The penguin to the left in the accompanying photo is about to land on an ice oe. Just before it lands, is its speed greater than, less than, or equal to its speed when it left the water?
Midterm I Study Guide Page 1 of 9 CH 37 objectives Topic: Plant form and function Reading: Chapter 37 1. List some major diﬀerences between plants and animals in the way they grow and their form and function. a. Plants have apical and lateral meristems. Apical meristems are located at the tips of the root and shoot systems where primary growth occurs by division, elongation, and then diﬀerentiation into one of the speciﬁc plant tissue systems. (Protoderm-Dermal, Ground Meristem-Ground, Procambium- Vascular). After primary growth results in the growth in length/height of the plant, secondary growth then results in the plant increasing in girth. Its major function is to increase the amount of conducting tissue available and provide the structural support required for extensive primary growth. It produces wood, and maintain a vascular cambium between secondary xylem and phloem, as well as a cork cambium near the perimeter of the stem and root. b. Animals tend to grow to a maximum size, while plants undergo continuous growth. Growth also occurs through increasing the number of their cells, rather than elongating them. Cell division occurs in most tissues, while in plants they only occur at their meristems. Most cells lose their ability to diﬀerentiate at any age since they are not totipotent, while plant cells can diﬀerentiate into whatever the plant needs. 2. Identify the major structures in the shoot and root systems of plants. a. Root System: anchors the plant into the soil; takes in water, ions and nutrients; conducts water and selected ions into the shoot itself; obtains energy in the form of sugar from the shoot system; stores material produced in the shoot for later use i. Two types of roots: taproots run vertically while lateral roots run more or less horizontally Roots of trees generally extend beyond the width of their above ground ii. canopy, taking up over 80% of the plant’s total mass iii.Modiﬁcations 1. Anchor: adventitious roots anchor stems to walls and to other plants 2. Prop: stabilize the stem 3. Pneumatophores: allow gas exchange between roots and atmosphere b.Shoot System: repeating series of nodes, internodes, leaves, and apical and auxiliary buds; as the plant grows, the number of nodes, internodes, and leaves increases i. Stems: vertical above ground structures ii. Nodes: where leaves attach (Internodes: segments between nodes) iii.Leaf: appendage that projects from a stem laterally; photosynthetic organs 1. Consist of the blade: expanded structure of the leaf, and petiole: stalk part of the leaf iv. Axillary (Lateral) Buds: form just about the site of leaf attachment Midterm I Study Guide Page 2 of 1 9 v. Branch: a lateral extension of the shoot system that grow from axillary buds when conditions are correct vi. Apical Bud: the tip of each stem and branch where growth occurs that extends the length of the stem or branch vii.Modiﬁcations of the Stem 1. Water-Storage: cactus stems store water Stolons: produce new individuals at nodes aboveground 2. 3. Rhizomes: produce new individuals at nodes below ground, and store carbohydrates 4. Tubers: (potatoes) store carbohydrates such as starch 5. Thorns: provide protection from herbivores List the features of plant cells that are absent in animal cells. 3. a.ell Wall: outer rigid layer of the plant made of cellulose; provides support for the plant as it grows taller and taller; allows water, oxygen, and carbon dioxide to pass into and out of the cell b.ain Vacuole: ﬂuid-ﬁlled sacs that store food, water, and waste; also functions as an analogous lysosome found in animal cells c.hloroplast: green, oval organelles that contain chlorophyll; uses sunlight to make food for the plant; source of photosynthesis 4. Identify the three main tissue types in plants, and give examples of where they are found and the kinds of cells found in each. List how the diﬀerent tissue types function. a. Dermal tissue system (Epidermis): single layer of cells that covers the plant body and protects it; interface between the organism and the external environment; its primary function in shoots is to protect the plant body from water loss, disease-causing agents, and herbivores i.Cuticle: waxy layer that forms a continuous sheet on the sugar; made up of lipids (highly hydrophobic) ii.Stomata: specialized dermal cells that regulate gas exchanged and water loss (have two specialized Guard cells that change shape to open or close an opening in the epidermis, known as a Pore) iii.richomes: hairlike appendages made up of specialized epidermal cells; found in shoot systems and come in a wide variety of shapes, sizes, and abundances b. Ground tissue system: makes up the bulk of the plant body and is responsible for photosynthesis and carbohydrate storage i. Parenchyma: relatively thin cell walls and are the most abundant and versatile plant cells; parenchyma tissue in the leaves consists of the cells ﬁlled with chloroplasts, and is the primary site of photosynthesis and store starch granules; are Totipotent in that they