SIO 181: All Lectures
ATP
(Adenosine triphosphate) main energy source that cells use for most of their work
Do you notice any patterns between hypoxia tolerance and environmental temperature? What are the patterns in colder and warmer temperatures?
...
Draw two Davenport diagrams, one for a shark after eating a 1 kg fish, and another for the same shark after eating a 2 kg fish (~2 and 4 pounds, respectively). What type of acid-base disturbance took place? How does the shark compensate?
...
How will the Davenport diagram would look like for the painted turtle and the Crucian carp during the winter?
...
Now let's consider two different aquaculture facilities. One holds 20 seabass, and the other holds 40. Draw the Davenport diagram for one seabass from each facility.
...
The hemolymph of squid can carry 5 ml O2 / 100 mL, and the hemolymph of octopus can carry 1 mL O2 / 100 mL. Which animal do you think will have a higher hemolymph NBB capacity, and why?
...
What are the most important intracellular and extracellular buffer systems?
...
What are two characteristics of a good buffer system?
...
What happens in RBCs at the gills and at the tissues? How are H+ and CO2 linked to hemoglobin O2 binding and unbinding, and to O2 uptake and delivery?
...
Why water breathing animals cannot regulate blood pH via changes in gill ventilation rate?
...
Red Muscles
15% of muscle 10% of body mass Along lateral lines and base of fins Oxidative (aerobic), slow steady cruising swimming Highly vascularized (oxygenated blood) Abundant mitochondria Lower LDH activity Lower buffering capacity
White Muscles
85% of muscle 60% of body mass Most of the body Glycolytic (anaerobic), high intensity, high velocity, burst swimming Less vascularized Fewer mitochondria High LDH activity Higher buffering capacity
What is a potentially serious side effect of accumulating urea? How do sharks overcome this problem?
Ammonia excretion is very expensive (energy and ATP use) TMAO counteracts the denaturing effects of Urea
Bohr Effect
A decrease in O2 affinity at a low pH and a high CO2
Entropy
A measure of disorder or randomness.
Na+/K+-ATPase (NKA)
A protein found in the plasma membrane of all cells in the body that uses the energy of an ATP (hydrolyzes ATP) to move three Na+ ions out of the cell and two K+ ions into the cell, thus establishing concentrations gradients for these ions across the cell membrane Utilizes 20-80% of all the ATP in a cell
Metalloprotein
A protein that contains a metal ion cofactor Iron and Copper
Metabolic Depression
A reduction in the ATP needs of an animal (or a specific tissue) to below the level ordinarily associated with rest in a way that does not present an immediate physiological threat to life.
Homeostasis
A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level Requires energy
Name two strategies of freeze avoidance in animals
ACCUMULATION OF OSMOLYTES ANTIFREEZE PROTEINS
What does it mean that "hagfish thread cells exhibit extreme allometry"? What is the significance?
Allometry: The study of the relationship of body size to shape, anatomy, physiology and behavior
What is Telemetry?
Allowed physiological measurements in free diving animals
How is NH4+ produced in animals?
Ammonia - ammonium equilibrium = pH buffer Problem: NH4+ is toxic
What are three characteristics of circulatory systems that maximize O2 delivery to tissues?
ATP cannot be used to directly move gasses against their partial pressure Gas can only move from regions of high partial pressure to regions of low partial pressure Gas flow rate is proportional to the partial pressure difference between the two sites
What process produces H+ that can result in harmful acidification during oxygen limitation? Why it is not such a problem during aerobic conditions?
ATP hydrolysis generates H+ (acidification) Under aerobic conditions (enough O2) most of the H+ are consumed by reactions in Mitochondria (mitochondrial sink) As a result, ATP hydrolysis during aerobic conditions does not induce significant intracellular acidification Great capacity to excrete H+ across their gills, into the water Each cell has a very robust mechanism to regulate their intracellular pH
Phosphagen Mobilization
ATP stores
What are the ATPases?
ATPases: Enzymes that catalyze the hydrolysis of ATP (into ADP and Pi) and use the released energy to drive cellular processes that would not occur otherwise Not the only process that requires ATP, but are a significant one
What is the main role of urea in sharks? How is it produced?
Accumulation of urea/TMAO prevents large water fluxes Produced in the shark liver
Why is acid-base regulation so important?
Acid base homeostasis is essential for proper enzyme function (and therefore cell function and life) Related to H+ and pH: but more than just pH Routine metabolic reactions produce and consume H+ Some physiological functions produce or consume even more H+ (exercise, digestion) Hypoxia and Anoxia result in acidosis Some other environmental conditions can also affect Acid Base Homeostasis (elevated CO2 in kelp forest, coral reefs, mangroves, aquaculture)
Why acidic pH dissolves bone? How is this related to dental health?
Acid dissolves bone/tooth Some dissolution is already seen at pH <7, and it increases under stronger acidification (eg. coffee, soda, bacteria that produces lactic acid by fermentation) Fluoride in toothpaste and water supply promotes biomineralization at the tooth surface
How do gasses move throughout the circulatory system?
Addition of CO2 drives the reaction to the right, resulting in the generation of HCO3 and H+ (acidification) Removal of CO2 drives the reaction to the left, resulting in the disappearance of HCO3 and H+ (alkalinization) Addition of H+ drives the reaction to the right, resulting in the conversion of HCO3 to CO2 Removal of H+ drives the reaction to the right resulting in the conversion of CO2 into HCO3 and H+
What is the major advantage of accumulating gasses as a buoyancy mechanism? And the disadvantage?
Advantage: Very low density Disadvantage: Gasses are compressible
Oxidative Phosphorylation
Aerobic Respiration
What are potential applications of urea nitrogen salvage for human health?
Age-related sarcopenia (muscle loss) Nitrogen limited diets in developing countries Spaceflight!
Mention mechanisms that allow animals survive in hypoxia, but are not useful in anoxia, and explain why
All of the following are not useful in Anoxia, nor possible: Make more hemoglobin, lower P50, increased surface area of respiratory surfaces
What are the three mechanisms for nitrogen excretion, and what animals use which?
Ammonotelic Animals: Excrete NH4+ Urotellic Animals: Excrete Urea CO(NH2)2 Uricotelic Animals: Excrete uric Acid C5H4O3N4
Organism
An individual living thing that has an organized structure, can react to stimuli, reproduce, grow, adapt and maintain homeostasis
Define anadromous and catadromous
Anadromous: is the term that describes fish born in freshwater who spend most of their lives in saltwater and return to freshwater to spawn (Up-Running) Born in Freshwater, adult life in Seawater and spawn in Freshwater Catadromous: is living in freshwater and going to the sea to spawn (Down-Running) Born in Seawater, adult life in Freshwater, and spawn in Seawater
How is the thermoregulatory strategy of the opah unique among fishes?
Anatomical considerations of the pectoral swimming in the Opah Pectoral muscle: 37% of propulsive musculature Thick layer of adipose and connective tissue covering the pectoral muscle The more whole body form of endothermy appears to allow opay to maintain enhanced physiological function at depth
Crucian carp: where is lactate produced during anoxia? Where is it converted to ethanol? What are the advantages?
