SBI 3U
Date:__________________
Kingdom/Domain Eubacteria
How Important Are Microscopic Organisms?
Some inhabit our bodies (skin, eyelashes, digest food), are ________________
_____________________ ______________________, while others play key roles in ecosystems by
____________________ __________________________.
It was in the 17th Century that microorganisms were discovered with the invention of the microscope.
Structure of a Bacterial Cell
Bacteria such as E.coli found in your intestine have this basic structure:
Biologists identify and distinguish bacteria based partly on several important characteristics:
1) Cell shape
2) Cell wall structure
3) Motility
4) How they obtain nutrients
1) Cell Shape:
Spherical:
Rod-shape
Spiral
2) Cell wall structure
Bacteria have a ______________ _______________________ and a ___________ _______________.
The cell wall is made of peptidoglycan (a thick coat of sugars)
3) Motility
Flaggella - __________________________ tail to propel themselves toward food
Spiral-shaped bacteria use a corkscrew motion to move
Other bacteria glide on ______________ ___________________________ that they secrete
4) How they obtain nutrients
Nutritional Mode
Heterotroph
Takes up organic molecules from the
environment or by eating other organisms
Photoautotroph
they use sunlight to make carbon dioxide into
carbon compounds like sugar.
Photoheterotroph
Takes up organic molecules from environment
and by eating other organisms like basic
heterotrophs, and also uses light energy.
Chemoheterotroph
Uses energy released through chemical
reactions involving ammonia, hydrogen
sulphide, and similar compounds
Habitat
Example
____________________________________ are similar to plants because they play major roles as
producers. They supply a great deal of the world's oxygen, and are nitrogen fixers in aquatic
ecosystems.
Beneficial Effects of Bacteria - p.343
_________________________ of bacteria ____________ _________________ the damage they do.
Bacteria constitute most of the decomposers of dead plants and animals and are essential for converting
and recycling nature's raw materials into nutrients for living plants and animals.
Reproduction
Asexual - Binary Fission
In this process, a parent cell ________________ into two daughter cells, each receiving an
_____________ _________________ of genetic material (plasmids, chromosome).
Conjugation
Two bacterial cells _____________ to ____________________ ________________
_________________. Plasmids are transported through a "pilus" between the two cells.
p.346 #9, 10