Bio 111 - Chapter 18

Describe the structure and function of bacterial chromosomes.

Bacteria contain DNA that is arranged in a single circular chromosome. Bacteria also often have additional DNA in the form of smaller rings called plasmids.

Why are bacteria considered prokaryotic?

Because they are unicellular and do not have a nucleus.

How does genetic diversity occur between bacterial cells?

Binary fission

Explain the 3 types of bacterial genetic transfer

Conjugation, transformation and transduction

What are the similarities/differences in all viruses?

Differences:

Are viruses considered prokaryotic?

No. viruses are considered non-living particles. Not cells or composed of cells.

Are viruses considered living? Explain.

Non-living; they do not exhibit all seven properties associated with living organisms.

Why can bacterial cells reproduce so quickly?

The gestation period is much shorter-within a few minutes a bacteria can reproduce; within a few minutes, both reproduce making 4, then they reproduce making 8 and so on. Within a few hours, millions can be produced.

How do bacterial cells divide?

They divide a-sexually by binary fission. Offspring are genetically identical.

Explain the basic steps in viral reproduction.

Viruses need a host cell to reproduce. 1. Attachment 2. Entry 3. Integration 4. Synthesis 5. Viral assembly

Explain the differences in a *lytic* and a *lysogenic* cycle of viral reproduction.

lysogenic cycle is a viral replication cycle in which the virus's nucleic acid is integrated into the host cell's chromosome, a provirus is formed and replicated each time the host cell reproduces. The host cell is not killed until the cycle is activated. The lysogenic cycle takes a longer time period to destroy the its host cell. lytic cycle is a viral replication cycle in which a virus takes over a host cell's genetic material and uses the host cell's structures and energy to replicate until the host cell bursts, killing it. The lytic cycle kills the cell in very short time.

Why are offspring of bacterial cells usually genetically identical to the parent?

A-sexual organisms;bacteria, reproduce using binary fission. They split in two, so one bacterium becomes two bacteria. This always leads to daughter cells, and the offspring will be identical to the parent.

What is Plasmid?

Small circular pieces of DNA that exist independentaly from the bacterial chromosome.