And use fermentation to produce ETHANOL Muscle cells take up lactate and H+ from the blood and turn them into ethanol (alcohol) Lactate travels in the blood to the muscle cells Muscle cells use enzymes in mitochondria and the cytosol to turn lactate into ethanol
What anti-freeze strategy do polar fishes use and how does it prevent ice formation?
Antartic fishes create special antifreeze proteins (often glycoproteins) Lower the freezing point of the body fluids Bind to forming ice crystals Avoid the growth of the crystals No nucleation site for other crystals Effective at very low concentrations Cheaper and no osmotic problems
What are the differences/similarities between the Arctic and Antarctic?
Arctic: Polar Region Connected to other continents Inhabited by humans Land animals and plants (polar bears, reindeer) Many species have a circumpolar distribution and occur on different continents Antarctic: Continent Geographically isolated in the southern ocean No permanent human settlements No true land animals and plants Many species are endemic to Antarctica (They don't occur anywhere else) Both: Are beyond the polar circles Polar climates that are cold
Name the three major marine vertebrate groups that have evolved salt secreting glands independently.
Avian salt glands: Nasal salt glands (enlarged in marine birds; likely also in dinos) Reptilian salt glands: Lingual glands (on the tongue) OR sublingual glands (below the tongue) OR lachrymal gland (tear glands) OR nasal salt gland (just like birds)
Consider three respiratory pigments with the following P50: pigment A (P50=20 mmHg); pigment B (P50= 40 mmHg); pigment C (P50=25 mmHg). Arrange them in increasing order of O2 affinity (from lower affinity to higher affinity)
B, C, A 40 mmHg is the lowest O2 affinity to 20 mmHg which has the highest O2 affinity
Consider the white muscle of two different fish species. "Fish A" has 100 units of LDH activity, and the concentration of histidine compounds is 10 uM. "Fish B" has 2,000 units of LDH activity, and the concentration of histidine compounds is 200 uM. Which of the two fish species has a more active life style, "A" or "B"? Why?
B; Looking at white muscle, the more LDH activity, the more active the life style would be Higher performance fish: Higher buffering capacity (White > Red) Higher histidine-related compounds Higher LDH activity
What is barotrauma and how can it be overcome?
Barotrauma is an issue when a fish comes from a high amount of depth to a low amount of depth Deep DEEP water to surface level can cause this traumatic change in atmospheric pressure Fisheries should work to make sure that they do not grab fish at a fast pace because that is what kills the fish The gas bladder expands and can protrude out of the body and basically prolapse
Marine Biochemistry vs. Regular
Being surrounded by seawater Gases Salinity Light Pressure Temperature Waste Excretion Pollutants Locomotion
What are the A/B regulatory organs in air-breathing animals? And in water-breathing animals?
Blood - Mammal pH: ~7.40 HCO3: ~25 mM PCO2: 5% (~40 mmHg) Buffering capacity: Higher Blood - Fish pH: ~7.80 HCO3: ~5mM PCO3: .3% (~3 mmHg) Buffering capacity: Lower
Which fish will have a higher non-bicarbonate buffering (NBB) capacity in its white muscle, a blue fin tuna or a flounder? Why?
Blue fin tuna? More activity? Active species: Very high buffering capacity Robust A/B compensation Less Active Species: OK buffering capacity OK A/B compensation Sessile species: Poor buffering capacity Poor A/B compensation
Which organisms have hemocyanin?
Blue: Spiders, Crustaceans, some Mollusks, Octopuses, Squids
What is the advantage of having multiple buffers with different pKa's?
Buffering powers are additive Multiple buffers with adjacent pKas: very strong buffers over a broad pH range Free histidine, histidine-containing dipeptides, proteins, inorganic and organic phosphates
What is the function of Carbonic Anhydrase in RBCs?
CA (the enzyme that catalyzes the reactions) is one of the fastest enzymes CA can increase the CO2 hydration and dehydration reactions by as much as 1m! CA is highly abundant within RBCs CA activity is essential because RBCs only spend <1 second in heart and tissue capillaries where gas exchange takes place
Explain how the cuttlefish gas chamber regulates buoyancy
CUTTLEFISH!!!!! Cuttlebone: Has carbon carbonate that allows them to have separate chambers Also has a siphuncle duct and epithelium Cells with lots of mitochondria (energy) Chambers = compartments called Lamellae with liquid and gas (~10% of the animal's volume)
What is a "euryhaline fish"? How do they adjust their physiology to the different salinity environments?
Can live in a multitude of places and different waters
What type of diet do cephalopods have, and why is this essential for their buoyancy strategy?
Carnivorous, the more vegetarian means the harder it is to control buoyancy
Explain the changes in oxygen uptake mechanisms experienced by Arapaima as it grows larger. Why is the Arapaima considered an obligate air breathing fish?
Changes in gill and air-breathing organ characteristics during the transition from water to air breathing in juvenile Arapaima As the arapaima grows larger: Skin gets thicker Gill lamellae gets greatly reduced The air breathing organ (ABO) develops (modified swim-bladder)
Enzymatic Catalysts
Chemical reactions need "activation energy" to proceed (first they reach a transition state, which then decays into products with lower energy) Enzymes can decrease the activation energy Binding and Catalysis
What is the main function of chemiosmosis? What is the name of the enzyme that synthesizes ATP in this process?
Chemiosmosis is the movement of ions across a semipermeable membrane bound structure, down their electrochemical gradient ETC
What are examples of respiratory pigments, and in which animals are they found?
Chemistry of different colors of blood Red: Humans, and majority of other vertebrates Hemoglobin Blue: Spiders, Crustaceans, some Molluscs, Octopuses, Squids Hemocyanin Green: Some Segmented Worms, Leeches, Marine Warms Chlorocruorin Violet: Marine worms such as the Peanut Worms, Penis Worms and Brachiopods Haemerythrin
What is the main function of the citric acid cycle? What are other two names for this cycle?
Citric Acid Cycle: Krebs Cycle = Tricarboxylic Acid Cycle Further oxidation of carbon skeletons and generation of reducing powers (NADH)
Ectothermic Animal
Cold blooded Amphibians, Fish, Reptiles, Invertebrates
What are the two types of fish swim bladders?
Connected to the esophagus (open) Relies on gulping air at the surface NOT connected to the esophagus (closed) Rete mirabile (counter-current multiplier hemoglobin effect)
What is the difference between constitutive and facultative urea production? Name one fish that does each.
Constitutive means constantly urea production Facultative means urea production in pulses Intermittent
Why do intracellular fluids have a different composition than extracellular fluids?
Contains water and dissolved solutes and proteins The solutes are electrolytes, which help keep our body functioning properly. An electrolyte is an element or compound that, when dissolved in fluid, breaks up into ions. There are a lot of electrolytes inside the cell, but potassium, magnesium, and phosphate have the greatest concentrations.
What is convergent evolution?
Convergent evolution: When organisms that are not closely related, independently evolve similar traits or mechanisms as a result of having to adapt to similar environments and physiological problems
O2 Equilibrium Curve (OEC)
Cooperativity between the 4 Hemo subunits gives the OEC its sigmoidal shape Binding O2: Binding of O2 to the 1st subunit induces a conformational change in the other subunits, which increases Hb attraction for O2 Releasing O2: When the 1st subunit releases O2, it induces the reverse effect, which lowers Hb attraction for O2
Compare and contrast the strategies used by crucian carp, Amazonic fishes, vampire squid, painted turtle, and mussels during hypoxia/anoxia.
