BSCI 207 Exam 3

Ruminants are animals with _____ in their _____. This is beneficial to the animal because? examples?

-...with microbes in their ruminant guts -beneficial to the cow because they break down cellulose into usable molecules -produces essential vitamins and amino acids -recycle waste nitrogen from host metabolism into microbial protein; digested by host into amino acids to make host proteins -the cow chews cud (ruminates) to expose more surface to the microbes; added saliva keeps pH from dropping too low in rumen.

When ADH level is high, walls of distal convoluted tubule have _______ aquaporin density. What happens?

-ADH= antidiuretic hormone= decrease urine flow= high aquaporin density= high permeability to water -functions like proximal tubule (ions pumped back into blood & water follows, yielding reduced volume of urine that is isosmotic with blood plasma)

What are the apoplast and symplast?

-Apoplast: cell walls (lie outside of membrane), continuous meshwork -Symplast: passes through the continuous cytoplasm of the living cells connected by plasmodesmata. Selectively permeable membranes of root cells control access to symplast, so movement of water and solutes into symplast is tightly regulated

Unlike other soil nutrients, nitrogen in soil is not from weathering of rocks. Where does it come from?

-Bacterial composition of dead organisms -fixation of atmospheric nitrogen -plants cannot absorb nitrogen directly, take it in as nitrate

How is pepsin made?

-Enzyme secreting cell makes Pepsinogen, acid secreting cells make HCl, this low pH then converts Pepsinogens into Pepsin. -newly formed pepsins activate other pepsinogens.

External and Internal parasite?

-Internal parasite: heart worms, flatworms, ringworms; -External parasite: ticks

Which two steps does translocation (movement of sap) require metabolic energy?

-Loading and Unloading -Loading: transport of sucrose and other solutes from sources into companion cells and then into sieve tubes -Unloading: transport of sucrose and other solutes from sieve tubes into sinks

what happens in the ascending limb and descending limb?

-NaCl actively transported out into the interstitial fluid, diluting the fluid, and increasing ion [ ] in the interstitial fluid -fluid in descending limb reaches equill. with interstitial fluid -dilute fluid enters the collecting ducts, reaching osmotic equill. with interstitial fluid before exiting

What do CAM plants do with their stomata?

-Opposite from typical plants -typically grow in arid (dry) conditions -in dry conditions, such high cost to have stomata open -alternative way to photosynthesize: open stom. at night, close in sunlight because too risky -fix carbon at night, do the rest during the day

What is the purpose of mycorrhizae?

-Plants get help from these soil organisms -break down organic material in soil, freeing up nutrients, and some have very MUTUALISTIC relationships with plants

Midgut digestion: What are proteins, carbs, lipids broken down into?

-Proteins: amino acids -Carbs: simple monosaccharides such as glucose -Lipids: fatty acids and glycerol -these simple molecules can be absorbed by the gut

What else does transpiration do to the plant?

-Transpiration is not the only key to moving water through xylem, but also cools leaves (like human sweating) -evaporative cooling

How far can water travel in the apoplast?

-Water and minerals in APOPLAST can travel only as far as the ENDODERMIS, the innermost layer of the root cortex, BEFORE entering the symplast -at the Casparian strip, water/solutes must enter the symplast to cross the endodermis that would block them otherwise -mineral ions actively transported into xylem, making water potential (-), and water flows passively into the xylem by osmosis

Marine bony fish: Which way will water & ions tend to move between seawater and fish?

-Water moving out of the fish into the water because there is a higher osmotic pressure in the water (water moves from low to high osmotic pressure). -ions moving into the fish FROM THE GILLS -HYPO OSMOTIC

Which part of the tree are the phloem and xylem?

-Xylem: wood is the secondary xylem, adding layers causes increase in diameter -Phloem: innermost layer of TREE BARK

Glucose transport in and out of most cells in the body does NOT involve ____________ transport?

-active transport

How can a mammal kidney make such concentrated urine?