retain the capacity to divide and develop Midterm I Study Guide Page 3 of 1 9 into a complete, mature plant; important in healing wounds and in reproducing asexually via stolons or rhizomes ii.ollenchyma: have cell walls that are thicker in some areas than others, with a thinner and longer overall shape than parenchyma; often found just under the epidermis of stems, especially outside of the vascular bundles iii.clerenchyma: produce thick Secondary Cell Wall in addition to the relatively thin Primary Cell Wall found in all cells; lignin and cellulose; can support actively growing parts of the plant since they have an expandable primary cell wall; usually dead at maturity (WOOD) 1. Fibers: extremely elongated 2. Sclereids: relatively short, have variable shapes, and often function in protection; compose the tough seed coats and thick nut shells c. Vascular tissue system: functions in support and in long-distance transport of water and dissolved nutrients; moves the products of photosynthesis that are made and stored in ground tissue i. Xylem: conducts water and dissolved ions in one direction from the root system to the shoot system; consist of water-conducting cells called Tracheids and other conducting cells called Vessel Elements, which conduct water more eﬃciently than do tracheids, because their width and perforations oﬀer less resistance to ﬂow ii.Phloem: conducts sugar, amino acids, chemical signals, and other substances in two directions between the roots and the shoots; primarily consist of two types of parenchyma cells- Sieve-Tube Elements are long thin cells that have perforated ends called sieve plants and are responsible for transporting sugars and other nutrients; Companion Cells are not conducting cells, but instead provide materials to maintain the cytoplasm and plasma membrane of sieve- tube elements 5. What is the primary function of shoots What other functions can modiﬁed shoots serve a.Shoots: aboveground structures of repeating series of nodes, internodes, axillary buds, leaves, and apical buds i. Modiﬁcations 1. Water Storage: cactus stems store water 2. Stolons: strawberry stolons produce new individuals at nodes aboveground 3. Rhizomes: produce new individuals at nodes below ground and store carbohydrates 4. Tubers: store carbohydrates such as starch (potatoes) 5. Thorns: produce protection from herbivores 6.Diagram a stem and label the nodes, internodes, leaves, axillary buds, stipules. Midterm I Study Guide Page 4 of 9 7. Identify the diﬀerent types of meristems and where cell division and new growth takes place in the plant body. Type of Meristem Location Function Growth Primary Apical tips of the shoot *Protoderm: Growth Meristem and roots dermal tissue *Ground Meristem: ground tissue *Procambium: vascular tissue system Secondary Vascular between New cells that are secondary xylem produced to the Growth Cambuim and phloem outside of the vascular cambium differentiate into secondary phloem; new cells produced to the inside differentiate into secondary xylem perimeter of the Gives rise to Secondary Cork secondary phloem Growth Cambium stem and root (parenchyma and sclerenchyma cells) that transport sugars, maturity; Gives rise to secondary xylem (tracheids, vessels, parenchyma and sclerenchyma cells) that transport water well as structuralty as support 8.Distinguish between primary growth and secondary growth in plants. Midterm I Study Guide Page 5 of 9 a. Primary Growth: increase in length of the shoot/root system as a result of cell division in the shoot apical meristem; Apical meristems are located at the tip of each root and shoot; primary growth results in the three primary tissues of the plant body i. Protoderm —> Epidermis ii. Ground Meristem —> Ground Tissue System iii.Procambium —> Vascular Tissue System Secondary Growth: increase in thickness or girth of the plant as a result of cell division b. in the lateral meristem; produces wood; i. A cambium is a special type of meristem that diﬀers from an apical meristem in that it forms a cylinder that runs the length of a root or stem and is made up of a single layer of meristematic cells. Cells also divide in a way that increases the width of roots and shoots. ii. A cylinder of meristematic cells located between the secondary xylem and secondary poem inside the stem and the root are the vascular cambium. A cylinder of meristematic cells located near the perimeter of the stem and root are called the cork cambium. 