Unit 7: Bacteria and Archaea

What are the three domains of life?

Bacteria, Archaea, and Eukarya.

Which two domains consist of prokaryotes?

Bacteria and Archaea.

Are prokaryotes larger or smaller than eukaryotic cells?

Smaller—about 1/10 the size.

Do prokaryotes have a nucleus?

No, they have a nucleoid region.

Where is DNA located in prokaryotes?

In the nucleoid region, not in a nucleus.

What is the shape of the prokaryotic chromosome?

A single circular chromosome.

What is a plasmid?

A small, circular, self-replicating piece of DNA in prokaryotes.

What are plasmids used for in labs?

To carry genes of interest into prokaryotic cells.

How do prokaryotes reproduce?

By binary fission (asexual reproduction).

Why can prokaryotes evolve quickly?

Short generation times and large populations.

What is genetic recombination?

Combining DNA from two different sources.

What is horizontal gene transfer?

Movement of genes between different species.

What are the 3 ways prokaryotes can exchange genes?

Transformation, transduction, and conjugation.

What happens during transformation?

A prokaryote takes in DNA from the environment and integrates it.

What is transduction?

A bacteriophage (virus) transfers DNA between prokaryotes.

How does DNA get into the virus during transduction?

Random bacterial DNA is mistakenly packaged into the virus.

What is conjugation?

DNA is transferred directly between two joined prokaryotes via a "mating bridge."

What can happen after DNA transfer in all 3 methods?

Recombination—new DNA replaces a homologous section in the host.

What is the main source of genetic variation in prokaryotes?

Mutations.

Why do mutations have a big impact in prokaryotes?

Fast reproduction and large populations.