-amphibian osmotic U/P can't exceed 1.0, but mammal kidneys can yield U/P of 10 of 20 -proximal tubules function like those of other vertebrates; reduce volume of urine w/o changing osmotic pressure -distal tubules also similar in concentrating urine more or less depending on ADH levels -HOWEVER, in mammal kidney, deeper portions of COLLECTING DUCTS are surrounded by tissue fluid that is FAR more [ ] than blood plasma (not isosmotic) -at the start of collecting duct, osmotic pressure of surrounding tissue fluid is that of blood plasma (isosmotic), but as it moves through the collecting duct, the surrounding tissue fluid has INCREASING HIGH OSMOTIC PRESSURE -ions cannot easily diffuse into collecting duct (though they can through pumps when they're active) ****-when ADH lvl is high=collecting duct walls high permeability to water=water moves out into [ ] surrounding fluid=[ ] tubular fluid=tubular fluid reach equill. with the MOST [ ] tissue fluids just before leaving collecting duct= yield low volume of HIGHLY [ ] urine= osmotic pressure far high than that of blood plasma ****- low ADH lvl=collecting duct walls low perm. to water=no water moving out, but ions actively moving out into tissue fluid=high volume of dilute urine

Ascending vs descending limb of loops of henle?

-ascending limb is impermeable to water, active transport -descending limbs ARE permeable to water

Why do these larger organisms feed on such tiny prey?

-based on the 2nd law of therm., with each energy transformation, usable energy decreases (lost to surroundings as heat) -in a trophic pyramid, only 10% of energy transferred to each trophic level, so the lowest level has the most energy and also highest in population. -not as much energy is available at the higher trophic levels, so feed on low trophic level

Movement in phloem as compared to xylem?

-bidirectional, but individual sieve tubes move fluid in just one direction -in contrast to xylem, movement of fluid in phloem requires living cells

What enters through the glomerulus/bowmans capsule?

-blood enters each glomerulus at a pressure high enough that fluid from blood plasma is forced through tiny openings in walls of glomerular capillaries & then through inner wall of Bowman's Capsule -fluid enters lumen (central cavity) of Bowmans capsule -blood cells & proteins dissolved in plasma are LEFT BEHIND in plasma -water, salts, and small organic molecules such as glucose & amino acids pass through freely, ENTERING NEPHRON

Name some modes of feeding?

-bulk-feeding -substrate feeding internal parasite external parasite -suspension feeding -symbiosis with chemosynthetic and photosynthetic autotrophs -symbiosis with gut microbes

Kidneys of most animals can produce urine more dilute than blood plasma (U/P < 1), but kidneys of most animals _________ produce urine more [ ] than plasma (U/P > 1). Examples?

-cannot -these kidneys cannot correct problem if blood plasma is becoming too [ ] , cannot remove solutes from plasma and make urine more [ ] than plasma -i.e., fish, amphibians, lizards, snakes, turtles, most aquatic invertebrates

What are loops of henle?

-connects the proximal and distal convoluted tubules of the nephron -creates a [ ] gradient in the medulla (innermost portion) of kidney, increasing the osmotic pressure around collecting ducts -DO NOT THEMSELVES concentrate urine, but set stage by increasing osmotic pressure of tissue fluids around collecting ducts -nephrons in mammalian kidney oriented so all loops of henle are parallel -bowmans capsules and convoluted tubules in renal cortex, loops of henle & collecting ducts in renal medulla (deeper) -ascending and descending limbs multiplies effects of active ion transport -countercurrent multiplier (like countercurrent exchange but requiring active transport)

How is the insertion of aquaporins controlled?

-controlled by antidiuretic hormone (ADH=vasopressin) secreted by hypothalamus of the brain

Are xylem cells dead or alive?

-could be living or non-living -Xylem conducting cells, which are dead when they are mature, distribute water and mineral ions taken up by the roots to all the cells of the roots and shoots

What type of filtration do gill rakers use? Explain.

-crossflow filtration -concentration of food particles before swallowing -water is filtered out as food is collected

What happens to the diameter of tree trunks day/night?

-diameter increases at night, decreases during the day -analogy: when you suck hard on straw, it narrows, just like trees, narrows during the day when transpiration (water being sucked up) occurs and widens at night

Osmotic U/P can range from 0.1-4.0 (very dilute to very [ ] ) Under what circumstances might U/P be at each of these extremes?

