Transcript (b) Photosynthetic prokaryote

Chapter 27: Prokaryotes
1. Where can you find prokaryotes?
- EVERYWHERE!!
- Domain Bacteria & Archae
2. What do you know about bacterial structure, function & reproduction?
- 3 shapes: round (cocci), rod (bacilli) & helical (spirilla & spirochetes)
Figure 27.2 The most common shapes of prokaryotes
1 m
(a) Spherical (cocci)
2 m
(b) Rod-shaped
(bacilli)
(c) Spiral
5 m
Chapter 27: Prokaryotes
1. Where can you find prokaryotes?
- EVERYWHERE!!
- Domain Bacteria & Archae
2. What do you know about bacterial structure, function & reproduction?
- 3 shapes: round (cocci), rod (bacilli) & helical (spirilla & spirochetes)
- 1 – 5 µm dia. (eukaryotic cells 10 – 100 µm dia.)
- Cell wall outside plasma membrane w/ peptidoglycan (not archae)
- Gram (+) – lots of peptidoglycan
- Gram (-) – less peptidoglycan (more resistant to antibiotics)
Figure 27.3 Gram staining
Lipopolysaccharide
Cell wall
Peptidoglycan
layer
Cell wall
Outer
membrane
Peptidoglycan
layer
Plasma membrane
Plasma membrane
Protein
Protein
Grampositive
bacteria
Gramnegative
bacteria
20 m
(a) Gram-positive. Gram-positive bacteria have
a cell wall with a large amount of peptidoglycan
that traps the violet dye in the cytoplasm. The
alcohol rinse does not remove the violet dye,
which masks the added red dye.
(b) Gram-negative. Gram-negative bacteria have less
peptidoglycan, and it is located in a layer between the
plasma membrane and an outer membrane. The
violet dye is easily rinsed from the cytoplasm, and the
cell appears pink or red after the red dye is added.
Chapter 27: Prokaryotes
1. Where can you find prokaryotes?
- EVERYWHERE!!
- Domain Bacteria & Archae
2. What do you know about bacterial structure, function & reproduction?
- 3 shapes: round (cocci), rod (bacilli) & helical (spirilla & spirochetes)
- 1 – 5 µm dia. (eukaryotic cells 10 – 100 µm dia.)
- Cell wall outside plasma membrane w/ peptidoglycan (not archae)
- Gram (+) – lots of peptidoglycan
- Gram (-) – less peptidoglycan (more resistant to antibiotics)
- Many have a capsule outside cell wall for adherence
- Pili & fimbriae used for adherence
Figure 27.4 Capsule
Figure 27.5 Fimbriae
200 nm
Fimbriae
Capsule
200 nm
Chapter 27: Prokaryotes
1. Where can you find prokaryotes?
2. What do you know about bacterial structure, function & reproduction?
- 3 shapes: round (cocci), rod (bacilli) & helical (spirilla & spirochetes)
- 1 – 5 µm dia. (eukaryotic cells 10 – 100 µm dia.)
- Cell wall outside plasma membrane w/ peptidoglycan (not archae)
- Gram (+) – lots of peptidoglycan
- Gram (-) – less peptidoglycan (more resistant to antibiotics)
- Many have a capsule outside cell wall for adherence
- Pili & fimbriae used for adherence
- Motility (allows for taxis….+/-, photo & chemo)
- Flagella 25 nm wide
- Helical filaments in spirochetes
- Some secrete slimy chemicals for gliding
- Small genome, circular chromosome & plasmids
- Some have specialized infoldings of plasma membrane
Figure 27.7 Specialized membranes of prokaryotes
0.2 m
1 m
Respiratory
membrane
Thylakoid
membranes
(a) Aerobic prokaryote
(b) Photosynthetic prokaryote
Chapter 27: Prokaryotes
1. Where can you find prokaryotes?
2. What do you know about bacterial structure, function & reproduction?
- Cell wall outside plasma membrane w/ peptidoglycan (not archae)
- Gram (+) – lots of peptidoglycan
- Gram (-) – less peptidoglycan (more resistant to antibiotics)
- Many have a capsule outside cell wall for adherence
- Pili & fimbriae used for adherence
- Motility (allows for taxis….+/-, photo & chemo)
- Flagella 25 nm wide
- Helical filaments in spirochetes
- Some secrete slimy chemicals for gliding
- Small genome, circular chromosome & plasmids
- Some have specialized infoldings of plasma membrane
- Asexual reproduction – binary fission
- Genetic recombination by
- Transformation
- Conjugation
- Transduction
- Some become endospores (Anthrax)
Figure 27.9 An endospore
Endospore
0.3 m
Chapter 27: Prokaryotes
1. Where can you find prokaryotes?
2. What do you know about bacterial structure, function & reproduction?
3. How can prokaryotes obtain energy & carbon?
Table 27.1 Major Nutritional Modes
Chapter 27: Prokaryotes
1.
