DNA Flashcards
In 1928, Frederick ________ studied a pneumonia-causing bacterium. There were 2 strains, the virulent (__) and the nonvirulent (__) strain.
Griffith, S, R
In Griffith’s mice experiment, the __ strain on its own killed mice, the __ strain on its own did not kill the mice. Furthermore, when the __ strain was killed by ________, it did not kill the mice. However, combining the ________-killed virulent (__) strain with the live non-virulent (__) strain killed the mice.
S, R, S, heat, heat, S, R
Griffith called the transfer of virulence from the heat-killed S strain cells into the live R strain cells ________
transformation
In 1944, Avery, Macleod, and ________ repeated Griffith’s experiment using purified cell extracts. They treated the __ cells, and then mixed with the __ cells to inject the mice. They used two treatments: ________ digesting enzymes and ________ digesting enzymes.
McCarty, S, R, Protein, DNA
In the Avery, Macleod, and McCarty experiment, the removal of ________ from the transforming material didn’t inhibit its ability to transform R strain cells. However, the ________ digesting enzymes destroyed all transforming ability.
protein, DNA
The Avery, Macleod, McCarty experiment supported ________ as the genetic material (at least in bacteria)
DNA
Hershey and Chase (1952) investigated genetic material using ________, viruses that infect bacteria. They are composed of only ________ and ________. Hershey and Chase wanted to determine which molecule is the genetic material that is injected into the bacteria.
Bacteriophages, DNA, protein
In the Hershey and Chase experiment, Bacteriophage DNA was labeled with radioactive ________ (___), bacteriophage protein was labeled with radioactive ________ (___).
phosphorus, 32P, sulfur, 35S
In the Hershey and Chase experiment, only the bacteriophage ________ (___) entered the bacteria and was used to produce more bacteriophage. The conclusion is that ________ is the genetic material
DNA, 32P, DNA
DNA is a ________ acid composed of ________
nucleic, nucleotides
DNA is composed of a 5-carbon sugar called ________
deoxyribose
DNA has a ________ group attached to the 5- carbon of sugar
Phosphate
DNA has a ________ group attached at the 3’ carbon of sugar
hydroxyl
A ________ bond is the bond between adjacent nucleotides. It is formed between the (__’) PO4 group of one nucleotide and the (__’) OH group of the next nucleotide.
phosphodiester, 5, 3
The chain of nucleotides in DNA has a ___ to ___ orientation
5’, 3’
Erwin Chargaff determined that there is always an equal proportion of two-ringed ________ (A and G) and single-ringed ________ (C and T).
purines, pyrimidines
According to Chargaff’s rules, the amount of Adenine = ________, and the amount of Cytosine = ________.
thymine, guanine
Rosalind Franklin performed X-ray diffraction studies to identify the 3D structure of DNA, and discovered that DNA is ________
helical
________ and ________ (1953) determined the structure of DNA using evidence from others. They didn’t perform a single experiment themselves.
Watson, Crick
They key finding of the Watson-Crick model of DNA was that there are two intertwined chains of ________, creating a ________-________ structure
nucleotides, double-helix
The double helix of DNA forms two grooves: The larger ________ groove and the smaller ________ groove
major, minor
DNA strands are connected via ________ bonds between bases on opposite strands. The result is specific ________-________ (A-T and G-C)
hydrogen, base-pairs
The pattern of base-pairing is ________. A forms __ hydrogen bonds with T, and G forms __ hydrogen bonds with C.
complementary, 2, 3
DNA has an ________ formation, meaning that one end terminates in 3’ OH, and one end terminates in 5’ PO4. Two strands of a single DNA molecule have opposite ________ to one another
antiparallel, polarity
The ________ model of DNA replication is where both strands of parental DNA remain intact, and the new DNA copies consist of all new molecules
Conservative
The ________ model of DNA replication is where the daughter strands each consist of one parental strand and one new strand.
semiconservative
The ________ model of DNA replication is where new DNA is dispersed throughout each strand of both daughter molecules after replication
dispersive
Meselson and Stahl performed an experiment with heavy nitrogen (___) and combined it with lighter nitrogen (___). They determined that the ________ model is the correct model of DNA replication
N15, N14, semiconservative
DNA replication requires three things: Something to copy (parental ________ molecule), Something to do the copying (________), and building blocks to make the copy (________ ________)
DNA, enzymes, Nucleotide triphosphates
The stages of DNA replication are as follows: ________ - replication begins, ________ - new strands of DNA are synthesized by DNA polymerase, and ________ - replication is stopped
Initiation, elongation, termination
DNA ________ match existing DNA bases with complementary ________ and link them, building new DNA strands
polymerases, nucleotides
DNA polymerases all add new bases to the ___ end of existing strands, and synthesize the new strand in the ___ to ___ direction. They also require an ________ primer
3’, 5’, 3’, RNA
In Prokaryotic Replication (in E. Coli), there is a single ________ molecule of DNA. Replication begins at the ________ of replication, and proceeds in both directions around the ________.
