watson and crick – 1 st to propose structure of dna. requires precise transmission during...
TRANSCRIPT
![Page 1: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/1.jpg)
![Page 2: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/2.jpg)
• Watson and Crick – 1st to propose structure of DNA.
• Requires precise transmission during replication.
![Page 3: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/3.jpg)
http://www.ncbe.reading.ac.uk/DNA50/Resources/wc1993.gif
![Page 4: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/4.jpg)
• Prior to Watson, Griffith tested transmission.
• Griffith - injected live bacterial strains into mice.
• Mixed R strain of bacteria (harmless) with heat-killed S strain (harmful) and injected it.
• After mouse died, removed strain from mouse.
![Page 5: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/5.jpg)
![Page 6: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/6.jpg)
• Substance eventually found to be DNA - supported by injecting bacteria into viruses.
• Viruses consist of DNA (sometimes RNA) enclosed by protective coat of protein.
• To replicate - virus infects host cell; takes over cell’s metabolic machinery.
• Viruses that specifically attack bacteria - bacteriophages (phages)
![Page 7: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/7.jpg)
http://www.monografias.com/trabajos5/virus/Image164.gif
![Page 8: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/8.jpg)
• Transformation - change in genotype and phenotype due to assimilation of foreign substance (now DNA) by cell.
![Page 9: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/9.jpg)
http://www.swbic.org/products/clipart/images/bacteriophage.jpg
![Page 10: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/10.jpg)
• Hershey and Chase labeled protein and DNA - injected them into bacteria.
• Hershey and Chase concluded that DNA, not protein, is responsible for transmission.
• DNA doubles prior to mitosis.
![Page 11: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/11.jpg)
![Page 12: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/12.jpg)
• 1940’s - DNA made of bases (adenine, thymine, cytosine, guanine)
• Also known that sugar of one nucleotide attached to phosphate of another - forms backbone of DNA.
• Chargaff’s rules - even amount of thymine and adenine. (and guanine and cytosine)
![Page 13: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/13.jpg)
![Page 14: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/14.jpg)
• Watson 1st to figure DNA in helix shape + specific distance between nucleotides.
• Partnered with Crick – came up with double stranded model of DNA - double helix.
![Page 15: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/15.jpg)
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 16.5
![Page 16: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/16.jpg)
• Found purine (A, G) has to pair with pyrimidine (T, C) to achieve distance needed.
• Knew A - T (2 H bonds), C - G (3 H bonds
![Page 17: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/17.jpg)
![Page 18: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/18.jpg)
![Page 19: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/19.jpg)
• Each gene found to have unique sequence of nitrogen bases - DNA strands not all the same.
![Page 20: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/20.jpg)
http://academy.d20.co.edu/kadets/lundberg/dna_wallpaper/dna800x600.jpg
![Page 21: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/21.jpg)
• Each strand of DNA can be template to make more DNA.
• Cell copies DNA - each strand forms as template to determine new complementary bases.
• Nucleotides pair in complementary fashion, one by one.
![Page 22: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/22.jpg)
![Page 23: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/23.jpg)
• Semiconservative replication - each DNA molecule has one parent strand and one daughter strand.
![Page 24: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/24.jpg)
![Page 25: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/25.jpg)
• Even though process is amazingly quick, only about 1 in a billion nucleotides copied wrong.
• Proteins and enzymes also part of process, not just nucleotides.
![Page 26: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/26.jpg)
http://www.bio.miami.edu/dana/250/nucleotides.jpg
![Page 27: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/27.jpg)
• Origins of replication - where replication begins.
• Bacteria - 1 site - replication is bubble moving along DNA.
• Eukaryotes - many origins of replication on each chromosome.
• Origin sites - DNA strands separate forming replication “bubble” with replication forks at each end.
![Page 28: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/28.jpg)
![Page 29: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/29.jpg)
• Elongation of DNA catalyzed by 1DNA polymerase.
• Polymerase adds complementary bases to growing strand of new DNA.
• 2Helicase - untwists double helix of DNA at replication fork.
• 3Single-strand binding proteins help keep strands apart from one another during replication.
![Page 30: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/30.jpg)
![Page 31: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/31.jpg)
• Strands of DNA - antiparallel.• Sugar-phosphate backbones
run in opposite directions.• Each end of strand labeled
either 5’ end or 3’ end.
