Bio Exam 3 Review

• How is partial pressure related to the diffusion of gas molecules?

Gases diffuse from high à low par2al pressure - Breathing is more difficult at higher eleva2ons

How do gills oxygenate fish blood? Describe the mechanism

Gills are outgrowths of the body surface or throat that are used for gas exchange in aquatic animals. The one-way flow of water through gill lamellae has a profound impact on gill function, for a simple reason: The flow of blood through the capillary bed in each lamella is in the opposite direction to the flow of water. As a result, each lamella functions as a countercurrent exchanger left side: A slight gradient in partial pressure of oxygen (here, 10 percent) exists along the entire length of the lamella. 2. A large difference in oxygen partial pressure exists between the start and end of the system. In this example, the difference is 100% - 15% = 85% in the water and 90% - 5% = 85% in the blood. right side: A large gradient in partial pressure of oxygen (here, 100 percent) exists at the start of the system. The gradient in oxygen partial pressures declines rapidly and eventually disappears. A relatively small difference in oxygen partial pressure exists between the start and end of the system. In this example, the difference is 100% - 50% = 50% in the water and 50% - 0% = 50% in the blood. With this arrangement, only half of the oxygen in the incoming water has diffused into the blood. Countercurrent flow makes fish gills extremely efficient at extracting oxygen from water because it ensures that a difference in the partial pressure of oxygen and carbon dioxide in water versus blood is maintained over the entire gas exchange surface.

What are the major regions of the human digestive tract, and what are the main roles of each region discussed in lecture?

Mouth Site of mechanical and chemical processing (tongue manipulates food so that teeth can chew food; saliva digests carbohydrates) where digestion begins Salivary glands Secrete enzymes that digest carbohydrates; Salivary amylase hydrolyzes starch to maltose lingual lipase hydrolyzes tryglycerides and diglycerides into fatty acids supply lubricating mucus Peristalsis(wave of muscular contractions) moves food through esophagus to stomach - Food passes through in 6 seconds - Coordinated contrac,on is ini,ated by swallowing 3. Stomach Site of mechanical and chemical processing (digests proteins) Tough, muscular pouch - Sphincters control material movement - Muscular contrac,ons generate uniform consistency and solute concentra,on - Par,al diges,on of proteins - Highly acidic (HCl, pH 1.5) • Pepsin: hydrolyzes proteins into smaller polypep,des - Secreted as pepsinogen by chief cells 4. Small intestine Site of chemical processing and absorption (digests proteins, fats, carbohydrates; absorbs nutrients and water) Long tube (6 m), large surface area - Villi covers folds of organ - Microvilli cover villi structures • Structure increases rate of nutrient absorp,on - Lacteal and blood vessels transfer nutrients away 5. Large intestine Absorbs water and forms feces; contains symbiotic bacteria Primary func,on is to form solid waste - Colon: addi,onal water absorp,on and genera,on of feces - Rectum: holds wastes un,l elimina,on • Symbio,c bacteria in large intes,ne: - Ferment cellulose (addi,onal nutrient absorp,on) - Produce vitamin K, which is important in blood clohng and bone mineraliza,on 6. Appendix Contains immune tissue; harbors symbiotic bacteria 7. Anus Eliminates feces

Compare and contrast mycorrhizae and rhizobia

Mycorrhizae- fungi and plant roots that live in association are called mycorrhizae, Mycorrhizal fungi and plants are symbiotic ("living-together"), meaning that they live in physical contact with each other. Biologists estimate that more than 80 percent of all vascular plant species associate with mycorrhizal fungi. plants receive large quantities of nitrogen from mycorrhizal fungi. The fungal symbionts in these associations are particularly efficient at digesting macromolecules (proteins and nucleic acids) in decaying organic material and absorbing the amino acids (a source of nitrogen) and phosphate (H2PO4−) that are released -this material is otherwise unavailable to plants Rhizobia- nitrogen fixing bacteria at associate with root cells of legume plants

Describe the basic structure of the kidney

(key organ of the urinary system, responsible for water and electrolyte balance as well as the excretion of nitrogenous wastes). Mammalian kidneys occur in pairs and tend to be bean shaped. A large blood vessel called the renal artery brings blood that contains nitrogenous wastes into the organ; the renal vein is a large blood vessel that carries "clean" blood away. The urine that forms in the kidney is transported via a long tube called the ureter to a storage organ, the bladder. From the bladder, urine is transported to the body surface through the urethra and then excreted. In most vertebrates, the kidneys are located near the dorsal (back) side of the body. Most of the kidney's mass is made up of small structures called nephrons. The nephron is the basic functional unit of the kidney. The work involved in maintaining water and electrolyte balance occurs in the nephron.

How does water potential govern water movement?

-difference in environmental w determines the direction of water movement -water moves from high to low w

Describe how carbon dioxide is transported back to the lung and is released into the environment

...Carbonic anhydrase maintains CO2 gradient - Bicarbonate is transported into plasma - H+ bind to hemoglobin, which acts like a buffer Deoxygenated blood returns to lungs - PCO2 gradient favors movement of (unconverted) CO2 into alveoli - As CO2 diffuses into alveoli, PCO2 in blood drops • Reverse carbonic anhydrase reac2on occurs - HCO2 - accepts H+ à CO2 is regenerated - CO2 diffuses into alveoli • Hemoglobin picks up O2 - Hemoglobin has higher affinity for O2 as blood pH increases

Know the basic properties, cell types/structures, and functions of the three plant tissues discussed in lecture: ground tissue

-location of photosynthesis and carbohydrate storage, responsible for most of the synthesis and storage of specialized products such as colorful pigments, hormones, and toxins required for defense, plays a large role in structural support of the shoot system consists of three distinct tissues -parenchyma- most common and versatile ground tissue cells, filled with chloroplasts making it the primary site of photosynthesis, stores carbohydrates in roots. Totipotent (they retain the capacity to divide and develop into a complete, mature plant). Parenchyma cells can divide to produce a mass of undifferentiated cells called a callus which begin to develop roots -collenchyma- similar to parenchyma but are characterized by an unevenly thickened primary cell wall and are longer and thinner than parenchyma cells, not rigid, their ability to stretch allows stems to flex in the wind without tearing or breaking. Cells provide flexible structural support for shoots -Sclerenchyma- characterized by the presence of the thick, rigid secondary cell wall in addition to the relatively thin primary cell wall. Secondary cell wall contains the tough, rigid compound lignin in addition to cellulose. Specialized for supporting stems after growth has ceased. Usually dead at maturity (contains no cytoplasm) --two types of sclerenchyma, fibers (extremely elongated) and sclereids (relatively short, have variable shapes, and often function in protection

What is the difference between molarity and osmolarity?

