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DNA Replication Animation

This animation illustrates the process of DNA replication, ensuring the continuity of hereditary information. Explore the structure and function of DNA and RNA in this informative animation.

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DNA Replication Animation

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  1. Animation from: https://room114.wikispaces.com/file/view/DNARepAnima4.gif/31922479/DNARepAnima4.gif MODELING DNA REPLICATIONBy Kelly Riedell Link to cutoutsfor activity Essential Knowledge 3.A.1.LO 3.3 The student is able to describe representations and models that illustrate how genetic information is copied for transmission between generations. [See SP 1.2] 3.A.1.b.SP Modified from Building Macromolecules activity by KIM FOGLIA explorebiology.com

  2. Essential knowledge 3 .A.1: DNA, and in some cases RNA, is the primary source of5. DNA replication ensures continuity of hereditary information. a. Genetic information is transmitted from one generation to the next through DNA or RNA 5. DNA replication ensures continuity of hereditary information. ii. Replication requires DNA polymerase plus many other essential cellular enzymes, occurs bidirectionally, and differs in the production of the leading and lagging strands.X The names of the steps and particular enzymes involved beyond DNA polymerase, ligase, RNA polymerase, helicase, and topoisomerase, are outside the scope of the course for the purposes of the AP Exam. b. DNA and RNA molecules have structural similarities and differences that define function [See also 4.A.1] 1. Both have three components-sugar, phosphate and a nitrogenous base- which form nucleotide units that are connected by covalent bonds to form a linear molecule with 3’ and 5’ ends, with the nitrogenous bases perpendicular to the sugar-phosphate backbone. 2. The basic structural differences include: i. DNA contains deoxyribose (RNA contains ribose) ii. RNA contains uracil in lieu of thymine in DNA iii. DNA is usually double stranded, RNA is usually single stranded iv. The two DNA strands in double-stranded DNA are antiparallel in directionality. 3. Both DNA and RNA exhibit specific nucleotide base pairing that is conserved through evolution: adenine pairs with thymine or uracil (A-T or A-U) and cytosine pairs with guanine (C-G). i. Purines (G AND A) have a double ring structure ii. Pyrimidines (C,T, and U) have a single ring structure.

  3. Essential knowledge 4 .A.1: The subcomponents of biological molecules and their sequence determine the properties of that molecule. a. Structure and function of polymers are derived from the way their monomers are assembled. 1. in nucleic acids, biological information is encoded in sequences of nucleotide monomers. Each nucleotide has structural components: a five carbon sugar (deoxyribose or ribose), a phosphate and a nitrogen base (adenine, thymine, guanine, cytosine, or uracil). DNA and RANA differ in function and differ slightly in structure, and these structural differences account for the differing functions [See also 1.D.1, 2.A.3, 3.A.1] b. Directionality influences structure and function of the polymer. 1. Nucleic acids have ends, defined by the 3’ and 5’carbons of the sugar in the nucleotide, that determine the direction in which complementary nucleotides are added during DNA synthesis and the direction in which transcription occurs (from 5’ to 3’). [See also 3.A.1] LO 4.1 The student is able to explain the connection between the sequence and the subcomponents of a biological polymer and its properties [See SP 7.1] LO 4.2 The student is able to refine representation and models to explain how the subcomponents of a biological polymer and their sequence determine the properties of that polymer [See SP 1.3] SP1. The student can use representation and models to communicate scientific phenomena and solve scientific problems. SP 7. The student is able to connect and relate knowledge across various scales, concepts and representations in and across domains.

  4. Arrow from: http://www.harrythecat.com/graphics/b/arrow48d.gif STRUCTURE OF NUCLEIC ACIDS Built from NUCLEOTIDE SUBUNITS NITROGEN BASES CAN BE: ADENINEGUANINECYTOSINETHYMINEURACIL Image by: Riedell Sugar can be DEOXYRIBOSE (DNA)RIBOSE (RNA)

  5. http://student.ccbcmd.edu/courses/bio141/lecguide/unit6/genetics/DNA/DNA/fg4.htmlhttp://student.ccbcmd.edu/courses/bio141/lecguide/unit6/genetics/DNA/DNA/fg4.html http://student.ccbcmd.edu/~gkaiser/biotutorials/dna/fg29.html DNA has no URACIL RNA has no THYMINE PURINES (A & G) have 2 RINGS PYRIMIDINES (T, C, & U) have 1 RING

  6. Directionality of DNA nucleotide • You need to number the carbons! • it matters! PO4 N base 5 CH2 This will beIMPORTANT!! O 1 4 ribose 3 2 OH

  7. The DNA backbone 5 PO4 • Made of phosphates and deoxyribose sugars • Phosphate on 5’ carbon attaches to 3’ carbon of next nucleotide base CH2 5 O 4 1 C 3 2 O P –O O O base CH2 5 O 4 1 2 3 OH 3

  8. Double helix structure of DNA “It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material.” Watson & Crick

  9. Anti-parallel strands • Nucleotides in DNA backbone are bonded from phosphate to sugar between 3 & 5 carbons • DNA molecule has “direction” • complementary strand runs in opposite direction 5 3 3 5

  10. hydrogen bonds covalent phosphodiester bonds Bonding in DNA 5 3 3 5 ….strong or weak bonds? How do the bonds fit the mechanism for copying DNA?

