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What is a gene, and what does that have to do with
evolution?
CB 6.9
An Animal Cell
Videos:http://www.microscopyu.com/moviegallery/livecellimaging/a549/index.htmlhttp://sunflower.bio.indiana.edu/~rhangart/plantmotion/starthere.html
Information flow in cells
Protein
CB 5.25
Proteins are the “doers” of the cell.They act as:•Enzymes•Structural Support•Transporters•Signals
Genes code for proteins…
Chains of DNA can store information:
Information flow in cells
Protein
CB 5.25
CB 5.17The basic structure of amino acids
CB 5.17
the20 AminoAcids
CB 5.20Amino acids connect together to make proteins.
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
a gene - DNA used to produce RNA or protein
The relationship between DNA and genes
promoter coding region terminator non-geneDNA
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.
•~98% does not directly code for amino acids
•In a single human cell only about 3-5% of genes are expressed at a time.
Width of DNA
Length of human DNAin each cell
The length of DNA in each of your cells is longer than you are tall.
Power of Tenhttp://www.youtube.com/watch?v=BBsOeLcUARw
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.
a gene - DNA used to produce RNA or protein
The relationship between DNA and genes
promoter coding region terminator non-geneDNA
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)
CB 16.2Visualizing the perspectives about genes
Different strains of bacteria are injected into mice.
CB 16.2 Visualizing the perspectives about genes
CB 16.2 Visualizing the perspectives about genes
CB 16.2
What has happened to the bacteria?
Visualizing the perspectives about genes
CB 16.2
1. Genes act as units of heredity2. Genes are seen as a cause of disease3. Genes code for proteins4. Genes act as switches, controlling
development5. Genes are replicators (selfish gene)
Visualizing the perspectives about genes
CB 5.25
Genes are the parts of DNA that contain information.
Protein
CB 16.7In cells, DNA is a double-stranded helix
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)
CB 5.17
?
4 nucleotides in DNA
20 amino acids in proteins
CB 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 42:1 42 16
How can 4 nucleotides code for 20 amino acids?
IF
Ratio(nucleotide:amino acid) Possible combinations
1:1 41 42:1 42 163:1 43 64
How can 4 nucleotides code for 20 amino acids?
IF
Ratio(nucleotide:amino acid) Possible combinations
1:1 41 42:1 42 163:1 43 64
•There are more possible combinations than amino acids.
CB 17.4
Combinations of 3 nucleotides code for each 1 amino acid in a protein.
CB 17.5
the Genetic Code
Changes in DNA can change the protein
Changes in DNA can change the protein
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.
Protein
How is DNA used to make proteins and RNA?
Both proteins and RNA are involved in the processes.
CB 5.25
Differences between DNA and RNA
Protein
How is DNA used to make proteins and RNA?
Both proteins and RNA are involved in the processes.
CB 5.25
CB 5.25
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
promoter coding region terminator non-geneDNA
CB 5.25Genes 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
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
CB 13.5
As organisms reproduce the DNA is passed on to the next generations.