-molarity is the concentration (moles over liters) -osmolarity- the concentration of solutes in a solution, measured in osmoles (similar to mole but it takes into account molecules that dissociate in solution) per liter

Describe the extracellular and formed elements of blood

...formed elements Platelets are cell fragments that act to minimize blood loss from ruptured blood vessels. They do so by releasing material that helps form the blockages known as clots. ⦁ White blood cells are part of the immune system. They fight infections (as Chapter 51 will explain in detail). ⦁ Red blood cells transport oxygen from the lungs to tissues throughout the body. They also play a role in transporting carbon dioxide from tissues to the lungs. In humans, red blood cells make up 99.9 percent of the formed elements extracellular matrix called plasma (covers 50-65 percent of the blood volume)

How is mouthpart structure related to animal nutrition?

.Mammals chew their food and swallow distinct packets or boluses. The extinct mammal in FIGURE 44.2a illustrates one example of the many tooth shapes that evolved from the relatively simple and uniform teeth in the common ancestor of all mammals. Diversification of tooth shape has allowed mammals to exploit a wide range of foods. ⦁ Complex skull, jawbones, and associated musculature have evolved in snakes. The highly flexible structure that results allows snakes to ingest large prey whole Natural selection is particularly strong when it comes to food capture, because obtaining nutrients is so fundamental to fitness—the ability to produce offspring.

What is the root cap?

A group of cells that protects the root apical meristem. Cells produced by the meristem constantly replenish the cap, which regularly loses cells. Root cap cells are important in sensing gravity and determining the direction of growth. They also synthesize and secrete a slimy, polysaccharide-rich substance that helps lubricate the root tip, reducing friction and protecting the apical meristem as it is pushed through soil Three distinct populations of cells exist behind root cap: -the zone of cellular division: contains the apical meristem, where cells actively divide, along with the protoderm, ground meristem, and procambium, where additional cell division occurs -the zone of cellular elongation: made up of cells that are recently derived from primary meristems and that increase in root length -zone of cellular maturation: where older cells complete their differentiation into dermal, vascular, and ground tissues, contains root hairs

What is aldosterone? What region of the nephron is sensitive to aldosterone?

A hormone that adrenal glands release when Na+ levels in blood are low. Leads to the activation of sodium-potassium pumps and reabsorption of Na+ in the distal tubule. Aldosterone saves sodium and water and stimulates the secretion of K+ and H+ from the blood into the distal tubule

Describe how surface area and volume are related

Absorption occurs across the surface of the root and shoot system and cells that use absorbed nutrients have volume Absorption and nutrient distribution is efficient when plants have a large surface area/volume ratio (roots, leaves), while tissues with low surface area/volume ratio (tubers and seeds) are not involved in absorption

What is the difference between adaptation and acclimatization?

Adaptation describes a genetic change in a population in response to natural selection Acclimatization describes short-term phenotypic change to accommodate environment

Compare and contrast: surface tension, adhesion, cohesion

Adhesion- a molecular attraction among unlike molecules Cohesion- molecular attraction among like molecules Surface tension- force that exists among water molecules at an air-water interface

What is an organ? What is an organ system?

An organ is a structure that serves a specialized function and consists of two or more tissues An organ system consists of groups of tissues and organs that work together to perform one or more functions

Compare and contrast nitrogenous waste products: ammonia, urea, uric acid

Animals must remove excess ammonia generated in catabolic processes as nitrogenous wasteAnimals must remove excess ammonia generated in catabolic processes as nitrogenous waste ammonia is diluted to a low concentration and excreted in watery urine. (freshwater fishes) Diffuses across gills into surrounding water along its concentration gradient. high solubility in water, high amount of water required for excretion, high toxicity, in most bony fishes and aquatic invertebrates, method of synthesis is product of breakdown of amino acids and nucleic acids, low energy cost of synthesis, excreted in urine and diffuses across gills in mammals including humans and adult amphibians, enzyme-catalyzed reactions convert ammonia into a much less toxic compound called urea, which is excreted in urine. medium solubility, medium water required for excretion, medium toxicity, in mammals, most adult amphibians, sharks, rays, skates, synthesized in liver starting with ammonia or amino groups from amino acids, high energy cost of synthesis, excreted in urine uric acid- very low solubility, very low amount of water required for excretion, low toxicity, in birds, other reptiles, most terrestrial arthropods, synthesis starts with nucleic acids, high energy cost of synthesis, excreted with feces

What tissue is responsible for primary plant growth in plants?

Apical meristem- populations of undifferentiated cells that retain the ability to undergo mitosis The division of apical meristem cells, and differentiation of those cells, is responsible for primary growth

What are the three regions of the apical meristem?

Apical meristems are located at the tip of each root and shoot Protoderm- gives rise to the dermal tissue system (epidermis) Ground Meristem- gives rise to the ground tissue system which makes up the bulk of the primary plant body Procambium- gives rise to the vascular tissue system

Name and describe the three ways water can enter the vascular tissue of a plant: symplastic route, transmembrane route, apoplastic route

As water is absorbed, it moves through the root cortex toward the xylem along three distinct routes -The symplastic route is inside the plasma membranes. The symplast consists of the cytosol and the continuous connections through the cell via plasmodesmata -The transmembrane route is based on flow through aquaporin proteins-water channels located in the plasma membranes of many cells. Some water may also diffuse directly across plasma membranes -The apoplastic route is outside the plasma membranes. The apoplast consists of cell walls, which are porous, and the spaces that exist between cells. Water moving along the apoplastic route must eventually pass through the cytoplasm of endodermal cells before entering xylem

How does animal size affect the relation ship between surface area and volume?

Body size affects on how animals functon - Large animals need more food, produce more waste, take longer to mature, reproduce more slowly, and tend to live longer - Smaller animals lose heat and water more rapidly

What is nitrogen fixation and why is this relevant to plant soil and health?

