Transcript Conjugation: Transfer of DNA From Donor to Recipient Sex Pilus

Microbes
Bacteria and Protists
Three Domain Organizational Scheme
PROKARYA
Six Kingdoms
Bacteria
Archaea
Sizes of
Prokaryotic Cells
Non-living entities
made of genetic
material +
protective coat
Characteristics of
Bacteria and Archaea
• Prokaryotic
• Single Celled
• Many nutritional modes
– Heterotrophic
– Autotrophic: photosynthetic or chemosynthetic
• Reproduce by binary fission
• Gene transfer with conjugation
• Cell wall
Binary Fission
Conjugation: Transfer of DNA
From Donor to Recipient
Donor
Recipient
Sex Pilus
Archaea
• Unique lipid membranes,
cell walls, and ribosomal RNA
• Methanogens
– Convert CO2 to methane
– Found in swamps, hot springs,
vent communities, cow stomachs
• Halophiles - survive in a
concentrated salt environment
• Thermoacidophiles - thrive in a
hot, acidic environment
Prokaryotic Metabolism
1. Photosynthetic Bacteria
cyanobacteria—use H2O,
release O2
sulfur bacteria-- use H2S,
release sulfur
2. Chemosynthetic
Both bacteria and archaea
use chemical energy from
ammonia, nitrate or sulfur
Prokaryotic Metabolism
3. Heterotrophic—gain nutrients
from other organisms

pathogenic = disease -causing

non-pathogenic
 decomposers– live on dead

organic matter
nitrogen-fixing bacteria
convert nitrogen gas into
compounds plants can use
Flesh-eating Bacteria
Adaptations to Severe
Conditions
Endospore formation
protection against
desiccation and
temperature extremes
Anaerobic metabolism
can survive in the
absence of oxygen
Applying Your Knowledge
1. Photosynthetic
2. Chemosynthetic
3. Heterotrophic
Which type of metabolism is used by
A. Flesh-eating bacteria?
B. Bacteria that use light energy to produce
glucose?
C. Bacteria that harness the chemical energy
from sulfur to power their reactions?
Characteristics of Protista
•
•
•
•
Eukaryotic
Usually Single Celled
Live in moist environments
Many nutritional modes
– Heterotrophic
– Autotrophic
– Combination
• Sexual and asexual reproduction
Three Groups of Protists
•Plant-like: Algae
•Fungus-Like: Water Molds,
Slime Molds
•Animal-Like: Protozoa
Protist Reproduction
Asexual
Asexual reproduction
occurs by mitosis.
Sexual
Sexual reproduction
involves the exchange
of genetic material
across a cytoplasmic
bridge.
Algae
Photosynthetic
Using Chloroplasts
1. Single-celled
Algae
Euglenoids have
a single flagellum
Dinoflagellates move
with two whiplike flagella.
Diatoms have silica shells.
A “Bloom” of Dinoflagellates
Causes Red Tide
Algae
Photosynthetic
Using Chloroplasts
2. Multicellular
Algae
Fungus-Like
Protists
Heterotrophic by
Absorption
Water mold
Slime mold
The Life Cycle of a Cellular Slime Mold
Pseudoplasmodium
migrates toward
light, forms fruiting
bodies that produce
spores.
spores
fruiting bodies
nucleus
Single, amoebalike cells emerge
from spores,
crawl, and feed.
When food is
scarce, cells
aggregate into sluglike mass called a
pseudoplasmodium.
Protozoa
•Heterotrophic
by Ingestion
•Distinguished by
Locomotion
Sarcodines move
with pseudopodia
Sporozoans have no
means of locomotion
Protozoa
•Heterotrophic
by Ingestion
•Distinguished by
Locomotion
Ciliates use cilia
for movement.
Zooflagellates use
flagella for movement.
Applying Your Knowledge
1. Heterotrophic by Ingestion
2. Photosynthetic
3. Heterotrophic by Absorption
Which mode of nutrition is used by
A. Cellular Slime Molds?
B. Sarcodines like Amoebas?
C. Multicellular Algae?
D. Zooflagellates like Giardia?