9. Describe the process of wood and growth ring formation in plants that undergo secondary growth. —> 10. Draw a cross section of a woody stem, draw rings representing the vascular cambium and the cork cambium, and add arrows showing the direction of growth of each meristem. Label the pith, primary xylem, secondary xylem, secondary phloem, cork, and bark. —> 11. What is the primary function of leaves What other functions can modiﬁed leaves serve a. The primary function of leaves is to act as a photosynthetic organ. They maintain a very high surface area:volume ratio in order to maximize gas exchange, photon absorption, and sugar synthesis. b. Modiﬁed leaves i.Bulbs: onion leaves store food ii.ucculent: aloe vera leaves store water iii.endrils: pea tendrils aid in climbing iv.Floral mimics: red poinsettia leaves attract pollinators v.Traps: pitcher plant leaves trap entering insects, which are discouraged from ﬂying out by the hood, then are digested CH 42 objectives Midterm I Study Guide Page 6 of 9 Topic: Animal form and Reading: Chapter 42 function Online Flashcards: http://www.proprofs.com/flashcards/cardshow.phptitle=bio-162- test-1 12. Deﬁne an adaptation (natural selection, survival, reproduction). How does the structure of a trait relate to its function Provide speciﬁc examples. a. Adaptation: heritable traits that allow individuals to survive and reproduce in a certain environment better than those that lack the trait i. Result from: evolution by natural selection, which occurs whenever individuals with certain alleles leave more oﬀspring that survive to reproductive age when compared to the individuals that have diﬀerent alleles. ii. Example: Oryx that have certain mutates alleles are able to extract more water from their feces before expelling them survive better and produce more oﬀspring with that trait than those without the alleles to do so. 13. Deﬁne a ﬁtness trade-oﬀ. Work through and be able to interpret the experiment on cricket trade-oﬀs. a. Fitness Trade-Oﬀ: inescapable compromises between traits; compromises between energetic investment and the competing demands of reproductive and immune function i. Examples 1. Desert animals that sweat to cool oﬀ threaten dehydration. 2. Experimental work was done with crickets. Male crickets produce spermatophore, consisting of packet of sperm surrounded by a large, gelatinous mass, which they deposit onto the female’s reproductive site. The larger the gelatinous mass is (which the female eats), the greater the amount of sperm are able to transfer and fertilize eggs since it would take longer for the female to ingest it. The study looked at if there was a ﬁtness trade oﬀ between males investing energy into making larger gelatinous masses and less energy in immune responses. It showed that males with experimentally increased investment in reproduction had a lower ability to kill bacteria than control males, and that males with experimentally stimulated immune function had lower reproductive function than controlled males. 14.Compare and contrast the extent of phenotypic plasticity typically seen in animals and plants. a. Phenotypic plasticity: ability of an organism to change its phenotype in response to changes in the environment; comping mechanisms with environmental variation; encompasses all types of environmentally induced changes (morphological, physiological, behavioral, phenological) that may or may not be permanent throughout an individual’s lifespan (form is changeable based on environment) i. Plants 1. Root systems: continuously growing thanks to the apical meristems on the root tips; actively grow into areas of soil where resources are abundant, and stop growing or die back in areas where resources are used up or lacking 2. Shoot systems: grow constantly over the course of the individual’s lifespan, therefore allowing it to respond to changes in environmental conditions just as the root system; phototropism, in which shoot systems can bend toward sources of light if an individual is shaded on one side, is a prime example; 3. Leaves: even through they do not grow continuously, they exhibit phenotypic plasticity in regards to “sun leaves” vs. “shade leaves”; sun leaves are thicker and have a relatively small surface area which reduces water loss in areas of the Midterm I Study Guide Page 7 of 1 9 body where light is abundant; shade leaves are relatively thin and broad, providing a high surface area that maximizes absorption of rare photons ii. Animals: changes through phenotypic plasticity are a response to a change in their surrounding environment. For example, in ectothermic organisms, all aspects of their physiology are directly dependent on their thermal environment, and therefore highly responsive to changes in environmental temperature. Temperature change inﬂuences ﬂuidity of cell membranes, so ectotherms adjust the phospholipid composition of their cell membranes. 15. Describe the diﬀerence between adaptation and acclimatization (acclimation). a. Adaptation: heritable traits that allow individuals to survive and reproduce better than those without the traits; result of evolution through natural selection; developed over generations of individuals as a result of environmental changes in pressure on the organisms; long term i. Acclimatization: short term, reversible responses to environmental ﬂuctuations; being able to acclimate one’s self is an adaptation within itself b. Examples: i. Adaptation: Moths during the era of the Industrial Revolution slowly adapted from white to black phenotypes as black sod covered trees and left the lightly colored moths easier to predation. Those that were already dark colored were well hidden, able to survive and reproduce. Those grey or white were not able to do so, changing the allele frequencies of the organisms in the gene pool. ii. Acclimatization: Light-skinned humans are able to tan in color during warmer and sunnier seasons. Some tan more easily in having alleles that allow them to acclimatize eﬃciently to environments with intense sunlight. 