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What is a gene, and what does that have to do with evolution?

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Presentation on theme: "What is a gene, and what does that have to do with evolution?"— Presentation transcript:

1 What is a gene, and what does that have to do with evolution?

2 CB 6.9 An Animal Cell Videos: http://www.microscopyu.com/moviegaller y/livecellimaging/a549/index.html http://sunflower.bio.indiana.edu/~rhangart/ plantmotion/starthere.html

3 Information flow in cells Protein CB 5.25

4 Proteins are the “doers” of the cell. They act as: Enzymes Structural Support Transporters Signals Genes code for proteins…

5 Chains of DNA can store information:

6 Information flow in cells Protein CB 5.25

7 CB 5.17 The basic structure of amino acids

8 CB 5.17 the 20 Amino Acids

9 CB 5.20 Amino acids connect together to make proteins.

10 CB 5.20 Proteins are a string of amino acids Proteins are the “doers” of the cell. They act as: Enzymes Structural Support Transporters Signals

11 a gene - DNA used to produce RNA or protein The relationship between DNA and genes promotercoding regionterminatornon-gene DNA

12 Only a small percent of DNA codes for proteins CB 19.14

13 DNA Composition: In humans: Each cell contains ~6 billion nucleotides of DNA. This DNA is ~2 meters long and 2 nm wide. ~98% does not directly code for amino acids In a single human cell only about 3-5% of genes are expressed at a time.

14 Width of DNA Length of human DNA in each cell The length of DNA in each of your cells is longer than you are tall. Power of Ten http://www.youtube.com/watch?v=BBsOeLcUARw http://www.youtube.com/watch?v=BBsOeLcUARw

15 DNA Composition: In humans: Each cell contains ~6 billion base pairs of DNA. This DNA is ~2 meters long and 2 nm wide. ~1.5% directly codes for amino acids ~25% is genes In a single human cell only about 5-10% of genes are expressed at a time.

16 a gene - DNA used to produce RNA or protein The relationship between DNA and genes promotercoding regionterminatornon-gene DNA

17 Five Perspectives about Genes: 1.Genes act as units of heredity 2.Genes are seen as a cause of disease 3.Genes code for proteins 4.Genes act as switches, controlling development 5.Genes are replicators (selfish gene)

18 CB 16.2 Visualizing the perspectives about genes Different strains of bacteria are injected into mice.

19 CB 16.2 Visualizing the perspectives about genes

20 CB 16.2 Visualizing the perspectives about genes

21 CB 16.2 What has happened to the bacteria? Visualizing the perspectives about genes

22 CB 16.2 1.Genes act as units of heredity 2.Genes are seen as a cause of disease 3.Genes code for proteins 4.Genes act as switches, controlling development 5.Genes are replicators (selfish gene) Visualizing the perspectives about genes

23 CB 5.25 Genes are the parts of DNA that contain information. Protein

24 CB 16.7 In cells, DNA is a double-stranded helix

25 Five Definitions of Genes: 1.Genes act as units of heredity 2.Genes are seen as a cause of disease 3.Genes code for proteins 4.Genes act as switches, controlling development 5.Genes are replicators (selfish gene)

26 CB 5.17 ? 4 nucleotides in DNA 20 amino acids in proteins CB 16.5

27 How can 4 nucleotides code for 20 amino acids? IF Ratio (nucleotide:amino acid)Possible combinations 1:14 1 4

28 How can 4 nucleotides code for 20 amino acids? IF Ratio (nucleotide:amino acid)Possible combinations 1:14 1 4 2:14 2 16

29 How can 4 nucleotides code for 20 amino acids? IF Ratio (nucleotide:amino acid)Possible combinations 1:14 1 4 2:14 2 16 3:14 3 64

30 How can 4 nucleotides code for 20 amino acids? IF Ratio (nucleotide:amino acid)Possible combinations 1:14 1 4 2:14 2 16 3:14 3 64 There are more possible combinations than amino acids.

31 CB 17.4 Combinations of 3 nucleotides code for each 1 amino acid in a protein.

32 CB 17.5 the Genetic Code

33 Changes in DNA can change the protein

34

35 The fat cat ate the rat. change one letter The zat cat ate the rat.

36 The fat cat ate the rat. change one letter The zat cat ate the rat. The atc ata tet her at. delete one letter

37 CB 17.4 Combinations of 3 nucleotides code for each 1 amino acid in a protein.

38 Protein How is DNA used to make proteins and RNA? Both proteins and RNA are involved in the processes. CB 5.25

39 Differences between DNA and RNA

40 Protein How is DNA used to make proteins and RNA? Both proteins and RNA are involved in the processes. CB 5.25

41 Genes act as switches. The information in genes is what to make and when to make it. Protein

42 a gene Genes have three basic parts promotercoding regionterminatornon-gene DNA

43 CB 5.25 Genes contain the information to make RNA and/or proteins. Genes act as switches. The information in genes is what to make and when to make it. Protein

44 1. Genes act as units of heredity 5. Genes are replicators (selfish gene) For life to exist, the information (genes) must be passed on. CB 13.5

45 As organisms reproduce the DNA is passed on to the next generations.


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