Can't use nitrogen as it is, must be converted Relevant to plant because it binds O2. Certain bacteria and archaea are the only species that are capable of converting molecular nitrogen to ammonia. The steps in the process, called nitrogen fixation, are highly endergonic reduction-oxidation (redox) reactions. The key enzyme that catalyzes the reaction—nitrogenase—is found only in selected bacterial and archaeal lineages. Many of these organisms are free living, but some form important relationships with plants: N2 + 8e- + 8H+ + 16 ATP yields 2NH3 + H2 + 16 ADP + 16Pi 2nd part?**

Describe the four mechanisms of heat exchange

Conduction- the direct transfer of heat between two physical bodies that are in contact with each other. The rate at which conduction occurs depends on the surface area of transfer, the steepness of the temperature difference between the two bodies, and how well each body conducts heat Convection- a special case of conduction. During conduction, heat is transferred between two solids; but during convection, heat is exchanged between a solid and a moving liquid or gas. As the speed of the air or water flow increases, so does the rate of heat transfer Radiation- the transfer of heat between two bodies that are not in direct physical contact. All objects, including animals, radiate energy as a function of their temperature Evaporation- the phase change that occurs when a liquid become a gas. The other three can cause heat gain or loss, but evaporation is only heat loss. Large amount of energy is needed to heat water and produce evaporation

Know the basic properties, cell types/structures, and functions of the four types of animal tissues discussed in lecture: connective tissue

Connective tissue consists of cells that are loosely arranged in a liquid, jellylike, or solid matrix. Matrix comprises extracellular fibers and other materials, and it is secreted by the connective tissue cells themselves. Each type of connective tissue secretes a distinct type of extracellular matrix and the nature of the matrix determines the nature of the connective tissue -loose connective tissue- contains an array of fibrous proteins in a soft matrix; serves as a packing material holding organs and tissues together and as padding under the skin, fibroblasts cells make fibers and extracellular matrix in loose connective tissue -dense connective tissue- found in the tendons and ligaments that connect muscles, bones, and organs, dominated by tough collagen fibers, also secreted by fibroblasts -supporting connective tissue- firm extracellular matrix, bone and cartilage are connective tissues that provide structural support for the vertebrate body as well as protective enclosures for the brain and other components of the nervous system -fluid connective tissue- consists of cells surrounded by a liquid extracellular matrix. Blood, which transports materials throughout the vertebrate body, contains a variety of cell types and has a specialized extracellular matrix called plasma

How does the particle size of soil relate to: water retention, root penetration, oxygen content

Depending on their size and composition, the particles resulting from these processes are called gravel, sand, silt, or clay. Texture—the proportions of gravel, sand, silt, and clay—and other soil qualities vary as well. Soil texture is important for several reasons: ⦁ Texture of a soil affects the ability of roots to penetrate and obtain water and nutrients, as well as to anchor and support the plant body. For example, soil that is dominated by claysized particles tends to compact and resist root penetration. ⦁ Texture affects a soil's ability to hold water and make it available to plants. Water tends to adhere to clay and silt particles but runs through sand and gravel. ⦁ A soil's texture and water content dictate the availability of oxygen. Like other eukaryotes, plants have to take in oxygen to use as an electron acceptor during cellular respiration. The oxygen used by plant root cells is found in air pockets among soil particles. This explains why overwatering a plant is just as detrimental as underwatering it: Overwatering drowns a plant's roots

Know the basic properties, cell types/structures, and functions of the three plant tissues discussed in lecture: dermal tissue

Dermal tissue- epidermis, outermost layer of cell -shoot system: protects plants from water loss, disease, and herbivores --made up of cuticle (waxy layer that forms a continuous sheet on the surface of leaves and stems, hydrophobic and lipid so reduces water loss, but also gets in the way of gas exchange by reducing it) and stomata (pores that allow CO2 to enter and O2 to exit photosynthetically active tissues, surrounded by two specialized guard cells that open when adequate water is available allowing gases to move between the atmosphere and interior by diffusion, and closes when conditions are dry preventing large amounts of water loss) which reduce water loss --trichomes (hairlike appendages made up of specialized epidermal cells) deter herbivores with barbs or toxic compounds, reflect sunlight and keeping the leaf surface cool, and reduce water loss by forming a dense mat that limits transpiration -root system: includes root hairs, primary function is water and nutrient absorption

How does exercising affect breathing rate? Describe the mechanism

During exercise, exhalation is an energy-demanding, active process. Breathing is much more efficient during exercise, when the chest cavity undergoes larger changes in volume. When a person is breathing hard, over 2500 mL of air can move with each inhalation- exhalation cycle, but the 150 mL of dead space stays the same. Ac2ve muscle causes decrease in PO2 and increase in PCO2 (blood levels) - Increased CO2 leads to slight drop in pH of blood and cerebrospinal fluid - Neurons in brain and medullary respiratory center pH detectors sense change in pH - Breathing rate increases and normal PO2 and PCO2 levels in blood are restored

What is the casparian strip?

Endodermal cells are tightly packed and secrete a narrow band of wax called the Casparian strip. This layer is composed primarily of a compound called suberin, which forms a waterproof barrier where endodermal cells contact each other

What is an endotherm? What is an ectotherm?

Endotherm produces adequate heat to warm its own tissues Ectotherm relies principally on heat gained from the environment

Freshwater chloride cell vs saltwater chloride cell

Freshwater moves ions in the opposite direction of the seawater version. Have chloride cells in different locations on the gills for young and old fish show the same pattern. The pattern suggests that when the nature of osmotic stress changes, the nature of the gill epithelium changes. Specifically, active pumping of ions takes place in a different population of cells in seawater versus freshwater Chloride cells in different locaHons of gill epithelium remove salt in saltwater and import electrolytes in freshwater - Salt/freshwater Na+/K+-ATPases - Na+/Cl- /K+ cotransporter flips from basolateral to apical side in freshwater

How does a tissue's SA/V ratio relate to its function?

High SA/V has efficient absorption and nutrient distribution whereas low SA/V are not involved in absorption

What is antidiuretic hormone (ADH)? What region of the nephron is sensitive to ADH?

If an individual is dehydrated, the brain releases antidiuretic hormone (ADH). Collecting duct Triggers the insertion of aquaporins into the apical membrane. As a result, cells become much more permeable to water and large amounts of water are reabsorbed. Increases the cells permeability to urea, which is reabsorbed into the surrounding fluid. Helps create a concentration gradient favoring water absorption from the filtrate ADH saves water

Incomplete versus complete digestion tract? What advantages does a complete digestive tract provide the organism?

Incomplete digestive tracts have a single opening that doubles as the location where food is ingested and wastes are eliminated. The mouth opens into a chamber, called a gastrovascular cavity, where digestion takes place (FIGURE 44.5). 2. Complete digestive tracts have two openings—they start at the mouth and end at the anus. The interior of this tube communicates directly with the external environment via these openings (FIGURE 44.6). Advantages- -allows animals to feed on large pieces of foods, expanding their options -different chemical and physical processes can be confined to their own area so that they can happen independently and in order -one way flow of food and wastes so food can be eaten and digested without interruption

Describe how glucose homeostasis is maintained?