-drink a lot=plasma too dilute=kidneys make dilute urine by removing more water than solutes from plasma -sweat a lot/don't drink enough=plasma too [ ] = kidneys make urine more [ ]

What is bulk feeding?

-eating relatively large pieces of food (we do this)

Symbiosis with photoautotrophs and chemoautotrophs?

-example for first one: each individual coral is made up of polyps, and each polyp has algal cells in its gastrodermis; the photosynthetic products of the algal cells pass directly to the animal cells (coral) in each polyp -example for 2nd one: hydrothermal vent worms in the deep dark sea using chemoautotrophic bacteria for feeding: live near hydrothermal vents that supply them with H2S, the bacteria in the worms trophosome convert H2S to SO42; -the H2S supplied to the bacteria from the vents also allow the bacteria to supply the worm cells with organic compounds (use CO2 as carbon source) -trophosome contains the sulfur-oxidizing bacteria

What ability does plant partner have that could benefit fungal partner?

-fungal partner gets organic compounds such as sugars and amino acids from plant -up to 20% of photosynthate produced by terrestrial plant goes to arbuscular mycorrhizal fungi -fungal partner has huge SA:V and ability to penetrate fine structure of soil, dramatically increasing access to water and minerals, especially phosphorus -mycorrhizae are essential for normal growth of many plants; occur in >90% of terrestrial plants

*What type of relative osmolarity would a fish in fresh water be? (low amount of ions in freshwater)?

-hyperosmotic -all freshwater animals are hyperosmotic to freshwater -since the water has a lower salt [ ], the plasma must have a higher salt [ ], meaning its hyperosmotic. -water moving into the fish, excreting a very hypotonic (dilute) urine to expel all the excess water -makes them bloated; tend to lose ions by diffusion to environment -body fluids become too dilute; have to produce large volumes of water a day to get rid of excess water; in most cases, kidneys produce urine far more dilute than blood plasma (U/P <<1.0) -lost salts replaced by active transport of cells that use ATP to pump Na and Cl directly from freshwater environment into blood, although these ions are scarce in freshwater

Digestive enzymes in vertebrates?

-in mammals, amylase in saliva break down starches; food travels to stomach

What happens when there is an increase in blood osmolarity (for instance, after sweating profusely)?

-increase in blood osmotic pressure= high in solutes= release ADH by hypothalamus= high permeability to water= water entering the surrounding fluids= concentrated urine to prevent water loss

Both parasitic and carnivorous lifestyles have evolved ____________?

-independently in multiple plant lineages

Solution to 1st problem?

-ion exchange to make bound cations available to plants -protons bind more strongly to clay particles than do mineral cations, so they swap places-- releasing mineral nutrients into soil solution

Primary urine is ______ with blood plasma

-isosmotic (same osmotic pressure) with blood plasma -during passage through nephron, > half of water & ions are typically reabsorbed into blood plasma ([ ] urine can be >99%) -equivalent of all plasma water in body enters nephrons every 30 minutes

How do you increase or decrease water potential?

-it's lowered by increased solute (making solution more "attractive" to water) -it's increased by increased hydrostatic pressure

Some desert mammals can achieve U/P of 10 or even 20. Why is this important to them?

-keep from dehydrating; keep blood more dilute

What are nephrons?

-kidneys have many microscopic tubule called nephrons; they discharge into a single tube, the ureter, that carries fluid out of the kidney (via bladder and urethra in mammals)

Describe the plasticity of digestion.

-lab rat switched from low-protein to high-protein diet increases production of protein-digesting enzymes within 24 hours -in a week, secretion rates of these enzymes may increase 5-fold -switched from high-protein to low-protein diet, production of protein-digesting enzymes will drop -similar findings for carbs and lipids -absorption efficiency also ramps up and down

How does the structure of the midgut allow for most of the digestion and absorption to occur?

-large absorptive surface is achieved by the sheer length of the tubular small intestine -inner midgut wall highly folded and folds bear fingerlike projections (villi); they INCREASE the surface area of these folds

What do plants need to live?

-light -carbon, hydrogen, oxygen (from air and water) -mineral nutrients (from soil solution around roots)

What is substrate feeding? Examples?

