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Exam 1 (CH. 27-28)

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  • Prokaryotes

    Single celled organisms that make up domains Bacteria and Archaea

    (First and most abundant organisms on earth)

  • What is a gram stain?

    A test used to classify bacteria by cell wall composition

  • What is Gram positive test mean?

    Color?

    Bacteria have simpler walls with a large amount of peptidoglycan

    Blue (less resistant to antibiotics)

  • What is a Gram negative test mean?

    Color?

    Bacteria have less peptidoglycan and are more complex

    Red (more resistant to antibiotics)

  • The three shapes of prokaryotes

    Spheres (Cocci)

    Rods (Bacilli)

    Spirals

  • Cell walls (peptidoglycan)

    Provides structural support, maintains shape, and prevents the cell from bursting

  • Capsules

    Protects from drying out, helps stick to surfaces to form biofilms, and shields them from immune responses

  • Fimbriae

    Allow bacteria to attach to host tissue

  • Flagella

    Allow bacteria to locomote by swimming and navigating toward favorable environments

  • Major differences between Bacteria and Archaea?

    Bacteria use peptidoglycan while Archaea use other polymers

  • Pili

    Longer than the Fimbria and function to pull cells together enabling the exchange of DNA

  • Taxis

    The ability to move

  • Chemotaxis

    The movement toward or away from chemical stimulus

  • Three factors contribute to the high levels of

    genetic diversity observed in prokaryote

    populations:

    • Rapid reproduction

    • Mutation

    • Genetic recombination

  • Mutation

    Permanent change to DNA

  • Transformation

    The uptake of free floating DNA (allows bacteria to acquire new genes)

  • Transduction

    Foreign DNA being introduced into a cell

  • Conjugation

    Direct transfer of genetic material between two bacteria cells

  • How do these 4 obtain energy

    • Phototrophs

    • Chemotrophs

    • Autotrophs

    • Heterotrophs

    • Light

    • Chemicals

    • Require C02

    • Require organic nutrients

  • How to they metabolize with respect to 02

    • Obligate aerobes

    • Obligate anaerobes

    • Facultative anaerobes

    • Require 02

    • Poisoned by 02

    • Can use 02 if present

  • Major clades of Bacteria

    • Proteobacteria

    • Cynobacteria

    • Chlamydias

    • Spirochetes

    • Gram-positive bacteria

  • Major clades of Archaea

    • Euryarchaeotes

    • Theaumarchaeotes

    • Aigarchaeotes

    • Crenarchaeotes

    • Korarchaeotes

    • (Extremophiles)

  • Ecological roles:

    • Prokaryotes

    • Decomposers

    • Symbionts

    • Pathogens

    • Chemical Recyclers

    • Influence health and survival of multicellular organisms

    • Break down dead plants and animals

    • Form mutually beneficial relationships

    • Act as harmful parasites

    • Recycle organic matter and waste into inorganic nutrients

  • Protist

    An informal term used to refer to all eukaryotes that are not plants, animals, or fungi

  • Endosymbiosis

    A relationship between two

    species in which one organism lives inside the cell

    or cells of the other organism (the host)

  • Evidence suggests that mitochondria evolved

    before plastids and arose from an ______________?

    Alpha proteobacterium

  • Secondary endosymbiosis

    Red and green algae themselves were ingested by heterotrophic eukaryotes

  • Five major supergroups of eukaryotes:

    • Excavata

    • SAR

    • Archaeplastida

    • Unikonta

    • Rhizaria

  • Describe key protist clades:

    • Excavata: includes diplomonads and euglenozoans with modified mitochondria.

    • SAR: includes diatoms, brown algae, and apicomplexans.

    • Archaeplastida: includes red and green algae—closest relatives of land plants.

    • Unikonta: includes amoebozoans and opisthokonts (animals and fungi).

  • Mixotrophs

    Organisms that combine different nutritional strategies

    (carnivorous plants)

  • Alternation of generations

    a reproductive cycle where an organism shifts between a multicellular haploid (sexual) stage and a multicellular diploid (asexual) stage