Basallo, Jacqueline Period 3 February 20, 2002 Ap Biology

Chapter 27: Prokaryotes

1. List unique characteristics that distinguish archaea from bacteria. The term archeabacteria refers to the antiquity of the group’s origin from the earliest cells. Molecular systematic suggests that archaebacteria may be more closely related to eukaryotes than eubacteria. Eubacteria differs from archaebacteria in many keystructural, biological, and physiological characteristics.

2. Describe the three-domain system of classification and explain how it differs from previous systems. Many systematics favor organizing the diversity of life into three domains, a taxonomic level higher than kingdowms. Prokaryotes account for two of the domains: the domain Archaea and the domain Bacteria. These are the archaeabacteria and eubacteria. All eukarotes are placed in the third domain, Eukarya.

3. Using a diagram or micrograph, distinguish among the three most common shapes of prokaryotes. Refer to Pg. 500, Figure 25.1 - The most common shapes of prokaryotes

4. Describe the structure and functions of prokaryotic cell walls. Cell walls of prokaryotes contain a unique material knwon as peptidoglycan. The effect is a single, giant, molecular network enclosing and protecting the cell. There also exists gram- positive and gram-negative bacteria. Gram-positive bacteria have simpler cell walls, with a relatively large amount of peptidoglycan. The walls of gram-negative bacteria have less peptidoglycan and are more complex in structure.

7. Describe three mechanisms motile bacteria use to move. Motile bacteria use one of three mechanisms to move: * The most common motive force is by means of flagella, which may be scattered over the entire cell surface or concentrated at one or both ends of the cell. *A second motility mechanism characterizes a group of helical-shaped bacteria called spirochetes. Several filaments spiral around the cell under the outer sheath of the cell wall. Their basal motors are attached at teither end of the cell, and filaments attached at opposite ends slide past each other, behaving somewhat like the microtubules within eukaryotic flagella. *In the third mechanism of motility, some prokaryotes secrete slimy chemicals and move by a gliding motion that may result from the presence of flagellar motors that lack flagellar filaments.

9. Indicate where photosynthesis and cellular respiration take place in prokaryotic cells. Photosynthesis and cellular respiration take place in the plasma membrane. A pigment that captures light energy, known as bacteriorhodopsin, is built into the plasma membrane. Bacteriorhodopsin absorbs light and uses the energy to pump hydrogen ions out of the cell.

12. List the sources of genetic variation in prokaryotes and indicate which one is the major source. Genetic variation occurs in prokaryotes through mutation and gene transfer by transformation, conjugation, or viral transduction. Mutation is the major source of genetic variation in prokaryotes. Because generation times are measured in minutes or hours, a favorable mutation can be rapidly propagated to a large number of offspring.

13. Distinguish between autotrophs and heterotrophs. An autotroph is an orgonasim that needs only the inorganic compound as a carbon source. Heterotrophs require at least one organic nutrient as a source of carbon for making their organic compounds.

14. Describe four modes of bacterial nutrition and give examples of each. -Photoautotrophs are photosynthetic organisms that harness light energy to drive the synthesis of organic compounds fromn carbon diozide. -Chemoautotrophs obtain energy by oxidizing inorganic substances. -Photoheterotrophs can use light to generate ATP but must obtain their carbon in organic form. -Chemoheterotrophs must consume organic molecules for both energy and carbon.,

15. Distinguish among obligate aerobes, facultative anaerobes and obligate anaerobes. Obligate aerobes use oxygen for celular respiration and cannot grow without it. Facultatice aerobes will use oxygen if it is present but can also grow by fermentation in an anaerobic environment. Obligate anaerobes cannot use oxygen and are poisoned by it.

18. List the three main groups of archaea, describe distinguishing features among the groups and give examples of each. -Methanogens: Methanogens are among the strictest of anaeorobes, poisoned by oxygen. They live in swamps and marshes where other microbes have consumed all the oxygen. Methanogens are also important decomposers employed for sewage treatment. -Extreme Halophiles: These live in such saline places as the Great Salt Lake and the Dead Sea. Colonies of halophiles form a purple-red scum that owes its color to bacteriorhodopsin. -Extreme Thermophiles: Optimal conditions for extreme thermophiles are temperatures of 60 degrees celsius and 80 degrees celsius. These are the most closely linked to eukaryotes.

