Today: How do genes work? Discussions begin/began this week. Homework #1 posted

Information flow in cells Fig 5.26 Information flow in cells Protein

Proteins are the “doers” of the cell. They act as: Enzymes Fig 5.21 Proteins are the “doers” of the cell. They act as: Enzymes Structural Support Transporters Signals Proteins are a string of amino acids

The relationship between DNA and genes a gene - DNA used to produce RNA or protein promoter coding region terminator non-gene DNA

Only a small percent of DNA codes for proteins Fig 21.7

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.

The length of DNA in each of your cells is longer than you are tall. Fig 6.2 Length of human DNA in each cell The length of DNA in each of your cells is longer than you are tall. Width of DNA Power of ten: http://www.youtube.com/watch?v=A2cmlhfdxuY

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.

The relationship between DNA and genes a gene - DNA used to produce RNA or protein promoter coding region terminator non-gene DNA

20 amino acids in proteins fig 5.17 4 nucleotides in DNA ? fig 16.5

How can 4 nucleotides code for 20 amino acids? IF Ratio (nucleotide:amino acid) Possible combinations 1:1 41 4

How can 4 nucleotides code for 20 amino acids? IF Ratio (nucleotide:amino acid) Possible combinations 1:1 41 4 2:1 42 16

How can 4 nucleotides code for 20 amino acids? IF Ratio (nucleotide:amino acid) Possible combinations 1:1 41 4 2:1 42 16 3:1 43 64

There are more possible combinations than amino acids. How can 4 nucleotides code for 20 amino acids? IF Ratio (nucleotide:amino acid) Possible combinations 1:1 41 4 2:1 42 16 3:1 43 64 There are more possible combinations than amino acids.

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

Differences between DNA and RNA Fig 5.27

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

fig 17.5 the Genetic Code

Changes in DNA can change the protein Fig 17.22

Changes in DNA can change the protein... sickle-cell anemia

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

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

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

The information in genes is what to make and when to make it. fig 5.26 The information in genes is what to make and when to make it. Protein

Genes have three basic parts a gene promoter coding region terminator non-gene DNA

Genes contain the information to make RNA and/or proteins. fig 5.26 Genes contain the information to make RNA and/or proteins. The information in genes is what to make and when to make it. Protein

When to make a protein is critical for proper development.

fig 21.7 Genes are replicators (selfish gene)

Viruses infect living cells, take over, and produce more virus. fig 19.4 Viruses infect living cells, take over, and produce more virus.

Bodies are vessels for the transmission of genes

fig 21.8 Transposons

Transposons: mobile DNA fig 21.9 Genes are replicators (selfish gene) Transposons: mobile DNA

Barbara McClintock, discoverer of transposons fig 21.8 Barbara McClintock, discoverer of transposons

Transposons: mobile DNA fig 21.9 Genes are replicators (selfish gene) Transposons: mobile DNA

Retrotransposons: mobile and self-replicating DNA fig 21.9

fig 21.7 Genes are replicators (selfish gene)

Next: How do your genes make you, you? Discussions begin/began this week. Homework #1 posted