16. Identify the major tissue types in animals, and describe how their structure relates to their function. a. Four major tissue types in animals are given rise to from embryonic, undiﬀerentiated tissues. i. Connective: cells are loosely arranged in either a liquid, jellylike, or solid matrix and is secreted by the connective cells themselves. 1. Loose: contains an array of ﬁbrous proteins in a soft matrix; serves as padding/ packing material between organs (bone marrow and fat tissue) 2. Dense: provides connections; includes tendons and ligaments with tough collagen ﬁbers 3. Supporting: ﬁrm extracellular matrix; provide structural support and protection for the vertebrate body (bone, cartilage) 4. Fluid: cells are surrounded by liquid extracellular matrix; functions in transport (red and white blood cells) ii. Nervous: nerve cells and several supporting cells that transmit electoral signals and many other functions, such as supplying neurons with nutrients 1. Neurons transmit electrical signals for communication a. dendrites are highly branched; contact other cells b. axons are relatively long structures that carries electrical signals from cell body to other cells iii.Muscle: provide movement, mechanical digestion of food, heart beat, breathing, etc. 1. Skeletal: attaches to bones and exerts a force on them when they contract (voluntary movement) 2. Branched: cardiac muscles (involuntary movement) Midterm I Study Guide Page 8 of 1 9 3. Smooth: tapered at each end; form muscle that lines walls of digestive tract and blood vessel (involuntary movement) iv. Epithelial: covers outside of the body, lines the surface of organs, and forms glands; mainly functions as a barrier and protective layer 1. tissue itself has polarity to it: apical faces away from other tissues and toward the environment, while baso lateral faces internal area of organism; both are connected by bas lamina 2. Simple squamous: allows material to pass through by diﬀusion and ﬁltration and secretes lubricating substance; found in air sacs of lungs and the lining of the heart, blood vessels, and lymphatic vessels 3. Simple cuboidal: secretion and absorption; found in ducts and secretory portions of s,all glands and in kidney tubules 4. Simple columnar: absorption, as well as secretion of mucous and enzymes; ciliated tissues are in bronchi, uterine tubes, and uterus; nonciliated tissues are in the digestive tract and bladder 5. Pseudostratiﬁed columnar: secretes mucous, ciliated moves mucous; lines the trachea and much of the upper respiratory tract 6. Stratiﬁed squamous: protects against abrasion; lines the esophagus, mouth, and vagina 7. Stratiﬁed columnar: secretes and protects; lines the male urethra and the ducts of some glands 8. Transitional: allows the urinary organs to expand and stretch; lines the bladder, urethra, and the ureters 17. Explain how size and the surface area to volume ratio aﬀect physiological processes. a. The rate at which other molecules and ions diﬀuse depends on the amount of surface area is available. The rate at which nutrients are used and heat/waste produced depends on the volume of the organism. As an animal gets larger, its value increases much faster than its surface area. b. Metabolic rate is the overall rate of energy consumption in an individual. The bas metabolic rate is the rate at which an animal consumes oxygen while at rest, with an empty stomach, while under normal temperature and moist environment. i. As an organism’s size increases, its mass-speciﬁc metabolic rate must decrease, or else the surface area available for exchange of material would fail to keep up with metabolic demands 18.Does the surface area to volume ratio impose more of a limit on the upper body size of plants or animals Why a. The surface area to volume ratio imposes more of a limit on the upper body size of animals. This issue to the fact that they are more active and have a higher Basal Metabolic Rate than plants, so they cant have a larger surface area to volume ration or their BMR would not support them. 19. Give examples of how some structures are modiﬁed into a shape that alters surface area to volume ratio. i. Adaptations for diﬀerent organisms have allowed for increased surface area 1. Flattening: gills in a ﬁsh allow for more gas exchange to occur across the gills 2.Folding: portions of the digestive tract where nutrients are transported into the body. 3.Branching: capillaries have highly branched qualities, allowing for gases, nutrients and waste products to diﬀuse into/out of the blood 20.Deﬁne homeostasis. Midterm I Study Guide Page 9 of 1 9 a.Although conditions may vary as an animal’s environment changes, internal chemical and physical states are usually kept within a tolerable range. Homeostasis is deﬁned as stability in the chemical and physical conditions within an animal’s cells, tissues, and organs. b.Two approaches to achieving homeostasis: i. Conformation: body temperature remains constant as it conforms to the surrounding environment, so long as the environmental temperature remains constant (Arctic ﬁsh) ii. Regulation: mechanisms adjust the internal state to keep