Bio 205 Midterm
Closed circulatory system
-Blood flows in a continuous circuit of tubes from arteries to capillaries to veins -All vertebrates and some invertebrates like cephalopods and some annelids have a closed system -there is more complete separation of functions than in open circulatory systems -The blood volume is a low proportion of body volume for organisms with closed systems -The heart is the main propulsive organ and maintains high pressure to enable the rapid circulation of blood -Animals are able to deliver oxygen to tissues very rapidly
Regional heterothermy
-Blood surrounding swim muscles are warmer than blood in other parts of the body like gills -Many insect have regional heterothermy to maintain high heat near flight muscles -Endotherms can be regionally heterothermic, arctic birds and mammals have extremities that are much lower than their core temperature
Water breathing animals in saltwater
-Body fluids of marine fish are hypotonic relative to saltwater, so they lose water to the environment -To replace the lost volume of water they drink saltwater but then they need to get rid of the salt -Excess salt absorbed from saltwater is eliminated form the body by active transport in the gills, and by secretion of salts by the kidney -> The result of the combined osmotic work of gills and kidneys is a net retention of water
Adaptations of burrowing animals to prevent dehydration
-Burrows are cooler and relatively humid -Burrowing animals often use food and metabolic water as sources of water -They conserve water by concentrating urine by water absorption in the loop of Henle in kidneys, by defecating drier faces, and by losing less water via respiration by condensation of water in nasal passages
Thermogenic flowers
-Can produce heat -Can raise their temperature well above surrounding air even up to 45 degrees C -Plants that do this are usually large since they have more space to generate heat but also retain it -Explanations for why this happens -Not yet definitive answer but there are some proposals -It can help spread floral scents to attract pollinators -Heat was a reward itself, such as for an insect/ectotherm who is cold they may seek out a warm flower -For cold climates flowers flower early in spring so they can melt snow around them but also can protect themselves form damage by surprise first or snow -Corpse flower has increase in temperature to spread its scent to rainforest which smells like dead bodies to attract flies and beetles
RuBisCO
-Catalyzes carboxylation of RuBP -Large enzyme coded by both DNA from chloroplast and nuclear gene -Relatively slow and fixes 3-10 carbon per second -Most abundant protein on earth because since its slow you need a whole lot of it -Bifunctional enzyme because it can either bind to CO2 or O2 -RuBisCO was thought to have evolved from archaea and at that point there was no oxygen in the atmosphere -If RuBisCO fixes CO2 and combines it with RuBP you get 2 PGA molecule, but if it uses O2 you only get 1 PGA and you get 1 molecule f 2-P-glycolate (oxygenation) -Efficient is then halved by oxygenation and also phosphoglycolate is toxic because it inhibits enzyme involved in photosynthesis -To get rid of toxin it costs ATP
What allows water to move against gravity?
-Cohesion-tension theory: -There is a continuous water column through the plant so when evaporation removes water form surface of leaf more water is drawn up so there's always that continuous column -Water has unique properties one is that they form H bonds with property of cohesion, water wants to stick to itself , there's also adhesion which is attraction between water molecules and the walls of the xylem -Entire water column is held under tension which is the process that refers to stretching, so water has high tensile strength and water column can be pulled without it breaking
Homeostasis
-Condition of internal stability relative to external fluctuations and physiological processes that maintain it -All the processes involved in maintaining it -Applied to different facets of internal environment like pH, CO2 concentration in blood... -Can have more homeostasis in one parameter and less in another -Regulation is general term for processes organisms use to stabilize a parameter near a desired set point -Control theory is the framework for studying regulation (any process for regulating something at a set level)
Physical processes impacting heat transfer
-Conduction is the transfer of heat between objects or substances that are in contact with each other -> Energy is transferred form warm region to the cold region -Conduction in water is faster than in air because water has a higher thermal conductivity than air -> If an animal's body temperature is higher than that of its surroundings, it will lose heat more quickly in water than in air
Physical processes impacting heat transfer
-Conduction of heat from blood to blood: Countercurrent exchange in the vasculature helps retain heat -In addition to restricting blood flow to the periphery, some animals are able to extract heat from warmed blood and transfer it to cooler blood -This is accomplished by arranging the vasculature into counter current heat exchange -Seagulls with regional thermo, cold feet -> Restrict the amount of warm blood going to the feet -> Evolved mechanism to retain heat in blood -> Temp of blood going down to feet is warm and is cooled off because it transfers heat to the veins -> Heat transfer allows for conservation of heat from warm blood to cold blood -> IF it was cold blood coming back into the body that would cool the body
Conformers vs. Regulators
-Conformers conform to external environment, not regulating internal levels of parameter -Regulators have a zone a stability where it does lots of work to keep internal environment constant -Even regulators become conformers eventually if the environment is too extreme
Hydrostatic skeletons
-Consists of a fluid-filled body cavity surrounded by circular and longitudinal muscles -Cavity can be squeezed by muscle action to generate hydrostatic pressure -Plants have hydrostatic skeletons that maintain the shape of their organs -> Support of the herbaceous (non-woody) stems of plants depends on internal pressure by water and tension-resisting outer layer -This is why leaves wilt when they don't have enough water
Tracheal gas exchange system in terrestrial insects
-Consists of a series of air-filled tubes called trachea that penetrate from the body surface to the cells, acting as a pathway for the rapid movement of O2 and CO2 throughout the body -Air just circulates throughout their body -Because gas is circulated throughout the body cavity, this system bypasses the need for a circulatory system to transport gases between the respiratory surface and the tissues -The main trachea tubes open to the outside of the body through a row of pores called spiracles on either side of the body -Larger insects usually have some mechanism for generating air flow in the bigger tubes of their tracheal system -> Air sacs and tracheal tubes may be compressible, allowing changes in tracheal volume -> Control over diameter of spiracle to either increase air flow or decrease it
Physical processes impacting heat transfer: Convection
-Convection is the transfer of heat in a fluid via its movement -Most often convection causes a loss of thermal energy in animals -Wind blowing over your body vs still air -Process can accelerate heat transfer by conduction between a solid and a fluid because continuous replacement of the fluid maximizes the temperature difference between the two
Ectothermy vs. endothermy
-Deals with how organisms differ in the source of their body thermal energy -Ectotherms are animals that obtains its heat from the external environment -Endotherm are animals that generates internal heat from metabolism to maintain body temperature -Metabolic reactions in all organisms generate heat but only endotherms posses the physiological adaptations that enable them to retain this metabolic heat -> Helpful to think about endothermy vs. ectothermy as variation in the extended to which heat can be retained
Homeothermy vs. poikilothermy
-Deals with variability of body temperature -Homeotherms maintain a relatively table body temperature despite fluctuations in ambient temperature -Poikilotherms allow their body temperature to fluctuate with the environment
Programmed cell death
-Death not due to age or damage but preprogrammed -Can have a bunch of functions; like holes in leaves and pores in citrus fruit -Surrounding cells produce oils and oils accumulate in pores
Trajectory of growth in animals: Determinate vs. indeterminate
-Determinate growth means growth is finite -Indeterminate growth means growth continues indefinitely until death of the organism -Body growth is determinate in most animals, in general body growth slows down and then stops after sexual maturation
Organogenesis in animals and plants
-Different organs and tissues develop from the ectoderm, mesoderm, and endoderm during embryonic development
Expensive tissue hypothesis
-Digestive tract and brain are metabolically expensive thus according to this hypothesis there should be an inverse relationship between gut dice and relative brain size -Takes lots of energy to acquire food, certain amount of energy that need to eb devoted to different processes -Brain is also expensive -Two are both very expensive so you can't have both big -> Tradeoff between brain and gut size -If you're an organism with a low quality diet you need a very long digestive tract -> They'll have smaller brains -High quality diet = smaller gut = larger brain
Ventilation in the gills
-Directional flow of water is maintained by the action of skeletal muscles in the buccal and opercular cavities -Skeletal muscles pumps in the buccal and opercular cavities maintain flow of water over gills -The buccal cavity changes volume by raising and lowering the floor of the mouth -The operculum swings in and out, enlarging and reducing the size of the opercular cavities -There are valves over the entrance of the buccal cavity that maintain a unidirectional flow of water over the gills -Contract muscle pulls down emmrbdane and leads to negative pressure in the cavities so water rushes in -Pulling in of water through mouth and out through operculum -Many active fish ram-ventilate their gills, they open mouth to ventilate the gills by the forward motion of the body while swimming -> Passive -Other fish have sectional surface so they suck onto skin of shark, shark carries them so they can breathe but don't expend energy
Diffusion is lungs
-Distance travelled is the sum of the thickness of the alveolar tissue, the diameter of the interstitial space, and the thickness of the capillary wall -Generally O2 and CO2 have to move ~0.2 um from the lungs to the blood, a really small distance
Comparative functional morphology of hearts and closed circulatory systems
-Diversity in the number of circuits like having a circuit from heart to lungs as well as a circuit form heart to rest of body -Diversity in the number of chambers in the heart
Specialized organs for osmoregulation
-Diversity of organs -Examples; flame cells in flatworms, nephrosomes in annelids, malpighian tubes in bees....
Stomatal conductance
-Do very clear experiments that show how response of stomata to environmental cues -Takes same species of plants and grow under different conditions, stomata aperture opens but stays open for far less time under plant stress os they can't photosynthesis as much -There is a tradeoff function between water loss and CO2 gain -When stomata are largely closed plants can't reach full photosynthetic capacity without enough CO2 -Theres a sweet spot where you're maximizing CO2 gain with water loss but once you pass that then you lose more water than needed
Ways to uptake water
-Drinking -Uptake through body surface from water: Amphibians and fish -Uptake through body surface from air: Terrestrial arthropods can extract water vapour directly from the air via salivary glands that secrete a highly concentrated solution of potassium chloride -Oxidation or metabolic water -Water in food -Metabolic water from oxidation of food -Get most water form fat
Organogenesis
-During organogenesis, cells divide, move, differentiate, and addable into tissues and organs using instructions encoded in the genome -Remarkably, the correspondence between germ layer and organ type is the same in most animals, even those as distinct as human and flies -Growth factors and other singling molecules lead to changes in gene expression in stem cells that drive the differentiation into specialized cells for various tissue and organs -One direction flow as a cell starts to become specialized it can't go -After totipotent stem cells differentiate into specific tissue types, these cells generally lose the ability to differentiate into other types of cells -Totipotency is the ability of a single cell to divide and produce all of the differentiated cells in an organism, include extra-embryonic cells like placental tissue -Totipotent cells are those with the greatest differentiation potential
Snow ball Earth
-Earliest and longest ice age -Earth was entirely covered in ice and sown ~2.4 bya -Caused by photosynthesis -As photosynthesis continued organisms released oxygen which converted methane into carbon dioxide which is a way less potent greenhouse gas than carbon dioxide -Carbon dioxide traps less heat than methane
Heat coping strategies
-Either decrease how much light energy you absorbs or increase how much is dissipated Short term ~Leaf rolling/temporary wilting to absorbs less heat ~Dissipation via longwave radiation (radiative loss) ~Convection (sensible heat loss) ~Evaporation (latent heat loss) ~Latent heat loss by opening stomata which increases sweating of plant but can have huge loss by increasing dehydration Long term ~Increases edge area to surface area which increases sensible heat loss, wind blowing across leaf would increase (convection) ~Reflective coatings or hairs reduce absorption so light hits hairs and bounces off before hitting leaf tissue
Is obtaining energy discrete or constant?