19. List the major groups of bacteria, describe their mode of nutrition, some characteristic features and representative examples. A diagram presenting the Five Major Phylogenetic Groups of Eubacteria, describing their mode of function and characteristic features is available on Table 25.3, Pages 510-511.

24. Explain why all life on earth depends upon the metabolic diversity of prokaryotes. Prokaryotes, along with fungi, are decomposers that recycle chemical elements in ecosystems. Some prokaryotes live with other species in symbiotic relationships of mutualism, commensalism or parasitism. Bacteria have been put to work in laboratories, sewage treatment plants, and the food and drug industry. One especially exciting development has been the use of prokaryotes in recombinant DNA technology.

25. Distinguish among mutualism, commensalism and parasitism. Mutualism is a symbiotic relationship in which both the host and symbiont benefit. Commensalism is a symbiotic relationship in which the symbiont benefits but the host is neither helped nor harmed. Parasatism is a symbiotic relationship in which the symbiont benefits at the expense of the host by living either wihtin the host or outside the host.

Chapter 28: Eukaryotes 1. List the characteristics of protists. Protists are: * eukaryotes with cells that have a membrane bound nucleus *DNA that is associated with histone proteins *and organelles like that of mitochondria and chloroplasts. Many have flagella that enable them to move about. *There are approximately 60,000 living species of protists. They are found almost anywhere there is water and are an important constituent of plankton. *Nearly all protists are aerobic in their metabolism, using mitochondria for cellular respiration. There exists plant like, animal like, and fungus like protists.

3. Briefly summarize and compare the two major models of eukaryotic origins, the autogenous hypothesis and the endosymbiotic hypothesis. According to the autogenous hypothesis, eukaryotic cells evolved by the specialization of internal membranes originally derived from prokaryotic plasma membranes. According to the endosymbiotic theory the forerunners of eukaryotic cells were symbiotic associations of prokaryotic cells living inside larger prokaryotes.

4. Provide three major lines of evidence for the endosymbiotic hypothesis. 1. The feasibility of an endosymbiotic origin of chloroplasts and mitochondria rests partially on the existence of endosymbiotic relationships in the modern world. 2. Another line of evidence is the similarity between eubacteria and chloroplasts and mitochondria of eukaryotes. Chloroplasts and mitochondria are the approproate size to be descendants of eubacteria. 3. Also, the proposed ancestors of mitochondria were endosymbiotic bacteria that were aerobic heterotrophs. Perhaps they first gained entry to the larger cell as undigested prey or internal parasites. A heterotrophic host could derive nourishment from photosynthetic endosymbiont. And in a world that was becoming increasingly aerobic, a cell that was itself an anaerobe would have benefited from aerobic endosymbiont that turned the oxygen to advantage.

8. List five candidate kingdoms of protists and describe a major feature of each. I am familiarized with the kingdoms of protists, their features, and characteristics.

16. Distinguish among the following algal groups based upon pigments, cell wall components, storage products, reproduction, number and position of flagella, and habitat: a. Dinoflagellata : brown (chlorophylla, chlorophyll c, carentoids, xanthophylls), starch is their carbohydrate food reserve, have a lateral and a posterior flagella, have a submembrane cellulose as a cell wall component and live and marine and fresh water b. Bacillariophyta : are olive brown in color, have leucosin as a carbohydrate food reserve, have only one sperm, their cell wall component is hydrated silica in organic matric and they live in marine and fresh water c. Chrysophyta : are golden olive in color, have laminarin as their carbohydrate food reserve, have 1 or 2 apical flagella, cell wall composed of pectic compounds with silceous material and mostly live in fresh water . d: Phaeophyta : are olive brown in color, have laminarin as their carb food reserve, have 2 lateral flagella in sperm only, cell wall composed of cellulose matrix with other polysaccharides, and almost all are found in cold ocean water . e: Rhodophyta : tend to be red to black in color, have Floridean starch as their carb food reserve, have no flagella, cell wall is composed of cellulose matrix with other plysaccharides and mostly all are marine but some may be fresh water . f: Chlorophyta : green in color, have plant starch as their carb food reserve, have 2 or more apical or subapical flagella, cell wall composed of cellulose, mostly live in fresh water but some may be marine