it within limits that can be tolerated, no matter what the external conditions (if a mammal is hot, it sweats; if it is cold, it shivers) c.Epithelial tissues are responsible for forming the internal environment that can be dramatically diﬀerent from the external, since enzymes function under extremely speciﬁc conditions 21. Describe how mammals maintain homeostasis of body temperature (set point, sensor, integrator, eﬀector, hypothalamus). a.Homeostatic system pinpoints a set point, or a target range of conditions, and maintains this set point though three general components, all based on negative feedback (the diminution or counteraction of an eﬀe by its own inﬂuence on the process giving rise to is, as when a high level of a particular hormone in trebled may inhibit further secretion of that hormone, or where the result of a certain action ma inhibit further performance of that action) i. Sensor: senses aspect of the environment ii. Integrator: evaluates sensory information and “decides” whether response is necessary iii. Eﬀector: any structure that helps restore desired internal condition and return to set point 22.Compare and contrast endothermy and ectothermy, homeothermy and poikilothermy. Are endotherms most commonly homeotherms or poikilotherms What physiological mechanisms do they use to achieve this a. Thermoregulation: controlling body temperature i. Two extremes on the continuum of heat sources: Endotherms maintain a metabolism that produces adequate heat to warm its own tissues; Ectotherms rely on heat mainly gained from the environment to warm its bodies ii. Two extremes on the continuum of maintaining body heat: Homeotherms maintain a constant body temperature; Poikilotherms allow their body temperature to rise/fall depending on environment 1. Endotherms are most commonly homeotherms CH 43 objectives Midterm I Study Guide Page 10 of 1 9 Topic: Animal water and Reading: Chapter 43 electrolyte balance 1. Reading Notes: a. Diﬀusion: net movement of substances from regions of higher concentration to regions of lower concentration. i. Osmosis: special case of diﬀusion; net movement of water from regions of higher water concentration to regions of lower water concentration, across a selectively permeable membrane 1. Selective Permeability: (of a membrane) some solutes can cross more easily than other solutes can; phospholipid bilayers 2. Concentration Gradients: movement of solutes or water from higher concentrations to lower concentrations 2. Identify the reasons why water and electrolyte homeostasis are important in animals. a. Maintaining water balance is a matter of life in death. An animal achieves water balance when its intake of water equals its loss of water. Water balance is an important element in homeostasis- the ability to keep cells and tissues in constant and favorable conditions. b. Electrolyte: compound that dissociates into ions when dissolved in water and conduct and electrical current. The most abundant electrolytes are Sodium, Chloride, Potassium, and Calcium. Cells require precise concentration os these ions to function normally. i. Imbalances in humans can lead to muscle spasms, confusion, irregular heart rhythms, fatigue, paralysis, or even death. Deﬁne the terms osmolarity (compare with water potential), hyperosmotic, hyposmotic, and 3. isosmotic. a. Osmolarity: (of a solution) concentration of dissolved substances in a solution measured in osmoles/liter; an increase in solute concentration reduces the amount of water available for osmosis, eﬀectively lowering water concentration; if dissolved substances are separated by a selectively permeable membrane of which the solutes cannot cross, water moves via osmosis b. Isosmotic: solute concentrations inside and outside the organism are equal (marine osmotic conformers) c. Hyperosmotic: the solution inside the body contains more solutes than does the solution outside d. Hyposmotic: the solution inside the body contains fewer solutes than does the solution Midterm I Study Guide Page 11 of 1 9 outside 4. For each type of transport across plasma membranes (simple diﬀusion, facilitated diﬀusion, primary active transport, and secondary active transport), describe how and why a molecule moves across a membrane. a.Passive Transport: driven by diﬀusion along an electrochemical gradient and does not require the input of energy in the form of ATP b.Active Transport: occurs when a course of energy (ATP) powers the movement of a solute to establish an electrochemical gradient i. Ions and large molecules (glucose) do not cross phospholipid bilayers, most passive transport and active transport take place via membrane proteins (channels, carrier proteins, facilitated diﬀusion) ii. Primary Active Transport: a source of energy is used to move ions agains their gradients, like the Sodium-Potassium Pump (Na+/K+-ATPase iii. Secondary Active Transport: once a pump has established an electrochemical gradient; a cotransporter can use the energy stored in the electrochemical gradient across a cell membrane to transport a diﬀerent solute against its electrochemical gradient 1. Symporter, Antiporter 5. Compare and contrast the osmoregulatory challenges of living in the ocean, in