Eukaryotic Cell Microorganisms

When did the first eukaryotic cell appear?

1.8 billion years ago

LUCA

Last Universal Common Ancestor

LUCA of all eukaryotic cells was a single-celled microorganism closely related to what?

Archaea

endosymbiosis

mitochondria and chloroplasts originated from endosymbiosis

widely accepted

endosymbiotic theory evidence:

capable of independent division

contains a circular chromosome with bacterial DNA sequences

prokaryotic-sized ribosomes

enveloped by double membrane

mitochondria’s energy change

sites of cellular respiration, metabolic process that uses oxygen to generate ATP

chloroplasts energy change:

found in plants and algae, sites of photosynthesis

what is the genetic control center in eukaryotes?

nucleus (contains one or more chromosome)

ribosomes

protein factories

both prokaryotic and eukaryotic cells have these

not membrane bound

cells with high rates of protein synthesis have high numbers of ribosomes

what are the components of the endomembrane system

nuclear envelope

endoplasmic reticulum

golgi apparatus

lysosomes

vacuoles

plasma membrane

what is the function of the endomembrane system

regulates protein traffic and performs metabolic function

manufacturing and distributing cellular products

smooth endoplasmic reticulum

synthesis of lipids (oils, steroids, phospholipids)

detoxifies drugs and poisons

ER without ribosomes attached

rough endoplasmic reticulum

modifies proteins and shipment

ER with ribosomes attached

secretory proteins depart from ER wrapped in transport vesicles

golgi apparatus

shipping and receiving center

modifies products of ER

sorts and packages materials into transport vesicles

receives, refines, stores, and distributes chemical products of the cell

lyosome

cells garbage disposal

membranous sac of hydrolytic enzymes that can digest

work best in acidic environments

autophagy: lysosomes use enzymes to recycle the cells own organelles and macromolecules

vacuoles

membrane-bound sacs containing fluids or solid particles to be digested, excreted or stored

cytoplasm

everything inside the plasma membrane and external to the nucleus

cytoskeleton

network of fibers extending throughout the cytoplasm

gives animal cells shape and support

controls intracellular traffic

gives some ability to control movement

eukaryotic cilia

similar to flagella in structure

smaller and more numerous

eukaryotic flagella

x10 thicker than bacterial flagella

moves in a wave like manner

plasma (cytoplasmic) membrane

selectively permeable membrane enclosing the cytoplasm of a cell

separates cell from its surroundings

regulates the traffic of chemicals in and out of the cell

structure of the cytoplasmic membrane

fluid mosaic model

phospholipid bilayer and membranous proteins

glycocalyx

layer of material containing substantial amounts of sticky carbohydrates

strengthens the cell surface, helps attach cells together, contributes to cell-cell recognition

the glycocalyx can appear as:

network of fibers

slime layer

capsule

what does not have cell walls?

protozoa, helminths, animals, and some algae

structure of cell wall in fungi and most algae:

rigid and provide structural support and shape

different in chemical composition from bacterial and archaeal cell walls

fungi

thick inner layer of polysaccharide fibers composed of chitin or cellulose

thin outer layer of mixed glycans

algae

varied in chemical composition

various sugars along with minerals such as silicon dioxide and calcium carbonate

cell membrane

typical bilayer of phospholipids in which protein molecules are embedded

contain sterols of various kinds which provide stability

have similar function to those in bacteria

microbial eukaryotes can be defined by their morphology as:

protists

algae

fungi

protist

informal term referring to any eukaryotic microorganism that is not a plant, animal, or fungus

algae

include unicellular and multicellular eukaryotes that perform photosynthesis but are not plants

fungi

nonphotographic eukaryotic microorganisms with rigid cell walls composed of chitin

what are the two basic morphological types of fungi

hyphae

yeasts

yeasts

round to oval shape

asexual reproduction, budding

hyphae

long, threadlike cells found in the bodies of filamentous fungi

pseudohypha

chain of yeast cells

dimorphic fungi

can either take growth form depending on growth conditions

characteristic of some pathogenic molds

how does fungi propagate outward growth?

existing hyphae or by fragmentation

spores

primarily reproductive mode of fungi

can be dispersed through the environment by air, water, and living things

will germinate upon finding a favorable substrate and produce new fungus

asexual spores

formed by the hyphae of one organism

identical to the parent

sporangiospores

formed by successive cleavages within a saclike head called a sporangium, which is attached to a stalk the sporangiospore

conidiospores

free spores not enclosed by a spore-bearing sac

sexual spores result from:

fusion of nuclei from two opposite mating strains of the same species of fungus

algae

photosynthetic organisms such as seaweeds and kelp

widespread in fresh and marine waters

contribute to oxygen content of the atmosphere

algae structure

unicellular

colonial

filamentous forms

diatoms

one of the most prevalent groups on earth

cell wall contains silica

high diversity is useful in forensics of bodys of water

diatom structural materials

heat and fire-resistant products, sound proofing materials, polishes for drainpipes, porcelain, tiles

used as an insecticide

base in dynamite

diatom cosmetic products

soaps, deodorants, toothpaste

protozoa

“first animals”

most are harmless, free-living

few are pathogens

widely distributed

single-celled

protozoan cytoplasm extoplasm

clear outer layer involved in locomotion, feeding, and protectoin

protozoan cytoplasm endoplasm

granular inner region housing the nucleus, mitochondria, and food and contractile vacuoles

protozoan function

can move through fluids by pseudopods

cell membrane regulates food, wastes, and secretions

cell shape can remain constant

pathogens mainly live:

fluids of their host, such a plasma and digestive juices or actively feed on tissues

what is the main limiting factor for nutritional and habitat range:

moisture

trophoziote

motile feeding stage requiring ample food and moisture to stay active

cyst

dormant, resting stage when conditions in the environment become unfavorable

resistant to heat, drying, and chemicals

can be dispersed by air currents

important factor in the spread of disease

how to protozoa reproduce?

asexual mitotic cell division or multiple fission

helminths

adult ones are usually large enough to see with the naked eye

spend part of their lives in the gastrointestinal tract

flatworms

very thin, often segmented body plan

tapeworms and flukes

roundworms

elongated, cylindrical, unsegmented body

general worm morphology

multicellular animals that have some degree or organs and organ systems

most developed organ system in these in reproductive tract

reduction in the digestive, excretory, nervous, and muscular systems

complete life cycle includes:

fertilized egg, larval, and adult stages

where do adult helminths get nutrients and reproduce?

in the hosts body

helminth life cycle

must transmit an infective form to body of another host

where larva develops is the intermediate (secondary) host

adulthood and mating occur in the definitive (final) host

how many eggs can a helminth lay a day?

200,000 to 25 million a day

fertilized eggs are:

released into the environment

provided with a protective shell and extra food

vulnerable to heat, cold, drying, and predators