-Energy acquisition is discrete because we're not always eating food -We're attaining food from our environment intermediately -We use energy consistently -Thus there's an excess energy must be stored for later use, typically fats and carbohydrates -We acquire a bunch of energy while eating and don't use it all at once
Measuring metabolism
-Energy used in various metabolic processes support physiological processes like circulating blood, digestion, synthesis of hair/skin/gametes, and activities such as locomotion -All energy is reducible to heat so energy involved in biochemical reactions, energy in food, and energy required for physical activities are all expressed in units of heat -Direct way of measuring metabolic reactions is measuring the heat released by an organism because it correlates with intensity of activities -> Direct calorimetry= measuring heat production as way to measure metabolic rate -Oxygen is consume and CO2/water are produced -> Can also be measured for metabolic rate -Indirect measured of metabolism liked indirect calorimetry, respirometry, double-labeled water all can be converted mathematically into heat production
Evaporation
-Evaporation of water molecules from the surface of an object absorbs thermal energy from the object -Every liquid has its own eaten heat of vaporization, which is the amount of energy required to change it from a liquid to a gas of the same temperature -Evaporative heat exchange is almost always a heat loss from the animal -Sweating and panting as examples of evaporative heat exchange -Sweat is salty because there are more solutes in there to increase the amount of heat extracted form our skin since it increases the late heat of vaporization
Water loss to the environment via evaporation
-Evaporation through body surface contact with environment -Recall how surface area scales with volume (body size) -Ratio of surface area to volume is lower for larger animals so the rate of water loss will be lower for larger animals
Ways animals love water
-Evaporation through body surface contact with environment (perspiration) -Evaporation through respiration -Urine -Feces -Other secretions -Numerous adaptations to minimize or compensate for water loss -> Tolerance of water loss varies across taxa -> Tolerance of water loss is greater in organisms living in arid climates than organisms living in humid climates
Maximum efficiency of photosynthesis/Emerson experiments
-0.1 represents -Max out at 0.1 because 8-10 photons to make a molecule of oxygen -There is a rod drop effect, its a region that there is an increase in absorption (light is harvested more effectively) but there is a decrease in the product of photosynthesis -Photosynthetic machinery is not good at converting it to energy -Experiment where they shined far-red light at a beaker with photosynthetic organisms and then red light and compared rate of photosynthesis -You would predict that the effect would be additive but it's actually more than both of them combined -The extra boost suggests there is some benefit to taking in more wavelengths at a time -Led to hypothesis that there are 2 types of reaction centres absorbing different wavelengths and photosynthesis is more efficient when both are working at the same time
What's the best possible quantum yield for C fixation for C3 plants
-0.125 c fixed per photon -1 carbon fixed for every 8 photons -Max yield in lab is 0.10 c
Fish heart
-1 circuit -2 chambered heart -The respiratory and body circulation of fish are in series other than in parallel -some fish have an accessory pump -Blood is first pumped to gills then to the body but there is a large decrease in pressure
Allometry of bones
-1x length, 1x diameter, 1x cross-sectional area, 1x body mass -N^2 -N^3 -Bones have to support the increase in weight as body size increases -In order to keep the load per unit cross-sectional area on bones constant, the cross-sectional area of bones has to increase in proportion to mass -Therefore in this example, the diameter should increase by 8^0.5 in order for the load per unit cross-sectional area to be maintained -As length or diameter changes then body massy change to the ^3 (n^3) -But cross-sectional area will increase by n^2 -Mass and length are proportional, diameter and cross-sectional area are proportional
Reptiles: Turtles, snakes, lizards -> Heart
-2 circuit -3 chambered heart -Sometimes described as a 5 chambered heart because the ventricle is partially divided -> Have right and left systemic arches -> Functionally, the ventricle operates as if it were undivided
Amphibian hearts
-2 circuits -3 chambered heart -Amphibians have two completely separated atria but a single ventricle -oxygenated and deoxygenated blood is separated even though the ventricle is undivided -Pulmocutaneous arch is where there is lung/skin contact -Systemic arch is where there is body contact
Reptiles: Crocodiles
-2 circuits -4 chambered heart with two atria and two ventricle -Functionally crocodiles are the same as mammals in having complete separation of respiratory and body flow
Mammals and birds
-2 circuits -4 chambered heart with two atria and two ventricles -Right side pumps blood to the lung and respiratory system -Left side pumps blood to the body
Water from soil to root
-3 pathways water can move through roots -Apoplast is a continuous system of cell walls and intracellular spaces and lumens of dead cells and never actually enters a cell -Symplast pathway is where you enter root and water crosses cell membranes, network of cell cytoplasm connected by plasmodesmata so no membranes -Transmembrane is where water is permeating cell walls and it crosses each cell wall twice -At endodermis there can be water blocking by casparian strip which forces water through certain pathways
Apical meristems produce primary meristems, which then produce tissue systems
-3 types of primary meristems -Protoderm: On outside and produces epidermis, outer structure of cells that form plant skin -Ground meristem: Produces cortex which is made off undifferentiated cells, purpose varies between plants, they can sometimes be useful like storing carbohydrates or latex or essential oils -Procambium: Produces vascular tissues (xylem and phloem) which turns into plants lungs/transport system -Have apical meristem busy making cells, primary meristems are where they start to differentiate into different functions, by bottom you have functioning tissue systems
What is sunlight?
-A rain of photons made up of different wavelengths -The shorter the wavelength the higher the energy -<400 nm will causes damage to tissue -400-700 is sweet spot and makes up visible light, it's what's useful in photosynthesis because it excites electrons for nanoseconds which is enough time to capture their energy, if its not capture its dissipated as heat and the electron goes back to its ground state ->700nm is too small of energy to excite electrons
Seed dormancy
-A seed that could germinate, is still alive, is in conditions where it could germinate but doesn't -The seed is waiting, most seeds have some form of seed dormancy -If there's too many seeds germinating at the same time you'll get too much competition -> Mathematically its better to do things early because the faster you have generations the more great grand children you'll have except there are still competitive effects -By staying dormant longer you'll have more time for a seed to be dispersed -Better chance of surviving if they wait, once a seed is germinated its stuck, seedling needs to deal with whatever conditions its in (time of year and conditions) -If you germinate in fall then its gonna be covered in snow and seedling will die -Dormancy is so common because seeds are waiting for best time so seedling has greatest chance of survival -> Caused by mechanical constraint like strong shell, chemical inhibition, thermodormancy, photo dormancy, exclusion of water or oxygen
Fixing atmospheric N requires anaerobic conditions
-ANy organism that fix N2 have to maintain an anaerobic environment because N fixation needs environment with little oxygen because enzymes evolved in breaking apart nitrogen molecules have sites that facilitate the high energy exchange of electrons -> Those specialize sites are also very vulnerable to damage by oxygen -E.g. Filamentous cyanobacteria -They are multicellular, cyanobacteria form chains of cells -They have heterocyst where there is a especially thick cell wall and are derived from vegetative cells but they can't transform back -Heterocysts can't multiply -These cells can tell when cyanobacteria need N, they lack PSII so that they don't make O2 from splitting water to maintain anaerobic environment -Also means they can't photosynthesize sugars, so they send N to neighbouring cells in exchange for sugars -Heterocysts are produced at regular intervals -The vegetative know to become a heterocyst when the N gradient declines, if a vegetative cell isn't getting enough N it'll transform
Absorption spectrum vs Action spectrum
-Absorption spectrum (number of photons absorbed at that wavelength) is the wavelength a pigment absorbs -Action spectrum (oxygen produced at that wavelength) is how much a light-driven process is driven by a wavelength -Can measure output by taking a beaker filled with organisms and shine specific wavelength and measure specific output, you do it with a bunch of different wavelengths, compare and figure out which pigments are driving certain reactions -Can see absorption and action don't quite meet, gap means photosynthesis is less efficient, that where carotenoids are more active, they still capture light energy but they aren't as good at it as chlorophyll -If you divide you get oxygen produced per photon which is the quantum yield
Countercurrent heat exchange in fish
-Active fish like tuna -> Swim muscles are active and generate heat -Keep heat within body -Veins leaving the red muscle are juxtaposed to the arteries that supply blood to the muscle, allowing the transfer of heat from the veins back to the arteries and for the muscles to stay warm -Activity of muscles warms veins, it leaves muscle and there is countercurrent organization of arteries and veins (arteries are oxygenated blood from gills -> Cooling of blood at gills because they are so thin) cooler blood from gills is warmed up from the veins
Active transport of sugars into the phloem
-Active transport is accomplished using sucrose-proton symport system -AtPase pump in membrane which is pumping H+ out of the cytoplasm and into the apoplast which is establishing a a proton gradient across the membrane -H+ gradient then drives transport of sucrose across membrane into symplast of sieve cell
Phloem loading
-Actual movement of sugar from site of photosynthesis into the phloem stream -Mesophyll cells is where photosynthesis is actually taking place -Through process of photosynthesis CO2 becomes sugar which moves from one cell to neighbour via plasmodesmata -Movement from mesophyll cells into bundle sheets cell (plasmodesmata), then to phloem cells, there are different passages -Passive loading: Via plasmodesmata between phloemparankama and phloem cells -Active loading: Sugar is moving across membranes and is transported out of phloem paracnakta into cell wall space then into the companion cells of the phloem at which point it can move into the phloem stream -Apoplastic: Sugar enters apoplast before entering companion cell-sieve tube complex, sucrose is actively transported into the phloem sap (energy consuming) -Symplastic loading: Sucrose continues travelling in the cytoplasm and passing through plasmodesmata right into the phloem sap (not energy consuming process) -Some cells aren't connected by plasmodesmata
C4 and CAM photosynthesis
-Adaptations to "necessary evil" of water loss/CO2 gain tradeoff -CAM open stomata at night where there's less of a driving force for high rates of transpiration -C4 plants can avert CO2 concentration gradient by capturing CO2 and concentrating it inside of their tissues
Totipotency of plant cells
-Adult plant cells can be totipotent and have ability to give rise to fully differentiated plant -Stick carrot in water you can get new one -Take part of body thats already differentiated and from that grow new plant
Totipotency of plant cells
-Adult plant cells can be totipotent: Somatic cells have the ability to give rise to a fully differentiated plant -Can get de-differentiation of cells
Lungs in mammals
-Air pulled in through trachea, enter two bronchi, branch out into bronchioles, then terminate in alveoli -Alveoli is surface for gas exchange so increase in surface area -Alveoli are very thin-walled and CO2 diffuses from the blood into the alveolar sacs, while O2 diffuses from the alveolar sad into the blood
Air breathing animals living near saltwater
-Air-breathing animals utilize a diversity of strategies to minimize water loss to the air -Marine reptiles and birds will drink seawater to obtain water -They can't produce a concentrated urine that is significantly hyper osmotic to their body (contains less water) -Instead they have glands specialized for the secretion of salts in a strong hyper osmotic fluid -> Salt glands are located above the orbits and create hyper osmotic fluid and gets ejected though nostrils
Movement of blood from aorta to arteries to arterioles to capillaries to venules to veins to vena cava
-Along the way there are changes in pressure, cross-sectional area, and velocity of blood flow
Nitrogenous waste products
-Ammonia, urea, uric acid -Fish excrete ammonia -Mammals and some others excrete urea -Reptiles and birds excrete uric acid
Heterotherms
-An animal that obtains significant part of their heat from internal metabolism like an endotherm, but don't use this capacity in all parts of the body or at all times -Regional heterotherms use their metabolism to increase body temperate in specific regions of the body -Temporal heterotherms allow their bodies to cool but retain metabolic heat to maintain body temperature above ambient levels
Thermal neutral zone (TNZ)
-An animal typically spends most of its life in a range of temperatures that is optimal for physiological processes -The TNZ (thermal neutral zone) of a homeothermic endotherm is the range of ambient temperatures where metabolic rate remains near the basal metabolic rate -Thats where the ambient temperatures at which body temperature remains constant without resorting to a change in metabolic rate -Outside of the TNZ the body quicks up metabolic rate -There is the upper critical temperature (UCT) and lower critical temperature (LCT) where above and below those temperatures causes metabolism to increase over basal levels to maintain a constant body temperature -Doesn't apply to poikilotherms because they allow their body temperature to change with ambient temperature -The TNZ can change across seasons, over day, and with acclimation -> Its not static -> Think back to hibernation where TNZ changes
Pressure-Flow Hypothesis
-Analogous to cohesion-tension theory -Depends only on osmosis as the driving force of assimilates -Assimilates are transported from sources to sinks by the bulk flow of water along a gradient of osmotically generated turgor pressure -Building up turgor pressure which is physically pushing sap along -Monocot stem: Distributed throughout stem structure -Phloem and xylem are directly adjacent to each other -Dicot: Have ring
Acquiring nutrients
-Animals spend lots of time trying to acquire food -Selection pressures for animals to have optimal strategy for food acquisition -Animal physiology and morphology are the result of natural selection that favours effective acquisition of energy from food -Different organism occupy different habitats; look at morphology and that can reflect food acquisitor in its particular environment -Sessile species are immobile and acquire nutrients by filter feeding or surface absorption or trapping -Mobile animals acquire food by hiding, searching, stalking, pouncing, capturing, killing
Photosystem
