What are Bacteria?

1
What are Bacteria?

• Chapter 7, Section 1

2
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.

3
Who discovered bacteria?

• Antonie van Leeuwenhoek (in the later half of the
  17th century).

4
Where do Bacteria Live?

• Everywhere!
• Including, the soil, the air, your body, deep
  sea, hot springs, food

5
What does a Bacterial Cell look like?

• 3 basic shapes
• Cocci sphere-shaped bacteria
• Bacilli rod-shaped bacteria
• Spirilla spiral-shaped bacteria

6
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

7
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)

8
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.

9
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.

10
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.