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Definition
| The process by which a DNA molecule is copied, and how cells repair their DNA |
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| Transformation.... **in regards to DNA** |
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| A change in genotype and phenotype due to the assimilation of external DNA by a cell. |
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| Viruses that can infect bacteria. |
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Definition
| is little more than DNA (or sometimes RNA) enclosed by a protective coat, which is often simply protein. **to produce more viruses, a virus must infect a cell and take over the cell's metabolic machinery |
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| Significance of the Hershey-Chase experiment (radioactive phosphorous and sulfur incorporated into protein/DNA of a virus) |
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Definition
| It was a landmark study because it provided powerful evidence that nucleic acids, rather than proteins, are the hereditary material, at least for viruses. |
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| What are the three components of nucleotides? |
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Definition
| nitrogenous base, a pentose sugar (deoxyribose), and a phosphate group...the nitrogenous base is composed of adenine (A), thymine (T), guanine (G), and cytosine(C). |
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Definition
| 1) The base composition varies between species. 2) Within a species, the number of A and T bases are equal and the number of G and C bases are equal. **these rules were unexplained until the discovery of a double helix. |
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Definition
| refers to the structure formed by double-stranded molecules of nucleic acids |
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Definition
| Subunits run in opposite directions |
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Definition
| Nitrogenous bases with two organic rings (Adenine and guanine) |
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Definition
| Nitrogenous bases that have one organic ring (Cytosine and thymine) |
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| How do the nitrogenous bases bond? |
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Definition
| Hydrogen bonds... 2 H bonds can occur between A and T (only) and 3 H bonds can occur between C and G (only) |
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Definition
| Type of DNA replication in which the replicated double helix consists of one old strand, derived from the parental molecule, and one newly made strand. |
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Definition
| A Y shaped region where the parental strands of DNA are being unwound. |
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Definition
| Are enzymes that untwist the double helix at the replication forks, separating the two parental strands and making them available as template strands. |
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| Single strand binding proteins |
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Definition
| Once the parental strands are separated, these proteins bind to the unpaired DNA strands, keeping them from repairing. |
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Definition
| The untwisting of the parental strands cause tighter twisted and stain on the remaining part of the DNA strand. The Topoisomerase helps relieves this strain by breaking, swiveling, and rejoining DNA strands. |
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Term
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Definition
| The initial nucleotide chain that is produced during DNA synthesis is actually a short chain of RNA, not DNA.... This is called a primer... Primer is synthesized by the enzyme primase.... Primase starts a complementary RNA chain from a single nucleotide, adding RNA nucleotides one at a time, using the parental DNA stand as a template.... A completed primer is generally 5-10 nucleotides long.... The new DNA will start from the 3' end of the RNA primer. |
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Term
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Definition
| Enzymes that catalyze the synthesis of new DNA by adding nucleotides to a pre existing chain. |
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Term
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Definition
| Each nucleotide added to a growing DNA strand comes from a nucleoside triphosphate (a nucleoside is a sugar and a base, with 3 phosphate groups).... The sugar is deoxyribose... When each monomer is added to the growing strand, 2 phosphate groups are lost (pyrophosphate), this is exergonic and it what drives the synthesis. |
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Definition
| The new complementary DNA strand synthesized continuously along the template strand toward the replication fork in the 5'-3' direction |
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Definition
| A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in the 5'-3' direction away from the replication fork.... Refer to pg 316, primase makes a primer on the lagging strand. DNA pol III adds nucleotides to the primer forming Okazaki fragment 1. Once this fragment reaches the next primer, DNA pol III detaches. When Okazaki fragment 2 reaches Okazaki 1, the DNA pol III detaches and DNA pol I replaces the RNA by adding nucleotides to fragment 2. Once all the RNA has been replaced, DNA pol I detaches and DNA ligase can from a bond between the two fragments which completes that region for the lagging strand. |
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Term
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Definition
| A short segment of DNA synthesized away from the replication fork on a template strand during DNA replication.... These segments are joined together to make the lagging strand. |
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Definition
| Joins the sugar-phosphate backbones of all the Okazaki fragments into a continuous DNA strand. |
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Term
| Two factors to keep in mind about DNA replication |
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Definition
| 1)The various proteins that participate in DNA replication actually form a single large complex. 2)The DNA replication complex may not move along the DNA; rather the DNA may move through the complex during the replication process. |
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Definition
| Other enzymes remove and replace incorrectly paired nucleotides that have resulted from replication errors |
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Term
| DNA replication proofreading |
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Definition
| The DNA polymerases will proofread each nucleotide against its template as soon as it is added to the growing strand. Upon finding an incorrectly paired nucleotide, the polymerase removes the nucleotide and then resumes synthesis. |
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Definition
| A DNA cutting enzyme... Used to correct errors in DNA replication/ repair damaged DNA... It cuts out the damage part, and the gap it then filled by nucleotides (using the undamaged strand as a template.... DNA polymerase and DNA ligase are used to replace the nucleotides). |
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Term
| Nucleotide excision repair |
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Definition
| A repair system that removes and then correctly replaces a damaged segment of DNA using the undamaged strand as a guide. |
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Definition
| Do not contain genes; instead the DNA typically consists of multiple repetitions of one short nucleotide sequence |
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Definition
| An enzyme, it catalyzes the lengthening of telomers in eukaryotic germ cells, thus restoring their original length and compensating for the shortening that occurs during DNA replication |
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Definition
| Proteins... responsible for the first level of DNA packing in chromatin. Contain a positive charge which allows it to pack tightly with the negative charge of the double helix of DNA |
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Definition
| The basic unit of DNA packaging... consists of DNA wound twice around a protein core composed of two molecules of each type of histone... the amino end of each histone extends outward from the nucleosome... the DNA strand between nucleosome are called linker DNA. |
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Term
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Definition
| Packing results from interactions between the histone tails of one nucleosome and the linker DNA and nucleosomes on either side. this cause the DNA to fold and coil until it is 30nm in thickness (started from 10nm). |
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Term
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Definition
| The 30 nm fiber folds and coils and attached to a chromosome scaffold made of proteins, which makes the fiber 30nm fibers into 300nm fiber |
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Definition
| Visible as irregular clumps with a light microscope... "Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed" |
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Definition
| The less condensed form of eukaryotic chromatin that is available for transcription |
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