Chapter 5 Eukaryotic cells Flashcards
Eukaryotic appendages (motility)
-Flagella *10x thicker than bacterial flagella and more complex
*Long, sheathed cylinder w/ regularly spaced hollow microtubules in a 9+2 arrangement
-Cilia *shorter and more numerous, up to several thousand
* Found only in a single group of protozoa and certain animal cells
* Function as feeding and filtering as well as movement
Eukaryotic External Boundary layers
-Glycocalyx: *Composed of polysacharides
* Outermost boundary
*Forms a slime layer or capsule
-Cell wall: *Found in Fungi and algae
*Rigid and provides structure
*Different chemically than bacterial cell walls ( chitin or cellulose in fungi)
Cytoplasmic membrane
-Bi-layer of phospholipids embedded with protein molecules
-Contains sterols to stabalize
-Selectively permeable layers
-Transports nutrients in and wastes out
Nucleus
-Most prominent organelle
-Seperated from cytoplasm by nuclear envolope
-Necleolus *Stains intensly due to its RNA content
* Site for ribosomal RNA synthesis
Endoplasmic reticulum
-Microscopic series of tunnels used in transport and storage
-Rough ER
*Ribosomes attached to surface
*Proteins held for packaging and transport
-Smooth ER
*Does not contain ribosomes
*Synthesis and storage of non protein molecules
Golgi Apparatus
-Stack of flattened disc shaped sacs closley connected to the ER
-ER forms transitional vesicles that are picked up by Golgi
-Golgi adds polysacharides and lipids to the proteins in the transitional vesicles and pinches off condensing vesicles
-Site of protein modification and transport
-Conveyed to Lysosomes or transported as secretory vesicles
Lysosomes
-Cellular vesicles
-Originates from Golgi apparatus and contains variety of enzymes
-Storage
-Hold enzymes for digestion of food and protection against invading microorganisms
Vacuoles
-Cellular vesicles
-Membrane bound sacs
-All purpose storage system
Mitochondria
-Supply bulk of cell
-Divide independently of the cell
-Contain circular strands of DNA
-Bacteria sized ribosomes 70S
Mitochondria structure
-Cristae
*Folds on the membrane that hold enzymes and electron carriers of aerobic respiration
-Matrix
*holds ribosomes, DNA, and enzymes and other compounds used in digestion
Location of Ribosomes in Eukaryotic cells
-Scattered freely in the cytoplasm and cytoskeleton
-Attached to RER
-Inside mitochondria and chloroplasts
Size of Eukaryotic ribosomes
-80S
*Combo of 60s and 40S subunits
Cytoskeleton function
-Anchoring organelles
-Moving RNA and vesicles
-Permitting changes and movement
Three main types of cytoskeletal elements
-Actin filaments
*Determine shape of cells surface and vital for locomotion
- Intermediate filaments
*Provide strength and resistance to stress
-Microtubules
*Direct intracellular transport
Macroscopic fungus
mushrooms, puggballs and gill fungi
Microscopic fungi
-Yeasts
-Molds
Morphology of microscopic fungus
-Yeast cells grow round to oval shape and use asexual reproduction
-Hyphae are long threadlike cells on fungus or molds
-Psedohypha: chain of yeast during budding/reproduction
-Dimorphic fungi take either form depending on conditions or temp
Heterotrophic
-All fungi
-Acquire nutrients from a wide variety of substrates
Saphrobes
Obtain substrates from dead plants and animals
Parasites
-Live on bodies of living animals or plants
Reproduction strategies of fungi
-Primary mode is SPORE formation
-Outward growth of existing hyphae
-Fragmentation- separated piece can generate whole new colony
Sporangiospores
-Asexual spore formation of fungi
-enclosed in a sac like head and release when head ruptures
Conidiospores
-Asexual spore formation of fungi
-not enclosed and pinch off tip of a fertile hypha
Three types of fungal infections are acquired by
-Community acquired infections caused by environmental pathogens
-Hospital associated infections caused by fungal pathogens in clinical settings
-Opportunistic infections caused by pathogens infecting already weakened individuals
Benefits of fungi
-Decomp of matter and returning nutrients to the soil
-association w/ plant roots that increase water and nutrient absorption
-Food flavoring
-Alcohol, beer, wine, and gas that cause bread to rise
Protists
-Eukaryotic unicellular or colonial organism that lacks true tissues
(Algae and protozoa traditionally combined into Kingdom Protista)
Algae
-Group of photosynthetic protists
-Widespread inhabitants of fresh and Marine water
Primary medical threat of algae
-Ingestion of toxins during a red tide
Plankton
-Type of Algae
-Floating community of microscopic organisms
-Essential role in aquatic food web
-Produce most of earths oxygen
Protozoa
-Single cells containing all eukaryotic organelles EXCEPT chloroplasts
-Heterotrophic (require food in organic form)
-Organelles can be compared to mouths,digestive systems, reproductive tracts and legs
-about 65,000 species (most are harmless)
Free living protozoa
-Scavenge dead plants or animal debris
-Graze on live cells of bacteria and algae
Parasitic protozoa
-Live on fluids of host (plasma and digestive juices)
-May feed on tissues
Protozoa locomotion
-Pseudopods (false feet and feeding structures)
-Flagella (one to several)
-Cillia (over entire surface of cell)
Trophozoite
-Motile feeding stage of a protozoa
-Requires ample food and moisture to stay active
Cyst
-Dormant resting stage of a protozoa
-formed when lack of food or harsh environment
-Important factor for spreading disease
Classification of Protozoa based on how they move
-Flagella (form cysts and are free living)
-Amoeboid motion ( psudopods, freeliving and not infections)
-Cilia (Most develope cysyts and are free living and harmless)
-No motility Sporozoa (complex life cycles and all are parasitic)
Protozoan identification and cultivation
-Smeared on a slide w/ or w/out staining
-Identification (size, shape, type, number,presence of special organelles or cysts and number of nuclei)
Helminths
-Worms
large enough to be seen by naked eye (1mm -25m in length)
Two major groups of parasitic helminths
-Flatworms
*tape worms and flukes
-Round worms
*Pin worms
Worm morphology
-reproductive tract is most developed
- primitive digestive, excretory, nervous and muscular systems
-thick cuticles for protection
-mouth glands for breaking don tissue