Crucian Carp: Frozen Lake Ethanol Production Painted Turtle: Cold mud/water Buffering by carbonate from shell and skeleton Mussels: intertidal Succinate and propionate production through PEP branchpoint Vampire Squid: Oxygen minimum zone Amazonian Fish: Densely populated River/Swamp
Which environments and situations are associated with hypoxia in aquatic environments?
Densely Populated Environments: Organisms respire and deplete O2, especially at night in the absence of photosynthesis Tide pools, Mangroves, Coral Reefs, Kelp Forests Low Tide: Aquatic intertidal organisms cannot efficiently take up O2 from Air Seasonal hypoxia: Upwelling, algal blooms (including red tides) Permanent Hypoxia: Oxygen Minimum Zones
What is the osmotic gap?
Difference between the Intracellular Fluids and the Extracellular Fluids/SW Organic Osmolytes: 500 mM Important for maintaining internal volume regulation
Why do some divers accumulate lactate during a dive?
Diving mammals have high capacity for anaerobic metabolism First oxygen stores are used up Then animal switches to anaerobic ATP production Animal can continue diving without O2 But lactate and H+ accumulate!
Phosphagens
Does not require Oxygen First few seconds of intense activity ATP store and buffer Controls ATP flow between sites of synthesis and utilization
Glycolysis/Fermentation
Does not require Oxygen Takes place in the cell's cytoplasm Partial degradation of the carbon skeletons -> ~4% of the total energy from glucose Core glycolysis (makes ATP) and alternative endpoints (regenerates NAD+)
Draw Davenport diagrams for a tuna after 5 and 10 minutes of very intense swimming while it chases a prey. What type of acid-base disturbance took place? How does the tuna compensates it?
During foraging (hunting); White muscle sustains powerful swimming Anaerobic, high intensity-fast-burst swimming Obtains ATP from core glycolysis -> LDH Acidification: high buffering capacity, intra- and extra- cellular pH regulation
What happens to lactate during recovery from anoxia?
During recovery (back to normoxia), lactate levels go back to normal Lactate still has a lot of energy stored in its carbon bonds, so it would be wasteful to get rid of it Oxygen allows the oxidation of lactate in mitochondria (which makes 15 ATP) Excess ATP generated by aerobic respiration is used to convert lactate into glucose and store it as glycogen
Discuss Osedax eggs buoyancy in relation to their ecological niche.
Eggs are neutrally or negatively buoyant (They sink) Osedax Larvae with cilia (Allows them to swim around)
What is knotting and what does hagfish use it for?
Hagfish are able to bite without a jaw by using knotting Latch onto prey Tie themselves into a knot Pull the prey And then a piece of the prey's flesh will fall off and they can then enter the prey
Name one euryhaline shark and one ray species.
Elasmobranchs sharks: Some can tolerate some degree of brackish water Most cannot switch from NaCl secretion to NaCl absorption (at the gills) Kidneys cannot produce large amounts of dilute urine Urea would have to be excreted in freshwater and produced again when returning to sea water but it is very expensive Freshwater rays and skates Similar to bony fishes Little urea/TMAO Rectal gland is much reduced or absent Trade-off: cannot go to seawater (cannot accumulate urea or switch to NaCl excretion)
What is the main function of oxidative phosphorylation?
Electron transport chain (ETC) + chemiosmosis Generation of ATP
Hypercapnia
Elevated CO2 At night in coral reefs, mangroves, kelp forests... Photosynthesis and respiration during the day but only respiration at night Also in estuaries, upwelling, algal blooms, inside a whale carcass, OA Often associated with Hypoxia Acidosis
Carbonic Anhydrase (CA)
Enzyme that catalyzes the reaction that causes carbon dioxide and water to form carbonic acid Essential for CO2 Fastest Enzyme
V-type H+-ATPase (VHA)
Enzyme that uses ATP to transport H+ (acid)across biological membranes Protein pump
Why do fish eggs need to regulate buoyancy?
Even fish eggs must control buoyancy! They reduce the internal salt content (osmoregulation) Accumulate lipids (oil droplets)
Provide examples of physiological processes that depend on the NKA
Every cell: NKA is involved in cell volume regulation, pH regulation, nutrient uptake, waste product excretion Brain and Eyes: Uses ~60% of all the ATP used by neurons. It powers the action potentials and the neurotransmitter reuptake Intestine: It drives the absorption of nutrients, salts and water Liver: Uses ~25% of all the ATP used by liver cells to drive the movement of glucose, irons and other components Kidneys: Drives the absorption of amino acids and water excretion of waste products and blood pH regulation. Some can have up to 50m NKA pumps! Muscles: Helps maintain ionic gradients essential for muscle contraction 5 quintillion! Fish Gills: It consumes about 50% of all the ATP used by gill cells. It drives salt absorption and excretion and waste product excretion
How does a fish increase its respiratory surface area as it grows larger?
External gills: Evaginated from the body and project directly into the environmental medium (water) Internal gills: Evaginated from the body and project into a superficial body cavity through which the environmental medium is pumped Lungs: Invaginated into the body and contain the environmental medium Trachea: (Insects) Invaginated into the body; are simpler lungs Increased gill surface area is important for many processes including gas exchange, acid/base regulation, waste excretion, and filter feeding, and as such, is present across animal groups
Why is Marine Biochemistry Important?
Fascinating Reveals amazing adaptations to diverse environments You never know when it will come in handy, or where it will lead
What are the three major osmoregulatory strategies among marine vertebrates?
Fix 1: Drink seawater Fix 2: Absorb water in the intestine Fix 3: Excrete NaCl across the gills
How do notothenioid fishes without swim bladders regulate buoyancy?
Flounder effects: No swim bladder Nothothenoid species have colonized the entire water column despite not having swim bladders Buoyancy adaptations in notothenioids Reduced bone mass More cartilage than bone Hollow/Spongy bones filled with lipids Visceral lipid accumulation
What are the osmotic and ionic challenges experienced by freshwater bony fishes, and how do they deal with them? And fresh water elasmobranchs?
Freshwater bony fish: General problem: fresh water has lower NaCl and osmolarity than blood NaCl loss and water gain General strategy: Kidneys produce lots of dilute urine (pee a lot) Absorb NaCl across the gills Also obtain NaCl from food
What are the characteristic of the southern ocean?
Geographically isolated Climatically isolated Much colder than the arctic Very stable aquatic conditions Water is well mixed Water temp is stable -2C High O2 solubility at low temperatures Highly oxygenated water
What other cell types and organisms use an acid-excretion mechanism that is similar to that in Osedax root cells?
Giant Clams Convergent evolution of VHA for acid excretion and dissolution of hard calcium-based structures
Describe the mechanisms used by mussels to obtain energy during the tidal cycle.
Gills collapse, so they cannot efficiently extract O2 Extract O2 from the water within the shell (pallial cavity) until it is depleted Can oxygenate that water by gaping but desiccation might occur Hypoxia will ensue, and eventually anoxia... Opines are retained in the cell where they are produced Lactate exit cells through MCTs, but there are not any transporters for opines End products still have energy in their carbon skeleton, so disposing of them is not advantageous if food is scarce
What are the functions of urea excretion in the toadfish?
