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73 Cards in this Set
- Front
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What happens to our body when we drink water to maintain a dynamic "steady state"? |
H2O in --> Osmolality decreases in the blood--> This decrease is sensed by osmoreceptors in the brain--> Production of ADH--> H2O out---> Osmolality increase. |
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In the case of passive exchange, what is the amount dependent on? |
– The gradients of the moving substance – Permeability across the membranes of the substance – Surface to volume ratio |
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Which internal factors need to be kept in homeostasis in order for an organism to function? |
1. Gases: O2 and CO2 2. pH in the internal environment 3. Water, ions, and other osmolytes 4. Nutrients and waste products 5. Temperature 6. Volume and pressure of extra cellular fluids |
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What does it mean if something is a threat to homeostasis? What does an organism have to do in order to achieve homeostasis again? |
Threats are stressors that will affect the balance of homeostasis and energy is required to maintain it. For example: * Change in partial pressure of O2 or CO2 * Change in pH * Change in temperature * Predation * Injury * Lack of food When a threat to homeostasis occurs, reserved energy needs to be consumed in order to achieve homeostasis once again. |
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What is the difference between regulators and conformers? |
Regulator: * Possess a constant internal environment or homeostasis. * Maintain their body temperature. * The body fluids have a fixed osmotic concentration. * Consume large amount of energy. * Have a wide range of environmental distribution. Conformer: * Their body temperature changes according to that of environment. * Osmotic concentration of body fluids varies according to that of external medium. * They consume lesser amount of energy and are less active. * They (in most cases) have a narrow range of environmental distribution. |
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What is feedback regulation when a stressor is affecting an organism? What different kinds of feedback regulations are there and how does it work? |
Feedback regulation is the main component of homeostasis. A) On/Off system (a very rough system) B) Proportional system (On/Off working at the same time in "tonus"). The mechanism: 1. A stressor will affect a variable 2. This variable triggers a sensory system in the body 3. The sensor sends signals to an effector 4. Effector acts to regulate and maintain homeostasis. |
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What is Allostasis? |
The process of achieving homeostasis through physiological or behavioural responses. |
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What is developmental plasticity and phenotypic plasticity? |
Developmental plasticity: Changes in neural connections during development as a result of environmental interactions as well as neural changes induced by learning. Phenotypic plasticity: Short‐term changes in a character or trait to meet changes in the environment. |
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What are the roles of the cell membrane? |
The cell membrane (also called plasma membrane) have the role of: * Being a selective barrier * Being a selective transporter * Keeping up the membrane potential * Keeping up cell volume * Keeping intracellular homeostasis * Being an anchoring place for receptors * Being an anchoring place for cytoskeleton * Being an anchoring place for some enzymes * Creating connections between cells * Creating possibilities for communication * Being a receiver of communication signals |
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What is the membrane potential? Is it positively or negatively charged? What is the membrane potential range in millivolts (mV)? |
The difference in electric potential between the intracellular environment and the extracellular environment of a biological cell. With respect to the exterior of the cell, typical values of membrane potential range from –40 mV to –80 mV. (Negatively charged) |
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Why are there very low levels of Calcium ions inside the cell compared to the outside? |
Calcium ions (Ca2+) are second messengers that sends signals from the extracellular environment to the intracellular environment. In order for signal to be sent, a calcium channel must open and calcium ions can cascade into the cell which creates an activity inside the cell. This would not be possible if there were high amounts of Ca2+ inside the cell. |
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What are the three main lipids in the cell membrane? |
Sphingolipids- Play important roles in signal transmission and cell recognition. Cholesterol- Essential to maintain both membrane structural integrity and fluidity. Phospholipids- Major component of all cell membranes. Is critical to a cell's ability to function. |
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What does the term "amphifatic" mean when referring to membrane lipids? |
It means the membrane lipids has a polar head and non-polar tails. This formation allow them to form a membrane lipid layer. |