-Antenna complex + reaction centre -Antenna complex is a big satellite dish for light and comprised of 200-300 pigment molecules working together to harvest light energy and funnel it to a reaction centre -Benefit of having hundreds of pigment molecules working together is that one pigment absorbs a few photons per second, combining a bunch means capturing and harvesting more light energy to supply a more constant stream of light energy to the reaction centre -Pigments can only transfer energy to a longer wavelength absorbing pigment -Electron gets excited by a pigment and the energy gets transferred down to adjacent pigment that absorbs longer wavelength (resonance transfer), pigments are transferring electrons, they are transferring the energy -At the reaction centre the electron is lost/transferred -The reaction centre chlorophyll specializes in capturing longer wavelengths
Shoot development from apical meristems
-Apical meristem is right at top which is classical meristem, how plant grows taller -Zoom into apical meristem and see there always a dome of cells, that specifically is the apical meristem -Horn things are leaf primordia; cells start to differentiate and will become leaves -There are also bud primordium which will become bud then flower -Trichome
Importance of body size and shape when thinking about heat exchange
-As with so many of our discussion so far, surface area is very important for thermoregulation -Large animals suffer less heat loss because of smaller surface area to volume ratio -Slope is flatter than isometry so there is unequal change
Behavioural changes for heat regulation
-Behavioural changes in microhabitat: Animals can seek out conditions that maximize or minimize the process of conduction, convection, radiation, or evaporation -Small animals going in burrows -> escape heat -Behavioural control of surface area to volume: Animals can superficially change their surface area exposed to the environment by changing their posture -Animals can also reduce effective surface area by huddling with others
Photosynthesis in the real world
-Biochemical reactions critical to understanding photosynthesis -Variations in biotic and abiotic environment that the plants experience while doing photosynthesis effects photosynthesis rates -Less than 15% of sunlight that strikes leaves actually turns into carbohydrates -Quantum yield for C3 plants is 0.125 -The actual quantum yield is 0.1 -Actual quantum yield of photosynthesis seen in an entire plant is 0.04-0.07 -Low rate of photosynthesis has important implication for ecology, evolution, agriculture, forestry
Effect of temperature on photosynthesis
-Biochemical reactions have a temperature where they are optimized -Net sum of those biochemical reactions means photosynthesis for a given plant has a temperature where it is optimized -Under ambient CO2, good light and moisture, the response to warmer temperatures is mediated by rubisco because the warmer it get the more its affinity for O2 -Rate of photosynthesis increases but the rate of photorespiration creates even faster -Net gain of photosynthesis starts to fall -Different species have different optimum temperatures -Ones that are maximizing photosynthesis at a lower temperature are from colder places in the world
CAM (Crassulacean Acid Metabolism)
-Evolved independently multiple times -7% of land plants -40 families including orchids since they are family with most species of any plant lineages -Adaptations to an arid environment because it not only solved problem of rubisco but is most efficient at water retention -Some species can switch between CAM, C3, and C4 -Where C4 physically separates two carboxylation reactions CAM separates them in time -CO2 is collected only at night by opening stomata and carbon reaction happen during the day -Produces same 4C acid malate and accumulates through the night since reaction occurs nocturnally and cell pH drops so malate is stored in vacuole -Second carboxylation occurs during the day and malate is consumed -PEP carboxylase is used agin -Concentrates CO2 and minimizes O2 around rubisco -Reduces C lost to photorespiration -Maximizes H2O conservation since stomata isn't open during the day where water loss is tightened -Disadvantage is physical because there is only so much space in the vacuole, CAM plants stop when they run out of malate during the day for photosynthesis -Enforced inactivity slows growth of plant
Na+/K+ pump
-Example of primary active transport -Na+ transport is active as ATP hydrolysis is used so Na+ concentration gradient is established -Energy of Na+ concentration drives glucose transport across the membrane (secondary)
Getting rid of excess light
-Excess energy if not harnessed by photosynthetic machinery still needs to go somewhere -Sometimes it can excited oxygen which causes damage -Photo-oxidation" same process that clenches painting in sun can cause cell damage and death -Chloroplasts will form even layer of cell surface if they need light -Chloroplast can stack and hide to reduce amount of light being intercepted -Carotenoid pigments can dissipate energy to heat instead of letting it cause damage -Xanthophyll cycle: Violaxanthin with low heat dissipation can be converted to zeaxanthin which has high dissipation -Find highest concentration of zeaxanthin in evergreen during the winter because in winter plants don't have excess to unfrozen water, temperature too low for reactions, during environmental stress, getting more light then they can use
Identification of phloem as key tissue of translocation
-Exposed plants to CO2 labeled with C14 -When they exposed one leaf of a plant to radioactive CO2 fo 35 minutes they looked to see where that C14 ends up -Almost all of C14 molecules are restricted to sieve elements of the plants -Radioactivity is isolated in sieve elements of the phloem structures
Energy storage
-Fats vs carbohydrates -Fats are synthesize in adipose cells and the liver, its most effective forms of energy storage because the oxidation of fat yields TWICE the yield of energy per gram than carbohydrates, its also efficient because its stored in a dehydrated forms so it takes up less space -Some carbohydrates like glycogen are useful for energy storage because they can be rapidly converted to glucose for oxidation during intense activity -Easier to excess energy from carbs than fats so it depends on level of activity that an animal is going through
Secondary growth of wood and bark
-Feature of plant development and growth is wood -The rings of a tree are different growth periods where the tree has grown faster or slower -Can see young shoot with pith, primary xylem, vascular cambium, phloem, and epidermis -Older part of same stem will have growth that happens from vascular cambium in both directions, xylem and phloem is produced, epidermis is also dividing and growing (cork) -Even older branch will have continued process with generation of bark, layer of periderm as well as cork and dead secondary phloem (makes up bark)
Osmoregulation using gills
-Fish gills are highly permeable because they're needed for exchange of oxygen and carbon dioxide between the blood and the aqueous environment but gills also engage in active transport of salts -The epithelium of the gill (that separates the blood from external water) consists of pavement cells and chloride cells that use ATPase to actively transport salt out of the gills and into the saltwater
Adaptations for flight
-Fliers must also overcome gravity -Weight reduction by having hollow bones, large eye sockets, reduced jaw without teeth, reduced tail, spindly legs -They have large sternum which provides a point of attachment for flight muscles, legs retracted during flight to reduce drag -> Weight concentrated at centre of gravity
Domestication of plants through manipulation of development
-Focus on certain aspects of development and selecting for them -Select for size, select against having seeds -By selecting on different components of growth you get food we all rely on -Can manipulate growth to get colour results; like broccoli and broccolini are totally unrelated but look similar, cabbage, cauliflower, Brussels sprouts look very different but are actually the same species
How will environmental parameter influence stomatal conductance
-Follow plant over the course of a day -During dawn stomata will be more open because of sunlight allowing for photosynthesis to occur, no point in being open and taking up CO2 if there isn't photosynthesis -Increasing temp will make stomata close, evaporation increases because relative humidity (how much water air can hold at given temperature) in air will increase, air will be able to hold more water, so there's an increase in transpiration -During high winds stomata will close because boundary layer is more thin so there's more transpiration -If its very stormy then humidity increases so the air surrounding leaf has higher humidity transpiration will decrease because the water potential gradient is smaller and stomata will open more -Once it starts to rain the stomata can also be open since they don't have to worry about water loss -C3 plants can theoretically become more water efficient since they don't need to open up stomata as much (when it comes to increasing global CO2 levels with climate change)
Food absorption through exterior body surfaces
-Food diffuses into their soft body walls -Endocytosis is more active -Phagocytosis is when parts of the plasma membrane called pseudopodium extends out and envelopes food particle -Pinocytosis is where food particles bind to the cell surface, and the plasma membrane folds inwards to form an endocytotic cavity
Nutrient Deficiencies
-For a nutrient to be considered essential there are diagnostic symptoms when that element is withheld -Variability depending on plant species -Depending on nutrient the symptoms show up first in either young or old leafs -Depends on how mobile nutrient is in the plant -If nutrient is mobile the symptoms will show up in old leaves first that means they are shuttling nutrient to young leaves first
Gills for gas exchange
-Formed by the evagination or out-pocketing of the body lining -3 Types of gills -Tuft gill: Very simple, bump in surface with vascularization -> Example sea stars -Filament gill -> More surface area because of the filaments -Lamellar gills -> Most complicated, crustaceans have them -> Vertical gill arches with paired gill filaments -> Each filament has lamella used for gas exchange
Assimilate
-Formed from photosynthesis -Assimilated carbon form atmosphere -Need to be transported to other parts of the plant -translocation
C4 photosynthesis
-Found in 3% of plant species -Does 30% of carbon fixation on land -Includes whole grass family -Includes weeds too -Evolved independently more than 60 times in 19 plant families -Adds a step that separates CO2 intake and fixation from the Calvin benson cycle and enables concentrations of CO2 and H2O conservation -Two Carboxylations
Auxin
-Found in all parts of the plant but concentrations differ -Both be a switch on and a switch off at differing concentrations -Patterns of auxin concentrations help to determine the development of different organs -Only works if you cut stem and apply to wound -Activates a plasma membrane protein pump, pumps H+ back and forth to acidify cell wall, lower pH, certain enzymes are more active at low pHs and those enzymes will hydrolyze cellulose -By breaking cellulose, you weaken cell wall which chances the E part of the equation, cell wall is more elastic which also lowers Y
Control theory
-Framework for thinking about the process of regulation -Describes how deviations from a desired level (set point) are corrected -Negative feedback: Organism senses deviation, amplifier detects sensor and will convert the information from sensor into a useful signal that starts regulatory process -Starts process that brings disturbance back down to set point and therefore reverses a pattern
Transpiration ->
-Function of force divided by resistance -If force on top goes up then transpiration -If resistance on bottom goes down then transpiration goes down -Flux -Mols of water lost per leaf area per time (mol/cm^2/s) -Plants can't control water potential of soil or atmosphere but they have control over resistance
Anaerobic respiration: Plants
-Get oxygen poor environment form water logging of roots -Pyruvate can either get converted to lactic acid like animals but only happens in short term -Build of lactic acid changes pH in cells and lactate dehydrogenase will become less efficient -Plants have evolved an alternative pathway so they use pyruvate dehydrogenase converts pyruvate into a different compound acetaldehyde and then a second enzyme called alcohol dehydrogenase will make ethanol
Growth regulation by hormones
-Gibberellin -Auxin ... -Some effect many plant processes -Abscission is death of certain plant parts -Each of these hormones are groups of hormones that are related -Talk about general effects -To effect cell growth rate, they have to effect one of three components in equation -E is expand -P is pressure from water potential -Y is yield/threshold pressure required to expand cell
More on gills
-Gills have very thin membranes for rapid gas exchange -Protected by operculum -Water moves into mouth and out of operculum unidirectionally -Water moves in one direction because its flowing in opposite direction of blood = countercurrent flow -Get more saturation of oxygen in the blood this way -Concurrent flow: If water and blood are going in same direction then -> As you move forward there is diffusion of oxygen from water to blood until they reach equilibrium with saturation of 50% -Contercurrent flow: There is always oxygen transfer from water to blood
Aerobic respiration summary
-Glycolysis, electrons are carried by NADH to enter ETC -Pyruvate enters krebs -Krebs turns -Electrons get carried to ETC -Get little bit ATP form glycolysis and Krebs -Vast majority is from proton motive force -Without oxygen ETC gets backed up which backs up Krebs so only mechanism to produce ATP is glycolysis -Glycolysis is also linked to ETC so you still need mechanism to produce NAD+ so glycolysis continues -> Anaerobic respiration
What light wavelengths will be most common on the forest floor
-Green area will be enriched since chlorophylls let those wavelengths pass -Far red will also be enriched because only one photosystem is capturing that energy -Whole thing will be lower since leaves above are absorbing or reflecting at least some of all -PSII : PSI ~ 1.5 : 1 on regular -If a plant is stuck in the shade the plant would want to increase PSII because PSI relies on PSII for electrons so more PSII will allow for as much light to be captured as possible while still generating electrons
Growth in Animals
-Growth in animals is determinate -Embryonic development: Most adult organs are formed during embryogenesis, so embryos look like miniature adults -Totipotency and regeneration: cells in animals have limited totipotency
Compare and contrast animals and plants
-Growth: Animals are determinate Plants are both -Embryonic development Animal organs are formed during embryogenesis, so embryos look like miniature adults Plant have embryos that contain no adult organs, only meristems form which adult organs will develop post-embryonically -Totipotency and regeneration Animals have limited totipotency Plants have many cells that are totipotent and can regenerate
3 Important features of organisms
-Growth: Irreversible increase in size from increase in size and/or number of cells -Development: Qualitative changes during the lifespan like puberty in animals where you change from one state to another state -Reproduction: Ability to replace yourself with some babies
ATP synthesis fuelled by proton motive force
-H+ want to move across membrane and they can only go through ATP synthase -As 3-4 H+ have passed through there's enough torque to make ATP from ADP and phosphate -NADP+ gets reduced to NADPH -PSI uses light energy to transfer e- from PSII through a separate ETC to pass it to NADP+ enzyme which reduces NADP+ to NADPH which is then released to stroma for use in the sark reactions
Namib desert beetles
-Half the year there is fog rolling into dessert -Beetles hike to top of sand dunes and do hand stand to allow for water to condense on their back which will then slowly drip down to its head so they can drink it up
Krebs Cycle steps
