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| 1036383637 | 2 DNA strands are held together by.... | Hydrogen bonds between nitrogenous bases | 1 | |
| 1036383638 | pairs of nitrogenous bases in DNA double helix are held together by.... | Hydrogen bonds | 2 | |
| 1036383639 | First step in basic DNA replication | strands separate, each parental strand serves as a template that determines the order of nucleotides along a new complementary strand | 3 | |
| 1036383640 | Second step in basic DNA replication | complementary nucleotides line up and and connect to sugar-phosphate backbones of the new strands. Each strand consists of 1 parent strand, 1 daughter strand | 4 | |
| 1036383641 | Conservation Model of DNA replication | 2 parental strands reassociate after acting as templates for new strands, thus restoring the parental double helix | 5 | |
| 1036383642 | Semiconservative Model of DNA replication | 2 strands of the parental molecule separate, and each functions as a template for synthesis of a new, complementary strand | 6 | |
| 1036383643 | Dispersive Model of DNA replication | Each strand of both daughter molecules contain a mixture of old and newly synthesized DNA | 7 | |
| 1036383644 | Replication Fork | Y shaped region where parental strands of DNA are being unwound | 8 | |
| 1036383645 | Helicases | Enzymes that unwinds and separates the parental DNA strands to become template strands | 9 | |
| 1036383646 | Single-strand binding proteins | bind to unpaired DNA strands, stabilize unwound parent strands | 10 | |
| 1036383647 | Primase | Synthesizes the primer Starts a complementary RNA chain from a single RNA nucleotide adding RNA nucleotides one at a time, using the parental DNA strand as a template | 11 | |
| 1036383648 | DNA polymerases | Catalyze the synthesis of new DNA by adding nucleotides to a preexisting chain Require a primer and DNA template strand | 12 | |
| 1036383649 | Leading strand | The new complementary DNA strand synthesized continuously along the template strand toward the replication fork in the mandatory 5' to 3' direction | 13 | |
| 1036383650 | Lagging strand | A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5' to 3' direction away from the replication fork | 14 | |
| 1036383651 | Okazaki fragments | A short segment of DNA synthesized away from the replication fork on a template strand during DNA replication. Many such segments are joined together to make up the lagging strand of newly synthesized DNA | 15 | |
| 1036383652 | Synthesis of lagging strand Step 1 | Primase joins RNA nucleotides into primer | 16 | |
| 1036383653 | Synthesis of lagging strand Step 2 | DNA pol II adds DNA nucleotides to the primer, forming Okazaki fragment 1 | 17 | |
| 1036383654 | Synthesis of lagging strand Step 3 | After reaching the next RNA primer to the right, DNA pol III detaches | 18 | |
| 1036383655 | Synthesis of lagging strand Step 4 | Fragment 2 is primed, Then DNA pol III adds DNA nucleotides, detatching when it reaches the fragment 1 primer | 19 | |
| 1036383656 | Synthesis of lagging strand Step 5 | DNA pol I replaces the RNA with DNA, adding to the 3' end of fragment 2 | 20 | |
| 1036383657 | Synthesis of lagging strand Step 6 | DNA ligase forms a bond between the newest DNA and the DNA of fragment 1 | 21 | |
| 1036383658 | Synthesis of lagging strand Step 7 | Laggin strand in this region is now complete | 22 | |
| 1036383659 | Mismatch repair | Celluar process that uses specific enzymes to remove and replace incorrectly paired nucleotides | 23 | |
| 1036383660 | Nuclease | cuts damanged DNA strand at two points so damaged section can be removed | 24 | |
| 1036383661 | Enzymes involved with filling pre-damaged gap | DNA polymerase and DNA ligase | 25 | |
| 1036383662 | Telomeres | Tandemly repetitive DNA at the end of a eukaryotic chromosome's DNA molecule. Telomeres protect the organism genes from being eroded during successive rounds of replication. | 26 | |
| 1036383663 | Histones | Proteins that are responsible for the first level of DNA packing in chromatin | 27 | |
| 1036383664 | Nucleosome | Basic unit of DNA packing. Consists of DNA wound twice around a protein core composed of two molecules each of the four main histone types | 28 | |
| 1036383665 | Chromatin | Complex of DNA and proteins hat makes up eukaryotic chromosomes. When the cell is not dividing, chromatin exists in its dispersed form, as a mass of very long, thin fibers | 29 | |
| 1036383666 | DNA replication | the process of making a copy of DNA | 30 | |
| 1036383667 | transformation | the transfer of genetic material in the form of DNA fragments from one cell to another or from one organism to another | 31 | |