19. Distinguish between isogamy and oogamy; sporophyte and gametophyte; and isomorphic and heteromorphic generations. Isogamy is a condition in which male and female gametes are morphologically indistinguishable. Oogamy is a condition in which male and female gametes differ, such that a small, flagellated sperm fertilizes a large, nonmotile egg. A sporophyte is the multicellular diploid form in organisms undergoing alternation of generations that results from a union of gametes and that meiotically produces hapoloid spores that grw into the gametophyte generation. A gametophyte is the multicellular hamploid form in organisms undergoing alternation of generations, which mitotically produces haploid gametes that unite and grow into the sporophyte generation. Isomorphic generations are alternating generations in which the sporophytes and gametophytes look alike, although they differ in chromosome number. Heteromorphic is a condition in the life cycle of all modern plants in which the sporophyte and gemtophyte generations differ in morphology

Chapter 29: Plant Diversity 1

1. List characteristics that distinguish plants from organisms in the other kingdoms. Plants are nearly all terrestial organisms, although some plants have returned secondarily to water during their evolution. Aerial parts of most plants, such as stems and leafs, are coated with a waxy cuticle that helps prevent desiccation, a major problem on land. Gas exchange cannot occur across the waxy surfaces, but carbon dioxide and oxygen difuse between the interior of leaves and the surrounding air through microscopic pores on the leaf's surface call stomata.

2. Diagram a generalized plant life cycle indicating which generation is the sporophyte/ gametophytes, which individuals are haploid/diploid, where meiosis occurs and where mitosis occurs. Refer to figure 27.2, Page 548: Chapter 27, Plants and the Colonization of Land

4. Distinguish between the categories division and phylum. Plant biologists use the term division for the major plant groups within the plant kingdon. This taxonomic category corresponds to phylum, the highest unit of classification within the animal kingdom.

5. Using the classification scheme presented in the text, list the plant divisions; give the common name for each; and categorize them into nonvascular, vascular seedless and vascular seed plants

Common Name Nonvascular Plants Division Bryophyta Mosses Division Hepatophyta Liverworts Division Anthocerophyta Hornworts

Vascular Plants Seedless Plants Division Psilophyta Whiskferns Division Lycophyta Club mosses Division Sphenophyta Horsetails Division Pterophyta Ferns

Seed Plants Gymnosperms Division Coniferophyta Conifers Division Cycadophyta Cycads Division Ginkgophyta Ginkgo Division Gnetophyta Gnetae

Angiosperms Division Anthophyta Flowering Plants

9. List and distinguish among three division of Bryophyta. Byophyta (mosses), Hepatophyta (liver worms), and Anthocerophyta (hornworts). Bryophyteshave a waxy embryo on lang and gametangia that protect the gametes and the embryo on land, but they still require a moist habitt for fertilization and for imbibing water in the absense of vascular tissue. Lack of woody tissue dicatates their short stature.

14. List and distinguish among the four extant divisions of seedless vascular plants. * Division Psilophytai is a small group with relatively simple structures to which the widespread genus Psilotum (whiskferns) belongs. * Division Lycophyta consists of the lycopods, or club mosses-small, herbaceous survivors of a dominant ancient division that once included large treelike forms. * The horsetails belong to a single surviving genus of the division Sphenophyta. * Division Pterophyta consists of ferns, the most species - rich group of living seedless plants. The fronds of the sporophyte generation form sporangia that produce spores germinating into small gametophytes.

15. Distinguish between homosporous and heterosporous. Homosporous refers to plants in which a single type of spore develops into a bisexual gametophyte having both male and female sex organs. Heterosporous refers to plants in which the sporotype produces two kinds of spores that develop into unisexual gametophytes, either female or male.

16. Distinguish among spore, sporophyte, sporophyll and sporangium. Spore - In the life cycle of a plant or alga undergoing alternation of generations, a meiotically produced haploid cell that divides mitotically, generating a multicellular individual, the gametophyte, without fusing another cell. Sporophyte - The multicellular diploid forms in organisms undergoing alternation of generations that result from a union of gametes and that meiotically produces haploid spores that grow into gametophyte generation. Sporangium - A capsule in fungi and plants in which meiosis occurs and haploid spores develop. 18. Point out the major life cycle differences between mosses and ferns. The life cycle of a moss: The Gametophyte is the prevalent generation in the bryophyte life cycle. Most species of moss have separate male and female gametophytes which have antheridia and archegonia, respectively. The life cycle of a fern: After a fern spore settles in a favorable place, it develops into a small, heart-shaped gametophyte that sustains itself by photosynthesis. Most ferns are homosporous. Each gametophyte has both female and male sex organs, but the archegonia and antheridia usually mature at different times, assuring cross fertilization between gametophytes.

