Studying for Bio II Exam II | Page 1 | SPAM | Guild Forums

~RAZI3L~

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Posted: Mon Nov 05, 2007 9:22 am

I'm studying for my biology test while on Gaia. XD

Posted: Mon Nov 05, 2007 9:26 am

Special about Bacteria: They have peptidoglycan in their cell walls, and they have Formylmethionine at the initiator tRNA.

Special about Archaea: They have Ether-linked branched membrane lipids.

Special about Eukarya: They have a Nucleus, Organelles, 80S ribosomes, No Operons, Rarely any Plasmids, and 3 RNA polymerases.

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Posted: Mon Nov 05, 2007 9:30 am

Gram positive Bacteria- have lots of peptidoglycan
Gram Negative Bacteria - have less peptidoglycan with lipopolysaccharides
Archaea have no peptidoglycan with various glycoproteins

Bacteria have a phospholipid bilayer while Archaea have Ether-linkages that are branched.

Posted: Mon Nov 05, 2007 9:42 am

Differences in Bacteria/Prokaryotes:

Shapes:
cocci (spherical)
bacilli (rod shaped)
spirilli (helical shaped)

Metabolism:
Photoautotrophs (Light, CO2)
Photoheterotrophs (Light, organic molecules)
Chemolithotrophs (Inorganic compounds, CO2)
Chemoheterotrophs (Organic, Organic)

Respiration~:
Anaerobic -
-Glycolysis
-Fermentation
-anaerobic respiration
(utilize low energy acceptors other than oxygen such as: Sulfate, Nitrate, Carbon Dioxide, and Ferric Ions)

Types of anaerobes:
Obligate - can't live in O2
Facultative - Can switch from anaerobic to aerobic respiration
aerotolerant - Can live in O2, but can't switch

Aerobic - require O2
Obligate - can't live in absence of O2

Majority of prokaryotes are heterotrophs.

Movement:
Immobile
Corkscrew-like motion: Modified flagella called axial filaments
Rolling: Gliding Mechanism
Gas Vesicles - inflate and deflate
By Flagella (most common)

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Posted: Mon Nov 05, 2007 9:48 am

How Prokaryotes obtain Genetic Variation:

Conjugation - Transfer of plasmid DNA between individuals
Transductions - Transfer of DNA via phages between individuals
Transformation - Absorption of free DNA from the environment (can cross species)
Mutation = most variation

Posted: Mon Nov 05, 2007 9:56 am

Bacteria Clades:

Proteobacteria:

- Mostly gram negative
- Eukaryote Mitochondria arose from alpha-proteobacteria-like ancestor.

Cyanobacteria:

- Photoautrotrophs that use chlorophyll a and release oxygen
- Gram negative
- Responsible for initial oxygen rich atmosphere
- Chloroplasts of eukaryote derived from cyanobacteria

Chlamydias:

- All Chemoheterotrophic parasites
- Gram negative
- Cause of some STD's

Firmicutes:

- Mostly gram positive

Spirochetes:

- Gram negative
- Cause syphilis

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Posted: Mon Nov 05, 2007 9:59 am

Archaean Clades:

Euryarchaeota:

- Methanogens (obligate anaerobes)
- Halophiles (photosynthetic)

Crenarchaeota:

- Thermophiles - sulfur oxidizers
- Acidophiles

Posted: Mon Nov 05, 2007 10:07 am

Prokaryotes vs. Eukaryotes:
Prokaryotes - small, no nucleus, no organelles, no cytoskeleton
Eukaryotes - larger, membrane-bound organelles & nucleus, cytoskeleton

*Eukaryotes cope with being larger by having specialized compartments and a cytoskeleton

How Eukaryotes evolved:
1. Loss of cell wall
2. Involution
3. Pinched off involutions form internal membranes studded with ribosomes
4. Genetic info attached to membrane forming rudimentary nucleus
5. Cytoskeleton (actin and microtubules) formed.
6. Early digestive vesicles began forming lysosomes using enzymes from early endoplasmic reticulum.
7. A flagellum formed enabling propulsion.

