DNA as the Genetic Material Flashcards
the belief that genetic material passed down from parents to their children exists in the _____ and these structures explain inheritance patterns
Chromosome Inheritance Theory
Discovered the 3 major components that make up a nucleotide and how DNA and RNA are put together
Phoebus Levene
What 3 things are nucleotides made up of?
- Phosphate group
- Sugar
- Nitrogenous Bases
the amount of adenine is roughly equal to that amount of thymine and the amount of cytosine is about the same as the amount of guanine
Chargaff’s Rule
What do mispairings between bases, that aren’t detected and corrected by enzymes during replication, result in?
Mutations
the process of beaming x-rays onto a crystalline molecule to measure how the molecule bends the beams and then using those measurements to develop a 3D picture of the structure of the molecule
X-ray Crystallography
Who first used x-ray crystallography to photograph the 3D structure of DNA?
Rosalind Franklin
A double helix is composed of what 2 things?
- 2 very long sugar-phosphate backbones
- Base pairs
the 2 helical strands run parallel to each other but go in opposite directions
Antiparallel
What type of bonding is used in DNA structures?
Hydrogen Bonding
Why is hydrogen bonding important to DNA structure? List 3 things
- Allows the characteristic ladder shape to form
- This bonding is strong enough to hold the bases together
- This bonding is weak enough to break when needed
a nitrogenous base and a sugar without a phosphate
Nucleoside
a nitrogenous base, a sugar, and 1-3 phosphates
Nucleotide
DNA is an array of what?
Nucleotides
What 3 properties make DNA critically important to life?
- DNA can be copied
- DNA carries information and contains instructions for all the characteristics an organism will exhibit
- DNA can mutate and recombine > help an organism adapt and survive in a dynamic environment
the process of copying DNA
Replication
What 3 things is DNA replication essential for?
- Cell Growth
- Cell Repair
- Cell Reproduction
a series of events that leads to DNA replication and the division of cytoplasm and organelles to produce 2 daughter cells
Cell Cycle
Name the 2 main stages of the cell cycle?
- Interphase
- Mitosis
the process of copying DNA that results in each DNA molecule being made up of 1 old conserved strand of DNA and 1 newly synthesized one
Semiconservative DNA Replication
a DNA sequence with altered nucleotides
Mutation
a lab analysis that detects whether the DNA of the bacteria or virus is present in the patient to let you know which disease is causing the symptoms
Polymerase Chain Reaction Test (PCR Test)
How does a PCR test work?
It replicates small pieces of DNA many times > replicating the DNA from a virus or bacteria make the DNA much easier to find
commonly performed in canine patients to screen for this bacterial infection that can cause kidney and liver failure
Leptospirosis PCR
What are the 3 main stages in DNA replication?
- Initiation
- Elongation
- Termination
the phase of DNA replication in which a location on the DNA double helix is targeted for unwinding and the parent DNA is separated into 2 strands
Initiation
the phase of DNA replication in which new nucleotides are added to the newly synthesized DNA strands
Elongation
the phase of DNA replication that follows Elongation and ends the process
Termination
What are the 8 steps to DNA replication?
- Helicases breaks the hydrogen bonds between base pairs + other proteins keep the single strands of DNA from joining again
- Topoisomerases surround the “unzipped” separated strands of DNA and relax the twisting of the helices
- After helicase unzips the strands, the DNA replication fork forms
- Primase builds short stretches of RNA primers to start Elongation
- DNA polymerase starts where primase added RNA primers and adds new nucleotides to the RNA primers on each of the 2 newly synthesized DNA strand (different for leading and lagging strand)
- Ligase completes the sugar-phosphate backbone at nicks in the newly synthesized DNA between the Okazaki fragments to form a complete daughter DNA molecule
- RNA primers are removed and replaced with DNA
- The newly synthesized DNA is checked for any mistakes that may have occurred during replication
enzymes that unwind DNA at the origin of replication by breaking the hydrogen bonds between 2 DNA strands
Helicase
the specific point at which DNA begins to unwind in order to begin replication
Origin of Replication (DNA Replication Fork)
an enzyme that adds RNA Primers to a parent strand of DNA and acts as the initializer for DNA replication
Primase
enzymes that relieve the tension created by helicase and break the phosphodiester bonds between the nucleotides in the DNA backbone
Topoisomerase
the new strand of DNA that is made in fragments due to it running in the opposite direction as the parent DNA strand and runs 3’ to 5’
Lagging Strand
the new strand of DNA that is made continuously due to it running in the same direction as the parent DNA strand and runs 5’ to 3
Leading Strand
necessary for DNA polymerase to be able to bind and start the elongation process
RNA Primers
the enzyme that adds the appropriate nitrogenous base pairs to the template strand of DNA in order to create the complementary strand and must work in the 5’ to 3’ direction
DNA Polymerase
short discontinuous chunks of nitrogenous base pairs added to the lagging strand during semi-conservative replication
Okazaki Fragments
enzymes that help glue the Okazaki fragments together to form a complete daughter DNA molecule
Ligase
Discovered that DNA bases pair with each other and that the amount of each base is equal and that the rule of base pairing is true in other species
Erwin Chargaff
experiment that demonstrated that DNA replicates in a semi-conservative manner
Meselson-Stahl Experiment
Explain in 3 steps how the Meselson-Stahl Experiment demonstrated that DNA replicates semi-conservatively
- They labeled some DNA with nitrogen-15 (an isotope of nitrogen) in a solution
- They measured the density to determine how much nitrogen-15 was in the solution after each replication > isotopes are heavier than the normal element
- After each DNA replication, the labeled strands became rarer
a type of asexual reproduction and is the mechanism by which prokaryotic cells divide and results in offspring that are genetically identical to the parent
Binary Fission
What are the 3 steps to Binary Fission?
- The prokaryotic chromosome replicates
- The 2 copies of the chromosome associate with different parts of the cell membrane
- The cell pulls apart into 2 identical cells, each containing a copy of the prokaryotic genome
List 5 similarities between RNA and DNA
Both:
1. are nucleic acids
2. are made of chains of nucleotides
3. form nucleotides in the same way
4. form nucleic acids in the same way
5. have cytosine, guanine, and adenine bases
List 4 differences between RNA and DNA
- Ribose (RNA) vs Deoxyribose (DNA)
- Uracil Base (RNA) vs Thymine Base (DNA)
- Single Helix (RNA) vs Double Helix (DNA)
- Short Polymer (RNA) vs Long Polymer (DNA)
What indicates the length of a polymer?
The number of base pairs
Less base pairs = shorter polymer
How many hydrogen bonds are between adenine and uracil?
2
How many hydrogen bonds are between adenine and thymine?
2
How many hydrogen bonds are between cytosine and guanine?
3