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What is cholesterol needed for? |
Production of: * Cell membranes (also strengthens it) * Bile acids and cholin * Hormones Also very important to prevent cell leakage and increase the fluidity of the cell membrane. |
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What are the three main membrane proteins and what are they important for? |
Transmembrane proteins * Mainly acts as transporters of: - Channels - Enzymes - Carrier proteins Integral proteins Mainly acts as: - Receptors - Anchoring proteins - Recognition proteins - Enzymes Peripheral proteins Mainly acts as: - Receptors - Anchoring proteins - Recognition proteins - Enzymes |
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What are the different pathways occurring in polarised cells and what are tight junctions? |
Paracellular pathway: Transport between epithelia cells, is controlled by the tight junctions. (Only possible for water soluble molecules). Trancellular pathways: Transport through epithelia cells. Needs transporters. (easy for fat soluble molecules). Tight junctions= Barriers between epithelial cells that stops molecules from simply floating into/through the cellayer. |
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What are the driving forces for transporting substances across membranes? What do they do? |
1 a) Passive diffusion * Caused by an electrochemical gradient which creates the driving force for movement * Osmosis (passive diffusion of water) 1 b) Facilitated diffusion * Caused by selective channels in the membrane that can be opened * e.g. aquaporins and ion channels. 2 a) Primary active transport * Active transport by e.g. enzymes that costs energy * e.g. Na+, K+ ATPase 2 b) Secondary active transport * Transport against an electrochemical gradient caused by the primary active transport. * e.g. symport, antiport etc. |
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What are the differences between symport and antiport in active transport? |
Symport: Moves another molecule uphill from low concentration to high concentration (against its concentration gradient). Both molecules are transported in the same direction. e.g. glucose uptake. Antiport: Two species of ion or other solutes are pumped in opposite directions across a membrane. e.g. Na-hydrogen exchange. |
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What is osmoregulation and what is the main problem with this? |
The ability of animals to regulate salt and water balance intra‐ and extra cellular to achieve optimal conditions. The main problem however is the excretion of the nitrogenous waste that is produced in the process. |
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What are the three main strategies animals can have when excreting nitrogenous waste and what are their waste products? Pros and cons? Give an example of an animal for each strategy. |
Ammonotelic animals: Excrete nitrogen mainly as Ammonium (NH4+). - poisonous - requires water - excretion via passive diffusion e.g. Crabs. Ureotelic animals: Excrete nitrogen mainly as UREA. - less poisonous compared to ammonia - requires water and energy e.g. Sharks. Uricotelic animals: Excrete nitrogen mainly as URIC-ACID. - harmless - requires low volumes of water - low solubility e.g. Birds. |
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What is the difference between osmolarity and osmolality? |
Osmolarity= The amount of solved particles per liter of water Osmolality= the amount of solved particles per kilo of water |
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Define the following: Isoosmotic Hypoosmotic Hyperosmotic |
Isoosmotic = two solutions with equal number of particles Hypoosmotic = one solution that has fewer particles then a solution on a other side of a semi permeable membrane Hyperosmotic = one solution that has more particles then a solution on a other side of a semi permeable membrane |
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What is the Donnan equilibrium? What causes this? |
The behaviour of charged particles near a semi-permeable membrane that sometimes fail to distribute evenly across the two sides of the membrane. The usual cause is the presence of a different charged substance that is unable to pass through the membrane and thus creates an uneven electrical charge. In other words: It's an equilibrium that is not really in equilibrium due to large substances that can't pass the membrane. |
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Define the following: - Poikiloosmotic - Homeoosmotic - Euryhaline osmoconformer (give an example) - Euryhaline osmoregulator (give an example) - Stenohaline osmoconformer (give an example) - Stenohalineosmoregulator (give an example) and describe how their osmolarity changes in the internal vs external fluid when exposed to changes in the environment. |
Poikiloosmotic: an aquatic animal that is incapable of maintaining more or less constant osmotic pressure of body fluids when there is a change in water salinity. Homeoosmotic: keeps a relatively constant bodily osmotic pressure that is maintained independent of the osmotic pressure of the external environment. Euryhaline Osmoregulators: Can stand large fluctuations, become hyperosmotic in brackish environments. Can migrate to other habitats. e.g. marine invertebrates. Euryhaline osmoconformer: Can stand large changes and are isoosmotic to the environment. Can migrate. e.g. crabs. Stenohaline Osmoregulators: Can stand small changes and are hyperosmotic to the environment. Only in limnic environments. e.g. Freshwater invertebrates. Stenohaline osmoconformer: Can only stand small fluctuations and are isoosmotic to the environment. e.g. Hagfish. |
