Download Monerans Characteristics: → prokaryotes (no membrane bound

Monerans
Characteristics:
 prokaryotes (no membrane bound nucleus)
 no organelles (except for ribosomes)
 most are unicellular
 most monerans are bacteria
Reproduction:
• Monerans reproduce sexually or asexually.
Asexual  Binary Fission
The most common form of reproduction, binary fission
involves the chromosome being replicated and the cell
dividing to form 2 identical cells.
Sexual  Conjugation : process of exchanging genetic
material through cell to cell contact
1. bacteria become attached through hairlike
structures called pili
2. as cytoplasm moves through the pili, DNA passes
from one cell to another
**** Conjugation increases diversity in bacteria, which
increases survival.
**** Bacteria can reproduce very quickly, some only take 20
minutes!
Endospores:
Bacteria can adjust to survive bad environmental
conditions. Some can form endospores: heat-resistant, thick
walled, inactive bacterial cell; can be inactive for many years
(even centuries) and then break open to produce new bacterial
cells when conditions are favorable
Classification of Monerans
Using DNA, RNA, and proteins, you can classify them into 2
groups:
1. Archaebacteria: monerans living in very harsh
environments, often where no other organisms can live –
examples: acidic hot springs, undersea volcanic vents, very
salty water
2. Eubacteria: all other bacteria; live in much less harsh
conditions
Using shape to classify:
1. cocci: spheres
2. bacilli: rods
3. spirilla: spirals
Using respiration to classify:
1. aerobes: use oxygen during respiration
2. anaerobes: do not use oxygen for respiration, usually use
fermentation
Monerans in the Biosphere
 most numerous organisms in the biosphere
 monerans play a vital role – recycle important chemicals in
the environment (carbon, nitrogen, etc)
 act as decomposers: organisms that break down dead
organic material (imagine the earth without decomposers!)
Some monerans also have close relationships with other
organisms.
Ex. bacteria in a cow’s stomach
 bacteria benefit by getting nutrients
 cow benefits by the bacteria breaking down the
cellulose from the plants the cow eats
Bacteria and Disease
Many (but not all) bacteria can be harmful. Some diseases are
caused by bacteria – tuberculosis, strep, cholera, tetanus
• Antibiotics and Bacteria: Take all of your medicine, even
after you feel better!
Bacteria and Man: Beneficial Uses
1. break down hazardous wastes
2. decompose waste in sewage plants
3. help in making cheese, yogurt, vinegar
4. used in mining to extract minerals
5. used in genetic engineering to make products like
insulin and proteins to treat diseases