Prokaryotes Review:

• No true nucleus (no nuclear membrane)

• No cellular organelles

• Single celled

• The bacteria

Good or Bad Bacteria Activity:

• Decide if the bacteria on your card is a “good bacteria” or a “bad bacteria”

– What did you use to make your decision?– Are there any bacteria that ended up on both

sides?

Good or bad depends on you perspective! But for humans most “bad bacteria” produced toxins that negatively affect us.

Kingdom Monera:• All are prokaryotes

• Include bacteria and cyanobacteria (blue/green algae)

Classification of bacteria:

• They are classified into 2 groups:• Archaebacteria (old bacteria)• Eubacteria (true bacteria)

Archaeabacteria

• Live in extreme environments

• Inhabited the Earth billions of years ago

• Eukaryotes evolved from these 1.7 billion years ago (have the similar mRNA sequences and polymerases)

There are three main groups of Archaeabacteria

1. extreme halophiles

2. methanogens

3. hyperthermophiles

1. Extreme halophiles

• can live in extremely salty environments; – some species can live in water with salt

concentrations exceeding 15%.

• Most are photosynthetic autotrophs. – The photosynthesizers in this category are

purple because instead of using chlorophyll to photosynthesize, they use a similar pigment called bacteriorhodopsin that uses all light except for purple light, making the cells appear purple.

2. Methanogens

• are strict anaerobes that release methane as a waste product of cellular metabolism.

• Many live in mud at the bottom of lakes and swamps because it lacks oxygen and some (enteric bacteria) live in the intestinal tracts of animals. – A large number of methanogens colonize the

intestinal tracts of ruminary grazing animals, where they aid in the digestion of cellulose.

– The methanogens living in the human digestive tract can cause intestinal gas.

3. Hyperthermophiles

• live in extremely hot or acidic water; some species can survive temperatures over 100 degrees Celsius.

• The famous hot springs in Yellowstone are home to this type of Archaea.

• They also live around deep-sea vents. • Most hyperthermophiles are chemoautotrophs, meaning

that they use chemicals found in the water leaving the vents to directly produce ATP. – These hyperthermophiles often make the pools a greenish color

due to their metabolic waste. – They may also feed on dead organisms that have sunk from

higher levels of the ocean.

"Strain 121" has been able to double its population during 24 hours in an autoclave at 121°C (hence its name).

Eubacteria• Found everywhere!• Microscopic• Prokaryotic

– There are more bacteria in a person's mouth than there are people in the world.

Structure of bacteria:

Structure of bacteria:

• Cell wall: protect and maintain osmotic balance

• Capsule: found outside cell wall, added protection, helps attach the cell

• Nuclear material: contains the genetic information need for reproduction

• Flagella: for movement

Bacteria: Shape• Three main shapes:

1. cocci : spherical

2. bacilli : rods

3. spirillum: spiral/corkscrew

• Shapes are often used in their scientific name

More shapes of bacteria:• Vibrio = curved• Spirochete• Square• Star

Shapes can be combined with the following in names:

• Diplo: two

• Strepto: chain

• Staphylo: cluster of cells

Next time:

• Reproduction in bacteria

• Pathogenic bacteria