  11. Base pairing in DNA • Purines • adenine (A) • guanine (G) • Pyrimidines • thymine (T) • cytosine (C) • Uracil (U) • Pairing • A : T • 2 bonds • C : G • 3 bonds

  12. CHARGAFF’s RULES Erwin Chargaff analyzed DNA from different organisms and found A = T G = C Now know its because: A always bonds with T G always bonds with C A Purine always bonds to a Pyrimidine

  13. Copying DNA • Replication of DNA • base pairing allows each strand to serve as a template for a new strand • new strand is 1/2 parent template & 1/2 new DNA • semi-conservativecopy process

  14. HOW NUCLEOTIDES ARE ADDED DNA REPLICATION FORK http://bio.usuhs.mil/biochem4.html

  15. Cut down middle

  16. 5’ 3’ Flip sides tomake a double stranded DNA molecule Notice orientationof two strands 3’ 5’

  17. Replication: 1st step Watch REPLICATIONVIDEO • Unwind DNA • helicase enzyme • unwinds part of DNA helix • stabilized by single-stranded binding proteins helicase single-stranded binding proteins replication fork

  18. Unwinds and separatesdouble strand Releases tensionon strand as it unwinds Watch video

  19. Single strand binding proteins keep strands apart

  20. DNA Polymerase RULES Can’t start a chain Can only add onto existing one Can only add to an available 3’ end http://s0.pic4you.ru/allimage/3634/618671.png

  21. Adds RNA nucleotideprimer (8-10 bases)to start chain

  22. Kim Foglia slide Energy of Replication • The nucleotides arrive as nucleoside triphosphates • DNA bases with P–P–P • P-P-P = energy for bonding • DNA bases arrive with their own energy source for bonding • bonded by enzyme: DNA polymerase III ATP GTP TTP CTP

  23. Energy of Replication Where does energy for bonding usually come from? We comewith our ownenergy! energy YourememberATP!Are there other waysto get energyout of it? energy Are thereother energynucleotides?You bet! And weleave behind anucleotide! CTP ATP TTP GTP AMP ADP GMP TMP CMP modified nucleotide

  24. 3’ 5’ LEADING STRAND Grows CONTINUOUSLY in 5’ ↓3’ direction 3’ 5’

  25. Removes PRIMERS and replaces RNA nucleotides with DNA nucleotides

  26. Remember DNA Rules! • Can’t start a chain • Can only add onto existing one • Can only add to an available 3’ end PROBLEM !NO AVAILABLE 3’ END TO ADD ONTO

  27. TELOMERES = repetitive sequences added to ends of DNA strands to protect information in code • TELOMERASE can add to telomere segments in cells that must divide frequently • Shortening of telomeres may play a role in aging • Cells with increased telomerase activity allows them to keep dividing EX: Cells that give rise to sperm & eggs, stem cells, cancer cells ANIMATION http://stemcells.nih.gov/info/scireport/appendixC.asp

  28. X Remember DNA Rules! Can’t start a chain Can only add onto existing one Can only add to a 3’ end

  29. Remember DNA Rules! Can’t start a chain Can only add onto existing one Can only add to a 3’ end Start primer farther upstream

  30. Remember DNA Rules! Can’t start a chain Can only add onto existing one Can only add to a 3’ end

  31. As strand opens up now can add next primer and back fill LAGGING STRAND is built in smallsegments =Okazaki fragments

  32. Once strand is filled in primers must be removed

  33. Removes RNA primers and replaces them with DNA nucleotides Can’t replace thisprimer- NO 3’ end

  34. http://target.scene7.com/is/image/Target/13356914_Alt01?wid=450&hei=450&fmt=pjpeghttp://target.scene7.com/is/image/Target/13356914_Alt01?wid=450&hei=450&fmt=pjpeg LIGASE Joinsfragmentsto complete strand

  35. MISSING MISSING

  36. HOW NUCLEOTIDES ARE ADDED Dolan Learning Center 3D animation http://bio.usuhs.mil/biochem4.html

  37. Kim Foglia slide Okazaki ligase 3 3 3 3 3 3 3 5 5 5 5 5 5 5 Leading & Lagging strands Limits of DNA polymerase III • can only build onto 3 end of an existing DNA strand  Okazaki fragments Lagging strand AVG EUKARYOTIC FRAGMENT ~ 100-200 bases growing replication fork  Leading strand Lagging strand • Okazaki fragments • joined by ligase • “spot welder” enzyme DNA polymerase III Leading strand • continuous synthesis

  38. Kim Foglia slide DNA polymerase III 3 3 3 3 3 3 3 3 3 3 3 growing replication fork growing replication fork 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 Replication fork / Replication bubble leading strand lagging strand leading strand lagging strand leading strand lagging strand

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