MICROBES! Bacteria, MICROBES! Bacteria, Viruses, Protists, and Viruses, Protists, and

FungiFungi

Chapters 21-23March 2011

Chapter 20 Chapter 20 VocabularyVocabulary

1. Virus 2. Pathogen 3. Glycoproteins 4. Lytic cycle 5. Provirus 6. Lysogenic 7. Prions 8. Viroids 9. Pili 10.Bacillus/Coccus/Spirillum11. Capsule 12. Antibiotics 13.Endospores 14. Conjugation 15. Aerobic/Anaerobic

1. Virus

•so small they can be seen only with the aid of a powerful electron microscope.

•simplest viruses contain only a few genes, whereas the most complex may have more than a hundred genes•Most viruses infect only a very specific kind of cell.

viruses that infect bacteria are called bacteriophages.Latin for poison!

2. Pathogen

Disease causing agents! Bacteria viruses fungi and protists!

3. Glycoproteins

Receptor molecules on the outside of the virus.Proteins and carbohydrates attached.Used for recognition on the cell membrane or cell wall.

4. Lytic cycle

In a lytic infection, a virus enters a bacterial cell, makes copies of itself, and causes the cell to burst, or lyse.

Bacteriophage T4 is an example of a bacteriophage that causes such an infection.

The host cell lyses, releasing hundreds of virus particles that go on to infect other cells.

5. Provirus

The virus that has become part of the DNA of the host cell. also called a prophage.

6. Lysogenic

In a lysogenic infection a host cell is not immediately taken over. The viral DNA is then copied along with the host DNA without

damaging the host. Viral DNA multiplies as the host cells multiply. In this way, each generation of daughter cells derived from the

original host cell is infected. Bacteriophage DNA that becomes embedded in the bacterial host’s

DNA is called a prophage. Influences from the environment—radiation, heat, etc—trigger the

prophage to become active.

7. Prions

Miss folded proteinsCause diseaseNo nucleic acid involved!Mad Cow disease is an example

prions, short for “protein infectious particles.” Prions are misfolded proteins in the brain that cause a chain reaction of

misfolding in other normal proteins they contact, eventually clogging the brain tissue and causing disease

Many animals, including humans, can become infected with prions

8. ViroidsSmall RNA segments Cause disease in plantsPossibly can infect

animals

9. Pili Attachment structuresAlso used for reproduction

10.Bacillus

rods

10. Coccus

Round

10. Spirillum

spiral bacteria often cause bad diseases!

11. Capsule

Some bacteria have a slimy layer of polysaccharides and polypeptides, allowing them to attach to objects and providing protection.

12. Antibiotics Antibiotics

interfere with bacterial cell functions!

13.Endospores

Outer protective covering.Makes the bacteria more pathogenic! Bacterial endospores are

highly resistant to hostile physical and chemical conditions.

14. Conjugation

Transfer of genetic material from one bacteria to another.

New genetic recombination's occur

15. Aerobic/Anaerobic

Aerobic: Require oxygen

Anaerobic: Require No Oxygen!