-Have 3C pyruvate and first step is it has to be converted to acetyl-CoA which is a decarboxylation since CO2 is released -Acetyl-CoA is added to 4C oxaloacetate to make 6C Citrate -Series of steps ending in Succinyl-CoA which are decarboxylations to produce CO2 as well as NADH which will go to ETC -Next step is production of energy to make ATP in plants and GTP in animals -Series of interactions to get additional NADH and also restoration of oxaloacetate molecule -So many steps for control over release of products but also entry point can be anywhere, allows flexibility -Krebs is aerobic because there is an indirect independence -There are 4 oxidation reactions and NADH and FADH2 have to donate their electrons to oxygen so that they become NAD+ and FAD, without electrons being donate there would be a backup and krebs cycle would grind to a halt
Water potential examples
-Have a beaker of pure water: Pressure only exists in a closed system, solute potential is not a thing because there are solutes in pure water, gravitational potential is 0 because the relative gravity position is 0 for the beaker -> think fo reference height, there is not matrix potential because there is no colloidal molecules -Flaccid cell: No pressure potential because its limp and water isn't pushing against membrane, thee is solute potential since cells are full of solutes, no gravitational potential and no matrix -Calculate water potential of cell itself and then calculate water potential of solution -Flaccid cell in solution rate will move into cell because it has a more negative water potential -Water stopes entering/exiting cell once water potential is same as the solutions water potential
Allometry of body growth in ants
-Head size scales allometrically with body size (heads are relatively large in larger soldier ants)
Secretions involved at various steps in the digestive system
-Headgut: Contains salivary glands that secrete saliva which moistens food, acts as a solvent for food molecules, contains digestive enzymes to degrade food (amylase) and bicarbonate to neutralize acids -Foregut: Cells in the lining of the esophagus secrete mucus to facilitate the passage of food -Midgut: Stomach: There are specialized cells in the stomach lining that secrete gastric juice with a pH of 1.5 that contains hydrochloric acid and pepsinogen which is then converted to pepsin to be used to breakdown proteins -> Gastric juice also promotes absorption of vitamin B12 Small intestine: There are specialized cells in the lining of the duodenum that secrete enzymes that aid in digestion, there are two types of digestive secretions 1. Pancreatic juice which contains several protein and fat degrading enzymes as well as bicarbonate to neutralize the acidity of gastric juice 2. Bile which contains bile salts that are essential for digestion of fats
The heart
-Heart consists of one or more connected muscular chambers that are guarded by valves allowing blood to flow in only one direction -Contractions of the heart eject blood into the circulatory system -Having multiple heart chambers allows stepwise increases in pressure as blood passes from the venue to the arterial side of the circulation
Heat storage
-Heat storage leads to an increase in temperature of the heat-storing mass -The larger the mass the smaller its rise in temperature for a given quantity of heat absorbed -Thus large animals heat up and cool off more slowly than small animals because of their lower surface-to-mass rations -Heat transfer with the environment takes place at the body surface
Water properties
-High dielectric constant because of nature of water molecule you have partial negative and positive end so water molecules can bond to each other very closely and creates strong forces of cohesion between water molecules -Better solvent than other fluids -Water is biologically important that enable types of reactions that take place in water
Gibberellin
-Hormones critical in plants -Regulate and influence things including stem elongation, fruit growth, and seed germination -They works by causes hydrolysis of starch in internodes of plants -Internodes are area between two leaf nodes -As breaking starches apart glucose concentration increases and what you get is increased solute potential in the cell, so there is more negative water potential so water enters cell -Gibberellins will make it easier for water to enter the cell which increases turgor pressure (Operate on P component of equation)
Relationship between bone length and diameter
-If length doubles, diameter should increase by (2^3)^(1/2) or 2^(2/3) -If diameter doubles, length should increase by 2^(2/3)
Number of chambers
-If there are two chambers then there is one atrium and one ventricle -If there are three chambers then there are two atrium and one ventricle -If there are four chambers then there are two atria and 2 ventricles
Number of circuits
-If there's one circuit then blood goes from heart to the respiratory organ to the body then back to the heart -If there are two circuits then there's one circuit from heart to respiratory organ and back = pulmonary (lungs) and one system that's from the heart to the body and then back to the heart = systemic (body) -Pulmonary circuit has a lower pressure because of diffusion
Light intensity: Flexible and fixed responses
-If you grow plant in shade or in sunlight it will develop a different light curve, think of it as different light efficiency which means plants adapt to that light -> Phenotypic plasticity -> Different phenotype for the same genotype -Adaptive genetic difference: Compare sun plant vs a shade plant -Most plant reach photosynthesis saturation point well before the maximum amount of sunlight -On whole plants leaves shade each other so a whole plant is never fully saturated in sunlight
Absorption of nutrients from the digestive tract into the body
-In a unicellular organism, the products of digestion simply leave the food vacuole to enter the surrounding cytoplasm -In multicellular organisms these products must be transported across the absorptive epithelium in small intestine into the circulatory system and from the blood into tissues -> To maximize absorption, the surface area is enormously increased int he small intestine by a series of fold and vili
-Endothermy vs. ectothermy -Homeothermy vs. poikilothermy
-In general, most people think of ectotherms as poikilotherms and endotherms as homeotherms -But there are a lots of degrees of variation across these dichotomies -Poikilothermic animals living in very stable environments, usually cold ones, will have a more or less constant body temperature (like a homeotherm) -Marsupials are considered more poikilothermic than eutherian mammals because they allow body temperature to vary over a wider range -Ectothermic lizards will undergo behavioural homeothermy because they have preferred body temperatures for optimal metabolic functioning
The relationship between pressure and flow
-In order to move a fluid inside a tube there needs to be a pressure gradient -Pressure is created primarily by the heart -The greater about of pressure that a blood vessel has is close to the heart -These blood vessels have a large diameter and thick walls to be able to system that pressure -Pressure in the ventricle increases when the heart contracts -That pressure gets dissipated by the flow of blood because energy is used to overcome restart to flow through the vessels -Blood pressure falls as the blood passes from the arterial to the venous side of the circulation system
Translocation voerview
-In red you have xylem vessel which is upward movement of water -Sieve tube chichis series os sieve tube elements with golden balls representing sugars -Photosynthetic cells in leaf, sugar is transported one way or another through companion cell then sieve tube element, sieve tube is very high concentration of sugars -Because xylem and phloem are directly adjacent water flows to phloem through xylem so you ave top cell with huge volume of water generating turgor pressure which pushes sap down the tube -Osmotic gradient is generated by accumulation of sugar, water rushes ins which makes turgor -Bulk flow is where there's no compartmentalization
Mammalian kidney
-In terrestrial animals, the kidneys are important for the excretion of nitrogenous waste products (urea) stemming from the metabolism of amino acids -The excretion of nitrogen wastes are accompanied by an unavoidable loss of water -Kidneys re-absorb 99% of what they filter, and excrete the remaining 1% -The functional unit of the kidney is the nephron which has 3 main regions -> The proximal convoluted tubule, the loop of henle, and the distal convoluted tubule -Filtrate is squeezed out of blood and is composed of water, urea, and smaller ions (meaning red blood cells and proteins don't get filtered out of blood) -In the proximal convoluted tubule organic solutes (glucose, amino acids..) in the filtrate are absorbed as well as some sodium, potassium, and water is recaptured -In the loop of Henle water is extracted out of the filtrate, it pumps out salts to make the surrounding medium hypertonic relative to the filtrate, this way there's a concentration gradient for removing more water form the filtrate -In the distal convoluted tubule levels of potassium, sodium, and calcium are regulated in the filtrate
Evolutionary solutions
-Increased affinity for CO2 vs. O2 in higher taxonomic levels of plants so RuBisCOs likely hood to fix CO2 is higher -Increase CO2 concentration around rubisco which is what C4 and CAM plants do
Temperature-dependence of metabolism
-Increases in metabolism in a frog as temperature increases -But Q10 can be affected by temperature at which frog is acclimated -Metabolism and temperature will be different -Organisms can acclimate to particular environments so their metabolic processes acclimate too -Thermal acclimation: Environmental heat or cold elicits compensatory changes in physiology and morphology -An animal that cannot escape temperature stress will gradually undergo biochemical changes known as acclimations to help them cope -Acclimation occurs in individual tissues and in whole organisms -Because metabolic processes rely on enzymatic process, changes in enzymatic processes contribute to acclimation
Bidirectional movement of air in mammals
-Inhale and exhale -Diaphragm gets pulled down by contracting which expands chest cavity so lungs draw in air -As diaphragm relaxes it moves up and pushes air out of lungs -Get O2 rich air in, lung has to push out air that's O2 sparse -During exhalation alveoli aren't in oxygen -In fish gills are always exposed to oxygen rich air
Endoskeleton
-Internal framework of bones and cartilage -Support system to provide skeletal support, organ protection, and anchorage for muscles, which, of course, provide the motive force to cause an articulated movement of bones
Digestive systems
-Intracellular: Digestion happens within cytoplasm of organisms; food vacuoles contain food and enzymes will breakdown food and go into cytoplasm -In multicellular organisms that rely on intracellular digestion they have one gastrovascular cavity where food and waste go in and out of same opening -Extracellular: Digestion and enzymatic breakdown of food occur outside of cells -Compartmentalized alimentary canal with two opening (mouth and anus)
Seizing prey
-Invertebrates have diverse appendages to help them acquire their prey, also some have toxins, stinging cells to paralyze prey (hydra) -Toxins act on nervous system of their prey to immobilize them -Grasshopper mice prey on bark scorpions; they've evolved mechanism so the scorpions venom doesn't cause them pain (leads to temporary analgesia) -Vertebrates rely on teeth -Homodonty: Have teeth that are functionally and anatomically of the same type, size may be variable (e.g. reptiles, sharks) -Heterodonty: Have teeth with specialized or different functions -Carnivores: Have carnassial teeth good for slicing soft food -Herbivores: Hypsodont teeth that are very large and good for grinding fibrous food -Primates: Compression teeth that are good for pulverizing hard food
Body size and metabolic rate
-Larger animals use more energy to sustain themselves because they have more cells to require energy = Higher metabolic rate -So MR increases with body size -MR is the energy released per unit time -Follows power law -Described relationship between body size and metabolism -Log transform data -Slope = 0.75 -Isometry = 1:1 correspondence between two variables )slope is 1) -Allometry = relationship that's not isometric -Endotherms have a higher BMR than ectotherms; use part of metabolism for heating or cooling so that requires for energy to maintain homeostasis -Differences in how measurements are made between taxa -> BMR for ectotherms is at 20C while endotherms have temperature of 39C -Not good for infraspecific species variation but good for different species
Orthostichy: a column of leaves
-Leaves on same side of step and right above the other -Leaves have functional relationship to one another -Young plant was exposed to radioactive carbon and saw that radiation accumulates on leaves on same side as the leaf exposed to C14 -If you cut off old leaves on one side that are acting as sources, the young ones will get adopted by other old leaves
Leaves are determinate organs produced by shoot apical meristems
-Leaves originate form edges of the apical meristem -Process is regulated by plant hormones, transcriptional regulators and mechanical properties of the tissue
Stored energy
-Leftover energy is stored in stable chemical bonds in macromolecules -Stored carbohydrate in animals is glycogen -Stored carbohydrate in plants is starch -Both are polymers of glucose -Energy is stored as macromolecules because they are long term -Other storage molecules include fats, proteins -No animals make starch but some plants can make glycogen -E.g. Neotropical genus Cecropia makes starch for their own use and make glycogen for Azteca ants, they also provide a nest or them in cavities of the Cecropia stem, so the ant will defend the plant against herbivores
Symbioses between plants and N-fixing bacteria
-Legumes are called "N fixers" which isn't the plant doing the fixing its the bacteria -If you grow another legume it harnesses bacteria who will fix a bunch of N and if you plow back into soil the N is released -Way of increasing N available in soil -Legumes have to provide anaerobic environment for bacteria to fix N in so they regulate gas exchange to root nodules by maintaining a O2 concentration that is 10 000 x lower than in surrounding cells (mechanism not understood) -Plants have O2-binding proteins called leghemoglobins which has a high affinity for oxygen (Km ~ 10nM which is an inverse measure of affinity) -Protects nitrogenase from oxygen because all oxygen is bound up tightly in high affinity molecules called leghemoblogins -How do bacteria respire? -Leghemoglobins transfer oxygen directly to bacteria and its ETC terminal oxidase has an even greater affinity for O than of leghemoglobins so O is never just floating around
Life in water vs. land
-Less structural support is needed in water because water is much more dense than air -Largest animals are found in water and not in land
ATP synthesis in the chloroplast
-Light-dependent reaction also known as photophosphorolation -Generate ATP and is driven by light -Works by chemiosomosis which means there is a difference in ion concentration and/or electric potentials across a semi-permeable membrane which creates a potential source of energy -The ions want to cross to lower concentration side of the membrane -ETC produce electrochemical gradient from H+ split from water -The H+ will accumulate on one side (build up of potential) which creates proton-motive force -Photolysis is the e- breaking off of H2O -H+ stay in lumen -e- is transferred form reaction centre and passed down ETC starting with pheophytin, then PQ to form PQH2 (which takes 2 H+ from stoma), then to cytochrome complex which releases 2 more H+ to the lumen from stroma generating proton motive force -Converting NADP to NADPH which takes a H+ from stroma (increasing that gradient)
Body size and maximum velocity
