Unit 5 –Bacteria: Unicellular OrganismsC H A P T E R 1 5

R E A D P. 2 9 3 - 3 0 5

Bacterial Cell Structure: Prokaryotic

Single cellular – no membrane bound organelles – primitive

Parts of Bacteria1. Cell membrane2. Cytoplasm3. Ribosomes4. DNA in a nucleoid region5. Cell wall made of peptidoglycan for protection and support6. Flagella – movement7. Pili – used for reproduction (cilia)

https://www.youtube.com/watch?v=qCn92mbWxd4

https://www.youtube.com/watch?v=Lg-1Vv4-58M

Bacteria facts

Bacteria Cell Shape

3 major shapes –

1. cocci – round

2. bacilli – rod shaped

3. spirilli – spiral shape

Bacterial Taxonomy

1.Domain Archea

2.Domain Eubacteria

Domain Archea•Means “ancient”

•Simple prokaryotic cells, app. 1-10 micrometers in size

•Contains all basic components of any cell BUT lack peptidoglycan in their cell walls.

• Live in most extreme environments – preferring environments that typical organism would not be able to withstand.

1. Salt loving termed halophiles

2. Heat loving termed – thermophiles

3. Methane loving – termed methanogens

Domain Eubacteria•Typical bacterial organisms – prokaryotic

•1-10 micrometers in size

•Cell walls do contain peptidoglycan

Metabolic Diversity of BacteriaBacteria are very diverse in their nutritional requirements!

1. Photoautotrophs

2. Photoheterotrophs

3. Chemoautotrophs

4. Chemoheterotrophs

RememberAutotroph and heterotroph – refers to their carbon source.

Autotrophs – use carbon dioxide (CO2) to make their foodHeterotrophs – consume organic molecules - glucose

1. Photoautotroph

•Capable of photosynthesizing – these use light energy and CO2 to produce organic molecules (glucose) and ATP (adenosine triphpshpate –energy)

•Bacteria as well as plants and some protists use photosynthesis to make their own food

2. Photoheterotrophs

•Use light energy BUT require organic carbon molecules, such a proteins or carbohydrates (much larger that carbon dioxide).

•This nutrient type is found ONLY in Bactreria

3. Chemoautotrophs•Use CO2 for their carbon source BUT instead of light: they use various chemicals found in the environment for their energy source.

•This nutrient type is only found in Bacteria.

4. Chemoheterotrophs•Use organic molecules for both carbon and energy requirements

•This nutrient type is found in several different organisms including bateria, some protists, fungi and animals.

Bacteria Reproduction

Bacteria: Nitrogen Fixers

Nitrogen Cycle

Bacterial Oxygen Requirements

Reproduction in Bacteria•Bacteria reproduce through 2 reproductive methods: Sexual and Asexual. Bacteria Spend majority of time reproducing asexually (without sex).

•Very effective as there is no mate required.

•Population can increase very rapidly with very little time (quick life cycle.

•Unfortunately, with asexual reproduction – offspring are genetically identical to the parent cell. Without variation, a change in the environment could wipe out the entire bacterial population. So if you would like to keep the bacterial population, some reproductive methods to induce variation are necessary periodically.

1. Asexual Reproduction – Binary Fission

https://www.youtube.com/watch?v=WvKphSn6uTg

To begin the process, the parent cell will replicate its DNA so that it has two identical copies of genetic material. This DNA which is not bound within any organelle will simply attach to the cell membrane of the cell. Growth or increase in size of the cell will occur resulting in the two copies of DNA being farther apart from each other. Between these two DNA molecules, the cytoplasm and the cell membrane will split resulting in two identical cells.

2. Reproduction for Variation

A.

B.https://www.youtube.com/watch?v=hm8SZaFmlWg

https://www.youtube.com/watch?v=EJKgAPYAwiQ

C.

D.

https://www.youtube.com/watch?v=hZMRDx1g9OA

https://www.youtube.com/watch?v=txSq-7BchUQ

Transduction

What is the difference between a bacterial infection and a viral infection?