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78 Cards in this Set

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Nucleotide
The building block of nucleic acids, consisting of five-carbon sugars covalently bonded to a nitrogenous base and a phosphate group.
Pyrimidine
A six-membered ring of carbon and nitrogen atom. They have cytosin (C), thymine(T), and uricil (U).
Nitrogenous base
The nitrogen atom tends to take up H+ from the solution
Pentose
A five-membered ring of carbonds
Ribose
The pentose connected to a nitrogenous base, in the nucleotide of RNA.
deoxyribose
The pentose connected to a nitrogenous base, in DNA and missind an OH group on the 2' carbon.
Phosphodiester Linkage
Are between the phosphate of one nucleotide and the sugar of the next.
Purine
The six membered ring fused to a five-membered ring. The purines are adenine (A), guanine(G).
Base pairing rules
DNA A-T (Adenine-Thymine)
G-C (Guanine-Cytosine)
RNA A-U (Adenine-Uracil)
T-A (Thymine-Adenine)
What is the carbon numbering of deoxyribose?
1' Nitrogen containg a base
2' no OH
5' one or more phospahte
What are the structures of a nucleotide?
An organic molecule called a nitrogenous base, pentose, and a phosphate group.
What did Frederick Griffith discover about DNA?
Was studying Streptococcuc pneumoniae, a bacterium that cause pneuminia in mammal. In this he discovered the phenomenon transformation, now defined as a change in genotype and phenotype due to assimilation of external DNA by a cell.
What did James Watson and Francis Crick discovery about DNA?
First proposed that the double helix as the 3-D structure of DNA in 1953
What did Avery and Macleod discover about DNA?
They purified variuos chemicals from the heat-killed pathogenic bacteria, then tried to transform live nonpathogenic bacteria with each chemical. The transforming agent was DNA.
What did Hershey and chase discover about DNA?
That DNA is the genetic material of a phages ("bacteria eater") known as T2. ie, this is one of many phages that infect bacterium E. coli.
What did the Hershey and Chase experiment contain?
-phages are virus that infect bacteria.
-It demostrated that it was DNA not protein, that functioned as the T2 phage's genetic material.
-Viral proteins, labeled eith radioactive sulfur, remained outside the host cell during infection.
-in contrast, viral DNA, labeld with radioactive phosphorus, entered the bacterial cell.
What did the Federick Griffith experiment contain?
-the S strain of the Streptococcus pneumoniae, which was protected from a mouse's defensive system by a capsule, was pathogenic
-the R strain, a mutant lacking the capsule was nonpathogenic.
-Heat killed the S cells and live R cells called pneumonia and death.
- Live S bacteria could be relieved from the dead mice that had been injected with the mixture. Griffith concluded that molecules from the dead S cell had genetically transformed some of the living R bacteria into S bacteria.
What did the Watson and Crick experiment concluded?
Each nucleotide unit of the polynucleotide chain consists of a nitrogenous base (T, A C, or G), the sugar deoxyribose, and the phosphate group of one nucleotide is attached to the sugar of the next nucleotide in the line. The result is a "backbone" of alternating phosphates and sugars, from which the bases prpject.
What did Wilkins and Franklin discover about DNA?
Confermind the structure of DNA or double helix.
What did Wilkins and Franklin experiment conatin?
Franklin produced photographs by X-ray crystallography method. In which Wilkins and Crick based their model of DNA on data they exracted from Franklins x-ray diffraction photo and received the nobel prize
WHat did Chargaff discover about DNA?
The complementary base paring rules.
What else did Watson and Crick discover about DNA?
DNA replication, base paring enables existing DNA strands to serve as templates for complementary strands.
What did the Meselson-Stahl discover about DNA.
That the semiconervative model. WHich is the two strands of the parental molecules seperate, and each function as a template for synthesis of a newly complementary strand.
What dd the Meselson-Stahl experiment consist of.
Cultured E. coli for several genreations on a medium containg a heavy isotope of nitrogen, 14N.
-the bacteria incorporated the heavy nitrogen into their nucleotides and thin into their DNA.
-The scientists then transferred the bacteria to a medium containing 14N, the lighter, more common isotope of nitrogen.
-Thus, any new DNA that the bacteria synthesized would be lighter than the "old" DNA.
-they centrafuging the DNA based on density.
Template
The gene determines the sequence of base triplets along the length of an mRNA molecule. For each gene one of the two template is transcribed. This is known as a template.
Semiconservative model
The two strands of the parental molecule seperate, and each functions as a template roe synthesis of a new complementary strand.
Origin of replication
DNA replication begins at specific sites where the two parental strands of the DNA seperate to form a replication bubble.