Insulin (hormone secreted by pancreas when blood glucose levels are high) and glucagon (hormone secreted by pancreas when blood glucose levels fall)gas interact to form a negative feedback system capable of achieving homeostasis with respect to glucose concentrations in the blood.

Describe the Shoot System

Key function: harvests light and carbon dioxide to produce sugars Composed of stems (vertical aboveground structure), nodes (where leaves attach), internodes (segments between nodes), axillary buds (form at nodes just above site of leaf attachment), branch (derived from axillary bud), apical bud (tip of each stem and branch, location of growth)

Describe the Root System

Key functions: anchor the plant, absorbs ions and water from soil, moves water and ions to shoot system, obtains sugars from shoots, stores shoot products Composed of taproot (central root) and lateral roots (smaller roots that stem from the taproot)

Explain transpiration

Loss of water via evaporation from the aerial parts of a plant is called transpiration. Transpiration occurs whenever two conditions are met: (1) Stomata are open, and (2) the air surrounding leaves is drier than the air inside leaves.

What are the malpighian tubes? What is their role in insect osmoregulation?

Malpighian tubes are excretory organs that maintain water and electrolyte balance. Malpighian tubules have a large surface area, are in direct contact with the hemolymph, and empty into the hindgut. The Malpighian tubules are responsible for forming a filtrate from the hemolymph. This "pre-urine" then passes into the hindgut, where it is processed and modified before excretion maintain homeostasis in hemolymph To maintain homeostasis, insects must also carefully regulate the composition of a blood-like fluid called hemolymph. Hemolymph is pumped by the heart and transports electrolytes, nutrients, and waste products. To maintain water and electrolyte balance, insects rely on excretory organs called Malpighian tubule

Describe the structure of hemoglobin

Mammalian red blood cells are essentially bags filled with approximately 280 million copies of the oxygen-carrying molecule hemoglobin. Hemoglobin is a tetramer, meaning that it consists of four polypeptide chains (FIGURE 45.13). Each of the four polypeptide chains binds to a nonprotein group called heme (represented by black circles in the figure). Each heme molecule, in turn, contains an iron ion (Fe2+) that can bind to an oxygen molecule. As a result, each hemoglobin molecule can bind up to four oxygen molecules. In blood, 98.5 percent of the oxygen is bound to hemoglobin; only 1.5 percent is dissolved in plasma. By increasing the oxygen-carrying capacity of blood, hemoglobin made it possible for cellular respiration rates to increase. High rates of ATP production, in turn, support high rates of growth, movement, digestion, and other activities. tetramer of a and b subunits one heme functional group/subunit (prophyrin)

Diagram selective reabsorption in the proximal tubule

Na+/K+-ATPase in the basolateral membranes removes Na+ from the interior of the cell. The active transport of sodium ions out of the cell creates a gradient favoring the entry of Na+ from the lumen. 2. In the apical membrane adjacent to the lumen, Na+- dependent cotransporters use this gradient to remove valuable ions and nutrients selectively from the filtrate. The movement of Na+ into the cell, along its concentration gradient, provides the means for moving other solutes against a concentration gradient. 3. The solutes that move into the cell diffuse across the basolateral membrane into the interstitial fluid and then nearby blood vessels. 4. Water follows the movement of ions from the proximal tubule into the cell and then out of the cell and into blood vessels. Recall that water moves by osmosis across the membranes of these epithelial cells through membrane proteins called aquaporins.

Describe passive and active mechanisms of ion exclusion

Passive-Many ions do not enter the root symplast, simply because epidermal and cortex cells lack the requisite membrane transporters. If cells lack the membrane protein required for a certain ion to enter the cell, the ion won't enter ions are excluded because cells lack appropriate ion channels, occurs at epidermal and endodermal layers Active- exclusion by metallothioneins. Plants also have mechanisms for coping with toxins once they are inside their cells. One mechanism for coping with toxic concentrations of metals involves small proteins called metallothioneins. Metallothioneins bind to metal ions and prevent them from acting as a poison Another way-- A second mechanism for actively neutralizing specific toxins involves transport proteins located in the tonoplast—the membrane surrounding the large, central vacuole. Proteins in the tonoplast membrane allow plants to actively remove toxic substances from the cytosol and store them in the vacuole.

How is an animal's basal metabolic rate related to its surface area to volume ratio?

Smaller animals have higher BMR than large animals and consume more energy/gram of tissue

Describe the mechanisms for phloem loading and unloading

Pressure flow often requires that plants expend energy to set up a water-potential gradient in phloem. To establish a high pressure potential in sieve-tube elements near source cells, large amounts of sugar have to be transported into the phloem sap-enough to raise the solute concentration of sieve-tube elements loading- requires an expenditure of ATP and some sort of membrane transport system, but when sucrose concentrations are high, movement of sucrose into sieve-tube elements can also occur via passive diffusion through plasmodesmata Phloem unloading at sinks can be active or passive. When a sugar is unloaded against its concentration gradient, an expenditure of ATP and a second membrane transport mechanism are required two key observations: -sucrose is highly concentrated in companion cells -Strong pH difference inside/out of phloem cells Phloem Loading at Source 1. Companion cell proton pumps create electrochemical gradient that favors a flow of protons into companion cells 2. A symporter in the membranes of companion cells uses the proton gradient to bring sucrose into companion cells from the source cells 3. Once inside companion cells, sucrose moves into sieve-tube elements via plasmodesmata Phloem Unloading varies between types of sinks

What are key organelles in only plant cells?

Primary cell wall- made of cellulose, supports cell and defines shape some plants might have secondary cell wall Plasmodesmata- connects adjacent cell cytoplasm and segments of smooth ER Chloroplasts-sites of photosynthesis Vacuoles-stores and digests cell and waste, may store water and nutrients

What happens in each of the four nephron regions? Describe the mechanism.

