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Published byEvangeline Barber Modified over 8 years ago
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What is DNA? What does it do?
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DNA The Genetic Material Chapter 12: DNA
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Bodies are made up of cells All cells run on a set of instructions spelled out in DNA Bodies Cells DNA 3
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Role of DNA DNA is in EVERY living thing Store information Copy information Transmit information 4
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DNA DNA stands for D: Deoxyribose N: Nucleic A: Acid DNA monomer is a nucleotide 5
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Structure of DNA: nucleotides There are 4 different nucleotides found in DNA 1. Adenine (A) 2. Guanine (T) 3. Cytosine (C) 4. Thymine (G) 6
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Structure of DNA: nucleotides The monomers of DNA are nucleotides Sugar deoxyribose Phosphate group Nitrogen Base A, T, C, G 7
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Structure of DNA: Paired bases Bases match together A pairs with T A : T C pairs with G C : G hydrogen bonds between bases join 2 strands can separate easily 8
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DNA Double Helix Sugar-phosphate backbone (rails of ladder) Nitrogenous bases in middle (rungs of ladder) Create double helix (spiral) 9
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Anti-parallel strands Phosphate to sugar bond involves carbons in 3’ & 5’ positions 10
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Closure What are the monomers of DNA called? What are the 3 parts that make up DNA? What are the 4 monomers called? How are they paired? What is the structure of DNA shaped like? 11
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Intro What are the monomers of DNA called? What are the 3 parts that make up DNA? What are the 4 bases called? How are they paired? What is the structure of DNA shaped like? 12
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Making new DNA Copying DNA replication DNA starts as a double-stranded molecule matching bases (A:T, C:G) then it unzips… 13
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DNA replication Strands “unzip” at the weak bonds between bases Enzyme = Helicase Helicase 14
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DNA replication DNA polymerase Enzyme DNA polymerase adds new bases DNA bases in nucleus 15
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DNA Polymerase Copying DNA Build daughter DNA strand use original parent strand as “template” add new matching bases Enzymes = DNA polymerase 16
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New copies of DNA Get 2 exact copies of DNA to split between new cells 1 old strand and 1 new strand on each DNA polymerase DNA polymerase 17
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Okazaki fragments 18 DNA Ligase seals fragments together on lagging strand
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Editing & proofreading DNA At 1000 bases/second lots of typos Nucleases excise mismatched bases reduce error rate from 1 in 10,000 to 1 in 100 million bases 19
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What happens 1 st in replication? Enzyme? What happens next? Enzyme? Which way do bases get added? 20
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How does DNA code for cells & bodies? how are cells and bodies made from the instructions in DNA DNA Cells Bodies 21
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DNA has the information to build proteins DNA Proteins Cells Bodies proteins cells bodies DNA gets all the glory, Proteins do all the work 22
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nucleus DNA DNA is in the nucleus Proteins made by a ribosomes in cytoplasm Need to get gene (DNA) information from nucleus to cytoplasm mRNA makes a copy of DNA 23
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cytoplasm nucleus build proteins DNA RNA messenger RNA (mRNA) takes information from the nucleus to the ribosome mRNA 24
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mRNA From gene to protein DNA transcription nucleuscytoplasm a a a a a a a a a aa protein translation ribosome trait 25
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DNA vs. RNA DNA deoxyribose sugar nitrogen bases G, C, A, T T = thymine T : A C : G double stranded RNA ribose sugar nitrogen bases G, C, A, U U = uracil U : A C : G single stranded 26
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Transcription Making mRNA from DNA DNA strand is the template (pattern) match bases U : A G : C Enzyme RNA polymerase 27
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Matching bases of DNA & RNA RNA polymerase unzips Double stranded DNA AGGGGGGTTACACTTTTTCCCCAA 28
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Matching bases of DNA & RNA RNA polymerase matches RNA bases to DNA bases on one of the DNA strands U AGGGGGGTTACACTTTTTCCCCAA U U U U U G G A A A CC RNA polymerase C C C C C G G G G A A A A A 29
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Matching bases of DNA & RNA U instead of T is matched to A TACGCACATTTACGTACGCGG DNA AUGCGUGUAAAUGCAUGCGCC mRNA 30
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At the End Original DNA strands wind back together New mRNA strand leaves the nucleus 31
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How are DNA and RNA different? What kind of RNA is used in transcription? What is the enzyme used in transcription? Where does it go? 32
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a a a aaa a mRNA From gene to protein DNA transcription nucleus cytoplasm protein translation trait UCCCCCCAAUGUGAAAAAGGGGUU ribosome 33
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RNA to protein mRNA leaves nucleus mRNA goes to ribosomes in cytoplasm Proteins built from instructions on mRNA aa mRNA UCCCCCCAAUGUGAAAAAGGGGUU 34
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AUGCGUGUAAAUGCAUGCGCC mRNA mRNA codes for proteins in triplets TACGCACATTTACGTACGCGG DNA AUGCGUGUAAAUGCAUGCGCC Met Arg Val Asn Ala Cys Ala protein ? Codon is a block of 3 nucleotides codons ribosome 35
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several codons for each amino acid mutation insurance! Start codon AUG methionine Stop codons UGA, UAA, UAG The mRNA code 36
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Codon on the mRNA Anti-codon on the tRNA TACGCACATTTACGTACGCGG DNA AUGCGUGUAAAUGCAUGCGCC mRNA amino acid tRNA anti-codon codon UAC Met GCA Arg CAU Val 37
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ribosome mRNA to protein = Translation The reader ribosome The transporter transfer RNA (tRNA) aa tRNA mRNA UCCCCCCAAUGUGAAAAAGGGGUU GGU aa tRNA UAC aa tRNA GA C aa AGU 38
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transcription cytoplasm nucleus translation trait 39 DNA RNA Protein
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DNA transcription ribosome tRNA amino acids protein translation mRNA 40
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