They switch to urea production in crowded/confined space, or aerial exposure Excrete urea in pulses Facultative Urea Excretion
Fermentation
Glycolysis + End Point Anaerobic respiration
What is the implication of hagfish having high plasma [Cl-] for acid/base regulation?
HCO3- gain equals Cl- loss at all times: blood A/B regulation while maintaining charge balance Hagfish can accumulate large amounts of HCO3- because they have lots of Cl- in plasma
What are three requirements that are essential for achieving regional endothermy in fishes?
Heat Source (constantly contracting / heat producing muscle) Heat source must be insulated to minimize convective heat loss Countercurrent heat exchanger to minimize heat loss at the gills
Explain why the hemoglobin O2 affinity curve is sigmoidal
Hemoglobin's oxygen-binding curve forms in the shape of a sigmoidal curve. This is due to the cooperativity of the hemoglobin. As hemoglobin travels from the lungs to the tissues, the pH value of its surroundings decrease, and the amount of CO2 that it reacts with increases. Both these changes causes the hemoglobin to lose its affinity for oxygen, therefore making it drop the oxygen into the tissues. This causes the sigmoidal curve for hemoglobin in the oxygen-binding curve and proves it's cooperativity.
What are the similarities and differences between hemoglobin and hemocyanin?
Hemoglobin: Iron Metal that binds O2; Vertebrates: Inside the Red Blood Cells OR Invertebrates: Dissolved; 4 Subunits or Complex; Cooperative ; Performs better in O2 rich Environments Hemocyanin: Copper Metal that binds to O2; Dissolved in the Hemolymph; up to 48 subunits; NOT Cooperative; Performs better in cold and low oxygen pressure
How do blood O2, CO2, [lactate] and heart rate change during a dive and during recovery from a dive?
High O2 consumption after a dive Lactate is stored in the muscle during a dive, and converted back to glucose in the liver -> Gluconeogenesis Phosphogens -> creatine + Pi + ATP = creatine phosphate The blood (hemoglobin) and muscle (myoglobin) O2 stores need to be re-charged The spleen is re-filled with oxygenated red blood cells
Why is O2 consumption elevated after a dive?
High O2 consumption after a dive Lactate is stored in the muscle during a dive, and converted back to glucose in the liver -> Gluconeogenesis Phosphogens -> creatine + Pi + ATP = creatine phosphate The blood (hemoglobin) and muscle (myoglobin) O2 stores need to be re-charged The spleen is re-filled with oxygenated red blood cells
What is the function of the gas gland? What is the function of the oval?
High rates of CO2 and lactate/H+ production (aerobic and anaerobic metabolism) Acidify the blood running through small vessels - the capillaries
Name 6 adaptations that allow icefishes to transport sufficient O2 in their blood in the absence of hemoglobin.
High solubility of O2 at low temperatures Icefish can transport more O2 in the plasma compared to temperate fishes Low metabolic rate Compared to temperature fishes But still active predators! High blood volume 12% of BW (4x that of other fishes) Large Heart 3-4x that of Notothenioids with hemoglobin High cardiac output 5-6x of Notothenioids with hemoglobin Tissue adaptations to enhance diffusion Large capillary density and diameter High mitochondrial volumes High intracellular lipid contents
Explain the physiological challenges that salmon face as part of its reproductive cycle
Homing: Salmon return to their native streams to spawn The salmon in every little steam are a separate population Anadromous salmon die after spawning Important source of nutrients for terrestrial ecosystems, such as forests
Describe the three-step process for Osedax nutrition. How do they dissolve the bone? How do they take up amino acids, and lipids?
How do the Osedax dissolve the bones? Proton Pumps! Mechanism resembles human Osteoclasts However, Osedax do not have a gut, so how does it digest the nutrients that are absorbed from the bone?
Painted Turtle: What are the two mechanisms that prevent lethal acidification?
How does it prevent lethal blood acidification? Shell accounts for ~30% of the body mass (including ribs and vertebrae) Skull and other bones are another ~6% of body mass The bone mass of turtles is ~3-fold higher than in a lizard or mammal of the same size Shell and bone has lots of Ca2+ and CO32- Shell is perfused with blood (has blood vessels)
How do cells regulate their volume when they swell or shrink?
Hypotonic solution: More solutes on the inside of the cell; Less in the outside Hypertonic solution: More solutes on the outside of the cell; Less in the inside Cell volume regulation
What mechanisms may allow animals to survive in hypoxia, but are not useful in anoxia? Explain why
Hypoxia tolerant Amazon fishes and in general tend to have: High levels of hemoglobin and red blood cells Hemoglobin with low P50 Low activity levels High ability to produce ATP using fermentative pathways (end product: lactate) High ability to counteract or withstand acidification High gill surface area Other respiratory surfaces
In relation to their environment, what are the osmotic challenges experienced by marine invertebrates, hagfish, sharks, and bony fishes?
INTRAcellular: Marine Invertebrates: Accumulate lots of amino acids Hagfish: Accumulate amino acids AND TMAO Marine Elasmobranchs (Sharks, Rays, Relatives): Accumulate lots of Urea and TMAO, some amino acids Marine teleosts (Bony Fish): Accumulate some amino acids (much less than others) EXTRAcellular: Marine Invertebrates/Hagfish: Similar NaCl and Osmolarity to Seawater; No major adjustments needed; Iono- and Osmo-conformers Marine Elasmobranchs: About half NaCl amounts to Seawater; Similar Osmolarity to Seawater; Problem: Tendency to gain NaCl (through Urea + TMAO accumulation); Need to excrete excess NaCl (through rectal gland); Iono-regulators and Osmo-conformers Marine Teleosts: About one third NaCl amounts to Seawater; About 40% Osmolarity to Seawater; Problem: Tendency to gain NaCl; Need to: excrete excess NaCl (gills); Problem: Tend to lose water (dehydration); Need to: drink Seawater; Iono- and Osmo-regulators
What are the intracellular and the extracellular fluids?
INTRAcellular: Fluid contained within the cell Individual tissue cells containing intracellular fluids are bathed by interstitial fluid, with only the cell membrane separating the two EXTRAcellular: Fluid outside of the cell Surrounding Cells of Muscle Cells: Interstitial Fluid Surrounding Cells of Red Blood Cells: Blood Plasma
Provide examples of low density substances used to maintain buoyancy
Iceberg, Ship, Air Ship
What are the different mechanisms for intracellular and extracellular acid-base regulation?
Internal Origin Regular cellular metabolism Anaerobic metabolism during exercise or exposure to hypoxia Feeding External Origin Elevated environmental CO2 (hypercapnia) In aquatic environments, hypercapnia is the most common external A-B disturbance
What happens with the calcium carbonate that is produced during intestinal water absorption?
Intestinal carbonate precipitation (releasing chalk) Freshwater: different osmotic problem -> do not drink water -> no carbonate precipitates in the intestine Seawater: drink seawater -> carbonate precipitates in the intestine -> intestinal water absorption
What is the Davenport diagram and why it is useful?
In acid base physiology, the Davenport diagram is a graphical tool that allows display of Acid Base states. They illustrate the dynamic relationships between arterial blood pH, bicarbonate and non-bicarbonate buffers, and the partial pressure of carbon dioxide.
What ions does the NKA transport, and in which directions?