Renal Corpuscle- filters blood, forming a filtrate or "preurine" consisting of ions, nutrients, wastes, and water. Bowman's capsule surrounds glomerulus - Size-selecHve filtraHon device - Pressure from heart creates pre-urine - Water and solutes leave blood - Cells and proteins remain Proximal tubule- has epithelial cells that reabsorb trients, valuable ions, and water from the filtrate into the bloodstream. Epithelial cells contain: • Microvilli project from epithelial cells - Contains pumps, channels, cotransporters • Tons of mitochondria - Suggests that ion reabsorpHon requires energy Almost all nutrients and 2/3 of water and NaCl are reabsorbed in proximal tubule • Osmolarity of filtrate remains constant • Filtrate that exits: high level of wastes & low level of nutrients Loop of Henle- establishes a strong osmotic gradient in the interstitial fluid surrounding the loop, with osmolarity increasing as the loop descends. Permeable to water (passive transport out of filtrate), permeable to Na+, Cl- (passive transport out of filtrate), active transport of Na+, Cl- out of filtrate descending limb thin ascending limb thick ascending limb As fluid flows down the descending limb, the fluid inside the loop loses water to the interstitial fluid surrounding the nephron (passive) The fluid in the nephron loses Na+ and Cl- in the thin ascending limb (passive) Additional Na+ and Cl- ions are actively transported out of the nephron in the thick ascending limb. Kuhn hypothesis: countercurrent exchange model (b) Contrasting countercurrent with "concurrent" heat exchange Distal Tubule and Collecting Duct- reabsorbs ions and water in a regulated manner, one that helps maintain water and electrolyte balance according to the body's needs. Aldosterone present reabsorbs Na+, no Aldosterone present, does not reabsorb Na+ Filtrate that leaves loop of Henle is hyposmoHc - Contains urea, low ion concentraHon • AddiHonal water is reabsorbed in distal tubule and collecHng duct - Process is under hormonal control

General purpose of the root system versus the shoot system

Root system-anchors the plant, takes in water and nutrients from the soil Shoot system-harvests light and carbon dioxide to produce sugars Major goal of these systems is absorption. Roots absorb water and key nutrients, shoots absorb light Connected by vascular tissue

What are the main accessory organs of the human digestive tract, and what are the main roles or each accessory organ discussed in lecture?

Salivary glands Secrete enzymes that digest carbohydrates; supply lubricating mucus Liver Secretes molecules that aid in fat digestion Gallbladder Stores secretions from liver; empties into small intestine Pancreas Secretes enzymes and other materials into small intestine

How does digestion begin in the mouth? Which enzymes are involved?

Site of mechanical and chemical processing (tongue manipulates food so that teeth can chew food; saliva digests carbohydrates. Salivary amylase, the enzyme responsible for starch digestion in the mouth is one of the beststudied enzymes. Amylase cleaves bonds to release maltose from starch and glycogen, initiating the digestion of starch. Cells in the tongue synthesize and secrete another important salivary enzyme, lingual lipase (lingual refers to the tongue), which begins the digestion of lipids by breaking triglycerides into diglycerides and fatty acids. Salivary glands in the mouth not only produce amylase but also release water and glycoproteins called mucins. When mucins contact water, they form the slimy substance called mucus. The combination of water and mucus makes food soft and slippery enough to be swallowed.

Describe the mechanism used by the shark rectal gland and chloride cells to eliminate excess electrolytes from sharks and saltwater bony fish

Sodium Potassium ATPase pumps (3) sodium out of the cell (into extracellular fluid) creating a gradient that allows (2) potassium to go into the cell. By bringing sodium out, it creates a gradient that allows sodium and other ions to diffuse into the cell without an extra expenditure of energy Sodium, Potassium, and Chlorine all enter the cell through a cotransporter As chlorine builds up, it diffuses down the concentration gradient through the lumen of a gland through a chloride channel in the apical membrane Potassium diffuses out through channels in the basolateral membrane Sodium diffuses into the lumen

Compare and contrast water potentials in soil, plants, and air

Soil- water in soil generally has higher potential than water in the root system because in moist soil, the water that fills crevices between soil particles usually contains relatively few solutes and normally is under little pressure (exceptions: salty soils- lower w compared to roots due to dissolved solutes, dry soils- water adheres to soil particles creating tension that decreases w, irrigated soils-solutes remain in soil after water evaporates increasing solutes in soil) plants-saltadapted species often respond to low water potentials in soil by accumulating solutes in their root cells, which lowers their solute potential. These plants have enzymes that increase the concentration of certain organic molecules in the cytoplasm. As a result, they can keep the water potential of their tissues lower than that of salty soils and are able to absorb what little water is available. Species that are adapted to dry sites cope by tolerating low solute potentials (ex. ninebark shrubs are able to keep acquiring water and grow because the solute potentials of their tissues can drop to stay below the soil water potential) Plants that are adapted to wet sites cannot tolerate such low solute potentials in their tissues Air-in the atmosphere, water exists as a vapor with no solute potential. The pressure exerted by water vapor in the atmosphere depends on temperature and humidity. The lower the pressure potential, the faster liquid water evaporates into the atmosphere -dry air= few water molecules are present and the pressure they exert is low, increasing the rate of evaporation -warm air= water molecules move farther apart and also exert lower pressure (warm dry air has extremely low water potential -100MPa) -normally the water potential of the atmosphere is lower than the water potential inside a leaf

What factors affect gas solubility in aqueous environments?

Solubility of the gas in water Oxygen has very low solubility in water. Only 0.003 mL of oxygen dissolves in 100 mL of water for each increase of 1 mm Hg in oxygen partial pressure. Because of this low solubility, blood contains a molecule that binds to oxygen and delivers it to tissues. Without this carrier molecule, the rate of blood flow to tissues would have to increase dramatically to meet oxygen demand. gas solubility .003ml/100ml temperature: warm has less oxygen osmolarity: seawater holds less than freshwater partial pressure: if high, gas will leave ⦁ Temperature of the water As the temperature of water increases, the amount of gas that dissolves in it decreases. Other things being equal, warm-water habitats have much less oxygen available than cold-water habitats do. For a fish, breathing in warm water is comparable to a land-dwelling animal breathing at high elevation. ⦁ Presence of other solutes Because seawater has a much higher concentration of solutes than does freshwater, seawater can hold less dissolved gas. At 10°C, up to 8.02 mL of O2 can be present per liter of freshwater versus only 6.35 mL of O2 per liter of seawater. As a result, freshwater habitats tend to be more oxygen rich than marine environments. ⦁ Partial pressure of the gas in contact with the water Gases move from regions of high partial pressure to regions of low partial pressure. So if the partial pressure in a liquid exceeds that in the adjacent gas, the gas will bubble up out of the liquid. This is what happens when the cap is removed from a bottle of carbonated beverage. The partial pressure of carbon dioxide in the newly opened drink is much higher than it is in the atmosphere.

How does the casparian strip affect water movement into the vascular tissue of plants?