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Posted: Mon Nov 05, 2007 10:15 am

Endosymbiosis:

Peroxisomes - engulfed phagocytes, helped manage waste products
Mitochondria - engulfed alpha-protobacteria, cell's powerhouse
Chloroplast - engulfed cyanobacteria, made food for cell

Primary Endosymbiosis (2 membranes) - Red Algae, Green Algae, chlorophyta, and plants

Secondary Endosymbiosis (3 membranes) - Stramenophiles, Haptophytes, Dinoflagellates, & Euglenoids

Tertiary Endosymbiosis (4 membranes) - Dinoflagellates

Posted: Mon Nov 05, 2007 10:26 am

Variation in Protists:

Structural Support:

- Plasma Membrane
- Cell Walls made of cellulose
- Silicon in Plasma Membrane
- Shells or Tests made of silicon-oxide, cellulose plates, or calcium carbonate

Reproduction:

-Asexually via mitosis
1. Binary fission
2. Multiple fission
3. Budding
4. Spores
-Sexually
-Both

Metabolism:
-Photoautotrophic
-Ingestive or Absorptive Chemoheterotrophic
-Mixotrophic

-Both aerobic and anaerobic types

Movement:
-Pseudopods
-Flagella & cilia
-gliding via microtubules

Life Cycles:
-Alternation of Generations
a. Heteromorphic - generations differ morphologically
b. Isomorphic - generations don't differ morphologically
-Haplontic - sometimes no multicellular diploid stage, Only zygote is diploid, and acts as zoospore after meiosis.
-Diplontic - diploid most of life, Only gametes are haploid

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Posted: Mon Nov 05, 2007 10:49 am

6 Major Groups of Protists (PARAphyletic):

-No Mitochondria but mitochondrial genes in chromosome: Diplomonad & Parabasalid

Unicellular Flagellates - Euglenozoans
Euglenoids - 3 membrane Chloroplasts & Mitochondria w/ disk shaped cristae
Kinetoplastids - Single Large Mitochondrian w/ kinetoplast that edits mtRNA - (ex. Sleeping Sickness)

Alveoli (small membrane bound cavities under cell surfaces) - Alveolates
Ciliates - Have Cilia (ex. paramecium)
Dinoflagellates (cause red tide) - cellulose plates, and 4 membrane bound chloroplasts
Apicomplexa - Have Apical complex (system of organelles) Allows penetration of host plasma membrane

Hairy Flagella - Stramenophiles
Diatoms - silicon oxide glassy shells, 3 membrane chloroplasts, Store energy as chrysolaminarin (carb) and oils
Brown Algae (Phaeophyta) - ALL multicellular, cell walls contain cellulose, 3 membrane chlorplast (a&c pigments as well as carotenoid)
Water Mold (Oomycetes) - cell walls contain cellulose

Photosynthetic Pigments and Floridean Starch Storage - Red Algae
-Photosynthetic chloroplasts with double membrane
-contains phycoerythrin & phycocyanin that cause red pigment
-All also have chlorphyll a
-mostly multicellular
-Cell Walls made of cellulose

Photosynthetic Pigment and Starch Storage - Green Algae (Chlorophyta)
-Photoautotrophic with double membrane green chloroplasts (a&b pigments)
-colonial or filamentous multicellular
-most closely related to land plants-charophytes
-Clade includes non-protist plants

Single Flagella at Base- Opisthokonts
Choanoflagellates - Most closely related to animals
Microsporidians - Most closely related to Fungi
Includes non-protist animals & fungi

Others:
Pseudopods-
-Actinopods - thin stiff pseudopods, some form glassy endoskeletons
-Foraminifera - Unicellular amoebae, lack cell wall but produce calcium carbonate tests, slender pseudopodia
-Rhizopoda (Lobose Amoebae) - unicellular, lack cell wall

Slime molds - release spores from erect fruiting bodies, cellulose containing cell walls
-Plasmodial slime molds (Myxogastrida) - unicellular, and multinucleate, 2n most of life
-Cellular slime mold (Dictyostelida) - multicellular and colonial, Only zygote is 2n.