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learn.genetics.utah/content/cells/scale/

http://learn.genetics.utah.edu/content/cells/scale/. Knowing about the structure of DNA helps scientists understand its function. Functions of DNA: Carry on from one generation to the next determine the characteristics of an organism copy itself every time a cell divided.

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learn.genetics.utah/content/cells/scale/

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  1. http://www.ch.ic.ac.uk/local/projects/burgoine/cell-DNA.jpg

  2. http://learn.genetics.utah.edu/content/cells/scale/

  3. Knowing about the structure of DNA helps scientists understand its function • Functions of DNA: • Carry on from one generation to the next • determine the characteristics of an organism • copy itself every time a cell divided http://consciouslifestyles.files.wordpress.com/2011/10/baby-elephant-protect-wildlife.jpg http://www.edupic.net/Images/Mitosis/telophase.png

  4. Nucleotides and Bases • Nucleotides are the building blocks of DNA • Four different types of nucleotides – each with a nitrogen base • Represent the four bases with the letters A, T, C, and G

  5. Bases match up to each other. • Equal amounts of A and T. Same with C and G. (A=T and C=G) • A Biochemist named Chargaff was the first to record experiments showing this matchup of bases http://science.howstuffworks.com/life/cellular-microscopic/dna1.htm

  6. Double Helix • Double Helix: two parallel strands twisted together • The strand is made of phosphate and sugar • Bases are in between the strands (like rungs on a ladder) http://daddystractor.files.wordpress.com/2013/06/dna2.gif

  7. Before technology that could show us DNA up close, scientists had different ideas about what DNA might look like • Rosalind Franklin in the 50’s • Used X-Ray beams to take diffraction images of the structure of the DNA molecule.

  8. Crick • Watson and Crick were the first to publish a model of what DNA looks like • Read about Franklins images • Talked to Chargaff about base pairs Watson • developed a model showing DNA in a parallel structure called a double helix

  9. Their model was hypothesis, but since then hundreds of experiments have supported it. • New technology shows DNA up close and supports their model

  10. http://www.pbs.org/wgbh/nova/education/body/extracting-mummy-dna.htmlhttp://www.pbs.org/wgbh/nova/education/body/extracting-mummy-dna.html

  11. DNA Replication: The Process in which a cell copies its DNA • DNA has to copy itself every time a cell divides • DNA holds information that tells a cell what to do • This is why DNA has to be present in every cell

  12. The structure of DNA makes replication easy • The DNA molecule unwinds into two separate strands and then new strands are made. • An enzyme called Helicase makes the DNA molecule “unzip” a little bit • Enzymes: special proteins that kick start biochemical reactions in the body

  13. http://upload.wikimedia.org/wikipedia/commons/8/84/DNA_bubbles2.pnghttp://upload.wikimedia.org/wikipedia/commons/8/84/DNA_bubbles2.png

  14. The “unzipped” part of the DNA helix is where replication occurs • An enzyme called DNA Polymerase attaches nucleotides to the matching base on the exposed strand • This continues all the way down each strand until the new strands are made • The DNA then ‘zips’ back into the double helix form http://www2.estrellamountain.edu/faculty/farabee/BIOBK/diagrep_2.gif

  15. http://www.youtube.com/watch?v=zdDkiRw1PdU http://www.youtube.com/watch?v=GcrndR-zdyMb ( first 2 minutes)

  16. http://www.pbs.org/wgbh/nova/education/body/forensic-dna-analysis.htmlhttp://www.pbs.org/wgbh/nova/education/body/forensic-dna-analysis.html DNA solves murder mysteries (7 min vid) Covers DNA Replication

  17. Functions of DNA: • Carry on from one generation to the next • copy itself every time a cell divided • determine the characteristics of an organism • DNA Replication, Mitosis/Meiosis

  18. We need DNA because we need proteins • Practically everything a cell does (liver cells, skin cells, bone cells, and so forth) is based on proteins. http://legacy.owensboro.kctcs.edu/gcaplan/anat2/histology/rbc4.jpg

  19. DNA and RNA work together in protein synthesis • DNA has specific codes for the proteins needed in the body of a living thing • RNA does the dirty work for DNA http://biologytb.net23.net/text/chapter11/11images/11-12.gif

  20. RNA • RNA is another nucleic acid and is very similar to DNA in structure and composition • RNA has one strand instead of two • RNA has U instead of T

  21. http://commons.wikimedia.org/wiki/File%3ADifference_DNA_RNA-EN.svghttp://commons.wikimedia.org/wiki/File%3ADifference_DNA_RNA-EN.svg

  22. There are different types of RNA that do different things • Messenger RNA (mRNA) carries genetic information around • Transfer RNA (tRNA) brings amino acids to build proteins with http://barleyworld.org/sites/default/files/figure-09-10.jpg

  23. Transcription: Formation of messenger RNA using a DNA template • The DNA molecule unwinds into two separate strands • Helicase (enzyme) make the DNA molecule “unzip” • RNA nucleotides match up to the nucleotides on one of the DNA strands • Since RNA has U instead of T, it will look slightly different.

  24. Transcription: Formation of messenger RNA using a DNA template http://biologytb.net23.net/text/chapter11/11images/11-14.gif

  25. RNA Translation: The synthesis of proteins using the genetic information encoded in RNA • Information went DNA  RNA during transcription • Now the genetic information has to be “translated” from a nucleotide code into actual proteins • The sequence of nucleotide bases is a code for what proteins need to be made • The code says which amino acids to put together (Amino acids are what proteins are made of)

  26. RNA Translation: The synthesis of proteins using the genetic information encoded in RNA http://3.bp.blogspot.com/-TlKEq-Yd_uI/Ufon00C9PTI/AAAAAAAAA5o/AlD5pX8GRcc/s1600/biobook_cells_21.png

  27. Mutations • Sometimes there is a random error in DNA replication • The wrong base is put in the wrong place, a base is skipped, or bases aren’t matched up right • Whenever a change is made in the sequence of DNA we call it a Mutation • Mutation: A change in the nucleotide sequence of an organism’s DNA, ultimately creating genetic diversity. http://evolution.berkeley.edu/evolibrary/images/evo/dna-mutation.gif

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