What are Bacteria?
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Transcript What are Bacteria?
What are Bacteria?
Chapter 7, Section 1
What is a Bacterium?
One-celled organism.
Prokaryotic.
(Do not have membrane bound nuclei or
organelles.)
Can live alone or in groups or chains.
Smaller than plant and animal cells.
Who discovered bacteria?
Antonie van Leeuwenhoek (in the later
half of the 17th century).
Where do Bacteria Live?
Everywhere!
Including, the soil, the air, your body,
deep sea, hot springs, food…
What does a Bacterial Cell
look like?
3 basic shapes:
Cocci – sphere-shaped bacteria
Bacilli – rod-shaped bacteria
Spirilla – spiral-shaped bacteria
What does a Bacterial Cell
look like?
Typical Cell
Cytoplasm surrounded by both a cell
membrane and a cell wall.
One circular chromosome (genetic
material).
Ribosomes
What does a Bacterial Cell
look like?
Some Cells:
Plasmid (smaller circular piece of DNA)
Thick, gelatin-like capsule
Hair-like projections on cell surface
Slime layer (on outside)
Flagella (whip-like tail)
How do Bacteria Reproduce?
Asexually
Fission
Produces two new cells with genetic material
identical to the original cell.
Sexually
Conjugation
Two bacterial line up next to each other and
then exchange DNA through a fine tube.
Result is new combinations of genetic
material.
How do Bacteria Obtain Food
and Energy?
Producers
Use the sun to make food.
Break down chemicals to make food.
Consumers (majority of bacteria)
Break down dead organisms.
Parasitic.
How do Bacteria Obtain Food
and Energy?
Aerobic Bacteria (most bacteria)
Use oxygen during respiration to break
down food.
Anaerobic Bacteria
Do not need oxygen in order to survive.