1. PROKARYOTES

2. CLICKERS OUT !
GET READY TO USE THEM

3. STAND UP NOW
WITH CLICKERS IN HAND

4. WHEN I GIVE THE SIGNAL, HOLD YOUR BREATH AS LONG AS YOU CAN.
I will count the time off.
When you can’t hold your breath any longer,
Sit down and punch in the time in seconds that you held your breath.
It will be in increments of 10 seconds

5. Let’s review who the prokaryotes are
Bacteria are responsible for one of the greatest events in the earth’s history
The Oxygen Revolution
There are 2 major concerns to deal with:
How did we go from an anaerobicaerobic environment?
What metabolic changes were involved ?
Let’s review who the prokaryotes are

6. EUBACTERIA & ARCHAEBACTERIA
PROKARYOTES
EUBACTERIA & ARCHAEBACTERIA

7. WHAT ARE PROKARYOTES? Single cells No nuclear membrane Cell Wall
Single circular chromosome
No organelles such as mitochondria,
chloroplasts, ER, or Golgi.
~60 Phyla of Prokaryotes

8. LUCA= Last Universal Common Ancestor
CLASSIFICATION
Prokaryotes
LUCA= Last Universal Common Ancestor

9. Comparing Eubacteria & Archaebacteria
9+2

10. LUCA= Last Universal Common Ancestor
CLASSIFICATION
LUCA= Last Universal Common Ancestor

12. Domain Archaea. Kingdom Archaebacteria Includes Extremophiles
e.g. Methanogens
e.g. Halophiles
e.g. Thermophiles
Yellowstone National Park

13. Domain Bacteria Kingdom: Eubacteria
Simplest organisms
Smallest
Oldest (>3.5 BYA)
Originated in an
anaerobic environment
(i.e. without O2)

14. Prokaryotes Are Everywhere

15. Bacteria Are Everywhere
Human body composition:
10 trillion human cells
100 trillion bacterial cells
(90% of the cells in your body aren’t human)
Bacterial species living in human:
5,000—35,000 species in the intestine
species in the mouth
120 species on the skin

16. Exist as parasites Exist as mutualists Exist as commensals
We’re a walking ecosystem
Exist as parasites
Exist as mutualists
Exist as commensals

17. We’re a walking ecosystem
Total of microbial genes is 100x greater than human genome.
Our systems are linked together as a superorganism. We can’t live without the other. They produce vitamins we require B, H, and K.
They manipulate our immune system.

18. Plaque and tartar in teeth
Biofilm in catheters

22. Reproduction in Prokaryotes Binary fission (Not mitosis)

23. Genetic Variability
in bacteria

24. Plasmids
Plasmids = extra chromosomal DNA capable of independent replication
Numbers: 1- thousands
Important in horizontal or lateral gene transfer
Some carry antibiotic resistance genes

25. Genetic Exchange in bacteria
Conjugation
Pili attachment

26. Variability in Prokaryotes via
Mutation—high rate/unit time because of high speed of reproduction.
Conjugation
Transduction
Transformation
DNA is transferred
between organisms
Horizontal Gene Transfer
Can Genes be
passed between
Kingdoms?

27. Horizontal Gene Transfer
Bacteria sp1 Bacteria sp2
Bacteria Fungi (yeast)
Bacteria Plants
Fish Bacteria
Bacteria Insects
Bacteria Nematode worms
Greatly speeds the rate of evolution

29. The Oxygen Revolution

30. What is the Evolutionary Sequence of the Prokaryotes?
Hints from the energy transfer systems.
2 types of Energy Capture:
1) Heterotrophic= breaking down organic molecules to get energy (ATP)
2) Autotrophic= using non-organic molecules (self-feeders) to get energy.
a) Chemotrophic = chemosynthetic
b) Phototrophic = photosynthetic
Which was first?

31. Could chemosynthesis be the energy source for the first bacteria?
12H2S + 6CO2
C6H12O6 (=carbohydrate) + 6H2O + 12S
Purple sulfur bacteria
Bacteria living in the hydrothermal vents

32. Simple Photosynthesis in Green Bacteria
Light
H2S + CO C6H12O6 + S + ATP
Bacteriochlorophyll
No chloroplasts
1 Photosystem
H2S is source of H+ and e-
Sulfur is released
Anaerobic process –No O2

33. Photosynthesis Blue-Green Bacteria
Chlorophyll a
-No chloroplasts but Ch a is on internal membranes
in cytoplasm. 2 photosystems
- Does best in low 02 (10%)
- Can use H2O instead of H2S
Light
H2S + CO C6H S + ATP
H2O + CO C6H O2 + ATP
Light
This is the beginning of the Oxygen Revolution

34. Complex Photosynthesis in Plants
Light
H20 + CO C6H ATP
--Uses chlorophyll a and b to capture light in the chloroplast
--2 photosystems- ATP
--H2O is source of H+ and e-
--02 is released

35. 1) Chemosynthesis Inorganic chem. reactions (H2S)  S (Anaerobic)
2) 1 Photosystem Photosynthesis
Green Bacteria (Bacterial chlorophyll)
(H2S)  S (Anaerobic)
3) 2 photosystems photosynthesis
Blue green bacteria (Chlorophyll a)
(H2S or H20) S or O2
OXYGEN REVOLUTION BEGINS
4) Plant Photosynthesis
(H2O) O2
2 Photosystems
Chlorophyll a & b

36. Heterotrophic Nutrition
Could heterotrophic nutrition be first—
in organic soup?
Heterotrophic Nutrition
Glucose (6C)
2 ATP
2 Pyruvic Acid (3C)
Alcohol (2C)
Lactic Acid (3C)
Acetic Acid (2C)
Pyruvic Acid (3 C)

37. Heterotrophic Nutrition
Glucose (6C)
2 ATP
2 Pyruvic Acid (3C)
Glycolysis (Splitting of glucose)
Most organisms can do this suggesting it evolved early
Anaerobic
Only a small amount of energy released
Occurs in the cytoplasm
Incomplete breakdown of glucose
Alcohol (2C)
Lactic Acid (3C)
Acetic Acid (2C)
Pyruvic Acid (3 C)

38. NEXT TIME
PROTISTA