Microbiology Chapter 4

Front 1

History of Euakryotes

Back 1

Prokaryotes and Eukaryotes evolved from a different kind of cell, a precursor to both prokaryotes and eukaryotes called the Last Common Ancestor

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First primitive eukaryotes

Back 2

single-celled, over time began to aggregate and form colonies

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Eukaryotes formed when

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a larger cell sprung off of the Last Common Ancestor cell engulfed smaller prokaryotic cells that began to live and reproduce inside the cell- the coexistence is called endosymbiosis

Front 4

Eukayotes have

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ALL: cytoplasmic membrane, nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, vacuoles, cytoskeleton, and glycocalyx
SOME: a cell wall, locomotive appendages and chloroplasts

Front 5

Glycocalyx

Back 5

outermost layer that comes into direct contact with the environment, sometimes called an extracellular matrix; it is composed of polysaccharides; it protects and helps cells stick to surfaces and receive signals from other cells in the environment

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Cell walls

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cell walls of fungi are rigid and provide structural support and shaoe

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Cytoplasmic (cell) membrane

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-typical bilayer of phospholipids where protein molecules are embedded
-also contain sterols: serve as selectively permeable barriers

Front 8

Nucleus

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-separated from cell cytoplasm by nuclear envelope
-has a nucleolus has RNA
-chromatin made of DNA and histone proteins around which it is wound

Front 9

Endoplasmic Reticulum

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-used in transport and storage
Rough- transport materials from the nucleus to the cytoplasm
Smooth- processes, synthesizes and stores nonprotein molecules like lipids

Front 10

Golgi Apparatus

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site in cell where proteins are modified and then sent to their final destinations

Front 11

Nature's Assembly Line

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a segment of DNA is copied into RNA and passed to ER, then transported to Golgi apparatus where protein products are packaged into vesicles that are used by the cell for many purposes

Front 12

Lysosome

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contains variety of enzymes, involved in intracellular digestion of food and protect against invading microorganisms

Front 13

Vacuoles

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

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Mitochondria

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constant supply of energy

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Chloroplasts

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capable of converting energy of sunlight into chemical energy through photosynthesis

Front 16

Cytoplasm

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framework of cytoplasm anchors organelles, moving RNA and vesicles, and permitting shape changes and movement in some cells

Front 17

Fungi

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100,000
-macroscopic: mushrooms, puffballs
-microscopic: yeasts and molds

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Forms of fungi

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unicellular, colonial, multicellular (macroscopic organisms)

Front 19

Fungal cells: yeasts and hyphae

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Yeasts: round shape, asexual reproduction- budding, pseudohypha: chain of yeast cells
Hyphae: long filamentous cells of molds; some are dimorphic (morph b/w yeast and mold form)

Front 20

Fungi and Human Disease

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-Primary pathogens: make a healthy person look sick
-Opportunistic pathogens: attack people who are already weak (AIDS/cancer)
-Mycoses: fungal infections vary in the way the pathogen enters the body and the degree of the tissue involvement

Front 21

Other Harmful Effects Caused by Fungi

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-harmless spores can cause opportunistic infections in AIDS patients
-fungal cell walls: allergies
-toxins produced by poisonous mushrooms can cause death

Front 22

Beneficial Functions of Fungi

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decomposers of organic material
form stable associations with plant roots=more H2O
-fungi have been engineered to produce large quantities of alcohol, antibiotics and vitamins

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Fungal Nutrition

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-heterotrophic: acquire nutrients from organic substances
-saprobic: obtain nutrients from dead organisms
-parasitic: grow on bodies of living plants and animals

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The Protozoa

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most harmless
few species are responsible for millions of infections each year

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Nutritional and Habitat Range of Protozoans

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heterotrophic
free-living species
limiting factor: moisture
can live in extreme temperatures and pH's

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Life Cycles

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trophozoite: active
cyst: inactive and resistant to heat

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Life Cycles and Reproduction

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some only live in active, trophozoite phase
many alternate b/w cyst and trophozoite phase

Front 28

Major Pathogenic Protozoa

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Trichomas vaginalis- STD in women
Entamoeba histolytica and Giardia lamblia form cysts and are transmitted by contaminated water, food or soil

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The Helminths

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flatworms (flukes and tapeworms) and round worms
usually can see adult worms with naked eye

Front 30

Life cycles and Reproduction

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life cycle: fertilized egg- larval- adult stages
can lay up to 25 million eggs/day
adults can exist as sexes or hermaphrodites

Front 31

Helminth life cycle

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transmit infective egg to body of another host
-intermediate host: eggs/ larva develop
-definitive host: adults mature and mate
routes of infection are by oral intake, can penetrate unbroken skin

Front 32

Distribution of Parasitic worms

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50 species
all areas of the world
yearly cases: billions
50 million in USA