Replication fork
DNA replication proceeds in both directions from the origin. At each end of the replication bubble is a replication fork, a Y-shaped region where the new strands of DNA are elongating.
DNA ploymerase
Elogation of new DNA at a replication fork is catalyzed.As nucleotides agin wit complemenary base along a template strand of DNA, they are aadded by polymerase, one by one, to the growing end of the new DNA strand.
Elongation
New DNA is always in the 5' to 3' direction and starts at the 3' to 5'.
What did the Hershey and Chase experiment contain?
-phages are virus that infect bacteria.
-It demostrated that it was DNA not protein, that functioned as the T2 phage's genetic material.
-Viral proteins, labeled eith radioactive sulfur, remained outside the host cell during infection.
-in contrast, viral DNA, labeld with radioactive phosphorus, entered the bacterial cell.
What did the Federick Griffith experiment contain?
-the S strain of the Streptococcus pneumoniae, which was protected from a mouse's defensive system by a capsule, was pathogenic
-the R strain, a mutant lacking the capsule was nonpathogenic.
-Heat killed the S cells and live R cells called pneumonia and death.
- Live S bacteria could be relieved from the dead mice that had been injected with the mixture. Griffith concluded that molecules from the dead S cell had genetically transformed some of the living R bacteria into S bacteria.
What did the Watson and Crick experiment concluded?
Each nucleotide unit of the polynucleotide chain consists of a nitrogenous base (T, A C, or G), the sugar deoxyribose, and the phosphate group of one nucleotide is attached to the sugar of the next nucleotide in the line. The result is a "backbone" of alternating phosphates and sugars, from which the bases prpject.
What did Wilkins and Franklin discover about DNA?
Confermind the structure of DNA or double helix.
What did Wilkins and Franklin experiment conatin?
Franklin produced photographs by X-ray crystallography method. In which Wilkins and Crick based their model of DNA on data they exracted from Franklins x-ray diffraction photo and received the nobel prize
WHat did Chargaff discover about DNA?
The complementary base paring rules.
What else did Watson and Crick discover about DNA?
DNA replication, base paring enables existing DNA strands to serve as templates for complementary strands.
What did the Meselson-Stahl discover about DNA.
That the semiconervative model. WHich is the two strands of the parental molecules seperate, and each function as a template for synthesis of a newly complementary strand.
What dd the Meselson-Stahl experiment consist of.
Cultured E. coli for several genreations on a medium containg a heavy isotope of nitrogen, 14N.
-the bacteria incorporated the heavy nitrogen into their nucleotides and thin into their DNA.
-The scientists then transferred the bacteria to a medium containing 14N, the lighter, more common isotope of nitrogen.
-Thus, any new DNA that the bacteria synthesized would be lighter than the "old" DNA.
-they centrafuging the DNA based on density.
Template
The gene determines the sequence of base triplets along the length of an mRNA molecule. For each gene one of the two template is transcribed. This is known as a template.
Semiconservative model
The two strands of the parental molecule seperate, and each functions as a template roe synthesis of a new complementary strand.
Origin of replication
DNA replication begins at specific sites where the two parental strands of the DNA seperate to form a replication bubble.
Replication fork
DNA replication proceeds in both directions from the origin. At each end of the replication bubble is a replication fork, a Y-shaped region where the new strands of DNA are elongating.
DNA ploymerase
Elogation of new DNA at a replication fork is catalyzed.As nucleotides agin wit complemenary base along a template strand of DNA, they are aadded by polymerase, one by one, to the growing end of the new DNA strand.
Elongation
New DNA is always in the 5' to 3' direction and starts at the 3' to 5'.
Nucleoside tripohosphate
The nucleotide serves as a substrates fro DNA polymerase are nucleoside triphosphate, which are nucleoside triphosphates, which are nucleotides with tree phosphate groups. ie, ATP
Polymerization
Starts in the 5' to 3' direction and catalysis the phosphodiester bond between nucleotides. In this reaction it loss two phosphate as a pyrophosphate molecule.
Antiparallel
The two strands of DNA and their sugar-phosphate backbones run in opposite direction. The 5' to 3' strands runs
What chemical group is associated with the 3' and 5' ends of DNA?
3' hydroxyl and 5'is the sugar-phosphate backbone terminates with the phosphate group attached to the 5' carbon of the last nucleotide.
How does semi-conservative replication differ from conservative replication?
Semiconservative- the two strands of the parental molecules seperate, and each functions as a template for synthesis of new complementary strands.
conservative model- The prental double helix remains intact and a second, all new copy is made.
In what ways are the two strands "antiparallel"?