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Name four mechanisms used by Euryhaline regulators organisms exposed to hypo-osmotic stress. |
1. They can start to osmoconform at higher salinities. 2. Change permeability of the body surface 3. Increase the flow of urine 4. Active ion uptake from surrounding water |
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What are the problems and advantage of being a Hyper osmotic, hypo‐ionic osmoregulator (e.g. shark)? |
Problems: - The blood contains high levels of poisonous UREA - Gain ions via feed and gill epithelium - These high levels must be maintained in the body Advantage: - Passive water gain via diffusion through all epithelia --> No need to drink |
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What are the problems Hypo osmotic regulators? What are the solutions? |
Problem: - Ions diffuse into the body - Water diffuse out of the body Solution: - Extra‐renal excretion of monovalent ions - Renal excretion of divalent ions - Low urine production - Drink water |
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What is the Chloride cell and what is its function? |
They are cells in the gills of teleost fishes which pump excessive sodium and chloride ions out into the sea against a concentration gradient. In marine fishes they exclude excess ions present in sea water and in freshwater fishes they help in reabsorption of the ions. |
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How do the kidneys differ between marine mammals and marine birds/reptiles? |
Marine mammals: Have a very long loop of Henley which enhances renal excretion of salts. Marine birds and reptiles: have a small or lack loop of Henley. Needs extra glands to excrete salt (salt glands). |
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Define the following: Homeotherm Heterotherm Ectotherm Endotherm Stenotherm Eurytherm |
Homeotherm ‐ constant body temperature Heterotherm ‐ variable body temperature Ectotherm ‐ follows ambient temperature Endotherm ‐ generates and retains heat Stenotherm ‐ tolerates small changes in temperature Eurytherm ‐ tolerates large changes in temperature |
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What are the four means of heat transfer? |
1. Conduction:Direct transfer of heat between two physical bodies 2. Radiation:Transfer of heat between physical bodies at a distance (emitted from all matter with temp above absolute 0) 3. Convection:Transfer of heat by gas/fluid (ex. air) 4. Evaporation: Transfer of heat by phase transition. E.g.when liquid becomes gas– High energy molecules evaporate, remaining molecules now have lower kinetic E- (cooling effect) |
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How does heat transfer differ in water compared to air? |
Conduction is higher in H2O Convection is 50 – 200 times greater in air than in water No evaporation in H2O (because air is needed for evaporation to occur) |
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What are the main differences between ectothermic and endothermic animals in relation to energy output, temperature tolerance, behavioural factors etc. |
Ectotherms: * Internal temperature depends on the environment * Metabolic rate is 10 times lower than endotherms * Energy intake is low * Enzyme reaction can occur at a narrow-wide temperature range * Behaviour: basking in the sun and musce activity to increase body temp above the ambient temp Endotherms: * Internal temperature is independent on external temperature * Metabolic rate is 10 times higher compared to ectotherms * Energy intake is high * Enzymatic activity usually has a narrow temperature range in which it can occur * Behaviour: torpor & hibernation |
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What is the thermal neutral zone? |
It's the range of ambient temperature during which BMR can be maintained. (= no extra energy is needed to thermoregulate in TNZ). |
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How do endotherms thermoregulate during: Thermal Neutral Zone (TNZ) Below the Lower Critical Temperature (LCT) Above the Upper Critical Temperature (UCT) |
TNZ (No extra energy is needed): * Insulation adjustments (fur/blubber, morphology) * Vasomotor responses (dilation/constriction of blood vessels) * Postural changes Below the LCT (Extra energy needed): * Thermogenesis: Shivering * Non‐shivering thermogenesis: ex. BAT * Counter-current heat exchange Above UCT (Extra energy needed): * Evaporative cooling (sweating, panting) |
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What are the pros and cons of fur vs. blubber when it comes to thermal insulation? |
Fur pros: * Light weight * Better insulation for given volume and mass * Skin is maintained at or near body temp * Metabolically inert (doesn't cost energy to maintain) Fur cons: * Requires air layer and grooming * Compressed at depth- limits efficiency * Buoyancy changes with depth * Metabolically unavailable (can't be used for extra energy) Blubber pros: * No grooming required + can withstand fouling * Relatively incompressible * Buoyancy does not change with depth * Can be used as an energy reserve Blubber cons: * Heavier * Poorer insulation for given volume and mass (compared to fur) * Skin is at or near ambient temperature * Metabolically costly to maintain