The Casparian strip blocks the apoplastic route by preventing water from moving through the walls of endodermal cells and into the vascular tissue. The Casparian strip is important because it means that for water and solutes to reach vascular tissue, they have to move through the cytoplasm of an endodermal cell. Endodermal cells use ion channels to regulate what enters and what exits the vascular tissue and the casparian strip prevents leakage of solutes and water

What is Dalton's Law?

Total pressure of a mixture of gases is the sum of the par2al pressures

What is a source and what is a sink?

Translocation is the movement of sugars in phloem from source to sink within a plant -source: where sugars enter the phloem -sink: where sugars exit the phloem

What is turgor pressure? What is wall pressure?

The force exerted by the wall is called wall pressure (If a plant cell swells in response to incoming water, its plasma membrane pushes against the relatively rigid cell wall. The cell wall resists expansion of the cell volume by pushing back). As water moves into the cell, the pressure inside the cell, known as turgor pressure, increases until wall pressure is induced Turgor pressure induces wall pressure and counteracts additional movement of water into the cell

Be able to interpret data from a oxygen-hemoglobin equilibrium curve

The graph in Figure 45.14 is called an oxygen-hemoglobin equilibrium curve, or an oxygen dissociation curve or hemoglobin saturation curve. Note that the x-axis plots the partial pressure of oxygen in tissues. In effect, this represents "demand." Oxygen-depleted tissues, where demand for oxygen is high, are on the left-hand part of the horizontal axis; oxygen-rich tissues are toward the right. The y-axis, in contrast, plots the percentage of hemoglobin molecules in blood that are saturated with oxygen—a measure of "supply," or how many oxygen molecules on average are bound to hemoglobin. Each 25 percent change in saturation corresponds to an average of one additional oxygen molecule bound per hemoglobin molecule or one oxygen molecule delivered to tissues.

What is the cohesion-tension theory? Describe the mechanism

The leading hypothesis to explain long-distance water movement in vascular plants -states that water is pulled from roots to the tops of trees along a water-potential gradient, via forces generated by transpiration at leaf surfaces -relies on cohesion and tension Key: temperature generated by air-water interface is transmitted to water in xylem--> water in root xylem---> water in soil Mechanism: Water vapor diffuses out of leaf Water evaporates inside leaf Water is pulled out of xylem Water is pulled up xylem Water is pulled out of the root cortex Water is pulled from soil into root Water is pulled from root to leaf surface because xylem is continuous and cohesion Water transport does not require energy, solar powered process xylem structure contributes to movement of water by transpiration because tracheids and vessels of xylem are dead at maturity and have secondary cell wall, and water moves at bulk flow *

Describe the basic structure of the human lung

The lungs of mammals, in contrast, are finely divided into tiny sacs called alveoli. Each human lung contains approximately 150 million alveoli, which give mammalian lungs about 40 times more surface area for gas exchange than an equivalent volume of frog lung tissue. An alveolus provides an interface between air and blood that consists of a thin aqueous film, a layer of epithelial cells, some extracellular matrix (ECM) material, and the wall of a capillary. In addition to total surface area, the other major feature of lungs that varies among species is mode of ventilation alveoli, bronchioles, bronchi

What is cooperative binding versus noncooperative binding?

The most remarkable feature of the oxygen-hemoglobin equilibrium curve is that it is sigmoidal, or S-shaped. The pattern occurs because the binding of each successive oxygen molecule to a subunit of the hemoglobin molecule causes a conformational change in the protein that makes the remaining subunits much more likely to bind oxygen. change in shape makes subunits more likely to bind with oxygen noncooperative binding-As the dashed lines on this graph indicate, a relatively small change in oxygen delivery would occur when tissue PO2 changes from its resting level of about 40 mm Hg to 30 mm Hg. Specifically, hemoglobin would unload about 100% - 68% = 32% of its oxygen when tissues are at rest, and about 100% - 52% = 48% of its oxygen during exercise. This difference—about 16 percent—is much less than the 30 percent change observed with cooperative binding.

• What is the role of bile salts in digestion and absorption?

The pancreatic secretions include digestive enzymes that act on fats, in addition to enzymes that act on proteins and carbohydrates. Like the lingual lipase added to saliva in the mouth, the enzyme pancreatic lipase breaks certain bonds present in complex fats and results in the release of fatty acids and other small lipids. Before pancreatic lipase can act, the large fat globules that emerge from the stomach must be broken up—a process known as emulsification. In the small intestine, emulsification results from the action of small molecules called bile salts bile salts function like the detergents that researchers use to break up the lipids in plasma membranes work like detergents to emulsify large fat globules from stomach so pancreatic lipase can break down fats

Define Fick's Law of Diffusion? How can the variables in this equation be optimized to increase the rate of gas exchange?

The rate of diffusion of a gas depends on 5 parameters. Solubility of the gas in the aqueous film lining the gas exchange surface, the temperature, the surface area available for diffusion, the difference in partial pressures of the gas across the gas exchange surface, and the thickness of the barrier to diffusion Rate of diffusion=k x A x ((P2-P1)/D Optimized: A is large, meaning a large area is available for gas exchange. Based on Fick's law, it is not surprising that the respiratory surface in the human lungs would cover about 140 m2— about a quarter of a basketball court—if the epithelium were spread flat. 2. D is small, meaning the respiratory surface is extremely thin. In the human lung, this barrier to diffusion is only 0.2 μm thick—about 1/200th of the thickness of this page. 3. P2 - P1 is large, meaning the partial pressure gradient of the gas across the surface is large. High partial pressure gradients are maintained in part by having an efficient circulatory

What are the four regions of the nephron?

The renal corpuscle filters blood, forming a filtrate or "preurine" consisting of ions, nutrients, wastes, and water. 2. The proximal tubule has epithelial cells that reabsorb nutrients, valuable ions, and water from the filtrate into the bloodstream. selective reabsorption 3. The loop of Henle establishes a strong osmotic gradient in the interstitial fluid surrounding the loop, with osmolarity increasing as the loop descends. 4. The distal tubule reabsorbs ions and water in a regulated manner—one that helps maintain water and electrolyte balance according to the body's needs. 5. The collecting duct may reabsorb more water to maintain homeostasis. In addition, urea leaves the base of the collecting duct and contributes to the osmotic gradient set up by the loop of Henle regulated by ADH and aldosterone

• Describe the structure of the small intestine. What structural features increase the absorption potential of the small intestine?

The small intestine is a long tube that is folded into a compact space within the abdomen 6 m (20 ft). the organ's epithelial tissue is folded and covered with fingerlike projections called villi (singular: villus). In turn, the cells that line the surface of villi have tiny projections on their apical surfaces called microvilli (singular: microvillus). Microvilli project into the lumen of the digestive tract The enormous surface area of the small intestine increases the efficiency of nutrient absorption. And because each villus contains blood vessels and a lymphatic vessel called a lacteal, nutrients pass quickly from epithelial cells into the body's transport systems.