2.
3.
4.
Where can you find prokaryotes?
What do you know about bacterial structure, function & reproduction?
How can prokaryotes obtain energy & carbon?
What are the metabolic relationships to oxygen?
- Obligate aerobes – require O2
- Facultative anaerobes – prefer O2 but can do fermentation
- Obligate anaerobes – poisoned by O2 – can do fermentation & some can
use anaerobic respiration
5. What is the origin of photosynthesis?
- Cyanobacteria (formerly known as blue-green algae)
- H2S metabolizing bacteria mutated to use…….
- H 2O
- Released O2 reacted with dissolved iron
- Formed iron oxide precipitate
Figure 26.12 Banded iron formations: evidence of oxygenic
photosynthesis
Chapter 27: Prokaryotes
1.
2.
3.
4.
5.
Where can you find prokaryotes?
What do you know about bacterial structure, function & reproduction?
How can prokaryotes obtain energy & carbon?
What are the metabolic relationships to oxygen?
What is the origin of photosynthesis?
- Cyanobacteria (formerly knowns as blue-green algae)
- H2S metabolizing bacteria mutated to use…….
- H 2O
- Released O2 reacted with dissolved iron
- Formed iron oxide precipitate
6. Figure 27.12 shows the phylogeny of prokaryotes
Figure 27.12 A simplified phylogeny of prokaryotes
Domain
Archaea
Domain Bacteria
Proteobacteria
Universal ancestor
Domain
Eukarya
Chapter 27: Prokaryotes
1.
2.
3.
4.
5.
Where can you find prokaryotes?
What do you know about bacterial structure, function & reproduction?
How can prokaryotes obtain energy & carbon?
What are the metabolic relationships to oxygen?
What is the origin of photosynthesis?
- Cyanobacteria aka blue-green algae
- H2S metabolizing bacteria mutated to use…….
- H2O
- Released O2 reacted with dissolved iron
- Formed iron oxide precipitate
6. Figure 27.12 shows the phylogeny of prokaryotes
7. What are the differences between each of the domains?
Table 27.2 A Comparison of the Three Domains of Life
Chapter 27: Prokaryotes
1.
2.
3.
4.
5.
6.
7.
8.
Where can you find prokaryotes?
What do you know about bacterial structure, function & reproduction?
How can prokaryotes obtain energy & carbon?
What are the metabolic relationships to oxygen?
What is the origin of photosynthesis?
Figure 27.12 shows the phylogeny of prokaryotes
What are the differences between each of the domains?
What are some ecological impacts of bacteria?
- Chemical cycling
- Symbiotic relationships
- Mutualism – both organisms benefit (+/+)
- Commensalism – only 1 benefits (+/___)
- Parasitic – 1 benefits & the other harmed (+/-)
9. How can you determine if a pathogen causes a disease?
- Koch’s postulates
1. Find the same pathogen in all diseased individuals
2. Isolate the pathogen & grow it in pure culture
3. Induce the disease in naïve animals
4. Re-isolate the pathogen
Chapter 27: Prokaryotes
1.
2.
3.
4.
5.
6.
7.
8.
9.
Where can you find prokaryotes?
What do you know about bacterial structure, function & reproduction?
How can prokaryotes obtain energy & carbon?
What are the metabolic relationships to oxygen?
What is the origin of photosynthesis?
Figure 27.12 shows the phylogeny of prokaryotes
What are the differences between each of the domains?
What are some ecological impacts of bacteria?
How can you determine if a pathogen causes a disease?
- Koch’s postulates
1. Find the same pathogen in all diseased individuals
2. Isolate the pathogen & grow it in pure culture
3. Induce the disease in naïve animals
4. Re-isolate the pathogen
10. How can bacteria harm us?
- Disease – Lyme disease
- Exotoxin – secreted chemicals – botulism, cholera
- Endotoxin – released upon bacterial death - Salmonella