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| 7677978725 | Transformation | change in genotype and phenotype due to the assimilation of external DNA by a cell. Griffith discovered that killing pathogenic Streptococcus pneumoniae and mixing the remains with non-pathogenic bacteria caused this | 0 | |
| 7684034734 | Avery, MacLeod, McCarty | discovered that DNA was the transforming agent, not RNA or protein | 1 | |
| 7677978726 | Bacteriophages (phages) | viruses that infect bacteria | 2 | |
| 7684310426 | virus | dna in a protective coat, often protein | 3 | |
| 7684310427 | Hershey and Chase | discovered that DNA is the genetic material of T2 phage. showed that only dna entered the e coli cell, protein stayed behind. radioactive sulfur tagged the protein and radioactive phosphorus tagged the dna | 4 | |
| 7684310428 | T2 Phage | phage of e coli used in hershey chase experiment | 5 | |
| 7684310429 | Erwin Chargaff | Determined that the levels of A and T, and C and G are always equal in normal DNA. "chargaff's rules" base composition and a-t c-g | 6 | |
| 7684310430 | "handedness" of dna | right-handed | 7 | |
| 7684310431 | word describing the directional behavior of the two backbones of dna | antiparallel | 8 | |
| 7684310432 | purines | Adenine and Guanine 2 rings | 9 | |
| 7684310433 | Pyrimidines | thymine and cytosine and uracil 1 ring like the base of a pyramid | 10 | |
| 7684310434 | Adenine-thymine h bonds | 2 between A and T | 11 | |
| 7684310435 | cytosine-guanine h bonds | 3 between c and g | 12 | |
| 7685048106 | semiconservative | describes replication in which one strand is newly synthesized and one represents part of the original strand | 13 | |
| 7685048107 | Meselson and Stahl | proved semiconservative replication pretty much | 14 | |
| 7685048108 | origins of replication | short stretches of DNA having a specific sequence of nucleotides at which replication of the dna molecule begins | 15 | |
| 7685048109 | replication fork | A Y-shaped region on a replicating DNA molecule where parental strands of dna are being unwound | 16 | |
| 7685048110 | helicases | unwind DNA strands at replication forks by breaking hydrogen bonds | 17 | |
| 7685048111 | single-strand binding proteins | while helicase is doing its thing, these bind to the unpaired DNA strands, keeping them from re-pairing | 18 | |
| 7685048112 | Topoisomerase | an enzyme that alters the supercoiled form of a DNA molecule. relieves strain due to dna unwinding by breaking, swiveling, and rejoining dna strands | 19 | |
| 7685048113 | primer | a short segment of DNA that acts as the starting point for a new strand. initial nucleotide chain during dna synthesis. synthesized by enzyme called primase. generally 5-10 rna nucleotides long | 20 | |
| 7685048114 | primase | An enzyme that joins RNA nucleotides to make the primer. starts a complementary rna chain from a single rna nucleotide, adding more rna nucleotides 1 at a time | 21 | |
| 7685048115 | where does replication begin after the synthesis of the primer | at the 3' end of the rna primer | 22 | |
| 7685048116 | DNA polymerase | catalyze the synthesis of new dna by adding nucleotides to existing chain. dna pol 3 and 1 are the most important ones in e coli, but eukaryotes have like 11 | 23 | |
| 7685048117 | direction of dna polymerase strand elongation | 5' -> 3' direction, can only attach to 3' end | 24 | |
| 7685048118 | Leading strand synthesis | dna polymerase remains in the replication fork and continuously adds nucleotides as the fork progresses | 25 | |
| 7685048119 | lagging strand synthesis | dna pol works along the other template strand in the direction away from the fork. synthesized discontinuously, in a series of segments, called Okazaki fragments | 26 | |
| 7685048120 | Okazaki fragments | discontinuous segments of the lagging strand | 27 | |
| 7685048121 | dna pol 1 role in lagging strand synthesis | replaces the primers of the leading strand with DNA. these new strands are then joined to existing ones by ligase | 28 | |
| 7685048122 | primase as a molecular break | coordinates placement of lagging primers and rates of replication on leading and lagging strands | 29 | |
| 7685048123 | error rate in new completed dna molecule | 1 in 10 billion or 10^10 nucleotides | 30 | |
| 7685048124 | initial pairing errors between incoming nucleotidss and those in template strand | 1 in 10^5 nucleotides | 31 | |
| 7685369997 | mismatch repair | repair enzymes correct errors in base pairing from replication errors not caught by the dna polymerase | 32 | |
| 7685369998 | nuclease | DNA cutting enzyme | 33 | |
| 7685369999 | nucleotide excision repair | enzymes cut out incorrect bases and fill in correct bases. consists of nuclease, polymerase, and ligase action | 34 | |
| 7685370000 | thymine dimers | caused by UV radiation - adjacent thymine molecules in a dna strand becomes covalently bonded | 35 | |
| 7685370001 | Xeroderma pigmentosum | inherited defect in nucleotide excision repair enzyme. mutations in skin cells go uncorrected. | 36 | |
| 7685370002 | human telomere sequence | TTAGGG | 37 | |
| 7685370003 | telomerase | catalyzes the lengthening of telomeres in germ cells. not usually active in somatic cells | 38 | |
| 7685370004 | Nucleoid | area in a prokaryotic cell that contains a large, circular chromosome. dense dna, coiled and supercoiled. no membrane | 39 | |
| 7685370005 | Chromatin | complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells | 40 | |
| 7685370006 | heterochromatin | hetero is more compacted, similar to a metaphase chromosome. visible as irregular clumps under light microscope. largely inaccessible to cellular machinery due to compaction | 41 | |
| 7685370007 | euchromatin | The less condensed form of eukaryotic chromatin that is available for transcription. more dispersed. | 42 | |
| 7685523499 | histone | ~100 amino acid proteins. more than a fifth of histone amino acids are positively charged lysine or arginine, bind well to negatively charged dna. | 43 | |
| 7685523500 | nucleosome | repeating subunit of chromatin fibers, consisting of DNA coiled around histones - beads on a string. the string between the beads is called linker DNA. consists of dna wound around a protein core of 8 histones, 2 of each of the 4 main histone types. n-terminus histone tail extends out from the nucleosome. | 44 | |
| 7685523501 | levels of dna packing | the double helix, 10-nm fibers, 30-nm fibers, looped domaons (300-nm fibers), metaphase chromosome | 45 | |
| 7685523502 | 30-nm fiber | linker dna and histone tails interact. this level contains the 5th type of histone | 46 | |
| 7685523503 | looped domains | 300nm fibers. 30nm fibers wrap around a protein scaffold. the scaffold is rich in one type of topoisomerase | 47 | |
| 7685523504 | metaphase chromosome | one chromatid is 700nm wide. genes always end up in the same place at this level btw. | 48 | |
| 7685523505 | 10-nm fiber | nucleosome beads on a string | 49 |
