uNIT 7 BIO

What organisms are Eukaryotes?

Plants, Animals, Fungi

What is the structure of chromosomes in Eukaryotes?

Multiple, linear chromosomes in membrane bound nucleus

What organisms are Prokaryotes?

Bacteria and Archaea

What is the shape of Prokaryote chromosome

single circular chromosome

What type of cell are bacteria based on the amount of chromosomes?

Haploid

Being haploid, it is easier to identify what in bacteria than in eukaryotes?

Loss of function mutation

Why is it easier to identify mutation in bacteria?

Recessive mutations not masked

What is binary fission?

Asexual reproduction by copying its genetic material and splitting into two identical daughter cells

How do most bacteria produce?

Asexual

What is horizontal gene transfer?

Segment of genes from one organism to another

What are mechanisms of horizontal gene transfer?

Conjugation, transformation, and transduction

What has contributed to acquired antibiotic resistance?

Horizontal gene transfer

First step of bacterial genetics?

Start w/ a strain of E.coli bacteria that can grow on minimal media containing basic essentials for growth but lacking complex nutrients

What are prototrophs?

Cells that grow on minimal media

Characteristics of prototrophs

Synthesize needed organic molecules needed to survive from simple components, wildtype

Second step of bacterial genetics?

Use X-rays, UV irradiation, or chemicals to cause random mutations in chromosomes

Third step of bacterial genetics?

After mutagenesis, plate the mutated bacteria onto a rich medium that contains all complex nutrients (all amino acids and vitamins are now included in media) and see what colonies grow

Fourth step of bacterial genetics

use replica plating to transfer bacterial colonies back to minimal media

What are auxotrophs? Colonies that grow on rich media but not on minimal media

Characteristics of auxotrophs

Unable to synthesize needed material to grow on minimal medium, mutant

Fifth step of bacterial genetics?

Use replica plating to transfer auxotroph colonies to various mediums to determine what nutrient/vitamin the auxotroph can not synthesize

What is leucine autotroph?

Organism that can’t produce leucine on its own

What is a biotin auxotroph?

Organisms that can’t produce biotin

What is a methionine autotroph?

Organisms that can’t produce methionine on its own

What is bacterial conjugation?

Transfer of DNA from one bacteria to another by direct cell to cell contact

Donor cells contain what?

Plasmid and F factor

What is a plasmid?

A small circular piece of DNA

What is a F factor?

Fertility factor

What does the F factor plasmid carry?

Carries genes that allow for transfer of DNA from F+ cells to F- cells

Fertility plasmid

F factors, allow conjugation

Resistance factors

R factors, give resistance to antibiotics

Degradative plasmids

Allow the bacterium to metabolize an unusual substance

Killer plasmids

Encode toxic proteins that kill other bacteria

Virulence plasmids

Turn the bacterium into a pathogenic strain

Components of the Fertility (F) plasmid include

Transfer genes, replication genes, and oriT (origin of transfer), and insertion sequence

Role of transfer genes

encode proteins for making and operating sex pilus

Role of replication gene

encode proteins that cut and unwind plasmid DNA for replication and transfer

oriT (origin of transfer) role

place where plasmid DNA is cut and transferred into recipient cell

Role of insertion sequence

lets recombination in bacterial chromosome

Hfr stands for

High frequency of recombination

Where if the F factor integrated in Hrf cells

bacterial chromosome

What allows different genes to transfer between Hfr and F- strains

Interrupted conjugation at different times

DNA transfer through conjugation allows

Incorporation of bacterial chromosome by homologous recombination

What is the units for genetic map bacterial conjugation

minutes

What does F’ Factors carry

genes derived from bacterial chromosom

Plasmid

A DNA molecule that can exist independetly of the bacteria chromosome

Competent cell

Bacteria cell that can take up foreign DNA from environment

Nonhomologous recombination

The incorporation of a transformed DNA fragment into the bacterial chromosome at a random site

F’ Factor

F factor that has been excised from gene and carries part of that bacteria chromosome