNA from coming back together.
DNA Polymerase
Makes a complementary strand of DNA in the 5-3 direction.
DNA Ligase
A sort of “glue” that forms the bond between the fragments to form one continuous strand of DNA.
Helicase
The enzyme that breaks down the hydrogen bonds between bases to begin DNA Replication.
Primase
The enzyme that places the RNA Primer on the strand of DNA.
RNA Primer
The starting point of DNA where DNA Polymerase begins to build off of.
Antiparallelism
The formation taken when two nucleotides connect, going in opposite directions from one another.
Why is continuous synthesis of both DNA strands not possible?
DNA can only be replicated from the 5’ to 3’ end, but since the two strands are antiparallel, one of the strands is not going in the direction capable of replicating DNA.
Leading Strand
A continuous strand of DNA made in the direction of the Replication Fork.
Lagging Strand
A discontinuous strand that has Okazaki fragments created on it, linking the fragments of DNA together.
How is the Lagging Strand synthesized?
RNA Primers create sections of DNA called Okazaki Fragments, which are then joined into a continuous strand via DNA Ligase.
Okazaki Fragments
Small sections of DNA that are formed during discontinuous synthesis of the lagging strand.
How do the DNA Polymerase help with proofreading and repairing DNA?
It performs Nuclease, which is the cutting out of damaged DNA to replace it with undamaged alternatives, as damaged DNA leads to no formation of DNA strands.
Telomeres
Sequences of DNA that do not contain and genes, as they act as a buffer zone that protects the original DNA.
Genetically Modified Organism (GMO)
A plant, animal, or microbe that has had its DNA altered using genetic engineering techniques.
Restriction Enzyme
Proteins that cut DNA at specific sequences, acting like molecular scissors that can be used to cut and paste DNA fragments.
Gel Electrophoresis
A technique used to separate DNA fragments based on their size and charge.
Frederick Griffith
Transforming Principle - Noticed that the viral strain of bacteria would transform a non-virulent strain into a virulent; killing the mice.
Avery, McCarty & MacLeod
Used test tube assay instead of mice to test the transforming principle. Discovered that protein was not the transforming principle.
Hershey & Chase
“Blender Experiment” - Radioactive Sulfur (Protein) vs. Radioactive Phosphorus (DNA). Determined that the radioactive phosphorus which was used as a tag for DNA was found inside the cell.
Chargaff
Percent of adenine was equal to thymine while the percent of guanine was equal to cytosine.
Rosalind Franklin
X-Ray Diffraction, showing the uniform dimensions of DNA’s diameter.
Watson & Crick
Discovered the structure of DNA was a double helix and determined that the genetic code was found in the sequence of nitrogenous bases.