-Linear up till about 500 kg, as they get bigger they have large max speed -After 500 kg it decreases once again -Sprinting relies on energy stored in muscles, breakdown of glycogen -> Fast-twitch muscles undergo anaerobic metabolism using glycogen -Organism needs to come over inertia to start moving, and those very large animals have a harder time to overcome inertia -Takes to long for heavy animals to reach max speed, their energy supplies in muscle become depleted before they can reach it -Can see it in flying animals as well as swimming animals
Organism
-Living entity with capacity to function independently or develop such capacity -Viruses aren't included in this -Middle level of biological organization: Atoms, molecules, cells, tissues, organs, organisms, groups, populations, communities, ecosystems, biosphere -Each level of organization has emergent properties, property that you get at that level that you don't see at level below -Life is the quintessential emergent property of an organism
How is CO2 fixed
-Lollypop apparatus s a closed system filled with single celled algae -Experimenters can precisely control the input of both carbon and light -Can supply radioactive form of carbon dioxide (14CO2) to be able to trace carbon molecule -At bottom there is boiling methanol -Turn light to start up photosynthesis, the algae slurry falls into methanol which kills it instantly -Slurry of dead cells and concentrate it by evaporation and put sample on chromatographic paper -Develop it in one direction, turn paper and develop it again so you have molecules separated by size -Cover it with X-ray sensitive paper to see where molecules end up -Can see lots carbon molecules being produced of various sizes -PGA was first carbon product from photosynthesis
Carbohydrates
-Long term energy storage -Photosynthesis carbon reaction incorporate C from atmospheric CO2 to create stable, long-term energy storage molecules -Light-independent reactions, Calvin-Benson cycle -[CH2O]n
Morphology is a strong indicator if feeding methods
-Look at beak morphology of bird beaks -Form matches function -Skinny beak = get nectar from flowers -Large beak = dip netting to get fish -Beak diversity among Darwin finches; Across Galapagos islands there is diversity of beak morphology that correlates with diet -> Insect eaters vs cactus eaters vs seed eater -> Seed eaters have even more beak diversity -> Large ground finches eat large seeds so they need stronger beaks -Size beak can shape the types of sounds that birds make; variation in beak shape covaries with variation in the sounds that make up their songs (big beak=slow song=longer to open beak)
Look at empirical data
-Look at slope -Consistent with mathematical formulation -Diameter changes in a way so cross sectional area can sustain the increase in mass
Photosynthesis
-Looks like CO2 and water interact directly but thats not the case -Purple sulphur bacteria don't use water as their reducing agent they use H2S and don't get water, meaning O2 comes from water and not CO2
Relationship of BMR per kilogram of body mass to body size
-MR divide by mass of organism -Larger animals have lower mass specific metabolic rate than animals -M-S MR = aM^(-0.25) -With regard to endothermic animals, the rate of heat escape is a function of surface area and if the ratio of surface area to volume (body size) is lower for larger animals than for smaller animals, then larger animals have an "easier: time retaining heat -Therefore, M-S MR doesn't have to be as high for larger animals -Body temperature (which influences the rate of metabolic reactions) can also vary as a function of body size, there is some evidence that larger animals tend to have lower body temperatures than smaller animals -Mechanistically this negative relationship could be related to size-dependent variation in the number of mitochondria per cell, larger animals will have cells with fewer mitochondria than smaller animals
Measuring metabolic rate
-MR is the heat energy released per unit time -Can be used to calculate energy requirements of an animal -> Needs to take in as much energy through food as the total energy it stores/uses up so that it can survive -> Can understand how energetically costly particular activities are/environment are -Function as type of energy, body size, environmental conditions -Basal metabolic rate (BMR): Measured under conditions of minimum environmental and physiological stress (stable rate of energy metabolism) -> Homeothermic animals -Standard metabolic rate (SMR): And animal's resting and fasted metabolism at a given body temperature, used in most animals metabolic rate varies with body temp -Field metabolic rate (FMR): The average metabolic rate as an animal undergoes normal activities under normal conditions -> Used since animals will rarely be under conditions required for BMR or SMR -> Used for both homeothermic and poikilothermic animals
Filter feeding
-Many aquatic animals use filter feeding to capture good carried on water currents -Most are sessile -Have behavioural changes based on water currents, they will orient themselves to most effectively filter food through water current -Some species generate current through movement of body parts such as cilia and flagella -Considered passive but some organisms can generate currents themselves through flagella and cilia -The Bernoulli effect is used to increase the rate of water flowing through entrapment sites without energy expenditure; based on fact that fluid pressure drops as fluid velocity increases, the flow of water across opening at the top of some sponges will cause a drop of pressure which draws water though small holes (holes are surrounded by food capturing cells) -> Maximizes water entry -Large animals can also acquire food this way -They swallow water into their mouth and use their tongue as a piston to force water out through filters of hair-like keratin that captures small food items (flamingos and whales)
Thermogenesis to create regional heterothermy in some flying insects
-Many large insects are able to conserve metabolic heat from the activation of flight muscles -Note how the temperature at the thorax vs abdomen can exceed ambient temperatures
Air breathing animals in saltwater (e.g. marine mammals)
-Marine mammals do not posses salt glands, so they avoid drinking seawater and instead obtain their water entirely form their food intake and subsequent metabolism -Therefore, marine mammals face problems very similar to those of desert animals -Marine mammals are often endowed with efficient kidneys capable of producing hypertonic urine
Light intensity vs photosynthesis
-Measurement of how much photosynthetically active radiation is available to plants -Measure of how productive photosynthesis is -Intersect y axis at a negative number because if you turn off light plant is still doing cellular things to stay alive which takes energy
Meristems are the key structure for growth and generate the plant body
-Meristems are the equivalent of stem cells in animals -Meristem cells retain the ability to produce new cells indefinitely -Apical meristems in the shoot and root orchestrate primary growth, ultimately giving rise to every cell in the primary plant body (leaves, flowers) -Lateral meristems orchestrate secondary growth such as increasing thickness
Heat exchange and thermoregulation in animals
-Metabolic reactions have heat as a key feature to regulate cellular activity -Animals live in all different environments which can be described as variable temperatures -In oceans temperatures are fairly cold but very stable -In desserts there can be 40 degree cells days and below 0 nights
Effects of temperature on the metabolic rate of ectothermic animals
-Metabolism increases with ambient temperature -Enzymatic processes will be more active -BMR of ectotherms is measured at lower temp than endotherms -Temperature quotient: Number of times by which a reaction rate increases with a specified increase in temperature -The Q10 measures the change in reaction rate with every 10 degrees C change in temperature -THe temperature quotient will give the ratio of the rates of a reaction at two different temperatures
The concept of energy metabolism
-Metabolism is the sum total of all the chemical reactions occurring in an organism -Catabolism is the breaking down of complex, energy-rich molecules into simpler one -Anabolism is the assembly from simple substances into more complex molecules required by the organism -> Associated with repair, regeneration, and growth -Our bodies are constantly reinventing themselves by breaking down and rebuilding
How plants get enough light
-More PSII vs PSI reaction centres in understory plants -More chlorophyll per reaction centre to increase amount of light absorbing pigments -Light focusing via convex epidermal cells to take in funnel shape so light is concentrated to minimize light refraction -Leaf size and shape can change, top of the tree will have smaller than the shade ones -Leaf angle can also change -Solar tracking where plants can either turn towards or away from the sun
Major elements plants need
-Most important and common are carbon, hydrogen and oxygen but they aren't considered minerals because they aren't obtained form the soil -Nitrogen is found at 4x the amount of other mineral nutrients -Plants need way to obtained sufficient N -N, K, and P are most limiting minerals -They are more common in soils -Combinations of how much plant needs it and how much its available
Assimilating highly oxidized nutrients
-Most intensely reactive reactions in living organisms -Very metabolically expensive -Nitrate assimilation is critical but costly -Several processes to go through to convert nitrate to get nitrogen you want out of it its multiple toxic intermediates -Have nitrate converted to higher energy form nitrite which is toxic -Nitrite is converted to ammonium which is also toxic and higher energy -From there it can get converted to glutamine which is an amino acid and no longer toxic -Costs 12 ATP per molecule of nitrogen - If you did similar reactions in the reverse it would be explosive; TNT, gunpowder all those are based on rapid oxidation of N or S compounds -Toxic intermediaries: Animals have incredibly reverse reaction to the smell of ammonium because its so toxic -Plants need to process them quickly and store excess ammonium in vacuoles
CO2
-Most plant we see today evolved in low carbon world -Current CO2 is 400 ppm projected to reach 600 ppm by 2100 -CO2 compensation point -point where full saturation has been reached -Giving CO2 will increase rate of photosynthesis up to a certain saturation point if given adequate water, light and temperature -C3 plants should gain most from increasing CO2 because rubisco is directly acting with atmosphere
Mycorrhizae
-Mycorrhizal fungi form relationships with vast majority of plants -Endomycorrhiza invade plant cells within the roots -Ectomycorrhiza enter root but never permeate cell -Arbuscular mycorrhizae (ends) is most ancestral from and most common symbiosis in plant kingdom -Increase water and mineral uptake physically by increasing surface area (hype is very very small) and chemically where some act as decomposers to mobilize nutrients -Can absorb nutrients form 25 cm away from the root which is a huge extension -Critical for germination of most orchid species -In general plant provides carbohydrates to fungi in return but both partners can hoard their part of the deal in certain circumstances -New roots release strigolactones which attract mycorrhizal fungi to form mutualism
Nitrogen deficiency
-N in many cell components include chlorophyll, amino acids, nucleic acids -Animals can only synthesize some of their amino acids but plants synthesize all of them -Deficiency rapidly inhibits plant growth -Nitrogen is a mobile mineral -Depends on how quickly deficient develops Quick -Chlorosis (yellowing) of leaves -Leaves shrivel and fall off -Bottom leaves yellow first -gradient of symptoms Slowly -Build up of carbohydrates because you're not making amino acids without N -Slender woody stems -More anthocyanin (purple) maybe because lack of N messes up photosynthesis since you need N to make chlorophyll, increase sensitivity of light so more oxidative damage, anthocyanin function like sunscreen to prevent damage
How does nitrogen enter the biological cycle
-N is the major constituents of air (80%) but almost entirely unavailable because the two Ns are bonded together by a triple bond which no plant or animal has figured out how to break it -Lighting accounts for 8% of N thats biologically available, it creates highly reactive free radicals (from H2O and O2) that can attack N gas molecules to break apart triple bond which makes nitric acid which then falls as rain -Photochemical reactions makes up 2%: Nitrous oxide gas and ozone can come together to make HNO3 -Biological N fixation makes up 90%: Plants have evolve ability to cooperate with bacteria and get N that way, bacteria or cyanobacteria can fix N2 gas into ammonia, amino in water produce ammonium, most N fixing bacteria are free living in the soil and release N into environment as cells die and decay -> Bacteria live as symbionts in plant roots
Gas exchange
-Need to think of factors that effect rate of gas exchange -Rate of diffusion is governed by Fick's law; states that the flux of gas goes from regions of high concentration to low concentrations and is dependent on the distance separating the two sides and the difference in concentration -Rate of diffusion is faster when the difference in concentrations is larger and when the distance separating two substances is smaller
Root Pressure
-Not enough to explain how water gets to top of plant -Soil water is a dilute ionic solution so its water with studs dissolved in it -As roots absorbs water from soil ions are concentrated in xylem sap so water potential of sap goes down and there is a force for water to move into the xylem, meaning water can't really move backwards so pressure builds up -If you cut top of plant sap oozes out because its because pushed up by root pressure, can help fill embolisms
Normal (aerobic) respiration phase 1: Glycolysis
-Occurs in cytoplasm of all living things (prokaryotes and eukaryotes) -Oxygen independent reaction -Main reactions in classic glycolysis are almost ident ical in plants and animals -Take sugar substrate and partly oxidize (remove H) it to produce organic acid via 10 enzyme catalyzed reactions -So many steps allow organisms to control the release of energy and there are lots of intermediates so if another process produces that certain intermediate it can enter cycle -In animals substrate is glucose and OA is pyruvate -In plants substrate is sucrose (polymer of glucose and fructose) so alternate end product is malate which also serves in CAM and C4 plants
Normal respiration phase 2: Krebs cycle
-Occurs in mitochondria -Pyruvate enters mitochondrion and Krebs starts -Mitochondria and chloroplast both evolved as independent organisms and were engulfed by larger organisms -Mitochondria are important for releasing energy because metabolically active cells have a high concentration of mitochondria -Pyruvate is fully oxidized to CO2 which means all H are stripped and all energy is stripped -Electrons are used through ETC to generate H+ motive force and at very end the electron is donated to oxygen which drives ATP synthesis -Called aerobic respiration because oxygen is needed at end of chain to accept electrons
Different environments provide different osmolar challenges for an organism
-On land: Organisms in terrestrial environments must confront the danger of dehydration -Saltwater: Live in hyper osmotic environment, they lose water to environment -Freshwater: Live in hypo osmotic environment so water rushes into their body -The greater the gradient difference between the inside and outside and the greater the area of interaction, the greater the osmotic challenge
Food captured
-Once animals capture food it needs to be broken down for nutrient acquisition -Digestion system is first thing that forms during embryonic development -Essential role in providing nourishment through digesting and absorbing food, and removing indigestible materials and toxic by-products of digestion -Digestive systems vary considerably between organisms based on diets and feeding behaviour
How many photons does it take to drive photosynthesis?