![Page 32: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/32.jpg)
![Page 33: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/33.jpg)
• Nucleotides only be added to 3’ end.
• DNA strand can only elongate from 5’ end to 3’ end.
• Replication fork - problem - system because strands run in opposite directions (antiparallel)
![Page 34: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/34.jpg)
http://www.mie.utoronto.ca/labs/lcdlab/biopic/fig/11.16.jpg
![Page 35: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/35.jpg)
• 1 parent strand (leading strand - one that runs 3’ to 5’) used as template to keep complementary strand continuous.
• Other strand (lagging strand - one that runs 5’ to 3’) copied from fork in small segments - Okazaki fragments.
![Page 36: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/36.jpg)
http://www.biology.arizona.edu/molecular_bio/problem_sets/nucleic_acids/graphics/repfork1.gif
![Page 37: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/37.jpg)
• Fragments “glued” together by 4DNA ligase to form backbone (made of sugar and phosphate) of single DNA strand.
![Page 38: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/38.jpg)
![Page 39: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/39.jpg)
• Polymerase adds nucleotides to strands, cannot start whole process.
• Done by a piece of RNA - primer.
![Page 40: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/40.jpg)
http://www.biologie.uni-hamburg.de/b-online/library/bio201/primase.jpg
![Page 41: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/41.jpg)
• Once primer formed, polymerase adds DNA nucleotides to growing daughter strand of DNA.
• After, 5DNA polymerase (different) replaces original RNA with new complementary DNA nucleotides - no RNA left in strand.
![Page 42: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/42.jpg)
![Page 43: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/43.jpg)
![Page 44: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/44.jpg)
• Replication fork, leading strand copied continuously into fork from single primer.
•Lagging strand copied away from fork in short segments, each requiring new primer.
![Page 45: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/45.jpg)
![Page 46: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/46.jpg)
• Original errors in reading of template occur.
• Enzyme (DNA polymerase) removes mistake and replaces it.
• Some things can alter DNA outside of body.
![Page 47: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/47.jpg)
http://library.thinkquest.org/C0123260/basic%20knowledge/images/basic%20knowledge/DNA/polymerase%201.jpg
![Page 48: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/48.jpg)
• X-rays, UV rays can alter DNA after replication.
• Mistakes can be fixed after DNA synthesis - cell continually monitors DNA.
• 1Mismatch repair - special enzymes fix incorrectly paired nucleotides - happens in certain types of cancers.
![Page 49: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/49.jpg)
http://www.sinauer.com/cooper4e/sample/Figures/Chapter%2006/highres/CELL4e-Fig-06-24-0.jpg
![Page 50: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/50.jpg)
• 2Nucleotide excision repair -nuclease cuts out segment of damaged strand.
• Xeroderma pigmentosa (genetic disease) cannot go through process.
• Disease prevents person from going in sun - UV rays interfere with DNA replication (more susceptible to skin cancer - can’t fix mistakes)
![Page 51: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/51.jpg)
![Page 52: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/52.jpg)
http://162.129.70.33/images/xeroderma_pigmentosa_2_040620.jpg
![Page 53: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/53.jpg)
• Ends of DNA strand can break down from constant replication.
• Ends of chromosomal DNA molecules – telomeres - special nucleotide sequences.
• Telomeres protect genes from being eroded through multiple rounds of DNA replication.
![Page 54: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/54.jpg)
![Page 55: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/55.jpg)
• When telomeres shorten, telomerase uses piece of RNA to lengthen telomere.
• Telomerase has life span to certain tissues or organism.
• Important for telomerase to be in gamete cells so they can pass long telomeres on to zygote.
• Active telomerase in body cells can be responsible for cancer cells because cells keep dividing.
![Page 56: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/56.jpg)
• Proteins - link between genotype (what DNA says) and phenotype (physical expression)
• Beadle and Tatum – 1st to make connection between genes and enzymes that carry out genes (bread mold experiments)
![Page 57: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/57.jpg)
http://fig.cox.miami.edu/~cmallery/150/gene/17x3.jpg
![Page 58: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/58.jpg)
• Bridge between DNA, proteins - RNA.
• RNA similar to DNA - sugar ribose; contains uracil instead of thymine.
• RNA single-stranded.