| 1036383668 | bacteriophage | a virus that infects bacteria | 32 | |
| 1036383669 | virus | ultramicroscopic infectious agent that replicates itself only within cells of living hosts | 33 | |
| 1036383670 | double helix | two strands of nucleotides wound about each other; structure of DNA | 34 | |
| 1036383671 | antiparallel | The opposite arrangement of the sugar-phosphate backbones in a DNA double helix. | 35 | |
| 1036383672 | semiconservative | method of replication that implies that each new strand of DNA is half original and half new | 36 | |
| 1036383673 | origin of replication | Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides. | 37 | |
| 1036383674 | helicase | an enzyme that untwists the double helix at the replication forks, separating the two parental strands and making them available as template strands | 38 | |
| 1036383675 | single strand binding proteins | Proteins that bind to and stabilize the signle strands of DNA exposed when helicase unwinds the double helix in preparation for replication. | 39 | |
| 1036383676 | topoisomerase | A protein that functions in DNA replication, helping to relieve strain in the double helix ahead of the replication fork. | 40 | |
| 1036383677 | primer | An already existing RNA chain bound to template DNA to which DNA nucleotides are added during DNA synthesis., a short segment of DNA that serves as the starting point for DNA synthesis | 41 | |
| 1036383678 | DNA polymerase | enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule | 42 | |
| 1036383679 | DNA ligase | an enzyme that eventually joins the sugar-phosphate backbones of the Okazaki fragments | 43 | |
| 1036383680 | nucleotide excision repair | The process of removing and then correctly replacing a damaged segment of DNA using the undamaged strand as a guide. | 44 | |
| 1036383681 | telomerase | An enzyme that catalyzes the lengthening of telomeres. The enzyme includes a molecule of RNA that serves as a template for new telomere segments. | 45 | |
| 1036383682 | nucleoid | A dense region of DNA in a prokaryotic cell. | 46 | |
| 1036383683 | 30nm fiber | nucleosomes associate with each other to form a more compact structure - results from interactions between adjacent histone H1 proteins | 47 | |
| 1036383684 | looped domains | 30-nm fiber forms loops that attach to a protein chromosome scaffold, making up a 300-nm fiber | 48 | |
| 1036383685 | heterochromatin | Nontranscribed eukaryotic chromatin that is so highly compacted that it is visible with a light microscope during interphase | 49 | |
| 1036383686 | euchromatin | a region of DNA that is uncoiled and undergoing active transcription into RNA | 50 | |
| 1036383687 | gene expression | the process by which DNA directs the synthesis of proteins (or, in some cases, just RNAs) | 51 | |
| 1036383688 | transcription | synthesis of an RNA molecule from a DNA template | 52 | |
| 1036383689 | primary transcript | the initial RNA transcript from any gene, including those specifying RNA that is not translated into protein | 53 | |
| 1036383690 | mRNA | messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome | 54 | |
| 1036383691 | translation | The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule | 55 | |
| 1036383692 | ribosomes | The sites of translation, complex particles that facilitate the orderly linking of amino acids into polypeptide chains. | 56 | |
| 1036383693 | triplet code | 3 bases of DNA that code for a single amino acid | 57 | |
| 1036383694 | codons | mRNA base triplets | 58 | |
| 1036383695 | template strand | The DNA strand that provides the template for ordering the sequence of nucleotides in an RNA transcript. | 59 | |
| 1036383696 | reading frame | the way a cell's mRNA-translating machinery groups the mRNA nucleotides into codons | 60 | |
| 1036383697 | RNA polymerase | pries the two strands of DNA apart and joins together RNA nucleotides complementary to the DNA template strand, thus elongating the RNA polynucleotide | 61 | |
| 1036383698 | promoter | The DNA sequence where RNA polymerase attaches and initiates transcription | 62 | |
| 1036383699 | terminator | In prokaryotes, a special sequence of nucleotides in DNA that marks the end of a gene. It signals RNA polymerase to release the newly made RNA molecule, which then departs from the gene. | 63 | |
| 1036383700 | transcription unit | the stretch of DNA that is transcribed into an RNA molecule | 64 | |
| 1036383701 | start point | nucleotide where RNA synthesis actually begins | 65 | |
| 1036383702 | transcription factors | in eukaryotes, a collection of proteins that mediate the binding of RNA polymerase and the initiation of transcription | 66 | |
