STRUCTURE OF DNA DNA REPLICATION The Structure of DNA 4 The Structure of DNA DNA is wrapped tightly around histones and coiled tightly to form chromosomes DNA DNA is often called the blueprint of life ID: 1033161
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1. DNAYUSRON SUGIARTO, STP, MP, MSc
2. STRUCTURE OF DNADNA REPLICATION
3. The Structure of DNA
4. 4The Structure of DNA
5. DNA is wrapped tightly around histones and coiled tightly to form chromosomes
6. DNADNA is often called the blueprint of life.In simple terms, DNA contains the instructions for making proteins within the cell.
7. DNA by the numbersEach cell has about 2 m of DNA.The average human has 75 trillion cells.The average human has enough DNA to go from the earth to the sun more than 400 times.DNA has a diameter of only 0.000000002 m.The earth is 150 billion mor 93 million miles from the sun.
8. Why do we study DNA?We study DNA for many reasons, e.g., its central importance to all life on Earth,medical benefits such as cures for diseases,better food crops.
9. Chromosomes and DNAOur genes are on our chromosomes.Chromosomes are made up of a chemical called DNA.
10. DNA StructureDNA consists of two molecules that are arranged into a ladder-like structure called a Double Helix.A molecule of DNA is made up of millions of tiny subunits called Nucleotides.Each nucleotide consists of:Phosphate groupPentose sugarNitrogenous base
11. One Strand of DNAThe backbone of the molecule is alternating phosphate and deoxyribose, a sugar, parts.The teeth are nitrogenous bases.phosphatedeoxyribosebases
12. NucleotidesPhosphatePentoseSugarNitrogenousBase
13. NucleotidesThe phosphate and sugar form the backbone of the DNA molecule, whereas the bases form the “rungs”.There are four types of nitrogenous bases.
14. NucleotidesAAdenineTThymine GGuanineCCytosine
15. NucleotidesEach base will only bond with one other specific base.Adenine (A)Thymine (T)Cytosine (C)Guanine (G)Form a base pair.Form a base pair.
16. Four nitrogenous bases Cytosine C Thymine T Adenine A Guanine GDNA has four different bases:
17. Two Kinds of Bases in DNAPyrimidines are single ring bases.Purines are double ring bases.CCCC N NO NCCCC N N NNNC
18. Thymine and Cytosine are pyrimidinesThymine and cytosine each have one ring of carbon and nitrogen atoms.CCCC N NO NcytosineCCCC N NOOthymineC
19. Adenine and Guanine are purinesAdenine and guanine each have two rings of carbon and nitrogen atoms.CCCC N N NAdenineNNCCCCC N NO NGuanineNNC
20. Two Stranded DNARemember, DNA has two strands that fit together something like a zipper.The teeth are the nitrogenous bases but why do they stick together?
21. CCCC N NO NCCCC N NO NNNCHydrogen BondsThe bases attract each other because of hydrogen bonds.Hydrogen bonds are weak but there are millions and millions of them in a single molecule of DNA.(The bonds between cytosine and guanine are shown here.)
22. Hydrogen Bonds, cont.When making hydrogen bonds, cytosine always pairs up with guanine, And adenine always pairs up with thymine.(Adenine and thymine are shown here.)CCCC N N NNNCCCCC N NOOC
23. Important: Adenine and Thymine always join togetherA T Cytosine and Guanine always join togetherC G
24. DNA StructureBecause of this complementary base pairing, the order of the bases in one strand determines the order of the bases in the other strand.
25. G GATTAACTGCATC
26. DNA StructureTo crack the genetic code found in DNA we need to look at the sequence of bases.The bases are arranged in triplets called codons.A G G - C T C - A A G - T C C - T A GT C C - G A G - T T C - A G G - A T C
27. DNA StructureA gene is a section of DNA that codes for a protein.Each unique gene has a unique sequence of bases.This unique sequence of bases will code for the production of a unique protein.It is these proteins and combination of proteins that give us a unique phenotype.
28. STRUCTURE OF DNADNA REPLICATION
29. DNA
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31. DNA ReplicationDNA must be copiedThe DNA molecule produces 2 IDENTICAL new complementary strands following the rules of base pairing: A-T, G-CEach strand of the original DNA serves as a template for the new strand
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33. DNA ReplicationComplementary base pairs form new strands.
34. DNA Replication
35. DNA ReplicationSemiconservative Model: Watson and Crick showed: the two strands of the separate, and each functions as a for synthesis of a new complementary strand.Parental DNADNA TemplateNew DNA
36. DNA Replication Models
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38. Leading strandlagging strandReplication forkReplication fork
39. DNA
40. 1. Why is replication necessary? 2. When does replication occur?3. Describe how replication works.Use the complementary rule to create the complementary strand: A---?G---?C---?T---?A---?G---?A---?G---?C---?A---?G---?T---?Replication Quiz
41. 1. Why is replication necessary? So both new cells will have the correct DNA2. When does replication occur?During interphase (S phase).3. Describe how replication works.Enzymes unzip DNA and complementary nucleotides join each original strand.4. Use the complementary rule to create the complementary strand: A---TG---CC---GT---AA---TG---CA---TG---CC---GA---TG---CT---AReplication Quiz
42. Satu tim besar yang terdiri dari enzim dan protein lain menjadi pelaksana replikasi DNAProtein-protein yang berperan dalam replikasi DNAProtein pengikat untai tunggal: menjaga agar untai-untai tetap terpisah selama bertindak sebagai cetakan dalam sintesis untai-untai komplementer yang baru.Helikase: enzim yang berfungsi membuka heliks ganda di cabang replikasi, memisahkan untai lama.Primase: membentuk primer
43. Satu tim besar yang terdiri dari enzim dan protein lain menjadi pelaksana replikasi DNAProtein-protein yang berperan dalam replikasi DNADNA polimerase: pemanjangan untai DNA baruLigase: menggabungkan rantai DNA
44. Enzymology of DNA replicationDNA strand separationHelicases: unwind double strand DNASingle-strand DNA binding proteins (SSBs): participate in DNA strand separation but do not catalyze the strand separation process.They bind to single strand DNA as soon as it forms and coat it so that it cannot anneal to reform a double helix.Topoisomerases: introduce transient single or double stranded breaks into DNA and thereby allow it to change its form, or topology.
45. DNA polymerasesThree DNA polymerases (I, II, III)DNA polymerase I (102 KD): has three different enzymatic activitiesDNA polymerase3’-5’ exonuclease activity5’-3’ exonulcease activity(proof reading to increase fidelity)3’-5’ exo(remove RNA primers or damage DNA on its path)
46. Pol III holoenzyme10 subunitsMove at an extremely rapid rate (1000 nts/second)Proof reading
47. Eukaryotes have multiple DNA polymerases
48. THANK YOUYUSRON SUGIARTO, STP, MP, MSc