![Page 59: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/59.jpg)
http://gibk26.bse.kyutech.ac.jp/jouhou/image/nucleic/rna/rna_bb_st.gif
![Page 60: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/60.jpg)
• Nucleotides found in DNA and RNA - code - determines order of amino acids.
• 2 steps - transcription and translation.
• Transcription - DNA serves as template for complementary RNA strand.
![Page 61: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/61.jpg)
http://www.ktf-split.hr/glossary/image/nucleotide.gif
![Page 62: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/62.jpg)
• Transcription produces mRNA strand (messenger RNA).
• Translation uses mRNA sequence to determine order of amino acids - creates polypeptide.
![Page 63: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/63.jpg)
http://www.brooklyn.cuny.edu/bc/ahp/BioInfo/graphics/Transcription.02.GIF
![Page 64: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/64.jpg)
• Bacteria - transcription and translation occur at once.
• Eukaryotes, most transcription occurs in nucleus, translation occurs at ribosome.
• Before primary transcript can leave nucleus - modified during RNA processing before enters cytoplasm.
![Page 65: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/65.jpg)
![Page 66: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/66.jpg)
![Page 67: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/67.jpg)
• Genetic code - triplet code - series 3 nitrogen bases that code for specific amino acid.
• 64 possible combinations of nitrogen bases.
• Only 20 amino acids = each amino acid has more than 1 code.
![Page 68: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/68.jpg)
http://www.dls.ym.edu.tw/lesson/gen.files/codon.jpg
![Page 69: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/69.jpg)
• 61 of 64 codes specific to an amino acid.
• Other 3 - stop codons - determine when process stops.
• Specific code that signals start of translation - also codes for amino acid.
• Start begins correct reading frame of polypeptide.
![Page 70: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/70.jpg)
![Page 71: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/71.jpg)
• Transcription, 1 DNA strand - template strand, provides template for ordering sequence of nucleotides in RNA transcript.
• Translation, blocks of 3 nucleotides, codons, decoded into sequence of amino acids.
![Page 72: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/72.jpg)
![Page 73: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/73.jpg)
• Possible to take genetic code of 1 organism, place it into another - nearly universal.
• Firefly gene for luminescence transplanted into tobacco plant.
• Bacteria can be inserted with specific genes to synthesize genes in large amounts.
![Page 74: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/74.jpg)
![Page 75: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/75.jpg)
Synthesis and Processing of RNA
• mRNA transcribed from template of original gene.
• RNA polymerase separates DNA strands and bonds RNA bases along complementary strand.
• Bases can only be added to 3’ end.
![Page 76: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/76.jpg)
http://www.csu.edu.au/faculty/health/biomed/subjects/molbol/images/7_9.jpg
![Page 77: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/77.jpg)
• Specific sequences determine where transcription starts and where it ends.
• Promoter sequence – initiates; terminator ends.
![Page 78: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/78.jpg)
![Page 79: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/79.jpg)
• Presence of promotor determines which strand of DNA helix is template.
• Proteins (transcription factors) recognize promotor region (TATA box) and bind to promotor.
![Page 80: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/80.jpg)
http://www.nslij-genetics.org/pic/promoter.gif
![Page 81: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/81.jpg)
• After binding, RNA polymerase binds to transcription factors.
• RNA polymerase starts transcription.
![Page 82: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/82.jpg)
![Page 83: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/83.jpg)
• RNA polymerase moves along - nucleotides added to 3’ end.
• Single gene can be transcribed simultaneously by several RNA polymerases at a time.
• Growing strand of RNA trails off from each polymerase.
![Page 84: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/84.jpg)
![Page 85: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/85.jpg)
• RNA splicing - removal of large portion of RNA molecule because most eukaryotic genes and RNA transcripts have long noncoding (introns) stretches of nucleotides between coding regions (exons)
![Page 86: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/86.jpg)
http://ghs.gresham.k12.or.us/science/ps/sci/ibbio/chem/nucleic/chpt15/introndeletion.gif
![Page 87: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/87.jpg)
• RNA splicing removes introns, joins exons to create mRNA molecule with continuous coding sequence.
• Splicing done by spliceosome.
![Page 88: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/88.jpg)
![Page 89: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/89.jpg)
![Page 90: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/90.jpg)
• Translation - cell interprets codons along mRNA molecule.
• Transfer RNA (tRNA) transfers amino acids from cytoplasm’s pool to ribosome.
• Ribosome adds each amino acid carried by tRNA to growing end of polypeptide chain.
