Getting from DNA to proteins

Information flow in cells Protein CB 5.26

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

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)

Genes act as units of heredity…storing and passing on information. CB 14.15

Genes act as units of heredity… storing and passing on information.

Genes are seen as a cause of disease Mutations in the gene GPR143 lead to one form of albinism (

Genes are seen as a cause of disease

Protein Genes code for proteins CB 5.26

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

Genes act as switches, controlling development

Genes are replicators (selfish gene) CB 21.7

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

Bodies are vessels for the transmission of genes

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

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)

Protein Genes code for proteins CB 5.26

Chains of DNA nucleotides store information:

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

? 4 nucleotides in DNA 20 amino acids in proteins

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

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

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

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

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 of nucleotides than amino acids: redundancy

CB 17.5 the Genetic Code

Sickle-cell anemia is caused by a single nucleotide change in the hemoglobin gene CB 5.22

Changes in DNA can change the protein

CB 17.4 Changing the number of nucleotides in a gene is more dramatic than changing a nucleotide

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

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

CB 17.4 Combinations of 3 nucleotides code for each 1 amino acid in a protein. What does RNA do?

Protein RNA moves the information from the nucleus to the cytoplasm, where the protein is made? Both proteins and RNA are involved in the processes CB 5.26

Differences between DNA and RNA

CB 17.4 DNA is long and contains many genes; RNA is short and represents one gene.

Only a small percent of DNA codes for proteins CB 19.14

DNA Composition: In humans: Each cell contains ~6 billion nucleotides of DNA. This DNA is ~2 meters long and 2 nm wide.

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.

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.

There are 2 explanations for why so little of your DNA directly codes for proteins... CB 19.14

CB 5.26 Genes act as switches. The information in genes is what to make and when to make it. Protein

a gene Genes have three basic parts promotercoding regionterminatornon-gene DNA The promoter marks where the gene begins AND when the gene is expressed

CB 5.26 Genes act as switches. When to express a gene is critical for the cell/organism to function correctly. Protein

Development: differentiating cells to become an organism

Cells function differently because they express different genes.

The proper control of gene expression is critical for proper development.

What happens during development?

Developmental mutants of Drosophila melanogaster produced by altering single genes

Increases in cell number play a role…

…so does cell death.

CB Development of a mouse paw: yellow areas show dying cells

Development in animals is one way. Why?