PROKARYOTES CLICKERS OUT ! - PowerPoint Presentation

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PROKARYOTES

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CLICKERS OUT !

GET READY TO USE THEM

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STAND UP NOW

WITH CLICKERS IN HAND

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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

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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 ?

L

et’s

review who the prokaryotes are

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PROKARYOTESEUBACTERIA & ARCHAEBACTERIA

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WHAT ARE PROKARYOTES? Single cellsNo nuclear membrane

Cell Wall

Single circular chromosome

No organelles such as mitochondria,

chloroplasts, ER, or Golgi.

~60 Phyla of Prokaryotes

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CLASSIFICATION

Prokaryotes

LUCA

= Last Universal Common Ancestor

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Comparing Eubacteria & Archaebacteria

9+2

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CLASSIFICATION

LUCA= Last Universal Common Ancestor

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Domain Archaea. Kingdom ArchaebacteriaIncludes Extremophiles

Yellowstone National Park

e.g. Methanogens

e.g. Halophiles

e.g. Thermophiles

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Domain BacteriaKingdom: Eubacteria

Simplest organisms

Smallest

Oldest (>3.5 BYA)

Originated in an

anaerobic environment

(i.e. without O

2)

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Prokaryotes Are Everywhere

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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

300--500 species in the mouth

120 species on the skin

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We’re a walking ecosystem

Exist as parasites

Exist as mutualists

Exist as

commensals

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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.

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Plaque and tartar in teeth

Biofilm in catheters

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Reproduction in ProkaryotesBinary fission (Not mitosis)

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Genetic Variability

in bacteria

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Plasmids = extra chromosomal DNA capable of independent replication

Plasmids

Numbers: 1- thousands

Important in horizontal or lateral gene transfer

Some carry antibiotic resistance genes

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Genetic Exchange in bacteria

Conjugation

Pili attachment

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Variability in Prokaryotes viaMutation—high rate/unit time because of high speed of reproduction.Conjugation

Transduction

Transformation

Can Genes be

passed between

Kingdoms?

DNA is transferred

between organisms

Horizontal Gene Transfer

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Horizontal Gene TransferBacteria sp1 Bacteria sp2

Bacteria Fungi (yeast)

Bacteria Plants

Fish Bacteria

Bacteria Insects

Bacteria Nematode worms

Greatly speeds the rate of evolution

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The Oxygen Revolution

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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 = photosyntheticWhich was first?

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Could chemosynthesis be the energy source for the first bacteria?

12

H

2

S

+

6C

O

2

C

6

H

12

O

6

(=

carbohydrate

) + 6

H

2

O

+ 12

S

Purple sulfur bacteria

Bacteria living in the hydrothermal vents

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Simple Photosynthesis in Green Bacteria

Bacteriochlorophyll

No chloroplasts

1 Photosystem

H

2

S is source of H

+ and e-Sulfur is releasedAnaerobic process –No O2

H

2

S + CO

2

C

6

H

12

O

6

+ S + ATP

Light

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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

H

2

S + CO

2

C

6

H

12

0

6

+ S + ATP

H

2

O

+ CO

2

C

6

H

12

0

6

+

O

2

+ ATP

Light

Light

This is the beginning of the Oxygen Revolution

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Complex Photosynthesis in Plants

H

2

0 + CO

2

C

6

H1206 + 02 + 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

Light

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1)

Chemosynthesis Inorganic chem

. reactions

(

H

2

S)  S (Anaerobic)

2) 1 Photosystem Photosynthesis

Green Bacteria (Bacterial chlorophyll)

(H

2

S)

 S

(Anaerobic)

3) 2 photosystems

photosynthesis

Blue green bacteria

(

Chlorophyll

a)

(H

2

S or H

2

0)

 S or O

2

OXYGEN REVOLUTION BEGINS

4) Plant

Photosynthesis

(H

2

O)

 O

2

2 Photosystems

Chlorophyll a & b

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Heterotrophic Nutrition

Glucose (6C)

2 ATP

2 Pyruvic Acid (3C)

Alcohol (2C

)

Acetic Acid (2C)

Pyruvic Acid (3 C)

Lactic Acid (3C)

Could heterotrophic nutrition be first

—

in

organic soup?

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Heterotrophic Nutrition

Glucose (6C)

2 ATP

2 Pyruvic Acid (3C)

Alcohol (2C)

Acetic Acid (2C)

Pyruvic Acid (3 C)

Lactic 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

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NEXT TIME

PROTISTA