DNA Structure Double Stranded Double Helix Sugar Deoxyribose Base Pairs o A T pair 2 hydrogen bonds o G C pair in RNA G U 3 hydrogen bonds stronger o Adenine and Guanine purines 2 nitrogenous rings o Thymine Cytosine Uracil pyrimidines 1 nitrogenous pair rings RNA Structure Single Stranded molecule Sugar Ribose one more oxygen Uracil base instead of Thiamine U A base pair DNA Replication Purpose to create two complementary DNA strands 1 Helicase enzyme that breaks the hydrogen bonds of the base pairs and separates the DNA into two strands 2 Replication fork where the splitting of the DNA strand starts 3 Leading Strand top strand 5 to 3 o RNA Primase o DNA Polymerase only needed in the beginning of the process to prime or fill in a section of nucleotides that was just unzipped with RNA primers following the RNA primase to hook on it continues to add nucleotides base pairs down the replication fork Proofreading ability allows it to correct errors mismatched bases made during replication o Can only add strands from 5 to 3 sequence 4 Lagging Strand bottom strand 3 to 5 o Has to be copied in segments works opposite of leading strand so that goes in 5 to 3 direction working backwards o RNA Primase o DNA Polymerase lays down RNA primers in segments for the DNA polymerase to follow nucleotides and then works down the strand continuing to add nucleotides hooks on to newly laid down Can proofread and go back and correct mismatched bases made during replication o Okazaki Fragments individual segments consisting of RNA primers of nucleotides followed by the nucleotides laid down by the DNA polymerase along and replaces all of the RNA primers another kind of this enzyme comes joins all of the fragments o DNA Polymerase o DNA Ligase Transcription Unit o Promoter sequence o TATA Box A T T A T A A T A T A T A T Helps our enzymes figure out where to bind to the strand Upstream toward 3 prime end Downstream toward 5 prime end o RNA Polymerase TATA box towards the 5 prime end begins to unzip the DNA strand copies the DNA downstream of the Copies it into messenger RNA mRNA Basic necessities come from mother s egg Sends them into the nucleus to be matched tells the RNA polymerase to pull off o Termination Signal and stop o mRNA 5 cap Poly A tail RNA Splicing Small nuclear ribonucleo proteins a o Snurps special type of guanine 3 adds adenine combination of RNA and proteins recognize sequences that signal the start and end of the areas to be spliced o Splisosome A combination of Snurps and other proteins Is what actually does the editing Exons what will be spliced together and be expressed Introns what isn t needed Material gets recycled back into nucleus Takes out the nitrogenous bases that can be reused in either DNA or RNA Translation Processed mRNAs get fed into ribosomes in the rough endoplasmic reticulum o Ribosomes have binding sites that allow the mRNA to interact with the tRNA transfer RNA translation RNA translates from the language of nucleotides tRNA into the language of proteins one end have an amino acid other end have 3 nitrogenous bases o Triplet Codon the three bases that are matched at one o Anticodon time opposite bases in the ribosomes o AUG finds an tRNA with anticodon on mRNA the bases that are matched with their Starts of a polypeptide chain beginning of protein DNA Structures Primary structure single bonded sequence Secondary Structure sheets spirals double helix Tertiary Structure R Group Bonds Quaternary Multiple Proteins
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