BSCI 207 Final 14 12 2012 09 36 00 Archetypes and Ancestors The Quest for the Bilaterian Ground Plan Goal o Reduce the observed diversity of organisms to a more general abstraction The archetype Contains essential properties of many organisms not unique to only 1 Final archetype ground plan of the group Cuvier 1 archetype Geoffrey 4 archetypes Articulata and Vertebrata archetypes Rational Transcendental Morphology Von Baer s Law o General archetype characteristics of an organism to which a group belongs to develop before specific characteristics Evolution Morphology Present technique Homeotic Mutations mouse Homeobox Genes o Bithorax Duplication of Mesothorax region o Antennapedia antennae expressed as legs o Homeotic Vertebrate Extra lumbar sacral vertebrate in Most mutations in animals caused here 180 base region coding for 60 base aa homeodomain Homeodomain Regulates transcription of specific developmental genes Determines fate of cells structures and body regions during development Hox genes Type of homeobox genes that occur in clusters along a chromosome and differentiate regions of the body on the longitudinal axis Conserved sequences within an organism and orthologs Clustering almost always happens Homologs from some organisms can be inserted into other organisms with lethal mutants in certain Hox genes Properties of Hox Genes Spatial Colinearity Temporal Colinearity o Order of Hox genes along a chromosome determine the their expression along the anterior head posterior axis o Order of Hox genes in chromosomes determine their temporal sequence of expression in the embryo o Temporal time of expression during embryogenesis Examples colinearity o Vertebrate Hox genes show both temporal and spatial o Flies show only spatial colinearity Hox genes expressed at the same time Reasoning o Unknown but upstream Hox genes may try to protect from alterations by downstream genes to maintain the polarity of the anterior posterior axis Examples Chordin chd in vertebrates and short gastrulation sog in arthropods o Both function as establishing dorsal ventral axis of body Pax 6 Vertebrates and eyeless Arthropods o Establishes light receptor field o Mutations in Pax 6 may lead to cataracts Amphioxus engrailed AmphiEn Chordate and engrailed en Arthropod o Segmentation Nkx 25 vertebrates and tinman arthropods o Heart morphogenesis mesoderm formation Distal less Dlx Chordate and distal less dll Arthropod o Proximo distal axis of appendages Nutrient Assimilation you are what you eat Major aspects of Complex Organisms o Gathering and ingesting nutrients o Break down complex molecules o Transport simple molecules into the cells of organism Cellular Transport Why does it reach equilibrium o Equal concentrations in and out probably by diffusion o Feedback mechanism in cells Determining Rate of Solute Transport Measured in micromoles min Linear Graph o No transport sites simple diffusion across membrane Graph with limit exponential o Cell possesses specific transport sites that are limiting Exhibits a measurable rate of affinity for solute and maximum rate of movement Facilitated Diffusion transport Affinity Ka 1 2 Tmax x Measured in mM Ka 1 affinity Diffusion of Glucose via GLUT 1 protein Glut 1 inactivated by high intracellular ATP Ion Channels Artificial channels by antibiotics such as Gramicidin Alpha helix Potassium Channel is voltage gated to allow K into the cell Active Transport Requires energy because is independent of concentration or electrochemical gradients Direct use of ATP Na K ATPase in cell membranes Indirect use of ATP Co transported ion Na gradient for transport of glucose and aa Sodium gradient is an example of co transport or symport Sodium and glucose going in same direction Oil Water Partition Coefficient S oil S water Permeability Chart Aquaporins Allow only water to travel through cell membrane Hydro phyllic on inside hydrophobic on outside facing the hydrophobic tails of phospholipid bilayer More than 16 discovered as of 2009 First noted in 1995 by Peter Agre Only accommodates H2O in single file manner Osmosis Water moves from areas of high concentration to low concentration Remember water movement goes in OPPOSITE direction as solute p RT DC p Osmotic pressure in Osmolar OsM R gas constant typically 8 315 J K 1 mol 1 T temperature in degrees K DC concentration gradient of non permeable solute molecules Osmoles Total number of solute particles in solutions all species 1mM glucose 1mOsM solution 1 mM NaCl 2 mOsM solution Tonicity of a solution Hypertonic environment water rushes out shrinks Hypotonic environment water rushes in lyse Isotonic environment no net movement Basic Trends for water balance Terrestrial o Water loss and MUST GAIN SODIUM Aquatic Marine WATER o Water Gain and MUST ACCUMULATE SOLUTE IONS o Water loss and MUST REMOVE SOLUTES GAINED FROM SEA Single celled Organisms Fresh Water ions o Contractile Vacuoles o Pump out water and use membrane ion pumps to accumulate o Pump out salt and prevent leakage of water Sea Water Fresh Water H2O Ions Ions H2O Sea Water H2O Ions H2O Ions Separated Body Fluid Cavities Around 300 mOsM for most vertebrates Osmoconformers Internal body fluid p is equal to that of environment but do regulate solutes ions not same solute concentration as environment Usually requires formation or loss of non toxic solute o Amino acids amino acid metabolites urea etc Adjustable solute molecules must be non toxic and minimally interactive with proteins Osmoregulators Must pump water and or solutes Internal p is regulated independent of environment Stenohaline Organisms that cannot handle the wide fluctuations in salt concentration of water Euryhaline Able to adapt to a wide variety of salinities Freshwater Osmoregulators body fluids tend to dilute Problems o Gain water o Lost salt via diffusion Solution o Pump in salt o Minimize water diffusion Saltwater Osmoregulators body fluids tend to concentrate o Problems Solutions o Gain salt from water o Lose water via osmosis o Pump out salt o Minimize water diffusion Anadromous fish deal with both hypo and hypertonic environments Salmon Shark Rectal Gland Excrete salt from the body fluids Accomplished by transporting Sodium and Chlorine ions from body fluid into urine Use urea as osmotic solute Nitrogenous Wastes Ammonia o Most aquatic animals o Very toxic o Soluble in water lots of water needed to remove Uric Acid Urea o Low toxicity o Not soluble in water o Birds and reptiles hard shelled o
View Full Document
Unlocking...