Chapter 30: Plant Diversity 2

1. Describe the adaptations of seed plants that have contributed to their success on land. The sucess of seed plants on land may be attributed to three developments: further reduction of the gametophyte and its retention within the sporophyte; replacement of swimming sperm with pollination; and development of the seed, which functions in protection and dispersal of embryos.

2. List the four divisions of gymnosperms. The four divisions of gymnosperms include: Coniferophyta, Cycadophyta (cycads), Ginkgophyta (ginkgo), and Gnetophyta.

3. Describe the structures of ovulate and pollen cones of a pine and distinguish between the two. Each tree usually has both types of cones. Small pollen cones produce small microspores that develop into the male gametophytes. Larger, more complex ovulate cones usually develop on separate branches of the tree and make larger megaspores that develop into female gametophytes. From the time young ones take the tree, it takes nearly three years for a complicated series of events to produce mature seeds. The scales of the ovulate cone then separate and the winged seeds travel on the wind. A seed that lands in a habitable place germinates, its embryo emerging as a pine seedling.

4. Describe the life history of a pine and indicate which structures are part of the gametophyte generation and which are part of the sporophyte generation. The pine tree is a sporophyte. The gametophyte generation develops from haploid spores that are retained within the sporangia. Conifers are heterosporous. Each tree usually has both types of cones. Small pollen cones produce small microspores that develop into the male gametophytes. Larger, more complex ovulate cones usually develop on separate branches of the tree and make larger megaspores that develop into female gametophytes. From the time young ones take the tree, it takes nearly three years for a complicated series of events to produce mature seeds. The scales of the ovulate cone then separate and the winged seeds travel on the wind. A seed that lands in a habitable place germinates, its embryo emerging as a pine seedling.

6. Distinguish between pollination and fertilization Pollination is the placement of pollen onto the stigma of a carpel by wind or animal carriers, a prerequisite to fertilization. Fertilization is is the union of haploid gametes to produce a diploid zygote.

9. List and give examples of the two classes of Anthophyta. The division Anthophyta is split into two class: Monocotyledones (monocots) and Dicotyledones (Dicots). Examples of monocots are lilies, orchids, yuccas, palms, and grain crops, among others. Among the many dicot families are roses, peas, buttercups, sunflowers, oaks, and maples. 10. Compare the life cycles of mosses, ferns, conifers, and flowering plants in terms of: a. Dominant life cycle stage (gametophyte/sporophyte) b. Whether they are homosporous or heterosporous c. Mechanism of gamete transfer.

11. Describe some refinements in vascular tissue that occurred during angiosperm evolution. The origin of refined xylem tissue for transport and support contributed to the rise of angiosperms. The cells that conduct water in conifers are tracheids, believed to be a relatively early type of xylem cell. The tracheid is an elongated, tapered cell that functions in both mechanical support and movement of water up the plant. In most angiosperms, shorter, wider cells called vessel elements evolved from tracheids.

12. Explain how evolution of the flower enhanced the reproductive efficiency of angiosperms. The evolution of the flower greatly improved reproductive efficiency, as it is a remarkable apparatus that enhances the efficiency of reproduction by attracting and rewarding pollen carrying animals.

15. Define fruit and explain how fruits are modified in ways that help disperse seeds. A fruit is a mature ovary. As seeds develop after fertilization, the wall of the ovary thickens. Fruits protect dormant seeds and aid in their dispersal. Edible fruits are ingested by animals, most commonly mammals or birds,. Seed coats usually prevent digestion of seeds, whch may deposit in its feces some distance from the parent plant.

16. Diagram the generalized life cycle of an angiosperm, identify which structures are haploid, and explain how it differs from the life cycle of a pine. The life cycle of an angiosperm: The flower of the sporophyte produces microspores that form male gametophytes (pollen) and megaspores that for female gametophytes (embryo sacs) within ovules. Pollination brings the gametophytes together in the ovary. Fertilization occurs, and zygotes develop into sporophyte embryos that are packaged along with food into seeds. See Figure 27.22 on page 566.

