Bio100B Review #3 (Exam I)
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What do all organisms have in common?
- - Plasma membrane
- - Ribosomes
- - Metabolic pathways
- - Conservative DNA replication
- - DNA that encodes protein
How do prokaryotes differ from eukaryotes?
- - Circular DNA
- - Unicellular
- - No organelles
- - Divide by binary fusion
What are the general characteristics of prokaryotes?
- - DNA not in nucleus
- - DNA localized in nucleoid
- - Lack organelles
- - Small size
- - Wide spread and diverse
Why are prokaryotes so successful?
- - Very diverse and wide spread
- - Structural, functional and genetic adaptations
- - Morphological structure
What is the function of the cell wall and how does it differ between Bacteria, Archae and Eukaryotes?
- -The cell wall maintains the cell shape
- - Provides physical protection
- - Prevents cell from bursting in hypotonic envirnment.
What are the 3 types of bacteria morphology?
- - Capsule
- - Pili & Fimbriae
- - Flagella
How are Gram+ bacteria different from Gram- bacteria?
- Gram + indicates peptidoglycan in simple cell wall, it traps violet/blue dye
- Gram - indicates less peptidoglycan between cell wall and innner & outer cel wall membrane (pinkish/purple color)
What functions does the capsule on a prokaryote serve?
- Protects vs. immune systems of other organisms
- Allows attachment to other cells
How does the reproductive strategy in prokaryotes facilitate adaptation?
- - Reproduce quickly by binary fission
- - Divide every 1-3 hours
- - Horizonal gene transfer
- - May form endospores (viable dormant state)
What are the four major nutritional modes in prokaryotes?
1. Photoautotrophs (photosynthesis)
2.Photoheterotrophs (use light but need carbon)
3. Chemoautotrophs (energy from oxidizing inorganic substances)
4. Chemoheterotrophs (obtain both energy and carbon from complex organisms)
* most bacteria and archae are chemoheterotrophs.
Describe the various oxygen requirements of bacteria?
- I . Anaerobes (do not use oxygen)
- --Obligate anaerobes: oxygen is poisonous
- -- Aerotolerant anaerobes: not damaged by oxygen
- -- Faculatative anaerobe: use both aerobic and anaerobic metabolic pahtways.
II. Obligate aerobes (require oxygen)
Describe the 7 groups of bacteria.
- Gram positive Bacteria
- Hyperthermophilic bacteria:
- Hadobacteria: extreme thermophiles
- Cyanobacteria: photosynthetic, fix nitrogen, source of chloroplasts
- Spirochetes: Gram - unique axial filaments
-Chlamydias: gram - live only as parasites
-Proteobacteria: became mitochondria of eukaryotes
Describe the general characteristics of Archaea.
- Separation of the Archaea domain based on genome sequencing
- All lack peptidoglycan in cell walls
- Many live in extreme habitats
- Many others are common in so8il and in the oceans
Describe the Crenarcheota & Euryarcheota.
- -most thermophilic or acidophilic
- -Lives in hot sulfur springs (70-75 C)
- -Methanogens obligate anaerobes
- -Extreme halophiles
- -live in salty environments
How are prokaryotes beneficial to the biosphere? Beneficial/harmful to humans?
- I. Beneficial part of bioshphere
- -Chemical recycling
- -Nitrogen fixation
- -Prey/mate attraction
- II. Harmful/Benefits for humans
- -Human pathogens
- -Tools in molecular biology
- Production of vitamins, hromones, biotech products.
What are the general characteristics of viruses?
- -Not cellular
- -Do not replicate independantly
- - Do not metabolize
How are viruses classified?
By the nature of their genomes
What are some of the structural changes we see in the occurrence of eukaryotic cells?
- I. Loss of cell wall
- -Flexible cell surface
- -Infolding (leading to nuclear membrane)
- -Increased surface area
- - II. Development of cytoskeleton
- -Allow changes in shape
- -Movement of materials
- -Microtubules may be precursors to flagella
- -Phagocytosis and digestive vacules
How does the endosymbiotic theory apply to evolution of eukaryotic cells?
- I. Proteobacterium endosymbiont
- - incorporated & evolved into mitochondrion
- -function to detoxify O2 produced by cyanobacteria
- II. Cyanobacterium endosymbiont
- - Evolved into chloroplasts of green & red algae
Why are protists considered the “grab bag kingdom”?
- - Single celled eukaryotes, some multicellular
- -Diverse assemblage
- -Asexual and sexual reproduction
- -Nutritionally diverse
Describe the ALVEOLATES and its members (dinoflagellates, apicomplexans, ciliates).
- - Alveoli beneath plasma membrane
- - All unicellular, most photosynthetic
Dinoflagellates: mostly marine and photosynthetic, endosymbionts of corals, two flagella
Apicomplexans: parasites of animals, have one end (apex) with organelles, contain apicoplast
Ciliates: Heterotropic, have macronuclei and micronuclei, reproduce asexually by binary fission, have trichocysts (darts)
What are unique characteristics of the EXCAVATA in general, and the clades within (Diplomonads, Parabasalids, Euglenozoans)?
Characterized by its cytoskeleton some with excavated feeding groove.
Diplomonads and Parabasalids: Mostly anaerobic, lack plastids, mictochondria lack DNA.
Euglenozoans: Spiral/crystalline, rod inside flagella, diverse nutritional modes
Describe the STRAMENOPILES and its members (diatoms, brown algae, oomycetes).
Hairy and smooth flagella
- -Diatoms: unicellular algae with silica tests
- - Important phytoplankton, marine and freshwater
- -Fix 1/5 of all carbon fixation on earth.
- -Lack flagella
- Brown Algae
- -most are marine
- -gametic life history
- -water molds
- -cell walls of cellulose, not chitin
- -no longer have plastid
- -absorptive heterotrophs
Describe alternation of generations and the sporic life cycle of the brown algae.
Describe the RHIZARIA and their modes of injestion. How do Radiolarians differ from Foraminiferans?
- -Many posess threadlike pseudopodia
- -Unicellular and mostly aquatic
- - Make lare component of ocean sediments
- - Include Radiolarians and Foraminiferans
- Photosynthetic symbiont, calcareous multichambered test, amoebas with threadlike pseudopodia, injest food
- -Radial symmetery
- -Thin stiff pseudopodia
- -Fusted tests of silica
- -Feed by engulfing food
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