freshwater, and on land. Osmoregulation: process by which living organisms control the concentration of water a. and electrolytes in their bodies; osmotic stress occurs when the concentration of dissolved substances in a cell or tissue is abnormal (water and solute concentrations are diﬀerent from their set point) b. For many marine invertebrates, achieving homeostasis is relatively easy with respect to water and electrolyte balance, since seawater is a fairly constant ionic and osmotic environment; nearly matches the normal electrolyte concentrations found within these animals (organismal osmoconformers in isosmotic marine environment) c. Many bony ﬁsh are osmoregulators: they actively regulate osmolarity inside their bodies to achieve homeostasis by keeping the osmolarity lower than that of the surrounding seawater; most important in the gills; seawater is hyperosmotic in comparison to the tissues of marine ﬁshes; replace lost water by drinking large quantities of seawater; however, this brings in extra electrolytes, to which they actively pump it out of the body i. Trade-oﬀ between gas exchange and water and electrolyte balance d. Marine ﬁshes are under osmotic stress because they lose water and gain solutes; freshwater ﬁshes are under osmotic stress because they gain water and lose solutes. e. Land animals are not constantly in contact with water or sources of electrolytes, causing them to be the ultimate osmoregulators that actively have to go out in search for sources of water and electrolytes. Land animals constantly lose water to the surrounding environment, just like marine animals do but just in evaporation rather than osmosis. Epithelial cells in certain parts of the body maintain a moist surface in order to protect the integrity of their plasma membranes and to facilitate diﬀusion of Midterm I Study Guide Page 12 of 1 9 gases across respiratory epithelia. Animals on land must constantly replace water and electrolytes. 6. Diﬀerentiate between osmoconformers and osmoregulators. a. Osmoconformers: conform to the osmotic qualities in their surrounding environments b. Osmoregulators: actively regulate their water and electrolyte concentrations and content 7. Compare and contrast how marine (both cartilaginous and bony ﬁshes), freshwater, and diadromous ﬁshes osmoregulate. a. Marine bony ﬁsh are osmoregulators by keeping the osmolarity of their tissues lower than seawater. The diﬀerence in osmolarity is most important in the gills. Water tends to ﬂow by osmosis out of the gill epithelium. As a result, marine ﬁshes replace the lost water by drinking large quantities of seawater, bringing in excess electrolytes, causing it to go further out of whack. However, they rid themselves of these extra electrolytes by actively pumping ions out of their bodies and back into seawater using membrane proteins found in the gill epithelium. b. Freshwater ﬁsh osmoregulate in an environment that is hyposmotic relative to their tissues. Therefore, they gain water through osmosis into their tissues though the gill epithelium. In order to achieve homeostasis, freshwater ﬁsh excrete large amounts of water in their urine and do not drink. They replace electrolytes by obtaining food or actively transporting them from the surrounding water across the gills. c. Diadromous ﬁsh (life in fresh and marine water): frequently, physiological adjustments are made while organisms are in the intermediate, brackish waters while going between one aquatic environment to another. These changed include changing their drinking rate, the degree of concentration of their urine, and the direction of ion- pumping in the gills. 8. Identify the three main types of nitrogenous wastes produced by animals, and give examples of an animal that produce each type. a. Ammonia (NH3): excess amino aids and nucleic acids can be broken down in catabolic reactions that result in ammonia production; toxic to cells because it raises the pH of Midterm I Study Guide Page 13 of 1 9 intracellular and extracellular ﬂuids enough to poison enzymes when at higher concentrations; can be dissolved in water, causing ammonia excretion to result in water loss. i. Freshwater ﬁshes: ammonia is diluted to low concentration and excreted in watery urine. ii. Freshwater and marine ﬁshes: diﬀuses across the ﬁlls into surrounding water along a concentration gradient. b. Urea: ammonia that has undergone enzyme-catalyzed reactions; much less toxic compound than ammonia i. Mammals and adult amphibians (urine) c. Uric acid: ammonia that has gone under reactions; white, paste-like substance i. Terrestrial arthropods, birds, other reptiles 9. Identify the costs and beneﬁts of each type of nitrogenous waste, focusing on the trade-oﬀ between production of uric acid and urea. Attribute Ammonia Urea Uric Acid Solubility in Water (moles/L) high medium very low Water loss high medium very low Energy Lost low high high Toxicity high medium low Groups where it is the bony fishes, aquatic mammals, amphibians, birds and the reptiles, most primary waste invertebrates cartilaginous fishes terrestrial insects and spiders (arthropods) production of breakdown of synthesized in the liver, synthesis starts with amino Method of synthesis amino acids and nucleic acids starting with amino groups acids and nucleic acids from amino acids Method of excretion in urine, and diffuse across tin urine (mammals); diffuses with feces gills across gils (sharks) 10. Diagram the mechanisms of NaCl excretion in the shark rectal gland and of reabsorption in the human proximal tubule (use terms: osmosis, concentration gradient, facilitated diﬀusion, primary active transport, secondary active transport). Midterm I Study Guide Page 14 of 1 9 11. Describe how Malpighian tubules function in insect osmoregulation. 