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What are the differences between white and brown adipose tissue? |
White adipocytes: - Mainly energy‐storing function ‐Convert triglyceride into Free Fatty Acids (FFA) ‐FFA are released into the blood and transported to the mitochondria of other cells where it is oxidized by respiration into ATP (Energy) Brown adipocytes: ‐Brown adipose tissue (BAT)‐ brown color due to the large number of mitochondria. ‐Highly vascularized tissue ‐Found in cold‐acclimated, hibernators, newborns in the centre of the body. ‐FFA is here oxidized within the adipocyte that express mitochondrial uncoupling protein(UCP) which generate heat rather than ATP (Only used to generate heat, not energy.) |
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What is Q10? |
Q10= A measure of the temperature sensitivity of an enzymatic reaction rate or a physiological process due to an increase by 10°C High Q10 means that the animal is highly temperature dependent. |
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What are the different strategies for fish living in extremely cold temperatures? |
Freeze intolerant: * Can undergo ”Super-cooling”/undercooling * Colligative ”antifreezers” * Non‐colligative ”antifreezers” (=Higher mortality) Freeze tolerant: *Freeze‐nucleating agents --> allow extracellular fluid to freeze (=Lower mortality) |
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What is super-cooling? |
The process of cooling a liquid below its freezing point without it becoming a solid. This is done by colligative antifreezers |
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What are the differences between colligative and non-colligative anti freezers? |
Colligative anti freezers: * Lowers freezing point in proportion to concentration with e.g. Na+, Cl- or glycerol. Non‐Colligative antifreezers * Do not lower freezing point in proportion to concentration * Bind to sites where ice is spreading and prevents growth of ice e.g. anti-freeze proteins. |
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What are ice nucleating agents and what do they do? |
‐Ice nucleation agents(proteins) catalyze the formation of ice in ECF ‐Omolarity increase in ECF freezing point decrease ‐H2O diffuses out from ICF ‐Cell osmolarity increase and freezing point decrease - ECF freezes, ICF remains intact. |
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What is growth? Which three factors affect growth? |
A change i size (weight or length) over time. & Change in calories stored as somatic or reproductive tissue Metabolism, Intake and Excretion affect growth. |
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What exactly is weight growth? |
Weight growth is largely soft tissue growth: * Muscle growth * Fat deposition * Gonadal development Weight growth is reversible |
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What are the differences between red white muscles? |
Red muscles * small, slow * oxidizing metabolism with mitochondria * myoglobins, lipid‐rich * always active at moderate swimming speeds White muscles * large, fast * glycolytic metabolism * active at high swimming speeds |
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Define hypertrophy and hyperplasia and which animals use what. |
Hypertrophy: increase of the diameter of the myocyte, used mainly by small or slow growing fish and mammals. Hyperplasia: increase of the myocyte number, mainly used by large and fast growing species (does not exist in mammalian organisms).. |
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What are the three main strategies to store fat in fish? |
* High or low muscle fat
* Large or small liver * Much or little visceral fat |
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What exactly is length growth? |
* Skeletal growth * Determines the functional size * Permanent |
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What is a condition factor? |
The condition factor refers to the relationship between the length and the weight of the fish and can be used to quantitatively evaluate the condition of an individual fish. |
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Which are the main hormones controlling growth? |
* GH & IGF-1 * Insulin * Thyroid hormones (T3 & T4) * Ghrelin and leptin (Ghr and Lep) |
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What exactly do leptin and ghrelin do in mammals? |
Leptin Increases: - Energy expenditure - Fatty acid oxidation - Lipid catabolism - Carbohydrate catabolism And Decreases: - Food intake - Fat mass Ghrelin Increases: - Food intake - Lipogenesis - Fat mass - Body weight |
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What does Orexigens and Anorexigens do? |
Orexigens: Stimulate food intake Anorexigens: Decreases food intake |
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What happens to fish during their parr‐smolt transformation? What are two of the environmental ques that triggers this? |
Pre‐adaptation of anadromous (fresh to salt) salmonids to a marine life‐history stage. The process prepares the fish for downstream migration and transition to the marine life-stage. Smoltification includes increased salinity tolerance, increased metabolism, downstream migratory and schooling behavior, changing colours and olfactory imprinting. Environmental cues such as photo period and temperature triggers this change. |