In muscles, NKA is associated with the enzyme Creatine Phosphokinase (CPK) Facilitates the supply of ATP from Phosphor Creatine Ions: Na+ and K+ ions
Mention five characteristics found inside a decomposing whale carcass
In vitro experiments suggest that the interior of a decomposing whale carcass may have a very low pH and a very high CO2 Pork muscle and liver in sealed containers filled with seawater pH dropped to ~5 and pCO2 raises to 30 mmHg after just 4 days of incubation Ammonia increased significantly
How does pH affect enzyme function and activity?
Intracellular pH = pH of the cytosol = pHi The pHi of most cells is between 7.0-7.5 pH units Some cells can have a pH as low as 6 and as high as 8 Other intracellular compartments have different pH pHi can change depending on activity levels, aerobic or anaerobic conditions Some examples of Enzymes affected by pH changes Enzymes have an optimum pH at which they work more efficiently Enzymes in core glycolysis Excessive intracellular acidification can inhibit core glycolysis and thus ATP production
Why are the concentrations of NH4+ and Na+ inversely related in buoyancy compartments?
Inversely proportional Because positive/negative charge ratio must be maintained neutral
How do marine invertebrates make up for the osmotic gap, and why is this important?
They use Amino Acids for osmoregulation of intracellular fluids!
Why there is little flexibility to change the diffusion coefficient (K) of respiratory surfaces?
K is the diffusion coefficient: It depends on the specific gas, temperature, and ease with which gas can pass through the material separating the two media For our purpose, the material is the layer of tissue that forms the respiratory surface
What are hagfish two ways of feeding?
Knotting Slime clogging
Painted turtle: why is there massive accumulation of lactate during anoxia? Where is lactate accumulated?
Lactate dehydrogenase (LDH): Enzyme that oxidizes NADH to NAD+ and reduces to lactate ATP hydrolysis generates H+ that can build up and be toxic Monocarboxylate transporter (MCT) Massive lactate accumulation during anoxia Water bubbled with N2: anoxia leads to anaerobic metabolism Massive lactate accumulation Water bubbled with air: O2 across skin allows some aerobic metabolism in mitochondria Much less lactate accumulation (and some consumption of lactate)
Describe the enzymatic differences in the liver of Magadi tilapia compared to the Sugano river tilapia (no need to know specific enzyme names)
Lake Magadi tilapia has much higher levels of enzymes of the urea cycle in liver and much higher urea levels in plasma
Opah
Large elliptical brightly colored deep-sea fish of Atlantic and Pacific and Mediterranean
Epithelia
Layers of cells covering internal or external surfaces
What is a supercooled state?
Liquid below its freezing point
Describe the experiment that established the relationship between feeding status and buoyancy during shark migrations between California and Hawaii
Liver size (and thus buoyancy) depend on nutritional status As the shark gets larger, so does its liver -> slower sinking rate Migration!
What triggers the activation of PEPCK at the PEP branch point?
Longer term Hypoxia/Anoxia (longer than 3h)
What are hagfish strategies for dealing with low Oxygen levels?
Low metabolic rate Large volume of blood Hemoglobin with low P50 Some capacity for O2 uptake across the skin High capacity for anaerobic metabolism (lactate production) (high resistance to acidosis)
Hypoxia
Low oxygen saturation of the body, not enough oxygen in the blood
Hypocapnia
Lower CO2 levels Alkalosis
Explain the "lip mechanism" used by the Tambaqui to increase O2 uptake, and the experiment that established its importance
Lower lip is highly vascularized During exposure to hypoxia, the lower lip becomes expanded and facilitates O2 uptake from the surface water by skimming Drawing oxygenated surface water over the expanded lower lip increases blood oxygen content by up to 30% Lip efficiency: Additional O2 taken up by the lower lip
Alternative Endpoints
Main function is to regenerate NAD+ BUT has implications on ATP yield and acidic load
How can cell walls prevent water fluxes? What are their limitations?
Maintaining cell consistency, cell walls resist the changes in volumes (like the rigid shell of an egg) Tradeoff with rigid cell walls: Don't prevent cell shrinkage Limit diffusion of gasses Expensive to build (Requires lots of ATP and energy) Still requires other mechanisms of osmoregulation
What was the composition of the extracellular fluids of the most ancient marine animals?
Major ions in seawater and in the extracellular fluids of animals Ancient organisms had osmotic balance with seawater
What are the three general mechanisms to cope with hypoxia?
Make more Hemoglobin Make hemoglobin with lower P50 Increase surface area of respiratory epithelium Metabolic Depression Not all hypoxia tolerant animals are able to use all of these strategies!
What is the mammalian dive reflex (name the 2 major components) and why does it prolong the duration of a dive?
Mammalian adaption to meter out the existing O2 stores during a dive Reduction in heart rate (bradycardia) Triggered by water receptors around the nose, mouth and pharynx Arterial chemoreceptors (blood pH and PO2) in the carotid bodies Reduces metabolic rate and O2 consumption
What are the osmotic and ionic challenges experienced by marine bony fish, and how do they deal with them?
Marine bony fishes need to gain water and secrete NaCl Osmotic problem 1: Higher osmolarity in seawater Dehydration Osmotic problem 2: More NaCl in seawater NaCl gain and disruption of homeostasis
Alternative Pathways
Maximize ATP to H+ production ratio, but cannot sustain the same ATP production rate
Describe step by step how hagfish slime is produced and how it helps protect against predators
Mechanism for hagfish slime production Glue protein in thread cells dissolve Thread unravels Mucin swells It attaches to thread proteins Movement further pulls thread, more mucin attaches -> slime Safety Mechanism Pressure from a predator's bite triggers the contraction of the slime gland muscle As GTCs and GMCs are pushed through the pore, their external membranes shear, exposing their contents Thread and mucin interact with seawater
How does the vampire squid match ATP supply and demand?
Mechanisms to save energy While all other cephalopods are carnivorous, the vampire squid feeds on food particles that fall from the surface ocean This feeding mode is passive (requires little energy) Detritivore: An animal that feeds on dead particulate organic material (detritus) Vampire squid hemocyanin has the lowest P50 among all cephalopods Also low O2 consumption rate and high gill diffusion capacity
Countercurrent Exchange
Medium and blood flow in opposite directions Blood always encounters medium with a steady O2, partial pressure difference Maximizes partial pressure difference between water/air and blood Blood can achieve higher O2 saturation Fish ventilate the water by: Buccal pumping, spiracle (sharks and relatives) Opercular pumping (bony fish) Ram ventilation (swiming with the mouth open) Invertebrate animals have similar mechanisms
What are the different types of A/B stress?
Metabolic Acidosis: reduced pH due to increased metabolic acid (H+) production (anaerobic metabolism) Metabolic Alkalosis: elevated pH, most times due to increased metabolic HCo3 Respiratory Acidosis: reduced pH due to elevated CO2 levels (increases H+) Respiratory Alkalosis: elevated pH due to lower CO2 levels (decreases H+) Not very common in marine animals
Aerobic Metabolism
Metabolism that can proceed only in the presence of oxygen Takes place in the Mitochondria Includes the TCA cycle Complete degradation of carbon skeletons
Why do they have abundant mitochondria?