The nucleotide's phosphate group attached to the 5' carbon deoxyribose. The phosphate groups of one nucleotide is joined to the 3' carbon hydroxyl is attached to the 3' carbon of the terminal deoxyribose. At the opposite end, the 5'end, the sugar phosphate backbone terminates with the phosphate group attached to teh 5' carbon of the last nucleotide.ie, the two sugar phosphate backbones are essentially upside-down relative to each other.
leading strand
Along one template strand, DNA polymerase can synthesize a continous complementaru strand by elogating the new DNA in the mandatory 5'to 3' direction.
lagging strand
To elongate the other new strand of DNA, polymerase must work along the template away from the replication fork.
Okazaki fragments
Polymerase works away from a replication fork and synthesis short fragments of DNA. "O" is the first fragment made.
ligase
Joins the Okazaki fragments into a single strand.
Primer
DNA polymerase cannot actually initiate synthesis of a polynucleotide: they can only add nucleotide to the end of an already existing chain. The preexisting chain is a primer, is a shor stretch of RNA.
Primase
An enzyme the joins the RNA nucleotides to make the primer.
Helicase
An enzyme that unwinds DNA by breaking H-bonding between base pairs and opens the replication fork.
Topoisomerase
Releaves super coiling of DNA ahead of replication fork.
Single-stranded binding protein
Binds to a single strand DNA template and keeps template seperate. Therefore, keeping them from H-bonding.
In what direction is new DNA made?
5' to 3'
What are the functions of DNA polymerase I in prokaryotes?
- DNA polymerase
- 5' to 3' polymerase
-5' to 3' exonuclease activity (removal of nucleotides)"ONLY POL I"
-3' to 5' exonuclease activity (proofreading)
- bonds 3'-OH end of a polynucleotide to a free 5' neucleotide triphosphate.
What are the functions of DNA polymerase III in prokaryotes?
-Is a DNA polymerase
-elogation enzyme
-5' to3 ' polymerase
-3' to 5' exonuclease activity (proofreading)
- bonds 3'-OH end of a polynucleotide to a free 5' neucleotide triphosphate.
Eukaryotic Polymerase alpha
-5' to3 ' polymerase
-initiates DNA synthesis
Eukaryotic Polymerase
-5' to3 ' polymerase
-3' to 5' exonuclease activity (proofreading)
-analogous to Pol I
Eukaryotic Polymerase
-5' to3 ' polymerase
-3' to 5' exonuclease activity (proofreading)
-Majority leadinf synthesis
Eukaryotic Polymerase
-5' to3 ' polymerase
-3' to 5' exonuclease activity (proofreading)
-Possiblity completes lagging strand
Eukaryotic Polymerase
-5' to3 ' polymerase
-3' to 5' exonuclease activity (proofreading)
-mitochondrial DNA synthesis
Why does DNA polymerase need a primer?
They can't actually initiate synthesis of a polynucleotide; they can only add nucleotide
WHy does DNA polymerase synthesis in the 5' to 3' direction?
DNA polymerase is responsible for copying the DNA templates are only able to "read" the parental nucleotide sequence in the 3' to 5' direction, and they synthesis the new DNA strands in the 5' to 3' (antiparallel direction)
What is the source of energy for the DNA polymerase reaction?
5' to 3' synthesis ensures that incomming nucleotides is always the source energy for the reaction.
Why is DNA "discontinous" on the laggin strand?
As a replication bubble opeans, a polymerase synthesizes a shor t segment of DNA. As the bubble grows, another short segment of the lagging strand can be made in a similar way.
How are Okazaki fragments converted to one continous DNA molecule?
By DNA ligase
How does semi-conservative replication ensure faithful replication of an original double-stranded DNA molecule?
Applying the base-pairing rules: two strands are complementary; each stores genetics information neccessary to reconstruct the other. When a cell copies a DNA molecule, each strand serves as a template for ordering nucleotides into one complementary strand.
Telomerase
Enzyme that lengthens the template strand of the DNA on a lagging strand
- In it has an RNA molecule tha can base pair with the section of the template lagging strand at the 3' end.
-The purpose is to prevent shortening of chromosomes.
Telomeres
Have a special nucleotide sequence (TTAGGG). Tis DNA protects the organism's genes from being eroded through successive rounds of DNA replication.
Telomeres
A short nucleotide sequence (TTAGGG). This sequence protects the organism's genes from being eroded through successive rounds of DNA replication.
Telomerase
Enzyme that lengthens the template strand of the DNA on lagging strand.
- it extends on the 3' end of the laggin strand.
- The purpose to prevent shortening of chromosomes.