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44 Cards in this Set
- Front
- Back
chromatin |
a complex of DNA and protein |
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transformation |
a change in genotype and phenotype due to assimilation of foreign DNA |
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bacteriophages |
viruses that infect bacteria, composed of only DNA and protein |
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DNA is _________ __________ |
nucleic acid
` |
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the building blocks of DNA are _________ |
nucleotides |
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nucleotides |
composed of 5 carbon sugar called deoxyribose, a phosphate group (PO4, neg. charge), a nitrogenous base (A, T, C, G) |
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_____ has directionality |
DNA |
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the _________ _________ is attached to the 1' (prime) location of the 5-carbon deoxyribose |
nitrogenous base |
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the _________ __________ is attached to the 5' (prime) carbon of deoxyribose |
phosphate group |
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a free _________ __________ is attached at the 3' (prime) carbon of deoxyribose |
hydroxyl group |
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DNA has a ___ end and a ____ end |
3' , 5' |
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nitrogenous bases |
thymine, adenine, cytosine, guanine |
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phosphodiester bond |
connects adjacent nucleotides, formed between the phosphate group of one nucleotide and the 3' ---OH of the next nucleotide |
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the chain of nucleotides has a ________ orientation |
5'-to-3' |
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Chargaff's Rules |
amount of adenine = amount of thymine amount of cytosine = amount of guanine always have an equal proportion of purines (A &G) and pyrimidines (C & T) |
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double helix |
consists of 2 sugar-phosphate backbones, and nitrogenous bases toward the interior of the molecule |
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the two strands of nucleotides are ___________ to each other |
antiparallel |
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antiparallel |
one nucleotide is oriented 5' to 3', the other 3' to 5', two strands wrap around each other creating the helical shape |
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A forms ____ hydrogen bonds with T |
two |
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G forms ______ hydrogen bonds with C |
three |
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semiconservative model DNA replication |
each strand of DNA acts as a template for the synthesis of a new strand |
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DNA replication requires 3 things |
-something to copy: parental DNA molecule -something to do the copying: enzymes -building blocks to make copy: nucleotide triphosphates |
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initiation |
DNA replication begins at an origin of replication |
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elongation |
new strands of DNA are synthesized by a DNA polymerase |
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termination |
replication is terminated differently in prokaryotes and eukaryotes |
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prokaryotic DNA replication |
chromosome is circular and replication begins at origin of replication proceeding in both directions around the chromosome |
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___________ chromosomes have a single origin of replication |
bacterial |
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in prokaryotic DNA replication, the double helix is unwound by the enzyme __________ |
helicase |
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in prokaryotic DNA replication, ______-______ __________ __________ bind to and stabilize single-stranded DNA |
single-strand binding proteins |
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DNA polymerase III (Pol III) |
is the main polymerase responsible for the majority of DNA sythesis- adds nucleotides to the 3' end of the daughter strand of DNA |
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DNA polymerases |
-match existing DNA bases with complementary nucleotides and link them -all have several common features: add new bases to 3' end of existing strands, sythesize in 5'-to-3' direction, REQUIRE A PRIMER OF RNA |
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DNA replication is _______________________ |
semidiscontinuous |
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semidiscontinuous |
-Pol III can only add nucleotides to the 3' end of the newly synthesized strand -DNA strands are antiparallel to each other |
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________ _________ is synthesized continuously (in the same direction as the replication fork), ________ ________ is synthesized discontinuously creating Okazaki fragments |
leading strand, lagging strand |
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primase |
RNA polymerase that makes RNA primer- can start an RNA chain from scratch |
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DNA ligase |
closes gap between adjacent fragments |
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DNA polymerase I |
removes RNA primer and fills in gap with nucleotides |
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primase |
sythesizes RNA primer |
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eukaryotic DNA replication have multiple __________ ____ __________ |
origins of replication |
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With each round of DNA replication in eukaryotes, the linear chromosome becomes ___________ |
shorter |
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telomeres |
region at the end of linear (eukaryotic) chromosmes- protect ends of chromosomes from nucleases and maintain their integrity- gradual shortening of chromosomes with each round of cell division |
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telomeres __________ with age |
shorten |
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telomeres |
repeated DNA sequence on the ends of eukaryotic chromosomes |
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telomerase |
contains an RNA region that is used as a template so a DNA primer can be produced- typically only found in gamete-producing cells or lymphocytes of older multicellular organisms- ensures longer telomeres in zygotes |