-living in or on their source -example: caterpillar mining into the leaf

Discuss Transpiration-cohesion-tension model.

-look at image -transpiration from the surface of the leaves causes evaporation of water on the mesophyll walls, generating tension on the water in the xylem. Cohesion of water molecules in the xylem transmits the tension from the leaf to the root, causing water to flow through the xylem from the roots to the atmosphere (leaves).

Where is sugar made in plants?

-made in the leaves and stored in roots -moves up or down, as compared to water that just moves from roots to leaves (up)

Xylem overview:

-main way to bring water up=tension, negative to even more negative water potential the higher up you go -tension (pulling from above) on xylem accounts for most of the flow -not main way: osmosis (pushing from below) is limited to roots, contributes little to flow in TALL plants -bulk flow of water from roots to leaves mediated by continuous water potential gradient

How is photosynthate in leaves transported through plant?

-mainly sucrose is actively transported(use E) into sieve tube elements in phloem and moved throughout the plant

____________ can produce [ ] urine with U/P > 1

-mammals, birds, insects -some insects achieve U/P of 8 and birds reach 2 or 3

Suspension feeding?

-many aquatic animals sift small food particles from the water -examples: mussels, whale sharks, basking sharks, all use gill rakers -baleen whales have baleen plates, lots of fibers that intermingle and collect food particles -blue whales, eat mostly only krill

What if U/P ratio = 2.0?

-more solute [ ] in urine than plasma, so making plasma more dilute; less concentrated. -urine is less watery than plasma, so kidney is removing more solute than water from blood plasma, making plasma more dilute -kidney is decreasing osmotic pressure of plasma; decreasing solute [ ] in plasma

What stimulates opening/closing of stomata? How does stomata regulate transpiration rate?

-more sunlight=photosynthesize -not open at night because need sunlight to photosynthesize -if CO2 levels are low, then open stomata to photosynthesize -water loss=close stomata -time of day (circadian rhythm) -high [K+] in guard cells: H2O flows IN by osmosis; guard cells turgid, open -low [K+] in guard cells: H2O flows OUT by osmosis; guard cells flaccid, closed. -think of 2 elongated balloons whose tips are joined at a fixed distance apart: when full, big hole forms; when nearly empty, hole collapses.

Are most marine invertebrates osmoconformers or osmoregulators?

-most are osmoconformers -most osmoconfomers can't survive at low salinity; most that can survive are hyperosmotic regulators -most osmoconformers ALSO do not survive in water much more dilute than seawater; marine mussels are osmoconformers that can thrive at a wide range of salinities

What is vascular tissue in a plant made out of?

-most plants have this -made out of xylem and phloem, through which materials are distributed throughout the plant

*Describe a sharks plasma [ ]

-most sharks & their relatives have ion [ ] similar to those of marine bone fishes and much lower than seawater (hypoionic) -but OSMOTIC PRESSURE of blood is slightly higher than that of seawater; body fluids have high [ ] of 2 organic solutes (urea, mainly) and trimethylamine oxide (TMAO) -because blood is HYPEROSMOTIC to water, sharks experience slight osmotic influx of water into their body through gills -for sharks and relatives, ~40% of blood osmotic pressure is attributable to urea, as opposed to most aquatic animals whose blood osmotic pressure is due to inorganic ions in its plasma. -sharks tend to gain water by osmosis AND ions by diffusion

Animal digestive enzymes are diverse

-nearly all animal phyla characterized by a tubular through-gut -most molecules ingested cannot pass through gut epithelium (look at image); food must be broken down with the help of enzymes to yield smaller molecules that can cross gut epithelium and enter blood capillaries

What is the source?

-net producer of carbohydrate (photosynthesizing leaves or storage organs digesting stored reserves)

*Typically, stomata open during the day and close at night. Why would this be beneficial to plants?

-no sunlight during the night time, so no photosynthesis

How about anions? (negatively charged minerals)

-not bound to clay particles, more accessible, but more easily leached from soil

*Briefly describe what happens in the oral cavity, stomach, and small int.

-oral cavity: carb digestion with saliva -stomach: pepsin -small int: more carb digestion

What are osmoconformers and osmoregulators?