Mitochondria provide the ATP for the NKA needed for the general processes
Describe the mechanism for NaCl excretion in rectal gland cells, step by step.
Mitochondria provides ATP for NKA NKA keeps intracellular Na+ very low (ONLY STEP USING ENERGY) Excessive K+ accumulation is prevented by the basolateral K+ leak channel Low Na+ drive Cl- import into the cell (together with Na+ and K+) through NKCC Opposite charges attract one another (same repel each other) Cl- wants to leave the cell Cl- leaves the cell through the only route it has: The apical CFTR, into the lumen of the rectal gland Na+ follows through the paracellular pathway (in between cells) NaCl is excreted
Tidal Gas Exchange
Mix of fresh and stale medium blood flows along the respiratory surface Sporadic generation of water currents using muscular contractions Sponge, corals, mussels, and other organisms can also stir the boundary layer using ciliary beating These strategies are important for feeding Used by sea cucumbers!! And the Fitzroy turtle
Hagfish
Most basal extant vertebrates: Diverged from the other branches of the vertebrate lineage (~500m years ago) Evolved in seawater Feed inside carcasses of dead animals: High CO2, Low pH, high Ammonia Slime Production
Describe the three most common types of blood A/B stress experienced by aquatic animals, and how they compensate them
Most common A/B disturbances in aquatic animals Respiratory acidosis: caused by elevated pCO2 Metabolic acidosis: caused by addition of H+ Metabolic alkalosis: caused by addition of HCO3
How do hemoglobin and myoglobin interact to ensure O2 delivery to muscle? And maternal and fetal hemoglobin to ensure O2 delivery to the fetus?
Myoglobin: Related to hemoglobin, but only has one subunit. So it does not have a cooperative effect for O2 binding Higher affinity for O2 than hemoglobin Role: Store O2 (rather than transport it) and to further help Hemoglobin offload O2
What are the advantages and disadvantages of each nitrogen excretion mechanism?
NH4+ Excretion: Only accumulates so much before it is toxic (in this case 50uM = .05mM) NH4+ is highly soluble in water-> it can be excreted to the surrounding water and it will diffuse away Urea Excretion: Is 20-fold less toxic than ammonia, so it can accumulate 20-fold more Urea is also highly soluble in water Has 2 nitrogen/molecule
Why does the lake Magadi tilapia excrete urea instead on NH4+?
NH4+ would be deprotonate to NH3 (gas) in the outside water, which would diffuse back into the fish Pumping out ammonia can just be brought back into the fish Constant urea excretion
What molecules does the NKA help transport by secondary active transport?
NKA also drives the movement of molecules across the epithelia Epithelia: A thin tissue layer in contact with the external environment Ie: skin, gills, lungs, kidney tubules, intestinal tract, nasal passage, mouth... Non-polarized cells: Red blood cells, muscle cells, fat cells, neurons Epithelial cells are POLARIZED
What percentage of total ATP does the NKA use in a developing sea urchin larvae? In which process(es) it is involved?
NKA can use up to 90% of all the ATP in developing sea urchin larvae Amino acid take up from sea water across the skin and skeleton calcification
Why does the NKA require ATP?
NKA is present in all animals cells Consumes about 20-80% of all the ATP in a cell Essential for pH regulation, osmoregulation, transport of molecules, energy metabolism, nervous signals and much more Uses energy from ATP hydrolysis to move 3 Na+ out of the cells and 2 K+ into cells in each cycle To transport Na+ and K+ from a place with lower concentration to a higher concentration, they must transport against the concentration gradient.
What animals have rigid buoyancy gas chambers? What are the advantages and disadvantages?
Nautilus Does not change volume with depth/pressure Requires energy, relatively slow It might break at higher pressure (limits depth)
What are the different body parts of Osedax?
No mouth, no gut They have gills though!
Normocapnia
Normal CO2 Levels
Explain mechanisms in respiratory surfaces and respiratory pigments that help maximize oxygen uptake and delivery during hypoxia. Give examples of organisms that use those strategies
Obtaining enough ATP through fermentative pathways (which do not require O2) However, it requires: Enough energy fuel (food) Being able to regenerate NAD+ Dealing with waste products Crucian Carp
What is the isolated dive hole protocol?
One hole in the diving area that is possible, that way they have to always come back to the one hole Penguin Farm
At which Whale Fall stage(s) Osedax appear?
Osedax: Bone-eating worms Appears in the 2nd (Enrichment opportunist stage) and 3rd (Sulphophilic-loving stage) stages where the bone(s) of the whale are exposed 1st (Mobile-scavenger stage) stage is just flesh and meat
How is Osedax mechanism of nutrition similar to that of hagfish?
Osteoclasts from vertebrate animals Goes into bones and secrete acids using the protein pump and can dissolve the bone in bodies Used for humans in bone-remodeling
For a given respiratory pigment (or blood), what is the difference between "oxygen binding affinity" and "oxygen carrying capacity"?
Oxygen Binding Affinity: Oxygen carrying capacity: Maximum amount of O2 held by one gram of each respiratory pigment
What is the aerobic dive limit (ADL)?
Oxygen stores (mL) / Oxygen consumption in mL/min Aerobic dive limit General strategy to increase dive time Increase oxygen stores
What are the challenges experienced by the vampire squid in the OMZ?
Permanent hypoxia Low metabolic rates: Lowest mass-specific MR of all deep-sea caphalopods Weak musculature, change from jet propulsion to fin swimming (less active -> requires less energy)
Describe the concepts of paracellular vs. transcellular ion movements.
Paracellular transport is the movement of substances across the epithelium through the intercellular spaces between the cells. Transcellular diffusion is the transport of molecules through both apical and basolateral membranes.
Name 3 adaptation by which diving animals increase their O2 stores.
Partitioning of O2 stores: Non divers often rely on the O2 storage in their lungs Divers store large amounts of O2 in the blood and in their muscles Hemoglobin as O2 stores More hemoglobin = more O2 BUT red blood cells are already saturated with hemo; produce more red blood cells = higher hematocrit Heart can have issues with this. Trade-offs with increasing hematocrit and heart issues Storage of red blood cells in the spleen Release red blood cells into circulation Larger blood volume
What are the three processes that take place in mitochondria to enable aerobic metabolism?
Phosphagens: Creatine phosphate + ADP + Pi -> ATP + creatine Glycolysis/Fermentation: Glucose + 2 ADP + 2 Pi -> 2-3 ATP + lactate/opine Aerobic Metabolism: Glucose + 36 (ADP+Pi) +6 O2 -> 36 ATP + 6 CO2 + 6 H2O
PEP Branch Point
Phosphoenol Pyruvate Continues RedOX reactions in mitochondria Net ATP production is 6 Consumes H+ Regenerates NAD+ Disadvantage: Produces ATP at a slower rate compared to the opine pathway
Explain the mechanism that fills up a closed swim bladder
Physoclist swimbladder Bony fish have a root effect: Large acidification induces the loss of O2 cooperativity, which maximizes O2 unloading from hemoglobin Gas gland: High rates of CO2 and Lactate/H+ production Acidifies the blood running through small vessels Rete mirabile: Extraordinary, wonderful net A small and dense network of blood vessels Multiplies the pressure of O2 O2 fills up the swim bladder by diffusion Oval = has muscular valve to release O2 into the blood by diffusion
What are potential industrial uses of hagfish slime? What are its advantages compared to synthetic and other biological polymers?
