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3/4 of the planet is covered with water. •The average depth of the ocean is 3800 meters. •For every 10 meters depth increase, pressure increases 1 atm.•low temperature (approximately 2-4°C) ○high hydrostatic pressure (up to 1,500 atm in the Mindanao Trench) ○no sunlight○Characterized by:•Sunlight necessary for photosynthesis does not penetrate to these depths and thus there is low food availability and this affects the adaptations of organisms at these depths•Deep sea - defined as the ocean below either 200 or 1000 metersDeep-sea species have characteristic depth distribution patterns which may be affected by pressure•inhibits a process that proceeds with a positive volume change ○accelerates a process that proceeds with a negative volume change.○Only if there is no net volume change is a process unaffected by pressure increases. Biochemical processes can be affected. ○rates of catalysisbinding of substratesassembly of subunits. Examples of what can be affected: ○Increased pressure•The volume changes associated with these processes may result from the interaction of enzymes and substrates with water. The water may be more organized by interactions with charged substrates or amino acids. Membrane fluidity is also affected. High pressure acts like low temperature causing membranes to “freeze.” •Pressure - acts on volume changes (of the entire solute-solvent system). Free vehicles (not attached to vessel), e.g., "monster" camerasOwned by the U.S. Navy and operated by Woods Hole Oceanographic Institution ○1966 recovered a hydrogen bomb lost in the Mediterranean Sea Explored the hydrothermal vents; surveyed the Titanic HOV Alvin (Human Occupied Vehicle)•Deep Submergence Vehicles, e.g., Johnson Sea Link, Alvinin the fall 1969 Alvin sank in 1540 m (water temperature 3°C) and was recovered 11 months later. On board were lunches for pilot and 2 scientists •Bullion soup, bologna sandwich with mayonnaise, apples Samples were eaten and they were “okay”Some put back in refrigerator at 3°C Decayed in 3 weeks The Story of Alvin’s LunchThe OceanTuesday, April 29, 20146:15 PM Learning Objectives final Page 1Decayed in 3 weeks Sparked interest in metabolic rates in the deep sea which continues to today •Biologically produced light used for (among a number of roles) species recognition, camouflage and in some cases hunting•Different wavelengths of light penetrate to different depths○Typical wavelengths of bioluminescence are in the blue range○Bioluminescence and color play role in "being invisible"•BioluminescenceThese fish belong to the family Macrouridae and are the predominant deep-sea teleost (boney) fish family. These fish also have the “common” name of grenadiers. •If one is interested in examining how organisms adapt to the high pressures of the deep sea, this family of fishes provides a useful model. Different rattail species occupy different depths and thus experience different pressure regimes. One can compare species that differ primarily in the variable of interest, hydrostatic pressure, without possible confounding variables such as phylogenetic distance or different lifestyles or body temperatures. •Rattails Learning Objectives final Page 2An extracellular chemical messenger (ex. Hormones)•What are first messengers?Synthesized from ATP○Cyclic adenosine monophosphate (cAMP)•Calcium•What are two examples of second messengers?A few 1st messenger molecules○Many 2nd messenger molecules○Amplify faint signal•Elicit a coordinated response •Each step in the cascade recruits more molecules○Amplification•What is signal amplification and how does it benefit the cell?Each step in the cascade creates more 2nd messenger molecules, amplifying the signal.•What is the role of phosphorylation cascades in signal amplification?Plasma membrane•Where are the receptors involved in cell signaling located? Epinephrine (adrenaline) activates a GPCR in liver cells (e.g., Fig. 11.10, 11.16, 45.7 and 45.9)•Calcium activates a phosphorylation cascade in skeletal muscle (after the Protein Kinase A step in Fig 11.16, activating the enzyme phosphorylase kinase)•Signal amplification in the breakdown of glycogen The relationship of adenylyl cyclase and cAMPCell SignalingTuesday, April 29, 20146:29 PM Learning Objectives final Page 3Adenylyl cyclase produces cAMP•The relationship of adenylyl cyclase and cAMPRegulated by the alpha subunit of the G - protein•Named after the alpha subunit•Stimulates adenylyl cyclase○Gs - stimulatory G protein•Decreases adenylyl cyclase○Gi - inhibitory G protein•How is adenylyl cyclase activity regulated?The transfer of phophate between their substrates. In other words, the steps of the signaling cascade•What reactions do protein kinases and phosphatases catalyze?Covalent transfer of phosphate group from ATP to specific amino acids of target protein○Post-translation modification○Enzyme which phosphorylates target proteins•What is the role of cAMP-dependent Protein Kinase (Protein Kinase A) in cell signaling? 2 regulatory subunits 2 catalytic subunitsIn the cytoplasm cAMP binds to the R subunitR2C2dissociates into an R dimer and 2 C monomersInactive kinase -- 4 subunits (a tetramer)○Protein kinase A -- R2C2•What are the subunits of Protein Kinase A and what do they do? C monomers catalyze phosphorylation reactions•What is the subunit composition of the active enzyme? In the cytoplasm cAMP binds to the R subunit•Of the inactive enzyme?What is G protein cycle? Be sure you know all of the steps in the cycle and can reproduce it from memory. Learning Objectives final Page 4Stimulates adenylyl cyclase○Gs - stimulatory G protein•Decreases adenylyl cyclase○Gi - inhibitory G protein•Golf- olfactory G protein•Gt - transducin, the G protein involved in vision•What are examples of the types of G proteins?Consists of 3 subunits (alpha, beta, gamma)•What are the subunits of G proteins?Inhibitory and stimulatory signals and receptorsWhat would happen if the G protein cycle is disrupted by mutations? Learning Objectives final Page 511.5, •11.6, •11.7, •11.9, ••11.10, •11.11,•11.12, •11.15 •11.16. •Figures Learning Objectives final Page 6Learning Objectives final Page 7Steady-state physiological condition•"constancy" of the interior environment of an organism•What is homeostasis?e.g. constant pH, body


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LSU BIOL 1201 - The Ocean

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