Prokaryotes, Protists, and Fungi

prokaryote domains included

bacteria and archaea

three shapes (prokaryote)

bacillus, coccus, spirillum

prokaryote diversity and ecological role

live and thrive everywhere even where most eukaryotes can’t; many use photosynthesis but some chemosynthesize

prokaryote feeding

most autotrophs through photosynthesis or chemosynthesis

prokaryote reproduction

asexually through binary fission and exchange genetic information through conjugation

endosymbiosis theory

eukaryotes evolved from prokaryotes; loss of rigid cell wall allowed membranes to fold inward, membrane flexibility (one cell could engulf another, and horizontal gene transfer between eukaryotes; energy producing bacteria lived inside of larger bacteria

origin of nucleus

nuclear membrane is an extension of ER network, protects and isolates the nucleus, and is thought to have evolved from infolding of plasma membrane

evidence for endosymbiosis

mitochondria and chloroplasts have their own DNA similar to bacteria’s; many antibiotics that inhibit protein synthesis in bacteria also inhibit protein synthesis in mitochondria and chloroplasts; mitochondria and chloroplast reproduce in the same way as bacteria

diversity and ecological role of protists

over 200,000 species; different cell surface structures, locomotion, nutritional strategies, and reproduction strategies

protist feeding

photosynthesis, consuming other organisms, or decomposing materials

protist reproduction

asexually through binary fission or sexually through conjugation

protist examples

paramecium, malaria parasite, kelp, and slime molds

paramecium

move via cilia; sexually reproduce; multiple mating types and 2 genetically different types mate (like male and female)

malaria parasite

plasmodium; complex life cycle; blood stage causes symptoms

kelp

not plants; have specialized regions; unlike plants have no vascular tissue

slime molds

can be many cells that sometimes cooperate in order to reproduce or be one huge cell with many nuclei; studied to understand evolution of multicellularity (transitional form)

fungi characteristics

single or multi-celled with different cell types; sexual or asexual reproduction; extract and absorb nutrients; body is a mass of connected hyphae (one continuous branching tube with many nuclei or chains of cells with pores; cytoplasm flows freely throughout hyphae allowing them to grow rapidly)

mycellum

mass of connected hyphae that can be many meters long; cell walls made of chitin, a polysaccharide

fungi diversity and ecological role

found in nearly every environment; important for plant nutrient uptake; live in symbiosis with many other organisms

fungi nutrition

heterotrophs that absorb nutrients; large surface to volume ratio; break down cellulose and lignin in woods

fungi reproduction

sexual or asexual; spores most common means of reproduction can form sexually or asexually that can remain suspended in the air for a long period of time

fungi examples

mushrooms and yeast