-One O2 needs two water molecules to be split to yield 4 e-, 4 H+ and O2 -Einstein's law predicts you need 1 photon per electron -You need 4 photons to make a molecule of oxygen since 4 electrons need to be excited -If you measure oxygen output of photosynthesis you expect one oxygen molecule for every 4 photons of light -Quantum yield is the efficiency of photosynthesis, how many products do you get for each quantum of energy (photons) -Yield of O2 tapers off when photosynthetic machinery reaches their capacity -Turn out it takes 8-10 photons per O2 molecule which can be explained by there being two light-driven reactions each requiring 4 photons
The root system
-One function is to uptake water and nutrients -The other function is to anchor plants and keep them in same spot so they don't fall over in storms
Human digestive system
-One way flow of food -Digestive tract is broken down into different components -Headgut: Mouth, detects, ingests and physically breaks down food into smaller part by chewing which exposes for surface area to enzymes in saliva -Foregut: Includes esophagus, important for storage and digestion ->Sometimes crop forms from esophagus -> Crops are used for food storage -Midgut: Digestion and absorption, stomach contains hydrochloric acid secreted by cells, more digestion happens in small intestine such as carbohydrates and fats, while also absorbing stuff -Hindgut: Absoprtion of minerals and water before undigested material is expelled, includes large intestine which has large microbiome to help digest cellulose in plants and produce vitamins
Osmoconformers vs osmoregulators
-Osmoconformers: Animals that do not actively control the osmotic condition of their body fluids and instead conform to the osmolarity of the ambient medium -Number of aquatic invertebrates that are osmoconformers -Osmoregulators: Animals that maintain an internal osmolarity that is relatively constant and can differ from the surrounding medium -Number of terrestrial invertebrates are osmoregulators
Gas exchange organs
-Oxygen and CO2 are key aspects of cellular respiration -During cellular respiration, O2 is required as the final electron acceptor, and CO2 is released -O2 needs to be supplied to all cells and CO2 needs to be transported away -Simple solution for unicellular organisms: Gas exchange through cell membrane -More of a challenge for multicellular organisms because not all cells are in direct contact with the outside medium so organism have evolved specialized surfaces on which gaseous exchange occurs -> In addition O2 and CO2 must be moved throughout the body
Metabolism varies as a function of speed
-Oxygen consumption increases linearly with increase in velocity -Rate of increase is steeper for smaller mammals than larger mammals -The difference in slope is because of limb lengths which longer limbs is more efficient for increasing velocity so there's less energy being used -Animals change limbs when they're changing speed = Energy efficiency -Galloping makes better use of elastic storage every, animals move in a way that increases the force provided by elasticity int heir tendons -Galloping animals arch their back to create and store elastic tension in bones and tendons -> Increases the metabolic efficiency
Gas exchange in air versus water
-Oxygen content is 28x higher in air than in water -Viscosity is 50-70x lower in air than in water -Density is 800x lower in air than in water -Diffusion coefficient of oxygen is 10000x faster -CO2 is less soluble in air than in water so its harder to release CO2 in air than in water -Water is much denser than air, which provides structural support and allows for delicate structure like gills to be exposed in the water -> Why gills collapse quickly when in air
Respiratory pigments
-Oxygen diffuses across respiratory epithelium into the blood, it binds to respiratory pigments (hemoglobin) in red blood cells -By binding oxygen, respiratory pigments increase the O2 content of the blood -Based on its solubility coefficient the O2 concentration in human blood is 0.3% volume but because of hemoglobin it can be up to 20%
C4 Advantages
-PEP carboxylase has no oxygenate activity so you don't get same oxygenation problem -Concentrates CO2 around rubisco Minimizes O2 around rubisco -Reduced carbon lost to photorespiration by >90% -Plants can close stomata to conserve H2O even though this increases the concentration of oxygen around mesophyll since increase inset affecting O2 -For same H2O loss C4 plants can fit twice as much carbon -Costs extra ATP and NADPH per carbon molecule fixed -There are more C4 plants in hot climates near equator
Red-drop effect
-PS II reaction centre preferentially absorbs red light (680 nm) -PS I reaction centre preferentially absorbs far-red light (700 nm)
Photosystems I and II working together
-PSII was discovered first -PSII is the one that can split water -4 photons come in and excites electron which gets passed to Pheophytin -Reaction centre looses its electron and gets passed through electron transport chain which generates ATP -The electron is transferred to PSI to reset it, it harvest light and its electron goes through another ETC -Once you donate an electron the PS needs another electron to restart -PSII replaces electron by splitting water -PSI replaces electron from PSII -Produces 2 short term energy storage molecules; ATP (fundamental currency of life) and NADPH (reducing agent for calvin cycle that helps turn CO2 into sugars)
Cells need to exchange materials with the environment
-Passive mechanisms: Don't require energy ~Diffusion is the movement of molecules due to their intrinsic kinetic energy and is from a region of high concentration to low concentration. It is faster in smaller molecules, in media of lower viscosity, and in higher temperatures -Slow over long distances and can only go in one direction ~Osmosis is diffusion across a semi-permeable membrane so solvent can pass but not solute ~Convection is the bulk flow of substances through closed ducts/tubes due to pressure gradient (think of straw where you create pressure by sucking) -Active mechanisms: Requires energy and can move things against a concentration gradient
Transport of solutes across cell membranes
-Passive transport 1. Diffusion 2. Ion channels 3. Carrier proteins -Active transport 1. Primary active transport: Involves ATP hydrolysis directly like Na+/K+ pumps 2. Secondary active transport (Co-Transport): Energy is used to create concentration gradient of one solute which then drives the transport of another solute (like H+ gradient from ATP hydrolysis)
Plants can punish cheaters
-Penalize nodules that don't fix nitrogen -Could be withholding sugars or oxygen -How to test experimentally without confounding N fixation with the strain of bacteria -Grew roots in artificial atmosphere so they infected plants with same N fixing bacteria and N fixing bacteria is normally a mutuals so it will fix N -Turned mutualist into a cheater by giving environment with no N -Did it at three different levels: Whole plant where they had one with N and one with Ar, did one called split root design where for a single pant half the roots had normal atmosphere with N and half with Ar, did it at nodule levels where some were cheaters and some weren't -Found was that the cheating nodules were smaller than normal nodules, and dissolved them there were way fewer bacteria which suggests those nodules are getting less resources form the plant so it is doing something to reduce population growth of bacteria -Measured O2 concentration inside cheating nodules and found that the O2 concentration was lower as well as O2 permeability -If plants starve bacteria of sugars they wouldn't be able to respire so there would be a build up of oxygen
Phloem sap composition
-Phloem is full of sugar -Some amino acids and ions but mostly sugar -Phloem sap can move up to one meter per hour which isn't as fast as xylem sap -Aphids are phloem feeders, and they have flexible stylets to pass around cells to penetrate phloem vessels
Translocation
-Phloem is key tissue -Experiment: Girdled plants involves removing bark -When bark is removed phloem is too -Water is still moving up through plant by transpiration -Photosynthates are being generated in leaves and go down plant but once they hit girdled ring they stop so there's an accumulation os sugary material above the girdle -Carbon assimilated through photosynthesis is essential for root growth leading to death of tree
Translocation review
-Phloem is the primary tissue through which photosynthetic assimilates are transported -Phloem cells have living cytoplasm at maturity -Sugars move from source tissues to sink tissues -this may be up or down the acid of the plant -Phloem loading and unloading may be symplastic or apoplastic -Sap flow is driven by turgor pressure
How to capture and store light?
-Photosynthesis -Goal is to convert light energy into chemical energy for storage -Earth transforming effect ~Oxygenated the planet ~Generates most of energy used by humans including food we eat, biofuels (wood), fossil fuels ~Captures and stores more than 100 000 tonnes of carbon a year ~Generates 3 times the energy consumed by humans per year
Fluid feeding
-Pierce and suck: Mosquitoes, leeches... -Have piercing mouth part and have anticoagulant chemicals in their saliva to prevent clotting of prey's blood -> Some suck sap from plants -Cut and lick: Black flies, lampreys, vampire bats..... -Have mouth parts for cutting and sponge like labia to transfer blood into esophagus -Vampire bats also have anticoagulants but also analgesic so prey doesn't feel cuts from bite
How is light absorbed?
-Pigments are molecules that absorb lights -Chloroplasts are full of pigments which act as receptors -Each pigment absorbs a characteristic set of wavelengths -Can see Chlorophyll A is most effective in early and end wavelengths, Chlorophyll B is little later and carotenoids are shifted even more and peak in more green light -Chlorophyll appears green because thats what its reflecting
Modified stems
-Plants can grow new parts of their body; see this all the time -Eyes of the potato; potato will generate new shoots through apical meristems -In evolutionary time this is true, cacti are modified stems, spines are modified leaves, plants are modular organism so they build themselves up by adding structures this gives developmental flexibility
Mining the Earth
-Plants fix all energy that enters biological systems but they also are major entry point for mineral nutrients making them foundation for energy, carbon, and nutrients into biosphere -Minerals come in through roots and are dissolved in water -Mineral nutrients have a huge effect on plant growth -Input of fertilizer allows us to get more food form same amount of land but its not directly relates -Green revolution: Dramatic increase in crop yields 1930s-80s due to high yield varieties, irrigation, and fertilizers -Increased yield outpaced by increased energy input - yield/energy input dropped ->50% energy used in agriculture is from N fertilizers which show how N is particularly important for plant growth
Water in soil
-Plants get water form soil -Water moves by bulk flow which is something that happens in closed systems and its movement o many water molecules at once -Moves form wet to dry soils -As plants absorb water around roots them create dry patch so since water moves by build flow to drier area plants pull water in through this process so water comes to plant -Water absorption requires contact, surface area of roots is very important because more contact points -There are finer and finer divisions of the root hairs to max surface area but there are also fungal mutualist to extend water absorption further -Younger structures of roots are more p permeable so that's what's soaking water
What is a key way in which many plants and animals differ in their growth?
-Plants have indeterminate growth which means they can grow throughout their lives -Some animals do too like fish but usually that have either determinate growth (stop at some point) or indeterminate (they row forever) -Plants have both, flowers or leaves are determinate, some parts have indeterminate growth like height or width
Growth in Plants
-Plants have parts with indeterminate growth = Root and shoots -Plants also have determinate growth like for flowers, leaves, fruits
What are plants coolest super power?
-Plants make their bodies from the atmosphere -Air and sunlight; plants construct themselves out of thin air -Ability to replace lost limbs; due to auxin which is central to plants ability to regrow limbs in forms of branches or leaves
Growth regulation by light
-Plants respond to three different aspects of light -Normal sunlight inhibits growth even though its key for photosynthesis -Respond to 1. Quality (wavelength) 2. Quantity (intensity and duration) 3. Direction -Different wavelengths inhibit or stimulate growth -Being in the dark stimulates plant growth because plants don't want to be in dark and grow towards light -Growth slows once it reaches light
Stomata
-Pores that open and closed and of that because of turgor -Guard cells on either side of pore, open or close depending on how turgid or flaccid they are -When they are turgid there are fibres that bulge outwards -When flaccid they fold closed -Produce hormones to respond to low water potential that move through plant and stimulate guard cells where solutes move either in or out of guard cells -Movement of solutes changes water potential, more solute inside cell water moves in -Stomata aperture (width of an opening) changes -As concentration of solutes increases inside cell the stomatal aperture opens as cell becomes more turgid
Energy required to move a fluid in series vs. in parallel
-Pressure differences cause flow so greater flow results from greater pressure difference -There is also frictional resistance which impedes flow -Difference in temperature / resistance gives you bulk flow -> Darcy's law -Hydraulic resistance -Poiseuille's law: Resistance is quantified as R = (8*length*viscosity) / pi*radius^4 -Resistance is lower in parallel than in series -Why capillary beds are organized in parallel -Organized in series the total resistance is the sum of all the resistors -If organized in parallel you take sum of inverse of all resistances and its much lower total resistance than series
Measuring plant growth
-Primary growth causes proliferation of shoots and roots -Secondary growth increases plant thickness (trees getting wider with more wood and bark) -Relative growth rate is the difference in growth -P is turgor pressure -Y is the yield, or threshold turgor pressure below which no expansion occurs, once you get turgor pressure stronger than Y, its strong enough to push cell to expand -If we're talking about a hormone that grows an individual cell in needs to effect something in the equation
Osmoregulation
-Process of maintaining the correct amount of water and solutes in the body (intracellular, extracellular, outside the body) -Process that controls the osmotic pressure in the tissues -Key driving force for water movement -Not that much of a difference of water between inside cell and outside cell -An animal connaît solve osmotic and ionic imbalances by sealing itself odd from the environment because nutrients must be acquired and waste product excreted -Osmosis is the movement of water from high to low osmotic potential -Osmolarity refers to the concentration of all solutes in the solvent -Hypoosmotic solutions have a lower osmolarity (more solutes) -Hyperosmotic solutions have a higher osmolarity (less solutes)
Lungs
-Produced by the invagination or in-pocketing of the body surface connected directly with the outside -Generally highly convoluted and vascularized -Some invertebrates have invaginated spaces that are convoluted to increase the surface area of gas exchange and are richly supplied with blood vessels -Lungs of tetrapods are formed by invagination of the pharynx or hind part of the mouth
Skeletons
-Provide structural support -Serve as muscle attachment -Would have a way for organisms to move -3 types -Endoskeletons: Bones/cartilage inside body, protection for organs, muscle attachment -Exoskeleton: Hard structure on outside of the body (chitin, CaCO3) -Hydrostatic skeleton: Simplest and consist of fluid filled body cavity surrounded by muscles -Bones grow as body grows -> Living tissue
Normal respiration phase 3: Mitochondrial e- transport chains
-Purpose convert NADH and FADH2 to ATP for use by cells -Transfers 2 e- from NADH/FADH2 to oxygen -ETC is fundamentally similar in all aerobic cells -1-4 completes and ATP synthase -As electrons are passed down chain H+ get released onto one side of membrane so there is an electrochemical gradient to create PMF -H+ want to go back through ATP synthase to the lower concentration, enzyme gets torque to convert ADP to ATP -Differences in plants (and many fungi and protist) -Have additional NAD(P)H dehydrogenase and an alternative oxidase, if ETC diverts to alternative pathway no ATP will generated but instead is produced into heat -Plants have this alternative pathway for heat as the final production
Physics and the various equations to describe the circulatory system
-Q is flow and is defined as the volume of a fluid that moves past a given point per unit time -The radius of a tube is related to it's cross-sectional area and affects its resistance -Circulatory systems are similar to electrical circuits with resistors arranged in series vs. in parallel -Q = V*A where V is the velocity and A is the cross-sectional area of the tube -In a closed circulatory system, bulk flow of blood remains constant in all parts of the system so if V changes A changes -In the network of capillaries the cross-sectional area of the path becomes very large, and therefore velocity drops rapidly