Describe how ions are actively transported into root cells-- draw and label a diagram describing the process

These proteins are found in the plasma membranes of root epidermal and cortex cells, and they are similar to the pumps that make it possible for companion cells to load sucrose into phloem against a strong concentration gradient. Recall that when a phosphate group from ATP binds to the pumps, they change conformation in a way that allows them to transport protons to the exterior of the cell In the membranes of root cells, the electrical gradient established by proton pumps, which favors the entry of positive ions, is strong enough to overcome the pH gradient, which opposes the entry of these cations. In essence, plant cells are batteries that are charged up to attract nutritionally necessary cations. 1) Proton pumps establish an electrochemical gradient 2) Cations enter root hairs via channels 3) Anions enter root hairs via cotransporters

Describe secondary active transport

When solutes move through cotransport proteins, secondary active transport occurs In many cases, the elctrochemical gradients established by pumps are used to transport other molecules or ions by two types of membrane proteins called cotransporters symporters- transport solutes against a concentration gradient, using the energy released when a different solute moves in the same direction along its electrochemical gradient Antiporters- solute being transported against its concentration gradient moves in the direction opposite that of the solution moving down its concentration gradient

What is the lacteal vessel and what type of molecules are absorbed by this structure?

a lymphatic vessel that is a part of villus and it absorbs nutrients

What is bulk flow?

a mass movement of molecules along a pressure gradient

Define osmoregulator

actively regulate osmolarity inside their bodies to achieve homeostasis. (marine body fish)

What is a countercurrent heat exchanger?

an arrangement in which fluids flow through adjacent pipes in opposite directions.. In a whale's tongue, heat is exchanged between the warm blood in the artery and the cool blood in the veins

Properties of cation and anions in soil

anions- typically dissolve in water, readily available for absorption by plant, also easily lost through leaching(pulling out of system) cations- dissolve in water, but interact with negatively charged soil particles, organic matter with negative amino acids, mineral anions of clay particles

Describe the Bohr shift

causes the oxygen-hemoglobin equilibrium curve to shift to the right when pH declines therefore decreasing hemoglobins binding ability to oxygen The Bohr shift is important because it makes hemoglobin more likely to release oxygen during exercise or other conditions in which PCO2 is high, pH is low, and tissues are under oxygen stress. Increasing temperature has the same result: It shifts the curve to the right, representing a greater unloading of oxygen to tissues at any given PO2.

Water potential gradient

causes water to move up through the plant. To move up a plant, water moves down the water-potential gradient that exists between the soil, its tissues, and the atmosphere soil, roots, leaves, air

What type of digestion happens in the stomach? Which enzyme is involved?

chemical digestion of protein Secretion of a protein-digesting enzyme in inactive form is important: It prevents destruction of proteins in the cells where the enzyme is synthesized pepsin

Anatomy of Phloem

consists largely of two cell types, sieve-tube elements and companion cells -continuous, goes from roots to shoots -vascular bundles, which contain xylem and phloem, run the length of plants, and certain bundles extend into specific branches, leaves, and lateral roots -each bundle is independent -fluid is not transferred between bundles

Know the basic properties, cell types/structures, and functions of the four types of animal tissues discussed in lecture: nervous tissue

consists of nerve cells, which are also called neurons, and several types of supporting cells. -neurons transmit electrical signals, which are produced by changes in the permeability of the cell's plasma membrane to ions -supporting cells regulate ion concentrations in the space surrounding neurons, supply neurons with nutrients, or serve as scaffolding or support for neurons Neuron cell structure vary widely in shape, but all neurons have projections that approach other cells Two types of projections, where the nucleus is located: dendrites- highly branched, relatively short axon: relatively long structure Dendrites facilitate transmission of signals from adjacent cells to the neuronal cell body; the axon carries electrical signals from the cell body to other cells, together they allow rapid signaling of information throughout the body

What components are present in phloem sap?

contains sucrose, minerals, mRNA, and hormones

Know the basic properties, cell types/structures, and functions of the four types of animal tissues discussed in lecture: epithelial tissues

cover the outside of the body and the inner surface of many organs, and form glands gland-organ that secretes specific molecules or solutions such as hormones or digestive enzymes provide protection water, nutrients, and other substances are transported, often selectively across epithelia -because the primary function of epithelia is to act as barriers and protective layers, it is not surprising to observe that epithelial cells typically form layers of closely packed cells Can be divided into two major types: simple epithelium (single layer thick) and stratified epithelium (multiple cell layers thick) -has polarity or sidedness. Apical side faces away from other tissues and toward the environment. Basolateral side faces the interior of the animal and connects to connective tissues. This connection is made by a layer of fibers called the basal lamina -have short life spans, exposed to harsh environments, likely to be killed or scraped away ex. esophagus cells live 2 to 3 days while large intestinal cells live max 6 days

What is humus?

decaying organic matter in soil

What is an essential nutrient?

element or compound required for growth and reproduction 17 essential elements C,H,O make up 96% of plant mass (from air and water) other 14 are mineral nutrients from soil -cannot be synthesized by the organism

Know the basic properties, cell types/structures, and functions of the four types of animal tissues discussed in lecture: muscle tissue

functions in movement related physiological activities -skeletal: attaches to bones and exerts a force on them when it contracts. Skeletal muscle is responsible for most body movements. It has long cells with a striated, or striped, appearance produced by an overlapping arrangement of proteins, voluntary movement -cardiac muscle: makes up the walls of the heart and is responsible for pumping blood throughout the body. The branching pattern of cardiac muscle allows electrical signals to spread throughout all cells of the heart, resulting in their coordinated contraction and relaxation, involuntary movement has intercalated disks -smooth muscle- form a muscle tissue that lines the walls of the digestive tract and blood vessels. Contractions and relaxation of smooth muscle help move food through the digestive tract and regulate blood pressure, involuntary movement