-osmoconformers: body fluids isotonic with surrounding water -osmoregulaters: actively maintain osmolarity of body fluids within narrow range

Other ways plants get their nutrients?

-parasites; 1% of flowering plant species get some or all of their nutrients (and sometimes energy) from other plants -carnivorous plants; digest insects

Why doesn't pepsin digest the cells that synthesize it?

-pepsin secreted in inactive form and activated by exposure to HCl in stomach lumen

What does sugar move through?

-phloem

Are phloem cells dead or alive?

-phloem cells are generally alive, transport carbs (mainly sugars) from sources (leaves, tubers, seeds) to sites where they are used or stored (sinks=growing tissues, roots, developing flowers and fruits).

Characteristics of phloem?

-phloem solute is 90% sucrose

Examples of evolution of digestive abilities?

-plant-eating insect host-shift -lactase production in human babies, but usually not in adults lactase breaks lactose molecules into monosaccharides, galactose, & gluclose several cattle-raising African tribes, as well as Northern Europeans, have independently evolved the ability to digest lactose as adults

Describe proximal tubule of nephron (mammal and amphibian)

-proximal tubule has nephron wall loaded with aquaporins (water channels) so highly permeable to water -Na and Cl (also glucose, amino acids) are returned to blood by active transport & water follows by osmosis -result is that as fluid moves through proximal tubule, volume is greatly reduced, but osmotic pressure is unchanged & still, matches that of blood plasma

What is the purpose of insulin and glucagon?

-regulate storage and release of nutrients in body -both hormones released by endocrine portion of pancreas -pancreas has exocrine portion as well

Many birds & non-avian reptiles associated with oceans or deserts have ____________________ that excrete a highly [ ] salt. Some marine fish too.

-salt glands in their head -excrete this salt because of their salty environment; too -but marine mammals manage with just their high-performance kidneys

What kind of transport is utilized for glucose transport?

-secondary active transport b/c its polar molecule from lumen of small intestine into intestine cells -sodium potassium pump keeps sodium [ ] higher outside the cell, this gradient allows glucose and Na to move into cells by facilitated diffusion with cotransporter protein

How does the kidney regulate blood plasma?

-selectively removes water and ions from blood plasma -this regulates the composition & volume of blood plasma

_______ mammals have lower U/P, __________ have high U/P. Why?

-smaller U/P have higher U/P, meaning their urine is more [ ] due to their high SA:V ratio; need to design kidneys to make urine more [ ] to retain water; they lose more water due to their high SA:V. -larger have lower U/P due to their low SA:V ratio

Discuss water potential

-solute potential + pressure potential -describes the tendency of a solution to take up water from pure water across a membrane -low water potential= more solute and less solute=net movement of water to wherever theres lower water potential

Different ways stomata responds? short term and long term responses

-stomata can open and close quickly (in minutes), not only in response to light level, but also CO2 concentration and water loss -over longer terms (days to weeks), plants can change number of stomata in response to environmental conditions. Shed leaves, make new leaves with more or fewer stomata.

Characteristics of nitrogenase?

-strongly inhibited by oxygen -plant roots are typically an aerobic environment -O2 levels in nodules regulated by leghemoglobin, a plant-produced O2 carrier protein related to hemoglobin -O2 levels kept low enough for nitrogenase to function, but high enough for aerobic respiration by bacteria (necessary to supply energy for fixation reaction).

What is the relationship between plants and nitrogen-fixing bacteria?

-symbiotic -some plants, especially LEGUMES, can form symbiotic relationships with certain bacteria that live in nodules that form on the roots, capture atmospheric N2, and make this nitrogen available to plants -legumes (members of the bean family) harbor these symbiotic nitrogen-fixing bacteria -n2 depleted soil not a problem for legumes because they can use n2 from atmosphere, unlike most plants that need it from the soil

Purpose of hindgut?

-temporarily stores indigestible waste -completes reabsorption of water and salts

What type of nitrogenous waste is excreted by mammals? Birds? Fish?

