Advanced biology prokaryotes
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Advanced Biology Prokaryotes. Chapter 28. The first cells (28.1). Isotopic Data Carbon-12 is found in microfossils This is used for carbon dating of organisms and carbon fixation Pathways include: Calvin Cycle (photosynthesis) Krebs Cycle (cellular respiration) Hydrocarbons biomarkers.

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Advanced Biology Prokaryotes

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Advanced biology prokaryotes

Advanced BiologyProkaryotes

Chapter 28


The first cells 28 1

The first cells (28.1)

  • Isotopic Data

    • Carbon-12 is found in microfossils

  • This is used for carbon dating of organisms and carbon fixation

    • Pathways include:

      • Calvin Cycle (photosynthesis)

      • Krebs Cycle (cellular respiration)

  • Hydrocarbons

    • biomarkers

  • The Earth formed approximately 4.5 billion years ago

  • The first fossil formations found on Earth are dated to 3.5 billion years ago

    • Microfossils

      • Fossil form of microscopic organisms


Prokaryotic diversity 28 2

Prokaryotic Diversity (28.2)

  • Prokaryotes are the oldest form of life.

  • They have a simple structure and

  • They are also the most abundant form of life on Earth

    • Cyanobacteria (photosynthetic) changed Earth’s atmosphere to be able to produce oxygen

  • Abundant amounts of prokaryotes – ~10% identified

  • New techniques to identify w/o culturing

  • Two groups:

    • Archae and Eubacteria


Prokaryotes can live anywhere

Prokaryotes can live anywhere

  • Found in deep sea caves, volcano rims and inside glacier formations

  • Some Archae are extremophiles – extreme environments such as hot springs, geysers, toxic gases and extreme cold (Anartica)

  • Extremes may indicate earth’s conditions 3.5 bya


Prokaryote vs eukaryote

Prokaryote vs. eukaryote

Prokaryotes

Eukaryotes

Unicellular and multicellular

Cell size – normally ≥10ųm

Membrane bound nucleus

Mitosis – sexual

Genetic Diversity via Mutations

Membrane bound organelles

Flagella and cilia w/microtubules – whiplike

Photosynthesis release oxygen

  • Unicellular

  • Cell size – vary

    • ≤1ųm up to 750 ųm

  • Single circular chromosome

  • Plasmids

  • Binary Fission – asexual

  • Horizontal gene transfer

  • No internal compartments – ribosomes differ

  • Flagella – single fiber – spin

  • Oxygenic and anoxygenic

  • chemolithitrophic


Advanced biology prokaryotes

  • Prokaryotes

  • Eukaryotes


Archae vs eubacteria

Archae vs. eubacteria

  • Plasma membrane in both but differs in glycerol link to hydrocarbon chains

  • Cell Wall– Peptiglycan in Eubacteria but not in Archae

  • DNA Replication differs by place of origin and proteins

  • Gene Expression – Archae may have more than one RNA polymerase


Classification

Classification

  • Classification of prokaryotes were gram staining and observations such as:

    • Can photosynthesize

    • Mobility

    • Unicellular or colonies

    • Spores or binary fission

    • Whether it is pathogenic

  • Now classified by evolutionary means using DNA analysis


Prokaryote cell structure 28 3

Prokaryote cell structure (28.3)

  • Three basic forms:

    • Rod shaped (bacillus)

    • Sperical shaped (coccus)

    • Spiral shaped (spirillum or spirochetes)


Cell structure

Cell structure

  • Cell wall determines cell shape

    • Lack cell wall, no particular cell shape

  • Flagella

  • Chains

  • Colonies

  • Branching filaments


Cell wall

Cell Wall

  • Cell wall basically contains peptidoglycan with a polymer that forms a strand of crosslinked polysaccharides with peptide chains

  • Archae may have pseudomurein or pseudopeptidoglycan


Gram staining

Gram staining

Gram + will stain purple

Thick Peptioglycanso traps crystal violet

Gram – will stain pink

Multiple layers does not trap crystal violet but will show the red dye


Other stuctures

Other Stuctures

  • Capsule

    • Gel type outer layer

      • Allows for adherance and evasion from immune system

  • Flagella

    • Structure that allows movement connected at cell wall and spins – made of protein flagellin


Advanced biology prokaryotes

  • Pili

    • Hairlike structure that allows movement (gram-), attachment and exchange of genetic information


Advanced biology prokaryotes

  • Endospores

    • Dormant stage in prokaryotes

    • Thick wall formed when environmental stress

    • Stay dormant for days to centuries

      • Examples: Tetanusor anthrax


Internal structures

Internal structures

  • Ribosomes

    • Smaller than Eukaryote ribosomes

    • Different proteins and RNA

    • Antibiotics will bind to these ribosomes blocking protein synthesis

  • Internal membranes

    • Respiratory membranes – photosynthesis

  • Nucleoid

    • Double stranded circular DNA (nucleoid region)

    • Plasmid – replicating circular DNA (small)


Prokaryotic genetics 28 4

Prokaryotic genetics (28.4)

  • CONJUGATION

  • Prokaryotes reproduce asexually

  • Exchange DNA through

    • Conjugation - transfer plasmids (F+/F- )

    • Transduction

    • transformation


Advanced biology prokaryotes

  • Transduction

    • DNA transfer from one bacterium to another via a virus


Advanced biology prokaryotes

  • Transformation (Griffith) – Cell death causes lysis that releases fragments of DNA into the environment where another bacteria incorporates it into its genetic material


Antibiotic resistance and mutations

Antibiotic resistance and Mutations

  • Due to its rapid reproduction a mutation in a bacterium can spread rapidly

    • Media growth (Nutrient Agar)

      • Auxotroph – need supplement

      • MRSA and VRSA

  • Plasmids can have resistant genes incorporated

    • E.coli found in digestive tract of humans vulnerable


Prokaryotic metabolism 28 5

Prokaryotic Metabolism (28.5)

  • Photoautotrophs – sunlight to build from carbon dioxide

  • Chemolithoautotrophs – oxidize inorganic substances such as ammonia to nitrite

  • Photoheterotrophs – Sunlight for energy and other molecules for carbon

  • Chemohetertrophs – carbon and energy from other molecules

  • Intake of energy and carbon – 4 Ways:

    • Photoautotrophs

    • Chemolithoautotrophs

    • Photoheterotrophs

    • Chemoheterotrophs


Human bacterial disease

Human Bacterial disease

  • See Table 28.1 on page 561.

  • Infective diseases by bacteria killed over 20% of US children before age 5 before the discovery of antibiotics by Pasteur and Koch

  • Bacteria can infect by various methods such as droplets in air, feces or pests


Beneficial prokaryotes

Beneficial prokaryotes

  • Symbiotic relationships

    • Mutualism – nitrogen fixation or digestion

    • Commensalism - live outside of organism without harming

    • Parasitism - infection

  • Prokaryotes can cause harm but there are some that are beneficial

    • Bacterial decomposers along with fungi put C, N,P, S back into the soil

    • Fixation during nutrient cycling of carbon and nitrogen


Advanced biology prokaryotes

  • Genetic Engineering

    • Human genes can be inserted into bacterium to produce human proteins such as insulin

    • Biofactories for enzymes, vitamins, antibiotics and industrial compounds

  • Bioremediation

    • Removing pollutants from water, air and/or soil

    • Bacterium used in wastewater treatment plants to breakdown raw sewage.

    • Future development in removing toxic waste


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