Know the basic properties, cell types/structures, and functions of the three plant tissues discussed in lecture: vascular tissue tissue

functions in support and in long distance transport of water and dissolved nutrients in vascular plants, moves the products of photosynthesis that are made and stored in ground tissue consists of two complex tissues: xylem- conducts water and dissolved nutrients in one direction: from the root system to the shoot system -includes water conducting cells as well as parenchyma cells and fibers -contains tracheids (long slender cells with tapered ends that have pits, gaps in the secondary cell wall where only the primary cell wall is present), vessel elements (shorter and wider than tracheids, have perforations in the end walls that lack both primary and secondary cell walls, conduct water more efficiently than tracheids do because their width and perforations offer less resistance to flow) (both of these dead at maturity and contain no cytoplasm), have thick, lignin-containing secondary cell walls; in essence, the cell walls form pipelines for the movement of water and nutrients from roots to shoots -phloem- conducts sugar, amino acids, hormones, and other substances in two directions: from roots to shoots and vice versa --made up of two specialized types of cells that are alive at maturity and lack secondary cell walls, includes fibers that aid in structural support ---sieve-tube elements- long, thin cells that have perforated ends called sieve plates. Responsible for transporting sugars and other nutrients, lack nuclei and most other organelles but directly connect to adjacent companion cells by means of numerous plasmodesmata ---companion cells- not conducting cells, but instead provide materials to maintain the cytoplasm and plasma membrane of sieve-tube elemetns

Compare and contrast glycogen catabolism and gluconeogenesis

gluconeogenesis-the synthesis of glucose from non-carbohydrate compounds. Glycogen catabolism is breaking down glycogen

Define osmoregulation

is the process by which living organisms control the concentration of water and electrolytes in their bodies.

Three ways to describe shoot, root, and leaves

morphological diversity, phenotypic plasticity, and modified roots, stems, and leaves

What is cation exchange

occurs in acidic soils Protons displace ca+ons (Mg2+, Ca2+) associated with nega+ve charges on soil par+cles - Ca+ons can be absorbed by nearby plants - Soil composi+on dictates ca+on exchange

Define osmoconformer

organims with body fluids that are isosmotic to the environment (invertebrates)

How is stomach acid generated? Which cell type is responsible?

parietal cells carbonic anhydrase catalyzes the formation of carbonic acid

Describe the leaf

photosynthetic organ of the plant it has a large surface area for absorbing photons simple leaf- blade: expanded portion, petiole: stalk region compound leaf- blade is divided into leaflets Needlelike leaves reduce water loss by transpiration (example of morphological diversity)

How are pancreatic proteases activated once they are secreted into the small intestine?

proteases- protein digesting enzymes, cleave peptides into monomers enterokinase activates the pancreatic enzymes and results in trypsin which then triggers the activation of other proteases (or protein digesting enzymes)

What is root pressure? What mechanism generates root pressure?

root pressure- a pressure potential that develops in roots, could drive water up against the force of gravity. Moving water up xylem, from root to shoot The movement of ions and water into the root xylem is responsible (pressure potential this creates) The Casparian strip in endodermal cells is essential for root pressure to develop. Without an apoplastic barrier between the xylem and the environment, ions and water would simply leak out of roots Mechanism of root pressure -solutes are actively pumped to xylem even when stomata is closed -this reduces w of xylem because water enters the xylem -generates positive pressure that moves water up xylem

Describe the four major regions of the ruminant stomach

ruminant stomach-specialized for digesting cellulose, symbiotic relationship with microbes and food consists of fatty acids and microbes Food initially enters the largest chamber, the rumen, which serves as a fermentation vat. The rumen is packed with symbiotic bacteria and protists. These organisms have enzymes called cellulase capable of breaking apart the chemical bonds in cellulose, yielding glucose. The rumen is an oxygen-free environment, and the symbiotic organisms produce ATP from this glucose via fermentation, releasing fatty acids as a by-product (see Chapter 9). These fatty acids are absorbed by the ruminant and used as an energy source. 2. The chamber adjacent to the rumen, called the reticulum, is similar in function. After plant material has been partially digested in the rumen and the reticulum, the animal regurgitates portions of that material into its mouth, forming a cud. The ruminant chews that regurgitated material further to enhance mechanical breakdown and then re-swallows it. 3. Processed food that moves out of the rumen enters the third chamber, or omasum, where water and some minerals are absorbed from cud. 4. The final chamber is the abomasum, which contains the ruminant's own digestive enzymes and corresponds to a true stomach (functions like a stomach and secretes digestive enzymes)

Define: secretin, cholecystokinin, gastrin

secretin- a hormone produced in the small intestine to stimulate the exocrine portion of the pancreas, is a polypeptide, cholecystokinin- a peptide hormone secreted by cells in the lining of the small intestine. Stimulates the secretion of digestive enzymes from the pancreas and of bile from the liver and gallbladder that aid in processing lipids gastrin- a hormone produced by cells in the stomach lining in response to the arrival of food or to a neural signal from the brain. Stimulates other stomach cells to release hydrochloric acids

Define solute potential and pressure potential

solute potential- determines water movement in response to different concentrations (always negative) pressure potential- determines water movement in response to physical pressure

What is the Pressure-Flow Hypothesis?

states that events at source tissues and sink tissues create a pressure potential gradient in phloem. The water in phloem sap moves down this pressure gradient, and sugar molecules are carried along by bulk flow -source to sink Active transport-uses energy to move molecules along an electrochemical gradient -membrane pump sends ATP to establish gradient -companion cell does active transport -plasmodesmata connects companion cell and phloem -water moves from xylem which is adjacent to phloem, into phloem by osmosis -that increases pressure in the source region -the increase in pressure moves it into the sink region

Calculate a surface area to volume ratio

surface area divided by volume

Predict water movement in an experimental system/diagram

textbook

Compare and contrast positive and negative ventilation

ventilation tends to disrupt water and electrolyte balance, and homeostasis must be maintained by an active osmoregulatory system -A frog lowers the floor of its throat, increasing the volume there and thus drawing in air from the atmosphere through the nasal passages and into the oral cavity. The animal then closes the nasal passages and contracts its throat muscles. These actions increase the pressure on air in the oral cavity and force it into the lungs. Pushing air into lungs -negative ventilation pulling air into lungs, The pressure inside the human chest cavity is about 5 mm Hg less than atmospheric pressure. This negative pressure surrounding the lung is just enough to keep the lung expanded. If a wound penetrates the chest wall and the pressure differential between the chest cavity and the atmosphere disappears, the lung on the side of the injury will collapse like a deflated balloon.

What vitamin is synthesized by the symbiotic bacteria of the large intestine?

vitamin K?

Define water potential and the water potential equation

water potential- the potential energy that water has in a particular environment compared with the potential energy of pure water at room temperature and atmospheric pressure (megapascals) -difference in environmental w determines the direction of water movement -water moves from high to low w water potential equation- w=wp+ws the potential energy of water in a particular location is the sum of the pressure potential and the solute potential