| 1036383703 | transcription initiation complex | the whole complex of transcription factors and RNA polymerase II bound to the promoter | 67 | |
| 1036383704 | TATA box | A promoter DNA sequence crucial in forming the transcription initiation complex., a DNA sequence in eukaryotic promoters crucial in forming the transcription initiation complex (the transcription factors recognize this); "tells RNA pol where to land" | 68 | |
| 1036383705 | 5' cap | a methylated guanine nucleotide added to the 5' end of eukaryotic mRNA | 69 | |
| 1036383706 | poly-A tail | The modified end of the 3' end of an mRNA molecule consisting of the addition of some 50 to 250 adenine nucleotides. | 70 | |
| 1036383707 | RNA splicing | process by which the introns are removed from RNA transcripts and the remaining exons are joined together | 71 | |
| 1036383708 | introns | a non-coding, intervening sequence within a eukaryotic gene | 72 | |
| 1036383709 | exons | expressed sequence of DNA; codes for a protein | 73 | |
| 1036383710 | spliceosome | A complex assembly that interacts with the ends of an RNA intron in splicing RNA, releasing the intron and joining the two adjacent exons. | 74 | |
| 1036383711 | ribozymes | An enzymatic RNA molecule that catalyzes reactions during RNA splicing. | 75 | |
| 1036383712 | domains | modular architecture on proteins consisting of discrete structural and functional regions | 76 | |
| 1036383713 | alternative RNA splicing | A type of eukaryotic gene regulation at the RNA-processing level in which different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns | 77 | |
| 1036383714 | aminoacyl-tRNA synthetases | an enzyme that joins each amino acid to the appropriate tRNA | 78 | |
| 1036383715 | tRNA | short-chain RNA molecules present in the cell (in at least 20 varieties, each variety capable of combining with a specific amino acid) that attach the correct amino acid to the protein chain that is being synthesized at the ribosome of the cell (according | 79 | |
| 1036383716 | anticodon | group of three bases on a tRNA molecule that are complementary to an mRNA codon | 80 | |
| 1036383717 | wobble | flexibility in the base-pairing rules in which the nucleotide at the 5' end of a tRNA anticodon can form hydrogen bonds with more than one kind of base in the third position (3' end) of a codon | 81 | |
| 1036383718 | rRNA | The most abundant type of RNA, which together with proteins froms the structure of ribosomes. Ribosomes coordinate the sequential coupling of tRNA molecules to mRNA codons | 82 | |
| 1036383719 | P site | holds the tRNA carrying the growing polypeptide chain. | 83 | |
| 1036383720 | A site | holds the tRNA carrying the next amino acid to be added to the chain | 84 | |
| 1036383721 | E site | This site is the place where discharged tRNAs leave the ribosome. | 85 | |
| 1036383722 | polyribosomes | An aggregation of several ribosomes attached to one messenger RNA molecule. | 86 | |
| 1036383723 | signal recognition particle | binds to the signal sequence and the ribosomal subunits and transports the complex to the ER | 87 | |
| 1036383724 | signal peptide | A stretch of amino acids on a polypeptide that targets the protein to a specific destination in a eukaryotic cell. | 88 | |
| 1036383725 | nucleotide-pair substitution | A type of point mutation in which one nucleotide in a DNA strand and its partner in the complementary strand are replaced by another pair of nucleotides. | 89 | |
| 1036383726 | mutation | change in a DNA sequence that affects genetic information | 90 | |
| 1036383727 | silent mutation | A mutation that changes a single nucleotide, but does not change the amino acid created. | 91 | |
| 1036383728 | nonsense mutation | A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein. | 92 | |
| 1036383729 | missense mutation | The most common type of mutation, a base-pair substitution in which the new codon makes sense in that it still codes for an amino acid. | 93 | |
| 1036383730 | point mutation | mutation that affects a single nucleotide, usually by substituting one nucleotide for another | 94 | |
| 1036383731 | insertion | A mutation involving the addition of one or more nucleotide pairs to a gene. | 95 | |
| 1036383732 | deletion | The loss of one or more nucleotides from a gene by mutation; the loss of a fragment of a chromosome | 96 | |
| 1036383733 | frameshift mutation | mutation that shifts the "reading" frame of the genetic message by inserting or deleting a nucleotide | 97 | |
| 1036383734 | mutagen | any agent (physical or environmental) that can induce a genetic mutation or can increase the rate of mutation | 98 |
