Origin of Life Flashcards
Composition of Early Earth Atmosphere
No free O2. CO, CO2, H2O, HS, CH4, NH3
What type of environment was early earth?
Reducing Environment
Oparine-Haldine
Reducing environment of earth led to monomers
Miller Urey
Simulated early earth environment. Synthesized NH3, CH4, H2O, and H2
RNA World Hhypothesis
RNA first life form
Metabolism-First Hypothesis
Metabolic network first life form
Order of life’s beginning
Inorganic molecules, organic molecules, proteinoids, protocells
Heterotroph
Can’t make own food
Autotroph
Makes own food
Cyanobacteria
Autotroph that released O2 as a byproduct, causing formation of ozone layer
Characteristics of Archae
Prokaryotic, branched hydrocarbon tails, packaged DNA, immune to antibiotics, cell walls made of polysaccharides
Methanogens
Archaea. Obligate anaerobes.
Extremophiles
Live in harsh conditions
Halophiles
Live in high salt concentrations
Thermophiles
Live in hot conditions
Characteristics of Bacteria
peptidoglycan cell wall. naked DNA.
Shapes of bacteria
Cocci (sphere) Bacilli (rods) spirilla (spirals)
Gram positive bacteria
Lots of peptidoglycan in cell wall. Stains purple
Gram negative bacteria
Little peptidoglycan. Stains pink
Groups of bacteria
Cyano, spirochetes, nitrogen fixing, Nitrifying bacteria
Plant-like protists
Euglenoids, diatoms, dinoflagellates, brown algae, rhodophyta, chlorophyta
Euglenoids
Flagella, pellicle that maintains cell shape, eyespot that allows for phototaxis, can become heterotrophic in absence of light
Dinflagellates
Two flagella, can be bioluminescent, contain neurotoxins
Diatoms
Unicellular, have hard silica shells
Brown algae
Seaweed
Rhodophyta
Contain red pigments
Chlorophyta
Green algae. Vary in sexuality
Animal-like Protists
Rhizopodia, Forams, apicomplexans, cellular slime molds, plasmodial slime molds, oomycetes
Rhizopodia
Single celled amoebas with pseudopodia
Forams
Have shells made of calcium carbonate
apicomplexans
apicoplast,
Ciliates
Cilia for movement
Plasmodial slime molds
Big mass
Cellular slime molds
Aggregate together stimulated by cAMP
Oomycetes
Have hyphae, no septa, coenycotic (multiple nuclei per cell)
What does cenocytic mean?
Multiple nuclei per cell. Due to lack of septa
Sexual Reproduction in Fungi
Haploid cells fuse in plasmogamy to become a dikaryon. Karyogamy undergoes to fuse the two haploid cells into a single diploid nuclei. Meiosis happens and then new haploid cells are produced.