Potential biotech advantages Production of fibers and films for solubilized hagfish slime thread proteins Potential applications
How have icefish adapted to excrete CO2 in the absence of red blood cell carbonic anhydrase?
Problem: CO2 Excretion Solution: Icefish make their own CA
Fermenation
Process by which cells release energy in the absence of oxygen Anaerobic Takes place in the cytoplasm Partial degradation of carbon skeletons Core glycosis
Diffusion
Process resulting from random motion of molecules by which there is a net flow of matter from a region of high concentration to a region of low concentration
Anaerobic
Process that does not require oxygen
Aerobic
Process that requires oxygen
Respiratory Pigments
Proteins that transport oxygen, greatly increase the amount of oxygen that blood can carry Increase blood O2 capacity O2 can be transported dissolved in circulatory fluids (plasma) However, solubility is typically low, so the amount of O2 that can be transported is also low "Respiratory pigments" are metalloproteins that reversibly bind O2
What proteins are present in rectal gland cells and are important for NaCl excretion? Where in the cell is each protein found?
Rectal gland cell has: Basolateral NKA; Na+/K+/2Cl co-transporter (NKCC); K+ Channel Apical Cystic fibrosis conductance regulator (CFTR) (Cl- Channel) Lots of mitochondria
Basolateral
Refers to the cell membrane which is oriented away from the lumen of the tubule
Apical
Refers to the cell membrane which is oriented towards the lumen
How long does it take to refill each slime gland? Does this mean that the hagfish is totally defenseless during this period? Why or why not?
Refilling a slime gland takes ~30 days Each gland is not completely emptied every time and not all glands are emptied at the same time
What are the different body regions that some fish are able to preferentially warm? What are the advantages in each case?
Regional Endothermy: Internal production of heat allowing for certain organs or parts of the body to be warmed
Aerobic Metabolism
Requires Oxygen Takes place in the mitochondria Includes the TCA cycle and oxidative phosphorylation Complete degradation of carbon skeletons -> ~40% of the total energy from glucose
Left Shift
Requires less oxygen Higher affinity for O2 Lower P50 Decreased temperature Decreased H+ (lower pH) Decreased PCO2
Right Shift
Requires more oxygen to achieve 50% saturation Lower affinity for O2 Decreased Affinity, Higher P50 Increased temperature Increased H+ (lower pH) Increased PCO2
What are three strategies used by organisms to maximize O2 uptake, transport and delivery for aerobic metabolism? Relate it to Fick's Law
Respiratory epithelium: The thinner the respiratory surface is, the faster gas diffusion takes place Large surface area Circulatory systems: Counter-current mechanism to maximize partial pressure difference between water/air and blood
Why do fishes that live deeper have a longer rete mirabilis in their swim bladders?
Rete mirabilis is longer in deeper fish Need to accumulate gas against larger hydrostatic pressure These can generate higher pressures
What are the four essential components of the Davenport diagram?
Rule 1: All A/B disturbances due to addition or subtraction of CO2 move along the non-bicarbonate buffering line If CO2 increases, the reaction moves to the right and three is more H+ and more HCO3 Rule 2: All A/B disturbances due to addition or subtraction of H+ move along the CO2 isopleths If H+ increases, pH decreases The reaction moves to the left and initially there is more CO2 and less HCO3 However, CO2 diffuses out of the system so it remains constant Rule 3: The slope of the NBB line is proportional to the NBB capacity The higher NB buffering capacity -> the steepest the NBB line -> the smaller the pH change when you add CO2 Higher buffering capacity: smaller pH change Lower buffering capacity: larger pH change
What is the osmolarity of a solution with 250 mM NaCl? And of a solution with 250 mM glucose?
Same molarity (same amount of solute) HOWEVER they have a different OSmolarity (different amount of solute PARTICLES) NaCl: 500 mOsm (Dissolves into 2 Substances: Na + Cl) Glucose: 250 mOsm (Dissolves into 1 Substance: Glucose)
How can some animals exceed their aerobic dive limit (ADL)?
Selective peripheral vasoconstriction Blood flow is maintained to vital tissues BLood flow is restricted to other tissues
Core Glycolysis
Several steps that are catalyzed by enzymes Use ATP to activate glucose for the upcoming reactions Other enzymes strip electrons away from glucose
Explain "sexual dimorphism" in Osedax.
Sexual Dimorphism: Large females and microscopic males Males are tiny and their job is to hook onto the female ovary and reproduce The female will "spawn" or throw her fertilized eggs out as a way to reproduce The only exception is the O. priapus which has a similar sized male and female
Why is a carnivorous diet essential for sharks?
Sharks and relatives, have a protein-rich diet Proteins are stored in the muscle, which gets larger as the shark grows Protein turnover and oxidative deamination
What does endemic mean?
Species that don't occur anywhere except at the place (aka antarctica)
Phoshagens
Simplest pathway Does not require oxygen Serve as a reserve of high energy phosphate used for rapid ATP utilization Serve as ATP store and buffer
What are some of the implications of the pH scale being logarithmic?
Since the pH scale is logarithmic, the changes in pH units are not linear. Meaning that a given change in pH is associated to different acid loads depending on the position in the pH scale Eg an acidification from pH 7.3->7.0 is much greater than one from 8 to 7.7 (5-fold greater) Log scales can be misleading because they show an equal difference on graphs
Describe the general buoyancy strategy
Static mechanisms of buoyancy control Get the animal closer to neutral buoyancy (saves energy) Are controlled by the animal, but respond slowly Dynamic Mechanisms of buoyancy control Get the animal closer to neutral buoyancy (saves energy) Are under active control and respond fast - eg. can be used to rise and sink as well
What is the cellular mechanisms for intestinal water absorption in marine bony fish? Describe it step by step.
Step 1: Drink! Marine fishes drink Seawater almost constantly! A lot of water, but also a lot of salt They must excrete NaCl across the gills Step 2: Absorb! To avoid dehydration and salt overloads They can absorb solute and water from their lumen (in the intestine) to the blood and plasma
Phosphokinases
Substrate level phosphorylation
How do "surface to volume ratio" and "countercurrent heat exchangers" contribute to thermoregulation?
Surface Area to Volume Ratios: Lower surface area to volume ratios are better This is because they can hold in more heat and are able to thermoregulate easier! Countercurrent Heat Exchangers: Flippers and blood vessels that can help facilitate movement of temperature
How does surface area scale compared to volume? What are the implications for gas exchange?
Surface area of the respiratory surface, total area of the skin, gill or lung The larger the organism, the larger the SA The larger the organism, the greater the number of cells, and thus the larger the volume More cells require more O2 to sustain aerobic metabolism
Why have some terrestrial tetrapods re-invaded the marine environment?
Take advantage of some sort of ecological niche Food Safety/Shelter
Why do sites of NH4+ accumulation for buoyancy have an acidic pH?
The sites of NH4+ accumulation have an acidic pH Buoyant body parts have higher NH4+ and lower Na+ and a lower pH (acidic) Acidic trapping
What is "buffering capacity"?
The ability of a buffered solution to absorb protons or hydroxide ions without a significant change in pH; determined by the magnitudes of [H+] and [OH-] in the solution
Hypoxia Tolerance
The ability to balance energy supply and demand
What is metabolic suppression? What are the main processes that get suppressed?