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Explain what happens when a flatfish metamorphose from larvae stage 8 to juvenile. |
Larval stage 8:
* Start of an early metamorphosis * Left eye migrates * Body depth increases * Right side gets more pigmentation Larval stage 9: * Metamorphic climax * Increasing body depth * Increasing pigmentation Juvenile: * Post metamorphosis * Elongated body-shape * Left side white, right side pigmented & patchy |
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What are the differences between salmon and halibut that needs to be considered when it comes to aquaculture? |
Salmon: * Established * Anadromous *Benthic eggs & larvae * Large,well developed * Dry feed from start * Pelagic adults Halibut: * Relatively new * Marine * Pelagic eggs & larvae * Small and less developed * Live feed to start * Benthic adults |
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What are the Norwegian legislation for the maximum density of salmon in fish farms? |
(The Norwegian legislation states that maximum density should be 25kg/m3 to prevent overcrowding, though in the wild they can live fine at 100kg/m3). |
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What are the main problems with aquaculture? Are there solutions? If so, what are they? |
* Aquaculture systems have a carrying capacity regarding available nutrients. (Solution: ?) * Escaped fish can cause genetic contamination of wild populations. (Solution: Create closed systems that makes it impossible for fish to escape?) * Antibiotics are used less in western aquaculture, but still used all over the world. (Solution could be to use more probiotics and vaccines instead). * Sea lice can be transferred from wild fish to captive ones in sea cages, they can then re-infect the wild fish. (One solution is to introduce sea lice cleaner-fish to the sea cages or have closed systems) |
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What's the main bottleneck when farming halibut and cod? |
The survivalof eggs and larvae. (For cod, there’s also the problem of early sexual maturation). |
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In aquaculture, what are the differences between norwegian and european lobster that needs to be taken into account? |
Norway lobster (Nephrops) - Low fecundity - Low temperatures, slow growth - Sensitive - Non-aggressive - Mass culture - Low market price European lobster - High fecundity - Higher temperatures, faster growth - Robust - Aggressive/ cannibalistic - Kept individually - High market price |
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Define the following: Viviparity (Histotrophic & Hemotrophic) Oviparity Ovoviviparity |
Viviparity: develop their embryos within the body. Development can occur in two ways: * Histotrophic viviparity: Development occurs in the body, however the offspring will rely on cannibalism of eggs or sibling embryos for nourishment. E.g. some sharks. * Hemotrophic viviparity: Development occurs in the body and the bearing parent provides the embryos with nourishment in the form of a placenta (in most cases). This is seen in most mammals. E.g. Whales Oviparity: lay eggs which allows the embryo to develop in an external environment, meaning there is little to no development within the parent. The shell casing protects the embryo and a yolk will provide nourishment. E.g. Sea turtles Ovoviviparity: develop their embryos in eggs, but the eggs themselves remain in the parent’s body until they are ready to hatch. In this case, there is no connection between the embryos and the placenta; instead the embryos receive nourishment from a yolk sac in the eggs. E.g. some sharks, such as dogfish. |
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What is hermaphroditism? Also define the following: Protoandry Protogyny Sequential hermaphroditism |
Hermaphroditic animals possess both male and female reproductive organs during their lifetime. * Protandry: Where an animal is born male and will during its lifetime switch to the female sex. E.g. Clownfish. * Protogyny: Where an animal is born female and will during its lifetime switch to the male sex. E.g. Wrasses. * Sequential hermaphroditism: An animal that may produce eggs at one stage of its lifetime and later on be able to produce sperm. In some species, switching sexes can occur multiple times. E.g. Jellyfish. |
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What is Growth hormone and what does it do? |
Growth Hormone (GH) is a peptide hormone produced by the pituitary glandafter it receives growth hormone releasing factors from the hypothalamus,which are transported in the blood. GH has many functions which increase theoverall growth rate of the organism. Cell growth, protein accretion, lipolysis, andbone and muscle growth are all accredited to the action of GH. GH also stimulates IGF-1 production in the liver. |
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What is Insulin-like Growth Factor-1 (IGF-1) and what does it do? |
Insulin-like Growth Factor-1 (IGF-1) is produced by the liver in response toGH. Similarly to GH, it stimulates cell growth and proliferation and burns fat.IGF-1 and GH have independent physiological effects, but can also actsynergistically to allow optimal growth rates, particularly of cartilage cells. |