-terrestrial animals: urea, uric acid, or other compounds related to uric acid. can be stored because far less toxic than ammonia, cost ATP to make though. (Not ammonia because no water around they can just let it dissolve in). E required. -mammals and most amphibians: urea -insects, spiders, reptiles, BIRDS: uric acid, usually as solid or semi-sold form (white stuff in bird shit) -fish: most water-breathing aquatic animals excrete ammonia, NO ENERGY REQ. ; ammonia is quite toxic, so [ ] in body fluids must be kept very low. (Not a problem for crayfish, squid, and fish because they can just let it dissolve, no E required.) SUMMARY: fish: ammonia mammals: urea birds reptiles: uric acid

Define osmosis

-the flow of water across a semi-permeable membrane from a region of low solute [ ] to high solute [ ] -osmotic potential (solute potential) important for water potential -if solute cannot diffuse, then water will move to equalize concentration

How to mammals achieve such high [ ] of urine?

-the loops of henle -15-20% of nephrons have LONG loops of Henle -long= more [ ] urine

If stranded on a desert island, should you drink water?

-the maximum Cl- [ ] in urine produced by kidneys is lower than Cl- [ ] in the seawater -we can't make the urine more [ ] than the seawater -(remember, most animals CANNOT produce U/P > 1, meaning urine more concentrated than plasma) -so must use additional water to EXCRETE Cl- that was taken in with seawater -BUT, other animals can excrete salts at higher [ ] than humans can, thus they are able to take in seawater & excrete salts in less water than they ingested -many marine bony fish excrete pure ions from gills

In practice, the nutritional value of different foods depends on.........

-the specific digestive systems of the animals consuming them -example: humans can't digest cellulose, but some insects produce cellulose-digesting enzymes or, like ruminant mammals, harbor symbiotic bacteria in their guts that do this work for them

What happens when there is a high concentration of sucrose in the phloem companion cells?

-these cells then have a high sucrose [ ] (=more negative solute potential), so water enters sieve tube elements by osmosis from xylem -water entering sieve tube increases turgor pressure at source end of sieve tube (=positive pressure potential), so sieve tube contents are pushed toward sink end

Why do mammals in wetter environments have a lower U/P ratio as compared to dry?

-they have perpetual access to water, meaning they can make their urine more dilute. don't have a problem with retaining water.

Problem with these marine bony fish? Solutions?

-they lose water to the environment by osmosis, dehydrating them; because they are hypo-osmotic -living in the ocean is like living in a desert -gain ions (Na, Cl) by diffusion from seawater, making body fluids too concentrated Solutions: Drink seawater & expend energy pumping ions across intestinal wall so water will enter blood from gut -use energy to excrete excess ions; specialized cells to move ions out to more concentrated seawater -U/P is 1.0 (urine more [ ] than blood), too low to keep body fluids more dilute than seawater, so vigorous extrarenal salt excretion -marine bony fishes expend 8-17% of daily ENERGY budget on osmoregulation

Why are crop soybeans rotated with crop corn?

-to cut fertilizer use and maximize overall profit

How is vertebrate digestion?

-tubular gut with accessory glands

What is the permeability of water in the distal tubule? What controls the permeability?

-unlike proximal tubule, wall of distal tubule has variable permeability to water -where aquaporins are inserted in epithelial cell membrane, water permeability is high

How do we scientists know that upward pressure does NOT move through the xylem or capillary action?

-upward pressure: experiment involving cutting at the base of a tree, putting the cut part in poison to kill the cells, poison still traveled up trunk, though when leaves killed, no more traveling. Concluded that living leaves are needed for transport -capillary action: calculations shown NO because cohesion not strong enough to raise water up >0.15M

How does nitrogen fixation work?

-uses nitrogenase to transform N2 into ammonia (NH3) -reduction of nitrogen gas -requires a large input of energy

What maintains the osmotic gradient in the medulla?

-vasa recta

How are carbs and other solutes translocated?

-via phloem from sources to sinks

When ADH level is low....

-walls of distal tubule wall have low aquaporin density=low permeability to water= ions still moving into plasma, but not water = dilute urine and high volume of urine -diuresis=high urine flow -ADH is antidiuretic hormone=decrease urine flow

How does water reach the xylem? (2 paths)

-water and solutes can move in the SYMPLAST by crossing a cell membrane and passing through plasmodesmata -OR through the APOPLAST without passing through a cell membrane

Guttation?

