1 Eukaryotic Cells Eukaryotic Cells The History of Eukaryotes The History of Eukaryotes They first appeared approximately 2 billion They first appeared approximately 2 billion years ago. years ago. Evidence suggests evolution from Evidence suggests evolution from prokaryotic organisms by prokaryotic organisms by symbiosis symbiosis . . Organelles originated from procaryotic Organelles originated from procaryotic cells trapped inside them. cells trapped inside them. -> Endosymbiosis -> Endosymbiosis
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Eukaryotic CellsEukaryotic CellsThe History of EukaryotesThe History of Eukaryotes
They first appeared approximately 2 billion years They first appeared approximately 2 billion years ago.ago.
Evidence suggests evolution from prokaryotic Evidence suggests evolution from prokaryotic organisms by organisms by symbiosissymbiosis..
Organelles originated from procaryotic cells Organelles originated from procaryotic cells trapped inside them.trapped inside them.
-> Endosymbiosis-> Endosymbiosis
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Endosymbiosis
Algae
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Eukaryotic CellsEukaryotic CellsEukaryotic Organisms in MicrobiologyEukaryotic Organisms in Microbiology
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Eukaryotic CellsEukaryotic CellsForm and Function of the Eukaryotic CellForm and Function of the Eukaryotic Cell
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Eukaryotic CellsEukaryotic CellsForm and Function of the Eukaryotic CellForm and Function of the Eukaryotic Cell
- an outermost boundary that comes into direct contact withan outermost boundary that comes into direct contact with environmentenvironment- usually composed of - usually composed of polysaccharidespolysaccharides- appears as a network of fibers, a - appears as a network of fibers, a slime layer slime layer or a or a capsulecapsule- functions in adherence, protection, and signal reception- functions in adherence, protection, and signal reception- beneath the glycocalyx - beneath the glycocalyx
-> Fungi and most algae have a thick, rigid cell wall.-> Fungi and most algae have a thick, rigid cell wall.-> Protozoa, a few algae, and all animal cells lack a cell -> Protozoa, a few algae, and all animal cells lack a cell wall and wall and have only a membrane.have only a membrane.
- compact sphere, most prominent compact sphere, most prominent organelleorganelle of eukaryotic of eukaryotic
cellcell- nuclear envelope composed of nuclear envelope composed of two parallel membranes two parallel membranes
separated by a narrow space and is perforated with poresseparated by a narrow space and is perforated with pores
- contains - contains chromosomeschromosomes- nucleolus – dark area for rRNA synthesis and ribosomenucleolus – dark area for rRNA synthesis and ribosome
Endoplasmic reticulum – two types:Endoplasmic reticulum – two types:
Rough endoplasmic reticulum (RER)–Rough endoplasmic reticulum (RER)– originates from the outer membrane of the nuclear envelop and extends in a continuous network through cytoplasm; rough due to ribosomes; proteins synthesized and shunted into the ER for packaging and transport; first step in secretory pathway
Smooth endoplasmic reticulum (SER)–Smooth endoplasmic reticulum (SER)– closed tubular network without ribosomes; functions in nutrient processing, synthesis and storage of lipids, etc.
- consists of a stack of flattened sacs consists of a stack of flattened sacs called cisternaecalled cisternae
- closely associated with ERclosely associated with ER
- Transitional vesicles from the ER Transitional vesicles from the ER containing proteins go to thecontaining proteins go to the
Golgi apparatus for Golgi apparatus for modificationmodification and maturation.and maturation.
- Condensing vesicles transport Condensing vesicles transport proteins to organelles or proteins to organelles or secretory secretory proteinsproteins to the outside. to the outside.
-> > vesicles containing enzymes vesicles containing enzymes that originate from Golgi apparatus that originate from Golgi apparatus used for breaking down material used for breaking down material
-> Trash bin of the cell !!!-> Trash bin of the cell !!!
-> involved in intracellular > involved in intracellular digestion digestion of food particlesof food particles and in and in protection protection against invading microbes against invading microbes (Phagocytosis) (Phagocytosis) andand absorbing any material (molecules) from outside (Endocytosis)
- found in found in algaealgae and and plant cellsplant cells
- outer membrane covers inner outer membrane covers inner membrane folded into sacs, membrane folded into sacs, thylakoids, stacked into granathylakoids, stacked into grana
- larger than mitochondrialarger than mitochondria
-> -> hyphaehyphae – long – long filamentousfilamentous fungi or molds fungi or molds
Some exist in either form – Some exist in either form – dimorphicdimorphic: :
mold-like at low temperature, yeast like at 37 degrees C,mold-like at low temperature, yeast like at 37 degrees C, characteristic of some pathogenic moldscharacteristic of some pathogenic molds
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Eukaryotic CellsEukaryotic CellsMacroscopic and Microscopic view – Macroscopic and Microscopic view –
Molds/fungiMolds/fungi
Mixed cultures of mold
Hyphal structures
Structural types of hyphae
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Eukaryotic CellsEukaryotic Cells
Macroscopic and Macroscopic and Microscopic view - YeastMicroscopic view - Yeast
Morphology of yeast
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Eukaryotic CellsEukaryotic Cells
Fungal NutritionFungal Nutrition
-> All are heterotrophic (org. Carbon Source)-> All are heterotrophic (org. Carbon Source)
-> Majority are harmless saprobes living off-> Majority are harmless saprobes living off dead plants and animalsdead plants and animals
-> Some are parasites, living on the tissues -> Some are parasites, living on the tissues ofof other organisms, other organisms, mycosesmycoses – fungal – fungal infectionsinfections
-> Growth temperature 20-> Growth temperature 20oo-40-40ooCC
-> Extremely widespread distribution in -> Extremely widespread distribution in manymany habitatshabitats
Mycellium growing on raspberries
Fungus growing on skin
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Eukaryotic CellsEukaryotic Cells
Fungal OrganizationFungal Organization
-> Most grow in loose associations or -> Most grow in loose associations or coloniescolonies
-> -> YeastYeast – soft, uniform texture and appearance – soft, uniform texture and appearance
-> -> Filamentous fungi Filamentous fungi – mass of hyphae called – mass of hyphae called myceliummycelium;; cottony, cottony,
hairy, or velvety texturehairy, or velvety texture
- hyphae may be divided by cross walls – - hyphae may be divided by cross walls – septateseptate
- - vegetative hyphaevegetative hyphae – digest and absorb nutrients – digest and absorb nutrients
- - reproductive hyphaereproductive hyphae – produce – produce sporesspores for reproduction for reproduction
-> All Fungi have asexual reproduction !!!-> All Fungi have asexual reproduction !!!