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What is Cortisol and what does it do? |
Cortisol is a glucocorticoid hormone produced by the adrenal glands. Itsprimary functions are as a stress response, and regulation of metabolism. Thismetabolic function includes the mobilization of amino acids, which allowsproduction of glucose (gluconeogenesis) to occur in the liver, and theconservation of blood glucose by the inhibition of uptake by adipocytes and muscle cells. Cortisol is also a crucial hormone during the process ofsmoltification. It increases saltwater tolerance by rapidly increasing NA+-K+-ATPase activity in gills, and increasing fluid uptake from the small intestine.These steps are vital as pre-adaptations to high salinity, allowing salmon smoltto osmoregulate successfully |
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What is Thyrotropin-releasing hormone (TRH) and what does it do? |
Thyrotropin-releasing hormone (TRH) is produced by the hypothalamus inresponse to reduced concentrations of thyroid hormones in the blood. It isreceived in the pituitary gland which then releases thyroid-stimulating hormone(TSH). The TSH is transported to the thyroid gland which produces both T3 andT4. T4 is the most abundant in the blood, but is deiodinised at the target tissueto form T3, which is more biologically functional. |
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What is T3 and T4 (Triiodothyronine and Thyroxine) and what does it do? |
The primary function of thesehormones is the regulation and increase of metabolic rate, as well as workingsynergistically with GH to promote bone growth. Additionally, they drive theprocess of metamorphosis; an increase in these hormones during smoltificationhas been linked to the increase in silvering, and reduced condition factor insalmon undergoing the process |
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What is Ghrelin and what does it do? |
Ghrelin is an orexigenic hormone produced by the stomach, mainly in responseto decreased levels of blood glucose, and energy deficiency. It isresponsible for triggering hunger and increasing the organism’s food intake,and subsequently energy generation as a response. It istherefore considered to be relatively fast-acting. Ghrelin also induces lipolysis;the breakdown of lipids into fatty acids and glycerol.As shown in figure 11, ghrelin can also be used to stimulate the release of GHfrom the pituitary, triggering either direct responses, or the release of IGF-1. |
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What is Leptinand what does it do? |
Leptin is an anorexigenic hormone produced by adipose tissue. It isresponsible for inducing ‘satiety’, and decreasing food intake. Leptin binds toreceptors in the hypothalamus, directly producing a behavioural response. |
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What is Prolactin and what does it do? |
Prolactin increases early in the smolt development and decreases at the peak ofsmolting. It inhibits actions of GH and smolt development itself. This means thatprolactin decreases the seawater-adapting processes |
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What is metamorphosis? |
Metamorphosis is a biological process which consists of a rapid morphological andphysiological change that usually occurs after birth or hatching. It entails rapid growthand a drastic change in the animal's body structure. |
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What is the difference between intensve and extensive aquaculture systems? |
Intensive: All the nutrition forthe culture stock comes from introduced feeds. Stocking density in intensivesystems varies greatly with the type of system and the cultured organism, butis always relative high. Extensive: Is used for pond culture and for organisms grown on or in various substrates,e.g. bivalve and seaweed culture. Apart from seaweeds and bivalves, aconsiderable amount of extensive aquaculture is of low-value fish, such ascarps and tilapia. (more "natural") |
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What are the different types of water exchange systems in aquaculture? |
Static systems: Ponds that are static have no exchange of water during the cultureperiod. Static pond culture is usually extensive with low densities, because ofmajor problems in maintaining water quality under conditions of a large biomassof cultured animals per unit volume of static water. Open systems: Open systems generally refers to fish farming in natural waterbodies, where cultural organisms are enclosed or protected. There is noartificial circulation of water through or within the system. Semi-closed systems: There is a degree of water exchange in semi-closed systems that isgreater than in static systems and much less than in open systems. Anothermajor difference between semi-closed and open aquaculture systems is that theculture water is continuously or frequently brought to the farm. The watersource may be freshwater, brackish or marine. Recirculating (closed)systems: Recirculating systems are usually characterised by minimalconnection with the ambient environment and the original water source.
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What are the differences between DHA and EPA? |
Docosahexaenoic acid (DHA): - 22 Carbon chain - 6 Double bonds Eicosapentaenoic acid (EPA): - 20 Carbon chain - 5 Double bonds |