-water coming out of leaves -Active transport of ions into xylem continues at night, xylem sap swells with water. When soil is wet and humidity of air is high, root pressure can result in guttation. -in short plants with low evaporation rates, water is literally pushed out of the leaves. Guttation is often mistaken for drew in the morning

How does a plant regulate water loss and gas exchange? (too much transpiration?)

-waxy cuticle on leaves and stems impermeable to water -stomata in leaves can open and close to allow water, O2, CO2 to move in and out of leaves -but, water doesn't really come in through stomata, just gases -guard cell membranes rich in aquaporins

What does water move through?

-xylem -roots to leaves (up only)

Basic steps for animal nutrient assimilation?

1) Eat (macroscopic) 2) Digest (break down into small molecules+waste) 3) Absorb/import small molecules 4) Excrete what is left

3 types of relative osmolarity of water-breathing aquatic animals?

1) Isosmotic animals have body fluids with SAME osmotic pressure as water in which they live 2) HypERosmotic animals have body fluids with HIGHER osmotic pressure than water in which they live 3) HypOsmotic animals have body fluids with LOWER osmotic pressure than water in which they live

Discuss the 4 functions of a fully functional stomach

1) Stores food before processing 2) Secretes HCl which helps break down food; in humans or dogs, stomach can reach pH of 0.8, like battery acid, 10X as acidic as lemon juice 3) Begins protein digestion by secreting pepsin; cells produce it 4) Mechanically squeezes food, mixes it with acid and digestive enzymes

Discuss two problems that plants may encounter while trying to uptake minerals from the soil solution (water in the spaces between soil particles, with dissolved minerals in it)?

1) most of the cationic molecules (Ca, Mg, K) are bound to negatively charged soil particles, so they are mostly not in solution 2) the concentration of minerals needed inside the plant is higher than in the solution (simple diffusion won't work)

Characteristics of body fluids? (3)

1) osmotic pressure 2) ionic composition (Na, K, Cl) 3) volume

How to generate protons to release minerals from clay particles? (2 ways)

1) proteins in root cell membrane actively pump protons out of cells 2)cellular respiration in roots release CO2, some of which dissolves in soil water, forms carbonic acid, and dissociates (ionizes) to form bicarbonate and free protons

If animal's blood plasma has overall osmotic pressure of 100 & urine of 25, what is the U/P ratio? Is the kidney making the blood plasma more or less concentrated?

25/100=0.25 -kidney is pulling out more water than solutes from plasma, so plasma is becoming more [ ] . (kidney is increasing the osmotic pressure of the blood plasma; increasing solute [ ] .

If urine is less [ ] than plasma, U/P is what?

< 1 -kidneys are making the plasma become more [ ]

If urine is more [ ] than blood plasma U/P is what?

>1 -kidneys are making the plasma become less [ ]

*Why does phylem transport need living cells?

Active transport involved, need living cells -loaded and unloaded

How must water and mineral ions cross root cell membrane and enter cells? (challenge and solution)

Challenge: cell membrane is hydrophobic, but water and mineral ions are polar -some mineral ions must move against their concentration gradient Solutions: aquaporin proteins (water channels) increase membrane permeability to water, so rate of osmosis can be regulated (though direction is always toward region of more negative water potential) -minerals and ions transported via ion channels and proton pumps

What is the cost to plants for maintaining these nitrogen-fixing bacteria?

Costs as much as 20% of a plant's photosynthetic output

Diuretic vs. antidiuretic substance? Diuresis vs Antidiuresis?

Diuretic= increases urine flow Diuresis=low ADH Anti=decreases urine flow Antidiuresis= high ADH

As rings of xylem tissue grow, what happens to the phloem?

Gets crushed because it is the inner layer of the bark

Low glucose levels?

