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1 DNA Replication What is it? When is it done? What is copied?

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Presentation on theme: "1 DNA Replication What is it? When is it done? What is copied?"— Presentation transcript:

1 1 DNA Replication What is it? When is it done? What is copied?

2 2 Two New, Identical DNA Strands Result from Replication

3 3 PROTEIN SYNTHESIS

4 4 Protein Synthesis After replication and cell division, each new cell has its own DNA Now, how do those cells use that DNA to make proteins? How do you go from DNA (nucleic acid) to protein (amino acid)?

5 5 Overview of Protein Synthesis Copy (mRNA) is made of gene mRNA sent out of nucleus Ribosomes use mRNA as instructions to make a protein

6 6 Protein Synthesis Two phases: DNA Two phases: DNA Transcription Transcription mRNA mRNA Translation Translationprotein

7 7 Transcription

8 8 Transcription In nucleus In nucleus DNA the template for mRNA DNA the template for mRNA RNA polymerase makes the mRNA RNA polymerase makes the mRNA

9 9 Only one DNA strand is used Just a portion of the DNA is copied (one gene) copy is called mRNA

10 10 RNA Differs from DNA DNARNA Deoxyribose sugar Ribose sugar Double strandedSingle stranded T (thymine)U (uracil)

11 11 Question: What would be the complementary RNA strand for the following DNA sequence? What would be the complementary RNA strand for the following DNA sequence? DNA 5-GCGTATG-3

12 12 Answer: DNA 5-GCGTATG-3DNA 5-GCGTATG-3 RNA 3-CGCAUAC-5RNA 3-CGCAUAC-5

13 13 Translation mRNA protein

14 14 Translation ribosome Ribosome reads the mRNA and makes protein mRNA

15 15 mRNA leaves nucleus ribosome attaches to mRNA ribosome reads the bases in groups of 3 (codon) AUGCUG codon

16 16 The ribosome uses the code to make the protein How? How do you go from nucleic acid to amino acid?

17 17 tRNA Carries amino acids to ribosomeCarries amino acids to ribosome Has anticodons that are complementary to mRNA codonsHas anticodons that are complementary to mRNA codons UAC Amino acid

18 18 AUGCUG UAC A

19 19

20 20

21 21 Genetic Code DNA contains a triplet code DNA contains a triplet code Every three bases on DNA stands for ONE amino acid Every three bases on DNA stands for ONE amino acid Codon: Each group of 3 bases on mRNA Codon: Each group of 3 bases on mRNA

22 22 r online.com/objects/index_tj.asp?objid=A P1302http://www.wisc- online.com/objects/index_tj.asp?objid=A P1302

23 23 Mutations 1.Gene Mutations 2.Chromosome Mutations

24 24 What happens when there is a mistake during replication? What could go wrong when the DNA is being replicated? program.htmlhttp://www.pbs.org/wgbh/nova/genome/ program.html

25 25 Gene Mutations 1.Point Mutations A. Substitution 2.Frame shift Mutations A.Insertion B.Deletion

26 26 Point Mutations – substitution One WRONG BASE is used OriginalThe fat cat ate the wee rat. MutationThe fat hat ate the wee rat

27 27 Examples of Point Mutations Sickle Cell Anemia

28 28 Examples of Point Mutations Tay SachsHemophilia B

29 29 Frame Shift Mutations A Insertion AAT AGG CAG GTT Deletion AAT AGG CAG GTT

30 30 Frame Shift Mutations A Insertion AAT AGG CAG GTT becomes AAT A AG GCA GGT … Deletion AA T AGG CAG GTT becomes AAA GGC AGG …

31 31 Frame Shift OriginalThe fat cat ate the wee rat. InsertionThe fat caa tet hew eer at.

32 32 Example of Frame Shift Mutation: Huntingtons Disease

33 33 Chromosome Mutations 1. Inversions 2. Duplications 3. Deletions 4. Translocations

34 34

35 35 Incorrect Chromosome Number – from nondisjunction during meiosis Trisomy 21 causes Downs Syndrome ders/whataregd/down/


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