11/03/09 Lecture 4:The Bacterial World 1

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Online bioscience course for grades 6-12

Fall 2009

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Class mechanics…

• Attend the online Office Hour on Tuesdays at 3 PM via tokbox-Discuss previous week’s video lecture• Online video lecture e-mailed every Wednesday-view lecture and prepare to discuss the following Tuesday• Comment on video lecture using website discussion board• Online Final Exam given 12/9/2009

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Lecture 4: The bacterial world

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Take Homes:

I. Bacteria have highly organized structuresII. The genome of bacteriaIII. Bacterial cell movement IV. Bacterial cell growth and metabolismV. Bacterial films and the “microbiome”

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The basic structure of a bacterium (prokaryote):

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Bacterial surface types:

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Diffusion:

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Active diffusion:

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Bacterial types:

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Bacterial conjugation:

http://en.wikipedia.org/wiki/Bacterial_conjugation

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Transformation:

http://en.wikipedia.org/wiki/Transformation_%28genetics%29

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The pGLO plasmid:

http://en.wikipedia.org/wiki/PGLO

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Bacteria use their flagella to move:

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The structure, assembly and function of the flagellum:

http://www.youtube.com/watch?v=Ey7Emmddf7Y

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Bacterial genome:

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Bacterial genome-”gene music”:

http://www.youtube.com/watch?v=G8ZAGi4ZlFI

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Take Home I

From their cell membranes and flagella down to the organization and replication of their DNA bacteria are highly organized and efficient structurally…

Bacteria have highly organized structures

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The flagellum “control circuit”:

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In bacteria, genes that are part of a “circuit” often are grouped together in the genome:

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The trp operon:

http://www.youtube.com/watch?v=8aAYtMa3GFU

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Take Home II

The DNA genome of bacteria is very highly organized and efficient…

The genome of bacteria

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Bacterial growth:

http://www.youtube.com/watch?v=gEwzDydciWc

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DNA replication:

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Bacterial motility:

http://www.youtube.com/watch?v=zlFRJftA2bU

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Bacterial motion and disease:

http://www.youtube.com/watch?v=YZIg8FL4alA

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Take Home III

The mechanisms and controls of movement in bacteria are highly varied and play a role in disease…

Bacterial cell movement

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In prokaryotes, chromosomal DNA replication starts from a single point (an ori) and proceeds bi-directionally…

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Semi-conservative DNA replication:

http://www.dnatube.com/video/3028/Semiconservative-Replication

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Glycolysis and fermentation:

http://www.youtube.com/watch?v=UmfYnjHs8nk

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Take Home IV

Bacterial growth and metabolic pathways are well defined processes…

Bacterial cell growth and metabolism

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Biofilms I:

http://en.wikipedia.org/wiki/Biofilms

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Biofilms II:

5 stages of biofilm development. Stage 1, initial attachment; stage 2, irreversible attachment; stage 3, maturation I; stage 4, maturation II; stage 5, dispersion. Each stage of development in the diagram is paired with a photomicrograph of a developing P. aeruginosa biofilm. All photomicrographs are shown to same scale.

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Biofilms III:Stromatolites, proof of Life's Origin

http://www.youtube.com/watch?v=4opsN_iQdEs

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The human microbiome:

http://www.youtube.com/watch?v=zzxEaGjXFZw

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Take Home V

Bacteria can form multicellular structures known as biofilms and also form complex symbiotic relation ships within higher organisms such as humans…

Bacterial films and the “microbiome”

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Next Week:

Higher cells

How higher cells are structured and how they function…

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instructorMark E Minie PhD

mark@meminie.com