Gas exchange in animals that dive
-Range of different depths at which mammals can dive and time they can be underwater for -Some of the most extreme divers can dive to nearly 3000 m and stay submerged for over an hour -> This can lead to hypoxia -The malian nervous system depends on aerobic respiration, so it needs to be supplied with oxygen throughout the dive -Diving animals solve this problem by utilizing oxygen stored in the lungs, blood and tissue -To minimize depletion of stores, oxygen is preferentially delivered to the brain and heart during a dive instead of things like digestion and non essential organs -Many have high hemoglobin levels in their blood as well as more blood in their body per body weight than in non-diving animals
What drives rate of transpiration
-Rate varies a lot -Rate of water loss is the balance between the forces that drive transpiration and resistances that are impeding it -Water potential gradient is primary force: Difference in water potential between the air and the soil -What's impeding it? -On surface of leaf most of the water is leaving through stomata but the rest of leaf surface is made of hydrated cells with potential to loose water, leaf is covered in waxy cuticle tor educe evaporation -Second point of resistance is the stomata -Lastly leaves have boundary layer which is an area of still air right next to leave, humidity in the still air layer is high compared to the surrounding ambient air since water is diffusing out of stomata and collecting in still air to reduce gradient between inside and outside of leaf -Plants work to increase boundary layer by having structure like leaf hairs and trichomes, work to trap warm unmoving layer of air -Leaf size and shape also affect the speed at which air moves over leaf and disturbs boundary layer
Water
-Required for light reaction(donates e- and H+) and respiration -Plants lose water as they take in CO2 by opening stomata -Beneficial to conserve water and there is a cooling effect from transpiration -Cooling effect of transpiration is directly related to water loss -Difference in CO2 gradient is more shallow than water vapour in the cell then in the air so water leaves cell faster than CO2 comes in -Water makes up 70% of organism and provides milieu for cellular respiration -Water is important for plant structure -Water limits productivity -Less warmth equals less productive ecosystems but also limit of water you get desert -> Water is critical to plants
Respiration
-Respiration is reverse of photosynthesis -Releases energy -These are net reactions, don't see path of individual electrons or H+ coming from water or forming water -In respiration hydrogens are stripped off of carbon to release energy -If any metabolite still has hydrogen attached to it then there still energy to be released
Water loss from respiration (breathing)
-Respiratory surfaces are a major avenue for water loss in air-breathing animals -The internalization of the respiratory surfaces (lungs) can reduce evaporativity loss in terrestrial vertebrates -But even within the lung, intake of dry air will cause evaporation of the moisture that is keeping the respiratory epithelium wet -Outging air is cooled by nasal passages during expiration, leading to condensation of water vapour of outgoing air -Organisms have evolved specialized organs such as gills, salt glands, kidneys, to solve osmoregulatory challenges
Seed germination
-Seed imbibition is the uptake of water by dry seeds, those seeds absorb a ton of water and will expand -Seeds are very dehydrated or 7-15% water, membranes aren't in normal state and aren't functioning properly with no metabolism and once the seeds take up lots of water the cells have turgor pressure and normal metabolic activity -> key for seed germination
Root hairs
-Seedling shave a fuzz which are the root hairs -Produced by epidermal cells; one of main function of epidermal cells -Plants absorbed water and nutrients so more surface area is better for uptake and root hairs are a really important way for rotes to increase surface area
Two types of thermogenesis
-Shivering thermogenesis: Heat is produced by contraction of antagonistic muscles such that there is little net movement of muscles -Non-shivering thermogenesis: Stored fat (brown adipose tissue that is typically located near the back and shoulder region) is oxidized through respiration that is uncoupled from ATP synthesis and all energy is dissipated as heat -> This form of thermogenesis is most common in small mammals and newborns of larger animals, especially those in cold environments -In addition to the pathways that produce heat as a by-product, endotherms posses specific thermogenic pathways with the main purpose being heat production
Apical meristems
-Shoot -Root -Primary meristem is active right at the tip (those are the cells that are doing dividing) -Vegetative shoot apical meristems produced vegetative structure like leaves -Inflorescence apical meristem is responsible for cluster of flowers (definition of inflorescence); keeps producing potential for floral meristem which then produces flower
Meristems generate the plant body
-Shoot apical meristems are at the tips of growing parts of the plant -Lateral meristems are above crowns -Root apical are below ground -Primary growth is at apical meristems, increases number of structures as well has height and depth -Apical meristems cause growth as well as producing new structures, leaf or flower or bud or branch, responsible for dividing and multiplying of plant parts -Plants don't have predetermined number of "things" unlike animals where you have set number -Lateral meristems cause secondary growth which are responsible for widening
Assumptions of the pressure-flow hypothesis
-Sieve plate pores must be unobstructed -Simultaneously bidirectional transport in a single sieve tube is importance -Because model is based on passive bulk flow of water it will have low ATP requirements -Unaffected by hypoxia, chilling, inhibitors of ATP production -Turgor must be higher n source sieve than in sink sieve -Maple syrup sap is xylem and not phloem
Companion cells
-Sieve tube elements have primary cell walls only -Have living protoplast at maturity -Lack nucleus, ribosomes, golgi apparatus, cytoskeleton -All that remains is plasma membrane, smooth endoplasmic reticulum, some mitochondria, some plastids -Remains alive at maturity
Allometric of body growth in humans
-Size of particular structures changes over development -Head size scales allometry with body size (proportion of body represented by the head changes with growth, heads are relatively small in adults)
Cost of locomotion decreases with body size
-Smaller animals have higher rates of rate strides because they have smaller limbs so those limbs need to move more rapidly with increase in velocity -Smaller animals exhibit higher rates of muscle shortening to achieve a given velocity for locomotion -Sampling across a wide range of taxa -Different body shapes, postures, ways to locate -Things to take into consideration: Different muscle properties across animals of different sizes contribute to this negative relationship, different body shapes, postures, ways to locomotive (like animals that stand close vs farther to the ground and different ways of flying) -Species variation in the ratio of fast-twitch muscles (less efficient) vs. slow-twitch muscles (more efficient -Small animals have less efficient muscles so cost of transport is higher -Relationship between body mass, surface area and volume are allometric (not isometric) -Allometric means the disproportionate growth of a part or parts of an organism as the organism changes in size -Ratio of surface area to volume is lower in larger animals -Frictional drag is related to the surface area of the animal, more surface area = more drag -Larger animals experience less drag per body mass than smaller animals because of their lower surface area to volume ratio
Cost of locomotion decreases with body size
-Smaller animals show higher rates of limb stride, wing motion, or tail beat to achieve a given velocity of locomotion than larger animals -Smaller animals exhibit higher rates of muscle shortening to achieve a given velocity of locomotion than larger animals -More limb strides to get certain distance -Modes of transport there is negative relationship with body size
What do non-mycorrhizae plants do?
-Some angiosperms don't form relationships -Hemiparasites are plants that tap into roots of neighbouring plants and suck up either their phloem or xylem via haustoria -Blow open stomata, hemiparasites have way more stomata open since their host is working to absorb water and they can create a pressure gradient
22 Elements are essential
-Some elements are only required in trace amounts -Amounts differ from species to species -Humans only need 15 out of 22, most abundant by mass being oxygen (65%), carbon (18%), hydrogen (10%) -> lots of our body is made of water
Example of recent neural control of thermoregulation research
-Some neutrons in the preoptic area of the hypothalamus are activated by warm ambient temperature -The activation of these neurons leads to physiological and behavioural responses to promote cooling -Trick brain into thinking body is too hot by activating these neurons
Source tissues and sink tissues
-Source tissues are any plant part that generates more sugar than it consumes -Tissues that are often source tissues are young but fully expanded leaves -Sink tissues are any plant part that can't meet their own nutritional needs -Expanding leaves, older leaves, roots, storage organs Look at picture -Seed is source tissue but as soon as plant has leaves the cotyledon wither and die -Carbon storm in cotyledons of germinating seed is source, then becomes sink as carbon gets put into storage organs -Hypocotyl is stem area below cotyledon and epicotyl is above -During reproductive stage the fruits are the highly competitive sinks -Youngest mature leaves send sugar up towards shoot tip -Oldest leaves send sugar to roots -Other leaves may send sugar in either direction -Vegetative growth slow during reproduction
Process of glycolysis
-Start with hexose sugar -It gets phosphorylated which requires ATP -You get a hexose phosphate -Molecule is split to get two 3 carbon molecule -Series of steps to get 2 3 carbon organic acids which produces NADH and ATP -4 ATP in the end -NADH important fo electron transport chain
Growth and development of organisms
-Starts from fertilization -Activates development
Hemiparasites
-Striga species are major parasites on crops such as corn and cause significant economic losses -Produce up to half a million extremely small seeds per plant and can stay viable in soil for many years -Seed don't germinate until they can sense the growing roots of another plant species, they sense strigolactone hormone -Root radically can grow up concentration gradient of the hormone
Physics of swimming
-Swimming animals need to support little weight on their own -Water has a density 800x that of air and is 70x as viscous -Select for animals with streamlined shapes to reduce drag and turbulence
Symbioses between plants and N fixing bacteria
-Symbiosis between legumes and rhizobia is not obligatory, they can live without each other -Symbionts seek eachtohte out under N limiting conditions -Plants secrete hormones called flavinoids from their roots -N-fixing bacteria move toward plants along concentration gradient of hormone -Bacteria respond to their own secretions of nod factors that cause root hairs to curl around bacteria where bacteria will dissolve the root cell wall -Chemical signals and cell division causes nodule at tip of the root -Bacteria get sugars in return -When the nodule dies it releases the N content as well as the bacteria so the bacteria can go back to being free-living -Not all rhizobia will fix N for them, they are called cheaters because they form nodules with plants and receive their sugars but won't give away N -Some bacteria go from good to cheaters -Plants can get rid of cheaters by cutting off sugar access
Phloem unloading
-Symplastic phloem via plasmodesmata -Apoplastic is movement through the cell wall space -Sucrose can be broken down into glucose and fructose and enter that way or enter via sucrose (apoplastic) -To maintain diffusion iraient, sucrose is metabolized upon entering the sink tissue
Permeability of the body surface
-THe skin acts as a barrier between the extracellular compartment and the environment but water can move across the skin -Permeability of the skin to water and solutes varies among animal groups -THe skin of amphibians and gills of fish are highly permeable to water and ions -Reptiles, some desert amphibians, birds, and many mammals have relatively impermeable skins, which allows them to minimize water loss through their skin -Exoskeletons of insects are covered by a cuticular layer that protects organism from water loss -> When ambient temperatures surpass the cuticular melting point, there is a sharp increase in evaporative water loss from the insect body surface
Water withholding experiment
-Taken plant and started withholding water and see soil water potential goes down gradually as water is taken up -Water potential in roots follows this cycle as stomata open and close and they dry out more, same with leaves -Eventually gets to point where water potential never gets to 0 even when stomata are closed and at this point plants begin to wilt
Temperature-sensitive neurons
-Temperature-sensitive neutrons in the skin relay information about ambient temperature to parts of the brain including the hypothalamus -Neurons in the hypothalamus directly sense body temperature -Information about ambient temperature is integrated with information about core body temperature and used to initiate various thermoregulatory responses -Like vasodilation, vasoconstriction, thermogenesis, behavioural changes -The hypothalamus have hot- and cold-sensitive neurons that "fire" when they detect brain temperatures that are warmer or cooler than the set point -> There are also distinct neural populations that help determine physiological responses like thermogenesis, blood flow to skin, shivering, sweating and behavioural responses
Water breathing animals in freshwater
-The bodily fluids of freshwater animals are generally hyper osmotic to their environment so water wants to move in -Animals are subject to swelling by movement of water into their bodies and to continual loss of body salts to the surrounding -They produce dilute urine to avoid this -Consume food containing salts -And extract salt directly from the environment via active transport -Proton ATPases within pavement and chloride cells of gills are used to move protons and generate a potential that draws sodium, chloride, and calcium into the cells -Amphibians compensates for the loss of electrolytes by active transport of salts from the aquatic environment into the animals
Thermoregulation and set-point temperature
-The body temperature of endotherms is very stable - under normal conditions remains with 1 degrees celsius -Slight deviations from the set point temperature of the body are mainly reverse by adjustments of conducting -Veins dilate which relaxes them and dissipates heat -They will contract to keep heat in -But in response to larger deviations, metabolic rate is increased and other responses like thermogenesis and evaporative cooling are activated
Bird lungs
-The direction of air flow is unidirectional so their lungs are always perfused with oxygen-rich air -Have air sacs that surround lung -Posterior and anterior air sad with lung between them -Takes 2 cycles for air to move through system -First inhalation air moves into body and is collecting in posterior air sac -During exhalation that air gets pushed over lung from posterior air sac -Inhalation of second breathe the air previously in lungs goes to anterior air sac -During second exhalation air is pushed out of anterior air sacs and out of body
Energetics of running
-The energy cost of running is higher than swimming or flying because the work efficiency of running is very low, mainly due to the centre of mass (CM) rising and falling with each step -Efficiency is lost as muscles push the body up and forwards, while gravity pulls it back down again -Leg muscles need to both fight gravity and also control the fall of the centre of mass before the next stride by slowing the rate of descent and absorbing shock
Exoskeletons
-The exoskeleton is generated by secretion to the outer surface of the body, where it hardens into a rigid structure -Muscles are attached to the inner surface of the exoskeleton -The exoskeleton both gives shape to the body and also anchorage to the muscles to allow for locomotion
Fun facts about heart rates
-The highest heart rates are found in small animal like shrews and hummingbirds -> 600 to 1300 bpm -Limit set by the maximum speed of muscle contractions -Blue whale is 6 bpm
The cost of locomotion
-The metabolic cost of locomotion is the amount of energy required to move a unit mass of animal a unit distance -Usually expressed in units of kilocalories per kilogram per kilometre -Represents energy expended above that used under basal conditions of rest
Boundary layer