The ability to reduce metabolic rate during exposure to environmental stress All processes are suppressed in anoxia/hypoxia, but NKA activity is suppressed the least and this reflects just how important it is! Gluconeogenesis Urea synthesis Protein Breakdown Protein Synthesis NKA
What are "temporal" and "regional" endotherms?
The animals in-between the two Ecto/Endo therms
What adaptations do divers have to maintain pH homeostasis during a dive?
The blood of diving animals has a higher buffering capacity compared to non-divers Primary Buffers
ATP can drive reactions
The energy from ATP hydrolysis can be coupled to reactions that are energetically unfavorable and will not happen otherwise
How do marine bony fishes deal with the excess NaCl load?
The excess NaCl is excreted across the gills by specialized cells using the same mechanism as shark rectal gland cells Cellular mechanisms for NaCl excretion across specialized gill cells Exactly the same mechanism as the Shark Rectal gland, except it is in the gills of the bony fish!
Why is the composition of the extracellular fluids of marine elasmobranchs different from that of marine bony fishes?
These animals at the Cambrian period had no major fluxes of water between cells and extracellular fluids No major fluxes of water between extracellular fluids and seawater/environment
Oxidation
The loss of electrons from a substance involved in a redox reaction.
How do you think the python will compensate blood alkalosis after a large meal? (e.g. after eating a deer)
The magnitude of the alkaline tide is proportional to the size of the meal
What are the major ions in seawater, and their concentrations?
The most abundant ions of seawater are Chloride (Cl-), Sodium (Na+), Sulfate (SO24-), Magnesium (Mg2+), Calcium (Ca2+) and Potassium (K+) By weight these ions make up about 99 percent of all sea salts Cl-: 510 mM Na+: 440 mM K+: 10 mM The rest make up the last 100 mM ~ 1060 mOsm
Convection
The movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, dense material to sink under the influence of gravity, which consequently results in transfer of heat
What are H+ and why are they important?
The proton H+ is a subatomic particle with a positive electrical charge In the atom, it balances the negative charge of the electron Proton can also be found free as hydrogen ion (H+) H+ is the smallest solute in physiological fluids and extremely reactive because of its strong positive charge in relation to its size
What is the rectal gland, and what is its physiological function?
The rectal gland is a sodium chloride secreting epithelial organ. The gland, composed of homogenous tubules of a single cell type, is an important model for secondary active chloride transport.
Chemical Equilibrium
The state in which the reactants and products have no net change over time. This is when the forward and reverse reactions occur at equal rates
Respiratory Epithelium
The thinner the respiratory surface is, the faster gas diffusion takes place If too thin, it would be too fragile, so this is why
What happens to ATP supply and demand in hypoxia-tolerant organisms? And in hypoxia-intolerant organisms?
These processes happen in all animals but Not tolerant species cannot make significant adjustments so everything happens very fast Tolerant species are able to decrease ATP consumption in a regulated manner
What is the significance of this for osmoregulation?
They are able to keep a steady flow of osmoregulation due to their ability to control their buoyancy and NH4+ counts
What are the two cells found in the hagfish slime gland that are essential for slime production?
Thread cells and Mucus cells with mucin vesicles
What type of protein makes the coiled structure in thread cells?
Thread cells: Each thread cell produces one and only one proteic thread (up to 60cm) Made of a keratin-like protein from the "Intermediate filament" family
Saturation and P50
To find P50: Find "50%" saturation in the y-axis Extend the line to the right until you hit the O2-Hb saturation curve From that point, extend a line downwards until you reach the x-axis That value is the P50
What is a tradeoff that conditions the affinity of a respiratory pigment for oxygen?
Tradeoffs and Regulations: O2 binds to an iron molecule Fe embedded in the heme group of hemoglobin In vertebrates, hemoglobin is packed inside RBC Hemoglobin are composed of 4 subunits: 2 Alpha and 2 Beta Each subunit has an iron-containing porphyrin called hemoglobin group that binds O2
What is secondary active transport?
Transport other molecules in and out of cells by this transport Uses Na+ gradient to move other molecules in or out of the cell
Why do Osedax roots require an abundant oxygen supply to be able to excrete acid and dissolve bones?
Trophosome: Specialized tissue in Osedax roots that host symbiotic bacteria O2 is necessary for CO2 production by aerobic respiration
Name 4 challenges that breath-hold divers experience during a dive.
Typically cold temperatures High density medium Buoyancy control Challenged vision Large pressure changes and decompression sickness (the bends) No ventilation or lungs
How do sharks and rays achieve buoyancy?
Using their livers to store lipids! Pectoral fins and asymmetrical tail provide dynamic lift
How are Osedax gill cells similar to shark gill cells?
VHA and gill cells likely mediate bicarbonate excretion to SW Similar to the base-secreting cells from sharks VHA can absorb or excrete H+ depending on its localization within the cell
How do some mammalian hibernators recycle urea in the winter?
Vertebrates lack urease The enzyme that converts urea back into NH3
What are the functions of myoglobin and how can it increase the duration of a dive?
Very high affinity (low P50): draws O2 from Hemo into the muscle Facilitates diffusion at higher concentration Myoglobin binds O2 and stores it in the muscles
Crucian Carp Example
Very hypoxia tolerant and one of the only anoxia tolerant vertebrates Can survive anoxia for months at 0 degrees C Carp has very low P50, and increased gill surface area Longer lamellae increase gill surface area by 7.5 fold They have reduced locomotion and general activity levels Swimming activity is reduced by ~75%
What is the viscosity of a fluid?
Viscosity is the internal resistance to deformation Thickness
How do Antarctic fishes overcome the increase in blood viscosity at low temperatures?
Viscosity of fluids increases in the cold Polar fishes keep a low viscosity Hct increases viscosity Polar fishes keep a low viscosity Icefishes have no red blood cells
What does it mean to be an endothermic or an ectothermic animal?
Warm Blooded vs. Cold Blooded Ectothermy: Body heat derived from outside (the environment) Endothermy: Body heat derived from inside (metabolic processes)
Endothermic Animal
Warm blooded Mammals, Birds
What factors affect O2 solubility in water?
Water holds much less O2 than air. In addition, gas solubility decreases with temperature and salinity Saltier or warmer waters hold even less O2
Why is extracting O2 from water much more difficult than from air?
Water holds much less O2 than air. In addition, gas solubility decreases with temperature and salinity Saltier or warmer waters hold even less O2 Water is more dense and heavier than air Requires ventilating more volume of a much heavier medium
Chemical Equilibrium Law
When a system is in equilibrium and is subjected to a change, the system re-adjusts itself to counteract the effect and reach a new equation
What type of nutrients are trapped in bone? How are whale bones unique?
While Osedax are not exclusive for whale bones, but they might be the most convenient and the best for their survival They also consume fishbones, even reptiles! Bones contain a significant amount of nutrients in the form of collagen Whale bones contain a lot of fat (ribs and jaws can be >80%)
Explain the relationship between intracellular buffering capacity and muscle activity
White/Red Muscles and pH buffering capacity in each
Osedax
Zombie worms, feed on whale bones w/sympiotic bacteria
Reduction
the addition of electrons to another substance