Bacteria

PROKARYOTES /BACTERIA

- Prokaryotes are cellular organism (unicellular)
- 2 domains: Archaea and Bacteria
- Most prokaryotic cells are very small (diameter 0,5 to 1.0um)
- Do not havemembrane-enclosed organelles (eukaryotic cells)

Not:

• nuclei
• mitochondria
• chloroplasts (plants)
• ER
• Golgi complex
• Lysosomes

- They have

• nuclear are, nucleoid, which containscircular DNA (not envelope)
• ribosomes on the dense cytoplasm and
• cell wall (surrounding the plasma membrane)

The bacterial cell wall includes peptidoglycan (complex polymer that consists ofsugars and polypeptides)

Differences in bacterial cell wall:

1. Gram-positive: bacteria that absorb and retain violet stain /very thick and consists of peptidoglycan.
2. Gram-negative: bacteriado not retain the stain when rinsed with alcohol/ has two layers: a peptidoglycan and one ticker.

It is important distinguishing between both when treating certain diseases (penicilina Works muchbetter agains gram positive)

• Some bacteria have hundreds of Pili: hairlike appendages that help bacteria to adhere to surfaces and are important in transmitting ADN between bacteria.
•Flagella: do not contain microtubules (unlike eukaryotes)

Produce a Rotary motion

Consists of 3 parts:

- basal body
- hook
- single filamento

The bacteria uses ATP to pump protons out of thecell. Diffusion of these protons back into the cell Powers the motor that spins the flagellum.
- Prokaryotes, Basic shapes:

• Spherical (Coccus ir cocci)
• rod shaped (Bacillus or bacilli)
•spirals



Bacteria and nutrition

There are 2 ways of obtaining nutrition:

- heterotrophs

Obtain carbon atoms from the organic compounds of other organisms

- autotrophs

are able touse carbon dioxide as a source of carbon

Based on the way to obtain energy:

- Chemotrophs (from Chemicals compounds)
- Phototrophs (from the Light)

The majority of the prokaryotes are...