circular, origin, chromosome
A ________ is DNA controlled by an origin
Replicon
E. Coli has three DNA polymerases, which all have 3’ to 5’ exonuclease activity ( ________)
proofreading
In prokaryotic replication, DNA polymerase ___ acts on the lagging strand to remove primers and replace them with DNA
I
In prokaryotic replication, DNA polymerase ___ is involved in DNA repair processes
II
In prokaryotic replication, DNA polymerase ___ is the main replication enzyme
III
In prokaryotic replication, ________ unwinds ________ bonds holding them together
helicase, hydrogen
In prokaryotic replication, ________ ________ ________ replicated DNA molecules to build a new strand of DNA
DNA Polymerase III
In prokaryotic replication, ________ makes the RNA primer so that DNA Polymerase ___ can know where to start.
Primase, III
In prokaryotic replication, ________ essentially glues DNA fragments together on the ________ strand.
ligase, lagging
Some DNA polymerase molecules can remove nucleotides, acting as ________. They can be ________ (cut DNA internally) or ________ (remove nucleotides from end of DNA).
nucleases, endonucleases, exonucleases
Helicases use energy from ________ to unwind DNA
ATP
________-________-________ proteins coat strands of DNA to keep them apart after helicase separates them.
Single-strand-binding
Unwinding of DNA by helicase causes torsional strain that can lead to additional twisting of the helix, called ________.
supercoiling
The enzymes that prevent supercoiling are called ________. The specific one involved in DNA replication is called DNA ________
Topoisomerases, gyrase
DNA fragments on the lagging strand are called ________ ________, and must be connected together.
Okazaki fragments
The ________ ________ is a partial opening of helix formed where double stranded DNA is being unwound. This is where DNA ________ occurs.
replication fork, synthesis
________ is the ability of a polymerase to stay attached
Processivity
The β subunit forms a “sliding clamp” to keep DNA Polymerase ___ attached to DNA (high processivity)
III
A ________ is a macromolecular assembly of enzymes involved in DNA replication. The two main components are ________ (primase, helicase, accessory proteins) and the ________ of two DNA Pol III’s (one for each strand)
Replisome, primosome, complex
Eukaryotic replication is more complex than prokaryotes due primarily to larger amounts of ________ in multiple ________, and a ________ structure (vs. circular chromosomes)
DNA, chromosomes, linear
In Eukaryotic replication, multiple ________ (origins of replication) are used for each chromosome
replicons
Before S phase in eukaryotes, ________ are loaded onto possible replication origins, but not activated
helicases
In Eukaryotic replication, priming uses a complex of both DNA polymerase ___ and ________.
α, primase
DNA polymerase ________ synthesizes the leading strand in Eukaryotic replication
epsilon (ε)
DNA polymerase ________ synthesizes the lagging strand in Eukaryotic replication
delta (δ)
Linear chromosomes (eukaryotic) have specialized structures found on the ends of eukaryotic chromosomes called ________. They are composed of specific ________ sequences
Telomeres, repeat
Telomeres protect the ends of chromosomes from ________. They are also not made by the ________ complex.
nucleases, replication
The last primer removed from the 3’ end of the lagging strand in eukaryotes cannot be replaced, and this would result in the ________ of chromosomes with each round of cell division. So, the enzyme ________ synthesizes the ________ repeat sequences at the end of the strand. This enzyme uses an internal ________ template, not the DNA itself
shortening, telomerase, telomere, RNA
Telomerase is ________ regulated. It is high in ________, and low in ________.
developmentally, childhood, adulthood
DNA damage constantly occurs. There can be random errors during ________. Luckily, DNA polymerases have ________ ability to counteract this.
replication, proofreading
________ are any agent that increases the number of mutations above background level. Examples are radiation and chemicals
Mutagens
There are two categories of DNA repair: ________ repair and ________ repair. The first targets a single kind of lesion in DNA and repairs only that damage. The 2nd uses a single mechanisms to repair multiple kinds of lesions in DNA.
specific, nonspecific
A ________ ________ removes incorrect bases incorporated during DNA replication. It replaces them with the correct base by copying the ________ strand.
Mismatch repair (MMR), template
________ is a specific repair mechanism that repairs damage caused by exposure to UV light. The ________ enzyme absorbs light in the visible range and uses the energy to ________ thymine dimers.
Photorepair, photolyase, cleave
________ repair is a nonspecific repair that removes and replaces a damaged region of DNA by DNA ________ using ________ ________.
Excision, synthesis, DNA Polymerase