12. Identify the major parts of the mammalian nephron and list the substances reabsorbed at each part. 13. Describe the roles of aldosterone and antidiuretic hormone in the formation of concentrated urine in mammals. a. Aldosterone increases active reabsorption of sodium, which allows for increased passive transport of water back into the system. b. Antidiuretic hormone increases water permeability in collecting ducts by providing more transmembrane aquaporins. Midterm I Study Guide Page 15 of 1 9 CH 44 Objectives Topic: Animal nutrition Reading: Chapter 44 1. READING NOTES a. Section One: Nutritional Requirements i. A nutrient is a substance that an organism needs to remain alive, while food is any material that contains nutrients. The amount of energy provided by foods is measured in kilocalories (Calories). Essential nutrients are nutrients that cannot be synthesized and must be obtained from the diet, including essential amino acids, vitamins, minerals, and electrolytes. b. Section Two: Capturing Food - The Structure and Function of Mouthparts i. In response to natural selection, mouthparts have diversified to exploit a diversity of food sources. The structures of jaws, teeth, and other mouthparts correlate with their functions in harvesting and processing food. c. Section Three: How Are Nutrients Digested and Absorbed i. Ingestion is the process of bringing food into the digestive tract, a chamber where digestion (the breakdown of food) takes place. Absorption is the uptake of specific ions and molecules across the membrane of the digestive tract. ii. An incomplete digestive tract has 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. A complete digestive tract has two openings; they start at the mouth and end at the anus; the interior of the tube communicates directly with the external environment via the openings. 2. Distinguish between an autotroph and heterotroph. a. Autotrophs make their own food, while heterotrophs gain food from others. 3. Describe the basic functions of the major nutrients important to animals. Compound Source Function Symptoms if Deficient Vitamin B1 legumes, whole formation of beriberi (fatigue, (thymine) grains, potatoes, coenzyme in critic nerve disorders, peanuts acid cycle anemia) Vitamin B12 red meat, eggs, coenzyme in anemia (fatigue and dairy products, and synthesis of weakness due to also synthesized by proteins and nucleic low hemoglobin bacteria in the acids and in content in the intestine formation of red blood) blood cells Midterm I Study Guide Page 16 of 1 9 Compound Source Function Symptoms if Deficient Niacin meat, whole grains component of pellagra (digestive coenzymes NAD+ problems, skin and NADP+ lesions, nerve disorders) Folate green vegetables, coenzyme in anemia oranges, nuts, nucleic acid and Vitamin legumes, whole amino acid grains, bacteria metabolism activity in the intestine Vitamin C citrus fruits, used in collagen scurvy tomatoes, broccoli, synthesis, prevents (degeneration of cabbage, green oxidation of cell teeth and gums) peppers components, improves absorption of iron Vitamin D fortified milk, egg aids absorption of rickets (bone yolk, also calcium and deformities) in synthesized in skin phosphorus in small children and bone exposed to sunlight intestine softening in adults Calcium dairy products, bone and tooth loss of bone mass green veggies, formation, nerve and slow growth legumes signaling, muscle response Chloride table salt or sea salt, fluid balance in weakness, loss of vegetables, seafood cells, protein muscle function digestion in stomach, acid-base balance Flourine flouridated water, maintenance of higher frequency of seafood tooth structure tooth decay Iodine iodized salt, algae,component of the goiter (enlarged seafood thyroid hormones thyroid gland) thyroxine and T3 Iron meat, eggs, whole enzyme cofactor, anemia, weakness grains, green leafy synthesis of veggies, legumes hemoglobin and electron carriers Minerals, Magnesium whole grains, green enzyme cofactor, nerve disorders leafy veggies synthesis of Electrolytes hemoglobin and electron carriers Phosphorus diary products, done and tooth weakness, loss of meat, grains formation, synthesis bone of nucleotides and ATP Potassium dairy products, nerve signaling, weakness, muscle meat, nuts, fruits, muscle response, cramps, loss of potatoes, legumes, acid-base balancing muscle function and other veggies Sodium table salt or sea salt, nerve signaling, weakness, muscle seafood muscle response, cramps, loss of blood pressure muscle function, regulation nausea, confusion Midterm I Study Guide Page 17 of 1 9 Compound Source Function Symptoms if Deficient