Increase glucagon secretions, break down of glycogen to release glucose into blood=breakdown of lipids and release of fatty acids into blood

Example of bidirectional movement of sugar in phloem? (we consume this)

Maple syrup: in the summer and fall, sugar made in leaves, stored in roots late winter: sap rises back to shoot to support leaf development (that's when trunks are tapped)

What are the 6 essential elements that plants need from soil? (macro)

Nitrogen, potassium, calcium, phosphorous, sulfur, magnesium

Structure of nephron

Open at one end, closed at the other -urine formation starts at the closed end, which consists of the cup-shaped Bowman's capsule enclosing a dense cluster of blood vessels known as a glomerulus

Primary urine vs. definitive urine?

Primary: fluid from blood plasma enters nephron at one end Definitive: final product of fluid: volume & composition of lfuid are modified as it passes through kidney & final fluid is passed out of the body -along way, materials can be both reabsorbed & secreted into the urine

Which are the accessory glands for vertebrate digestion?

Salivary glands, liver, and pancreas liver produces and secrets bile, which aids in digesting lipids pancreas produces digestive enzymes and bicarbonate solution

Describe movement of sucrose in phloem? (sucrose loading)

Sucrose loading: at source, sucrose is actively transported into phloem companion cells, from which it flows through plasmodesmata into sieve tube elements.

Describe the Ontogenetic shifts in nitrogenous waste excretion for a certain type of amphibian?

Tadpoles (aquatic larvae of frogs and toads) excrete ammonia across their gill membranes, but after they mature/metaphorphosis, adult frogs & toads excrete urea.

Peristalsis?

Two layers of smooth muscle surrounding the submucosa -interplay between squeezing and shortening by the neurons; how food is moved; working food down into intestines -sphincter muscles at key locations (entrances to stomach and small intestine) also control movement of food

Downside of opening of stomata?

Water loss

Even in sun, stomata may close on a hot, windy day. Why is this beneficial?

Windy=even more water loss

Can sources and sink change roles?

Yes, storage root such as sweet potato may be the sink at one time of the year and source at another time.

What kind of diffusion are proton pumps and ion channels?

active transport -needed to move mineral ions across cell membrane against electrochemical gradient -concentration of many mineral ions are lower in soil solution than within plant cells -may need to move negatively charged ions into a negatively charged cellular compartment

*Sucrose unloading?

at sink, sucrose is unloaded both passively and by active transport -water moves back into xylem, maintaining gradient of solute potential and pressure potential

What does most of a plants mass consist of?

carbon

Animals lacking in teeth often have...

crops and gizzards to grind food

*Why doesn't xylem transport require living cells?

empty tubes holding water depending on the sun for E

Movement of water into a cell by aquaporins is an example of what kind of diffusion?

facilitated diffusion

What is important about unloading?

it maintains gradient of solute potential, and hence pressure potential delivers sugars for storage (fruits) or for growth (new shoots in the spring)

longer loops mean?

larger maximum end-to-end NaCl gradients, thus increasing inner medulla NaCl [ ]

What is the sink?

net consumer of carbohydrate (flower, developing leaf)

thicker medullas and prominent renal papillae=?

producing more [ ] urine because longer loops of henle

What contains nitrogen atoms and nitrogenous wastes than can be toxic?

proteins and nucleic acids -carbs and fats break down during metabolism to CO2 and H2O, so easy to get rid of as opposed to nitrogenous wastes. -in some types of animals, kidneys have important role in excretion of nitrogenous waste

Increased blood sugar leads to what?

secreted insulin causes cells to take up glucose, stabilizing blood glucose concentration & stimulating glucose storage when it is abundant liver and muscle cells store glucose as glycogen insulin also stimulates storage of fatty acids as lipids in fat cells and use of amino acids in protein synthesis

Small vs large glomerulus?

small glom=short proximal and distal tubules=no loops of henle large=long tubules, loops of henle existent

In mammals, small intestine (midgut) has _____ diameter than large intestine (hindgut)

smaller

What does transpiration require?

sunlight

what is the single effect?

the difference in osmotic pressure and NaCl [ ] between the ascending limb fluid, and the adjacent interstitial fluid and descending limb fluid

What is osmotic pressure?

total [ ] of solutes (dissolved matter); water moves from osmosis from regions where osmotic pressure is low to where it is high (low level of salt to high level of salt)

What is a nephron?

vertebrate kidney tubule ~1 million nephrons in a human kidney