-The more windy it is the more that layer is disrupted/blown away -So transpiration increases with wind speed -Also function of leaf size: When talking about how far wind has to move over leaf it depends on direction -The shorter the path length the more the wind can disrupt boundary layer -Shorter leaf dimension in the same direction of the wind makes for thinner boundary layer
Rate of diffusion
-The rate of diffusion is faster when the difference in concentration is larger and when the distance operating two substances is smaller
Organogensis of the root
-The root is like an upside down shoot meristem -Has a root cap -Have apical meristem where cell division is happing -Have a zone of elongation where cells get longer instead of dividing -In zone of maturation they start to take on different functions, root hairs form here and are formed from epidermis -Root cap is important since dirt is very resistant and roots need to push their way through resistive soil, root cap is zone of cell made continuously to protect apical meristem -Roots have a quiescent centre with an unclear structure, some evidence that if apical meristem is hurt the quiescent cells will divide to make a new apical meristem but function is unclear
Hypotheses for the mechanisms driving metabolic scaling relationships
-The surface area hypothesis: The metabolic rate of animals that maintain relatively constant body temperature should be proportional to body surface area because the rate of heat transfer between the warm animal body and cool environments is proportional, all else being equal, to their area of mutual contact -Less heat loss for larger animals because of surface area to volume ratio being lower -Slope between metabolism and body mass should be 2/3 but its actually 0.75 for both ectotherms and endotherms -The cross-sectional area hypothesis: Cross-sectional area of any body part should be proportional to 0.75 power of body mass owing to allometric principles dealing with the way in which blood vessels branch in the body -> In order to minimize the energy dissipated in nutrient and blood transport, the volume of fluid used to transport nutrients is 0.75x the body mass
Determinants of body heat and heat exchange
-The temperature of an animals depends on the amount of heat contained per unit mass of tissue -> A calorie -The rate of change of body heat depends on 1. The rate of heat production through metabolic means 2. The rate of external heat gain 3. The rate of heat loss to the environment -The total amount of heat of an organism is the sum of heat from various sources, including heat form metabolic processes, stored heat, and heat gained and lost to the environment
Phloem
-The tissue responsible for movement of photosynthate throughout planet -Composed of sieve tube elements in angiosperms -Long tubular cells that are arranged in length of the plant -Sieve plates are areas with large pores in cell walls generated in end of sieve elements
Critical features of organism
-Thermodynamically open (energy entering and leaving) -Organizationally closed systems (identifiable identity) -Delimited from environment by membranes that control what goes in and out -Self-organizing and self-regulating: Characteristic shape, also body shape changes in ways that can deviate from mathematical predictions during growth and development -Cell death and replacement to renew themselves -Maintain constancy of their internal environment (homeostasis)
Apical meristems
-They can divide indefinitely so a shoot and root can continue to lengthen and grow forever -All plant organs arise from cell division in apical meristems, followed by cell expansion and differentiation -The primary meristems are the protoderms (epidermis), procambrium (vascular tissue), ground mersotem (remaining)
Leaves are determinate organs produced by shoot apical meristems
-They grow to fixed size then stop growing -Vegetative meristems
Temporal heterothermy
-Torpor and hibernation as examples of temporal heterothermy Torpor -Small animals because of their high metabolism are subject to starvation during periods of inactivity -> To avoid this some animals enter torpor which is a state of reduced temperature and metabolic rate -> Hummingbirds are very active during the day but enter a state of torpor every night -To break torpor animals use a burst of metabolic activity in the form of shivering or oxidation of brown-fat stores Hibernation -Its like an extended torpor that lasts weeks or months (but aroused periodically to empty their bladders and defecate) -Common in taxa that can store sufficient energy reserves such as bears, marmots, prairie dogs, hedgehogs and ground squirrels -During hibernation the brain thermostat is reset to as low as 40 degree Celsius below normal -If ambient temperatures reach dangerously low levels the animal will increase its metabolic rate or awake -Consequently thermoregulatory control is not suspended during hibernation, just a lower set point
Radiation
-Transfer of heat though electromagnetic radiation without direct contact between objects -Warmth from sunlight -Heat emanating from an individual
Bear hibernation
-Unlike ground squirrels and other small hibernators whose body temperature drops almost to freezing during hibernation, the body temperature of a bear drops by only about 6 degrees celsius -Yet their metabolism and oxygen consumption drops by 75% -While sleeping, bears take only one or two breaths per minute and with a heart rate of about 4 beats per minute
Vasodilation vs vasoconstriction
-Vertebrate animals can alter the blood flow to their skin, which affects the temperature gradient -Arteries and arterioles vasoconstriction and vasodilator in response to chemical signals from the brain -Vasodilation: Heat loss across the epidermis increases -Vasoconstriction: Heat loss across the epidermis decreases -Change in diameter of arterioles
Sieve-tube elements
-Very different from xylem -They are paired -Original mother cell, cell division occurs in second panel and is extremely uneven -Cell on left is destined to become companion cell, larger cell is sieve tube element -Get degradation of internal cellular components in sieve tube element but its still not dead -Nucleus degrades, vacuoles degrade but still has cytoplasm -At time of maturity you've got living companion cell and bag of cytoplasm -Needs new proteins or membrane all comes from companion cell -In xylem cells there is no cytoplasm or anything, it's just water -Phloem has different structure with living membrane because it serves regulatory function where as xylem is strictly physical
Water potential
-Water potential is what drives water movement -Know water potential of each media to calculate gradient to see which direction water will move in -Water potential is free energy of water but is made up of 4 features: pressure potential, solute potential/osmotic potential which matters if there's a membrane that separates the media, gravitational potential, and matrix potential -Add them up to get water potential -In cells you can usually ignore gravitational potential since cells are so small that difference in height is negligible -Usually ignore matrix potential since there aren't that many colloidal (tiny material spread out uniformly all through another substance) solutes -Cell in beaker of water: Water diffuses across membrane into cell until is explodes (animal) or expansion physically constrained such that osmotic potential equals pressure potential because of cell wall (plants)
Different animals use different forms of locomotion
-When comparing locomotion of various taxa the most metabolically expensive mode of locomotion is running then flying then swimming -Running is most expensive because it takes more energy to fight gravity
Cavitation
-When water column fails the formation of embolisms occurs -Bubble -Water column can't hold under tension when there's a bubble -Bubbles can come about through either direct puncture (inset bites) or xylem being broken during heavy wins, or freeze thaw, or droughts -When that occurs it prevents upward movement of water though wherever embolisms are -Because of how cells are fit together they can be bypassed temporarily
Gas Exchange
-When water reaches leaf surface -Water evaporates into intercellular spaces and becomes gas -Within tissue you've got mesophyll cells and from then it evaporates and moves outwards through stomata pores -CO2 enters through stomata -For a plant to photosynthesize the stomata need to be open must of the time which comes with cost of water lost -Both moves through diffusion which is based on concentration gradients, concentration gradients for water and CO2 are going in opposite directions -CO2 has a low concentration gradient: Ambient concentration is .4% and inside the leaf it goes down as CO2 is used up -H2O has a very steep gradient from inside to outside, its also smaller so it diffuses way faster -> Moves from high to low water potential -> -100 Mpa outside, 0 Mpa inside -> The gradient is almost 100 Mpa -To photosynthesize plants must constantly lose water -A large surface area for exchanging gases offers a large surface area for desiccation -Plants can only desiccate to certain point before they die
Anaerobic respiration in animals
-Wihtout oxygen -When O2 is used faster than its brought into cell then glycolysis becomes primary pathway for ATP production -O2 concentration in cell is falling -Glycolysis is faster but less efficient since net bent of ATP is small but now you have to regenerate NAD+ -Lactic acid fermentation is used to regenerate NAD+ -Pyruvate is converted to lactic acid by lactate hydrogenase enzyme which consumed NADH and produces NAD+ -Build up of lactic acid so it gets metabolized in uncle to glycogen or in liver to glucose -Experiment that got cheetahs to run on treadmill it proposed cheetahs were overheating during hunt so they need hours to cool down, but actually they don't heat up that much so it actually takes hours to recover form build up of lactic acid in muscles
Water: Roots -> Xylem -> Leaves -> Atmosphere
-XYlem is made up of dead cells that fit together to form a series of little pipes that move up through plant -They don't have cell membranes so water doesnt move from osmosis, it moves quickly with little resistance -As it moves from roots to leaves, it moves to leaf vascular and from there it moves out to photosynthetic tissues to sponge like mesophyll tissue, once its there it can evaporate from those cells into air spaces within leaf -> Changed from liquid to gas -> Gas phase is when it moves out through plant stomata
Structural adaptations for fast running
-You increase stride length with flexible spine -Spine flexibility allows the spine to curve and extend -Spine flexion occurs when front feet are on the ground -Spine extension occurs when back feet are on the ground -Thought to contribute about 10 km/hr to run speed
Body surface for gas exchange
-flatworms, annelids, amphibians -In frog tadpoles, respiratory gas exchange is conducted through the thin, gas-permeable skin, the gills, and their large tail fins -The skin of some aquatic newts contain about 75% of the respiratory capillaries -In frogs, the skin of the back and things which are areas exposed to air contain a richer capillary network than the skin of the underparts
Functions of animal circulatory system
1. Allows material exchanges with the absorptive surface of the digestive tract, providing a means of transport for absorbed food to all parts of the body 2. Serves as a vehicle of communication between different parts of the body 3. Serves the function of distribution, exchanging, and dissipation heat 4. Carries antibodies and blood cells that defend the body against infections and transports toxins to detoxification centres like the liver
C4 Two Carboxylations
1. C4 carbon fixation -Occurs in mesophyll cells that have fewer Calvin benson cycle enzymes so no rubisco -Need different acceptor enzyme: PEP carboxylase -Pep combines with CO2 to form 4 carbon acid called OAA -OAA then because malate another 4C acid using 1 NADPH -4C malate acts as a carrier/shuttle to take carbon to location of Calvin Benson cycle -PEP has much higher affinity for CO2 than oxygen 2. Carbon reduction -Occurs in chloroplast stroma of bundle sheets cells -4C malate comes in and is decarboxylated to produce CO2 and 3C pyruvate using NADPH -3C retunes to mesophyll -Rubisco now has no option because there's only CO2 to fix -Products of PS loaded into vascular tissue via plasmodesmata -Restoring CO2 acceptor and enzyme takes 2 ATP
Calvin-Benson cycle has 3 phases
1. Carboxylation -Chemical reaction where carboxylic acid group is produced by treating a substance with carbon dioxide -RuBP is a 5C molecule accepts CO2 -Makes a 6 C molecule which is unstable and generates 2 3C PGA molecules 2. Reduction -Reduction of PGA to G3P -Creates a carbohydrate -Requires ATP and NADPH -NADPH donates electrons to the 3C intermediate 3. Regeneration -Regeneration of RuBP molecule -Very complicated and takes 1 ATP -Several G3P molecule are rearranged to a RuBP molecule
Two challenges in photosynthesis
1. How to maximize carboxylation and minimize oxygenation by RuBisCO 2. How to take in CO2 while minimizing water loss? Both use the stomata -Both problems are most acute in hot climates because as temperature heats up RuBisCOs affinity to oxygen increases -Evolution has selected on plants that deal with these problems
Nutritional requirements obtained from food
1. Simple sugars used as substrates to generate energy or to synthesize other molecules 2. Aquire amino acid to build proteins 3. Lipids are used to make cell membranes as well as storage for metabolic energy 4. Salts are used for synthesis of nucleic acids, enzyme co-factors and for water balance 5. Vitamins are diverse group of organic compounds that animals can't synthesize but needed for functions 6. Water is essential solvent for biological reactions
Two stages of photosynthesis
1.Light-dependent reactions -Light energy is captured and used to extract electrons from water with a byproduct of oxygen -Electrons are used to make temporary energy storage molecules NADPH -H+ accumulate at lumen and are released under pressure to make ATP 2. Light-independent reactions -ATP and NADPH are converted into more long term storage molecules
Components of a circulatory system
Any circulation system has 4 essential components 1. A main propulsive organ (the heart) that forces blood around the body 2. An arterial system to both distribute blood to the body and act as a pressure reservoir 3. Capillaries for transfer of material between blood and tissues 4. A venous system to act as a blood reservoir and a system for returning blood to the heart
Physiological changes for heat regulation
Autonomic control: -Vertebrate animals can alter the blood flow to their skin -Activation of piloerector muscles increases the extent of fluffing of pelage and plumage (piloerection), which increases the effectiveness of insulation by increasing the amount of trapped, unstirred air (reduces convection) -Sweating and salivation during panting can cause evaporative cooling -Just means we don't think about it
C3 vs C4
C3 -Have palisade mesophyll layer on outside of leaf where photosynthesis takes place -All cells are capable of doing photosynthesis -Each chloroplast does a complete Calvin Benson cycle C4 -Separate carboxylation reactions into different cell types -Instead of just having palisade and spongy you have mesophyll cells surrounding the bundle sheath cell
What are the most energetically expense activities for humans?
Cycling, running, fast diving, uphill cross country skiing -Energy consumption during activity depends on body size, speed of locomotion, type of locomotion
Transpiration
Evaporation of water from the surface of leaf cells in actively growing plants and the process by which its replaced by water movement up form the soil -Plays important roles in plant physiology and functions here that movement of water comes with nutrient transport, evaporative cooling, used for growth and cellular respiration, turgor that maintains plant structure -Small proportion of water taken up from roots, vast majority is lost to transpiration -Crops can create their own climate
Open circulatory system
Open circulatory systems -Many invertebrates have open circulatory systems -The blood pumped by the heart empties via an artery into an open fluid space called a hemocoel -Blood bathes the tissues directly -The hemocoel is often quite large and can constitute 20-40% of body volume -Harder to alter velocity and distribution of blood flow but really blood can only be moved by body movements -> Because of this changes in oxygen uptake is usually slow and blood pressure remains low -Winged insects have accessory pumping organs which pump blood into the wings -> Normal body movements also help propel the blood around the body
What physical factors might determine how quickly a substance moves across a membrane?
The flux of a substance across a membrane is determined by: 1. Concentration gradient 2. Surface area of membrane 3. Thickness of a membrane 4. The permeability of the membrane
Basic steps of animal gas exchange systems
There are four basic steps involved in gas exchange systems used by most animals: 1. Breathing movements that supply air or water to the respiratory surface 2. Diffusion of O2 and CO2 across a respiratory epithelium 3. Bulk transport of gases by the blood 4. Diffusion of O2 and CO2 across various membranes inside the body such as cell walls of red blood cells or mitochondrial cell walls