Sulfur any source of amino acid swollen tissues, protein synthesis degeneration of liver, mental retardation 4. Give examples of how diverse mouthparts are related to the type of food eaten (e.g., insects, snakes, humans, cichlid fishes, etc.). Type of Feeders Example Description Image Sponges, Tubeworms filter small organisms or Suspension bits organic debris from Feeders water by means of cilia, mucus-lined nets, or other structures Deposit Feeders Earthworms, Sea cucumbers swallow sediments and other types of deposited material rich in organic matter Insects (butterflies, suck or lap up fluids, like Fluid Feeders mosquitoes) nectar or blood Mass Feeders Majority of all animals seize and manipulate chunks of food by using mouthparts such as jaws and teeth, beaks, or special toxin-injecting organs 5. Describe the structure and function of the major organs and tissues of the human digestive system, and predict how the structure of these organs might be different in other organisms that eat different types of food (e.g., cows, birds, snakes, and others). a. Mouth: site of mechanical digestion and chemical processing; saliva digests carbohydrates b.Salivary glands: secrete enzymes that digest carbohydrates and supply lubricating mucus c.Esophagus: transports food to the stomach d.Stomach: site of mechanical and chemical processing of proteins e.Small Intestine: site of chemical processing and absorption (proteins, Midterm I Study Guide Page 18 of 1 9 fats, and carbohydrates digestion; absorbs nutrients and water) f. Large Intestine: absorbs water and forms feces, contains symbiotic bacteria Liver: secretes molecules that aid in fat digestion g. h. Gallbladder: stores secretions from the liver, empties into small intestine i. Pancreas: secretes enzymes and other materials into small intestine j. Appendix: contains immune tissue; harbors symbiotic bacteria k. Anus: Eliminates feces into the environment 6. For the human digestive system, create a table describing how major nutrient types are digested and absorbed (e.g., in what part of the tract, by what enzyme(s), by what process). Figure44.7 a. Carbohydrates begin primary digestion through salivary amylase, the enzyme responsible for starch digestion in the mouth. It cleaves bonds to release maltose from starch and glycogen. The molecules then move through the esophagus, into the stomach, and through the lumen of the small intestine, where they are exposed to pancreatic amylase, which continues the digestion of carbohydrates that began in the mouth. Carbohydrate digestion ends with the release of monosaccharides (ie Glucose). It is moved into the epithelium of the small intestine through facilitated diffusion and cotransport as it is moved against its concentration gradient. It finally enters the bloodstream by facilitated diffusion. b. Lipids begin their digestion in the mouth after being exposed to lingual lipase, which breaks down triglycerides into diglycerides and fatty acids. They then travel through the esophagus and the stomach into the lumen of the small intestines. Bile salts and pancreatic lipase work together to break the bonds in fats, releasing fatty acids and monoglycerides. They enter the epithelium of the small intestine through simple diffusion with their concentration gradients, and are then modified into triglycerides, and lastly chylomicrons (protein-coated globules). They enter the bloodstream via exocytosis of the lymph vessels. c. Proteins travel through the mouth and esophagus into the stomach, where pepsin breaks the peptide bondsbgetwen certain amino acids in proteins, releasing polypeptides. In the lumen of the small intestine, trypsin, chymotrypsin, elastase, and carboxypeptidase work together to break the polypeptides into short peptides and amino acids. They enter the epithelium of the small intestine through facilitated diffusion and cotransport, where we are left simply with amino acids. These enter the bloodstream also through facilitated diffusion and cotransport. 7. Distinguish between the roles of bile and lipase in the digestion of fats. a. Bile: breaks up large fat globules, acting as an emulsifying agent b. Lipase: begins the digestion of lipids by breaking down triglycerides into diglycerides and fatty acids 8. Describe why and how the stomach produces acid. 9. Draw a negative feedback loop for blood glucose regulation, identifying the roles of insulin and glucagon. Midterm I Study Guide Page 19 of 1 9 10. Compare and contrast the causes, prevalence, and treatments of type I and type II diabetes mellitus. a. Type I: generally diagnosed earlier in life, genetic autoimmune disease in which the immune system attacks insulin-producing cells in the pancreas, treated with insulin injections b. Type II: generally diagnosed later in life due to environment and diet, cells become insensitive to insulin produced by the pancreas, treatment via diet and exercise 11. Predict the food habits of an animal (herbivore, omnivore, carnivore) based on the structure of its teeth and gastrointestinal tract. a. Herbivores have a longer gastrointestinal tract due to needing greater housing of symbiotic bacteria to digest the greater amount of cellulose taken in by the body