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Lecture #5: Nutrient Assimilation 2: pgs 961-965 Unicellular Organismso Small and non-polar molecules transported or diffuse through plasmao Larger molecules ingested with aid of specialized regions of the membrane Phagocytosiso Membrane engulfs the blob Cichlids of the East African Rift Lakeso East African Rift Lakeso o Overtime they have evolved to use different nutrient systems in this lake.  Home to Cichlids, > 300 specieso •Cichlid food sources include leafy algae, crust forming algae, plankton, fish, plants, snails, fish eggs, andplants!o •Each species evolved specialized pharyngeal jaws1o Cichlid Pharyngeal Jawsoo Teeth and what organisms have such teeth. We have two different types bc we are carnivores and omnivores.  Mammalian Jaws Herbivore vs. Carnivoreo Feature o Carnivoreoo Herbivoreo Teeth, Molars o Sharp jagged bladeso Flattened cuspso Canine teeth o Long, curved and sharpo Short and flattenedo Jaw motion o Shearing; no side to sideo Side to side, front to back; no shearingo Saliva o No digestive enzymeso Carbohydrate digesting enzymeso Stomach o Simple o Multiple chamberso Stomach pH o ~ 1 - 2 o 4 - 6o Length of small intestineo 3 – 6 times body lengtho 10 – 12 times body lengtho Colon o Short and smooth o Long and complex2o ***take close to pH acid breaks up peptide bonds (1-2 in carnivores)o In Herbivores they have a much longer small intestine.  Enzymes to match the meal!oo Three amino acid transport sites here.o Most of it is symport. o Chylomicrons – LDLs, HDLs (high density liquid protiends/ low density) these make chylomicrons from the fat If you don’t have the enzymes, Termites eat wood but lack cellulaseo So they rely on a protozoan, Mixotricha, which in turn relies upon at least 4 types of bacteria!o Inside of that organims there are 4 different types of sybiotic bacteria  Mixotricha: bacterial symbiontso Treponema attached to cell surface for locomotiono Rod shaped bacteria on the surface (protection?)o Spherical bacteria as internal endosymbionts to function as mitochondria! Mixotricha lacks mitochondria!Lecture #6: Water and Organisms 2: Multicellular strategies Advantage of a body cavity with body fluids separated or isolated from the surrounding water?oAlways have the same concentrations no need for movement of water Body fluid & cytoplasm:oBody fluids & cytoplasm ~ 300 mOsM for most vertebratesoVariable for marine invertebrates, protists, and bacteria, but cytoplasm is close to 300 mOsMoOsmoconformer vs Osmoregulator Multicellular aquatic or marine organismsoOsmoconformersInternal body fluid  is equal to that of environment but do regulate solutes & ionsUsually requires formation or loss of non-toxic soluteoAmino acids, amino acid metabolites, urea, etc. oOsmoregulatorsInternal  is regulated independent of environmentMust pump water and/or solutesoConformer – you go along with it3oWe are regulatorsoPi is the amount of pressureoOsmoconformers – there body fluids have the same concentration of solutes as their environment, but do not have the same ionic concentrations as their environment; oTaking solute in and out of water, so no net water movement. Adding or subtracting non-essential solutes– ones that will not effect the proteins.  Remember: cells of an osmoconformer have the same p as the environment, but not the same solute composition! Osmoconformer & OsmoregulatorooCertain point above which and below which they cannot regulate.  How do Osmoconformers adjust the  of the body fluids?oAdd or subtract solute molecules from the body fluidsoThe adjustable solute molecules must be non-toxic and minimally interactive with proteinse.g., many invertebrates use amino acids and derivatives. What is the osmoregulator doing to maintain a constant  ?oStenohalineoEuryhaline oSteno (narrow) haline (salt)….organisms that can survive over a narrow range of salt concentrations4oEury (wide) haline…organisms that can survive over a wide range of salt concentrations Salinity toleranceooCould see on exam. Would ask which one lives in brackish water (blue) – needs to be able to adjust. Marine environment living in – red.  Saltwater FishooEvery time consume food consume salt water. Always faced with gaining salt and losing water. Always with problem with body fluids getting too concentrated. Must produce a very concentrated urine (excrete salt) and at the same time lose very little water.  Life in Seawater – VertebratesoTypical solutes values (mmol/kg):ooDo not need to memorize this table. oSalmon – live in fresh and salt. They have a big problem oDogfish – have a high concentration of urea Freshwater Fish5ooWorried about gaining water and because there is very few solutes in the water it is always faced with losing to many ions in diffusion. Goldfish pea dilute water, almost constantly urinating. oLife in Freshwater – VertebratesoTypical solute values (mmol/kg): [Na+] [K+] [urea][total solute]Saltwater 450 10 0 1000Fresh-water<1 <1 0 ~2Goldfish 115 4 0 260FreshwaterRay150 6 <1 310 Salmon - anadromous fishooMarine fish is pumping ions out of its gills, freshwater fish is pumping ions into the bloodo*Salmon – as it leaves the ocean it take the ion pumps on one membrane of its gills it is removed and newion pumps are put in. As hatchlings are born in freshwater they are accumulating ions then as it swims 6out to the ocean overtime its ion pumps are being removed on one site and new ones put in on another side to pump ions out. Example of anhydrous fish – need to completely change their set up. o Crocodile tearsoThey have a gland in their eye that pumps salt out of a duct near their eye “crocidile tears” Sea gull tearsoSea gulls also have salt glands near eyes pumping out salt. Wondering since they are living in strange environment on east coast if they are losing their salt glands.  Your goldfish in distilled wateroUrea and methylated amines as osmolytesoBull sharks – most intense shark known. Went all the way into freshwater. Gives example of how sharks can adapt. oIn ocean faced with problem of accumulating salt and losing water. Have something that makes their body concentrations in their body are almost the same as the ocean water – use urea. Evolve cells/proteins that can stand high levels of urea – have a large amount of urea that helps them not have to worry about losing water.oWhen


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UMD BSCI 207 - Lecture #5

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