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

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)

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 (http://www.albinism.org/publications/what_is_albinism.html)

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 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

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)

Protein

Genes code for proteins

CB 5.26

Chains of DNA nucleotides store information:

CB 16.7In 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

1:1 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

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

1:1 41 = 42:1 42 = 163:1 43 = 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 DNAin 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.

Information flow in cells

Protein

Fig 5.26

Fig 13.5

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

MitosisFig 12.6

DNA replication precedes cell division

Fig 12.6

DNA nucleotides come in pairs Fig 5.27

Complementary base pairs suggest how DNA replication occurs

Fig 16.9

When DNA is replicated, mutations occur.

Fig 13.5

DNA must be replicated before it can be passed on. How it is passed on and how it gets modified impacts evolution.

Mutations: Sickle-cell anemia Fig 17.22

Correlation of malaria and sickle-cell anemia

Fig23.17

How do individuals and groups with different genes arise?

Evolution…

What is it?

How does it occur?