http://ludwig.lajuntaschools.org/science/Learn_Share/Entries/2009/10/12_AP_Biology__What_Are_Prokaryotes_files/shapeimage_2.png

• Structure of a Prokaryotic Cell

• Classification of Prokaryotes

• Identifying Prokaryotes

• Bacterial Nutrition: Obtaining Energy

• Bacterial Metabolism: Using Energy

• Bacterial Growth & Reproduction

• Significance of Prokaryotes

PROKARYOTES

http://s689.photobucket.com/albums/vv258/Moodle_Pics/?action=view&current=PROEUVENN.jpg&newest=1

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Small size, big impact! • Black Death (bubonic plague)

• Prokaryotes as decomposers “If prokaryotic decomposers were to disappear, the chemical cycles that sustain life would halt, and all forms of eukaryotic life would also be doomed. In contrast, prokaryotic life would undoubtedly persist in the absence of eukaryotes, as it once did [for about 1.5 B years when they first appeared 3.5 B years ago.]”

http://alchemipedia.blogspot.com/2009/09/plague-of-florence-1348-etching.html,

http://www.kimayahealthcare.com/Upload/AllImages/I_6_193_10_3191.jpg

Structure of a

Prokaryotic Cell

http://micro.magnet.fsu.edu/cells/procaryotes/images/procaryote.jpg

• Contributes to pathogenicity

• Site of antibiotic action

Cell wall

• May contain pigments & enzymes for photosynthesis

Cell membrane

• W/o cytoskeleton, cytoplasmic streaming

Cytoplasm

Nucleoid region

Ribosomes

• Lacks microtubules

Flagellum

• Shorter, thinner than flagella

Pili (sing. Pilus)

Classification of prokaryotes

Domain Bacteria

• peptidoglycan cell walls

• more members than

Archaea

• Ex. Streptococcus, E.

coli, cyanobacteria

Domain Archaea

• no peptidoglycan in CWs

• w/ some DNA /RNA sequences more similar to those of eukaryotes than those of bacteria

• many are extremophiles

• Examples

• Methanogens

• Halophiles

• Thermophiles

• Acidophiles

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

https://meyerbio1b.wikispaces.com/file/view/archaebacteria_vs_

eubacteria.png/58172168/archaebacteria_vs_eubacteria.png

http://upload.wikimedia.org/wikipedia/commons/thumb/f/f5/Grand_prismatic_spring.jpg/2

50px-Grand_prismatic_spring.jpg

Identifying Prokaryotes Cell Shape

• Three basic shapes:

• Bacilli (sing. bacillus)

• Cocci (sing. coccus)

• Spirilla (sing. spirillum)

• Cell arrangement:

• diplo-

• staphylo-

• strepto-

http://www.ibri.org/RRs/RR051/51bacterialshapes-Merc.gif

Identifying Prokaryotes Cell Wall Gram staining

• two dyes • crystal violet (purple)

• Safranin (red)

• two results • Gram-positive (purple, thicker

peptidoglycan layer)

• Gram-negative (red or pink, thinner peptidoglycan layer)

http://biofilmbook.hypertextbookshop.com/v003/r002/artifacts/images/labExercises/stain_diagram.jpg,

http://en.wikipedia.org/wiki/File:Gram_stain_01.jpg

Identifying Prokaryotes Movement

• Flagella

• Gliding on layer of

slimelike material

w/c they produce

• Nonmotile

http://www.nature.com/nrmicro/journal/v8/n9/fig_tab/nrmicro2405_F1.html

Bacterial Nutrition: Obtaining Energy

• Autotroph (“self-feeder”): can produce own food

• Heterotroph (“other feeder”): obtains energy from food (organic compounds) it consumes

• Phototroph: obtains energy from sun

• Chemotroph: obtains energy from inorganic compounds

Diverse adaptations allow prokaryotes to live in

nearly every environment imaginable!

Bacterial Metabolism: Using Energy

• Cellular respiration vs. fermentation

• Strict/obligate aerobes

• Facultative anaerobes

• Strict/obligate anaerobes

http://www.slic2.wsu.edu:82/hurlbert/micro101/images/hist24.gif

Bacterial Growth &

Reproduction

• Asexual reproduction

through binary fission

• No exchange or recombination

of genetic information

https://encrypted-

tbn3.gstatic.com/images?q=tbn:ANd9GcSFNiJzU9qun26Xp1JH18swIVYv8lpVzv2IKig

qcAEftjQ9di8MbA

Bacterial Growth &

Reproduction

Means of genetic recombination:

• Conjugation • Donor transfers genetic

information to recipient through sex pilus

• Transduction • Bacterial DNA is moved

from one bacterium to another by a virus

• Transformation • Bacteria takes up naked

DNA from the environment

http://upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Conjugation.svg/350px-Conjugation.svg.png,

http://www.pc.maricopa.edu/Biology/rcotter/BIO%20205/LessonBuilders/Chapter%209%20LB/Ch9b_print.html

Bacterial Growth & Reproduction

Spore formation • endospore

• thick internal wall encloses DNA and a portion of the cytoplasm

• bacterium to survives harsh conditions that would otherwise kill it

Importance of

Prokaryotes

• Evolution of life on earth

• Nutrient cycles

• Pathogens

• Medicines

• Symbiotic organisms

• Genetic engineering

• Bioremediation

• Food spoilage http://world.edu/wp-content/uploads/2011/12/cyanobacteria1.jpg,

http://upload.wikimedia.org/wikipedia/commons/thumb/f/fe/Nitrogen_Cycle.svg/320px-

Nitrogen_Cycle.svg.png, http://thehealthyapron.com/wp-

content/uploads/2011/02/Yogurt.jpg, http://en.wikipedia.org/wiki/File:Streptomycin-

1ntb-xtal-3D-balls.png, http://prod.biologybiozine.com/wp-

content/uploads/2011/09/beachCleanup.jpg,

http://en.wikipedia.org/wiki/File:Staphylococcus_aureus_VISA_2.jpg,

http://www.scq.ubc.ca/wp-content/GMcrop.gif