![Page 91: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/91.jpg)
![Page 92: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/92.jpg)
• tRNA links mRNA codon with amino acid.
• tRNA arriving at ribosome carries specific amino acid at 1 end, has specific nucleotide triplet, anticodon, at other.
• Anticodon base-pairs with complementary codon on mRNA.
![Page 93: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/93.jpg)
http://bioweb.uwlax.edu/GenWeb/Molecular/Theory/Translation/ribosome.jpg
![Page 94: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/94.jpg)
• tRNA synthesized like other forms of RNA.
• Once in cytoplasm, each tRNA used repeatedly to pick up and drop off that amino acid.
![Page 95: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/95.jpg)
![Page 96: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/96.jpg)
• Anticodons recognize more than one codon.
• Rules for base pairing between 3rd base of codon and anticodon relaxed (wobble).
![Page 97: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/97.jpg)
http://www.geneticengineering.org/chemis/Chemis-NucleicAcid/Graphics/tRNA.jpg
![Page 98: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/98.jpg)
• Each ribosome has 3 binding sites for tRNA molecules.
•P site holds tRNA carrying growing polypeptide chain.
•A site carries tRNA with next amino acid.
• Discharged tRNAs leave ribosome at E site.
![Page 99: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/99.jpg)
![Page 100: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/100.jpg)
http://nobelprize.org/educational_games/medicine/dna/a/translation/pics/translation2.gif
![Page 101: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/101.jpg)
• 1Initiation brings together mRNA, tRNA with 1st amino acid.
• 2Elongation - each amino acid added to previous one.
• 3 steps of elongation continue codon by codon to add amino acids until polypeptide chain completed.
![Page 102: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/102.jpg)
![Page 103: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/103.jpg)
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin CummingsFig. 17.18
![Page 104: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/104.jpg)
• 3Termination - 1 of 3 stop codons reaches A site.
• Release factor binds to stop codon, breaks bond between polypeptide and tRNA in P site - frees polypeptide.
![Page 105: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/105.jpg)
![Page 106: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/106.jpg)
• 2 types of ribosomes active in process.
• 1Free ribosomes suspended in cytosol synthesize proteins in cytosol.
• 2Bound ribosomes attached to endoplasmic reticulum.
![Page 107: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/107.jpg)
Fig. 17.21
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
![Page 108: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/108.jpg)
• Bacteria and eukaryotes have differences in details of processes.
• Eukaryotic RNA polymerases differ from prokaryotic; require transcription factors.
![Page 109: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/109.jpg)
• Differ in how transcription terminated.
• Ribosomes also different. • Prokaryotes can transcribe and
translate same gene simultaneously.
![Page 110: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/110.jpg)
![Page 111: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/111.jpg)
• Mutations - changes in genetic material of cell (or virus).
• Chemical change in 1 base pair of gene causes point mutation.
• Occur in gametes or cells producing gametes - may be transmitted to future generations.
![Page 112: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/112.jpg)
http://staff.jccc.net/PDECELL/evolution/mutations/mutypes.gif
![Page 113: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/113.jpg)
• If it results in replacement of pair of complementary nucleotides with another nucleotide pair - base-pair substitution.
• Can have little or no impact on protein function (silent mutations).
![Page 114: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/114.jpg)
http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/26_DNA_Transcription_files/image008.jpg
![Page 115: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/115.jpg)
• Missense mutations - code for different amino acid.
• Nonsense mutations - code for “stop” - leads to malfunctioning protein.
![Page 116: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/116.jpg)
Fig. 17.24
Copyright © Pearson Education, Inc., publishing as Benjamin Cummings
![Page 117: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/117.jpg)
• Insertions and deletions - additions or losses of nucleotide pairs in gene.
• Unless these mutations occur in multiples of 3 - cause frameshift mutation.
![Page 118: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/118.jpg)
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 17.24
![Page 119: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/119.jpg)
• Mutations can occur in many ways - during DNA replication, DNA repair, or DNA recombination.
• Mutagens - chemical or physical agents that interact with DNA to cause mutations (high-energy radiation - X-rays UV light).
![Page 120: Watson and Crick – 1 st to propose structure of DNA. Requires precise transmission during replication](https://reader038.vdocuments.site/reader038/viewer/2022110209/56649e155503460f94afeaed/html5/thumbnails/120.jpg)