-> Primarily through spores formed on -> Primarily through spores formed on reproductive hyphaereproductive hyphae
-> -> AsexualAsexual reproduction – reproduction – sporesspores are formed through are formed through buddingbudding or or mitosismitosis; ; conidia or sporangiosporesconidia or sporangiospores
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Eukaryotic CellsEukaryotic Cells
Fungal Reproduction - SexualFungal Reproduction - Sexual
-> -> SexualSexual reproduction – reproduction – sporesspores are formed following are formed following fusion of fusion of malemale
and female strainsand female strains and formation of sexual structure and formation of sexual structure
-> Sexual spores and -> Sexual spores and spore-forming structuresspore-forming structures are one are one basis for basis for
classification.classification.
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Eukaryotic CellsEukaryotic Cells
Fungal Reproduction – sexualFungal Reproduction – sexual
-> -> ZygosporesZygospores– – diploiddiploid spores (2n)spores (2n) are formed following are formed following fusion of fusion of malemale
Fungal Reproduction – sexualFungal Reproduction – sexual
-> -> AscosporesAscospores in a fruit in a fruit bodybody
Ascomycetes-> Penicillium
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Eukaryotic CellsEukaryotic Cells
Fungal Reproduction – sexualFungal Reproduction – sexual-> -> BasidiosporesBasidiospores – haploid sexual spores in a fruit – haploid sexual spores in a fruit bodybody
Fungi imperfectiFungi imperfecti (just asexual cycle know until now): (just asexual cycle know until now):
-> Deuteromycota – majority are yeasts and molds; no -> Deuteromycota – majority are yeasts and molds; no sexual spores known; conidiasexual spores known; conidia
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Eukaryotic CellsEukaryotic Cells
Roles of FungiRoles of Fungi
-> Adverse impact-> Adverse impact
- mycoses, allergies, toxin production- mycoses, allergies, toxin production- destruction of crops and food storagesdestruction of crops and food storages
-> Beneficial impact-> Beneficial impact
- decomposers of dead plants and animals- decomposers of dead plants and animals- sources of antibiotics, alcohol, organic acids, vitamins- sources of antibiotics, alcohol, organic acids, vitamins- used in making foods and in genetic studies- used in making foods and in genetic studies
-> Contain chloroplasts with chlorophyll and other pigments-> Contain chloroplasts with chlorophyll and other pigments
-> Produce large proportion of atmospheric O-> Produce large proportion of atmospheric O22
-> Most are free-living in fresh and marine water – -> Most are free-living in fresh and marine water – planktonplankton..-> Provide basis of food web in most aquatic habitats-> Provide basis of food web in most aquatic habitats
-> Classified according to types of pigments and cell wall-> Classified according to types of pigments and cell wall
-> Kelps, seaweeds, euglenids, green algae, diatoms, dinoflagellates,-> Kelps, seaweeds, euglenids, green algae, diatoms, dinoflagellates,
brown algae, and red seaweedsbrown algae, and red seaweeds-> Dinoflagellates can cause red tides and give off toxins that cause-> Dinoflagellates can cause red tides and give off toxins that cause food poisoning with neurological symptoms.food poisoning with neurological symptoms.
-> Used for cosmetics, food, and medical products-> Used for cosmetics, food, and medical products
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Eukaryotic CellsEukaryotic Cells
Kingdom ProtistaKingdom ProtistaProtozoaProtozoa
-> 65,000 species-> 65,000 species
-> Vary in shape, lack a cell wall -> Vary in shape, lack a cell wall
-> Most are unicellular; colonies are rare-> Most are unicellular; colonies are rare
-> Feed by engulfing other microbes and organic matter-> Feed by engulfing other microbes and organic matter
-> Most have locomotor structures – flagella, cilia.-> Most have locomotor structures – flagella, cilia.
-> Many can enter into a resting stage when conditions are-> Many can enter into a resting stage when conditions are
unfavorable for growth and feeding – unfavorable for growth and feeding – cystcyst..
-> Most are harmless, some are -> Most are harmless, some are animal parasitesanimal parasites