Chapter 31: Fungi

1. List characteristics that distinguish fungi from organisms in other kingdoms. *Fungi are a eukaryotic, primarily multicellular group. *All fungi are heterotrophs. *Fungi acquire their nutrients by absorption. *A fungus digests food outside its body by secreting powerful hydrolytic enzymes into the food. *The fungal vegetative bodies consists of mycelia, netlike collections of branched hyphae adapted for absorption.

2. Explain how fungi acquire their nutrients. All fungi are heterotrophs, acquiring their nutrients by absorption. There are saprobic decomposers, parasitic species, and mutalistic forms. In this form of nutrition, small organic molecules are absorbed from the surrounding medium. A fungus digests food outside its body by secreting powerful hydrolytic enzymes into the food.

3. Explain how non-motile fungi seek new food sources and how they disperse. I am aware of how non-motile fungi seek new food sources as I did a particular lab in my Biology Honors class on this particular area. 4. Describe the basic body plan of a fungus. The vegetative bodies of most fungi are usually hidden, being diffusely organized around and within the tissues of their sources. Except in yeasts, these bodies are constructed of basic building units called hyphae. Hyphae are minute threads composed of tubular walls surrounding plasma membranes and cytoplasm. The cytoplasm contains the usual eukaryotic organelles. The hyphae form an interwoven mat called mycelium, the feeding network of a fungus.

5. Distinguish between septate and aseptate (coenocytic) fungi. Although aseptate (coenocytic)forms occur - consisting of a continuous cytoplasmic mass with hundred or thousands of nuclei, most fungi have their hyphae partitioned into cells by septa, with pores allowing cell-to-cell continuity.

7. Distinguish among fungi and list some common examples of each. - The zygote fungi of the division Zygomycota, fungi that live in soil or decaying organic matter, include the familiar black bread mold. Asexual spores develop in aerial sporangia. The division is named for its sexually produced zygosporangia, which are dikaryotic structures capable of persisting through unfavorable conditions. - The sac fungi of the division Asymycota include plant parasites, fungal components of lichens, and saprobes. Asexual reproduction by conidia is common. Sexual reproduction involves the formation of spores in sacs, or asci, at the ends of dikaryotic hyphae, usually in ascocarps. - The club fungi of the division Basidiomycota include mushrooms, shelf fungi, puffballs, and rusts. Mycelia of club fungi can last years as dikaryons. Sexual reproduction involves the formation of spores on club-shaped basidia at the ends of dikaryotic hyphae in fruiting bodies, such as mushrooms.

8. Describe asexual and sexual reproduction in Zygomycota, Ascomycota, and Basidiomycota, and the sexual structure that characterizes each group. Zygomycota - Asexual spores develop in aerial sporangia. The division is named for its sexually produced zygosporangia, which are dikaryotic structures capable of persisting through unfavorable conditions. Asymycota - Asexual reproduction by conidia is common. Sexual reproduction involves the formation of spores in sacs, or asci, at the ends of dikaryotic hyphae, usually in ascocarps. Basidiomycota - Sexual reproduction involves the formation of spores on club-shaped basidia at the ends of dikaryotic hyphae in fruiting bodies, such as mushrooms.

9. Explain the difference between conidia and ascospores. Conidia are the naked, asexual spores produced at the ends of hyphae in ascomycetes. Ascospores are formed when cell walls develop around the nuclei.

12. Describe the anatomy of lichens and explain how they reproduce. Anatomy of a lichen - The upper and lower surfaces are protective layers of tightly packed fungal hyphae. Just beneath the upper surface are the algae, enmeshed in a net of hyphae. The middle of a lichen generally consists of loosely woven hyphae of the fungus. Reproductive structures generally form on the upper surface. A sexual ascocarp of the fungus and several asexual soredia that disperse both fungal and algal components.

Chapter 32: Animal Evolution

1. List characteristics that distinguish animals from organisms in the other four kingdoms. -Animals are multicellular, heterotrophic eukaryotes. Unlike the autotrphic nutrition of plants, animals survive by ingestion, eating other organisms or organic material that is decomposed. -Animals typically store their carbohydrate reserves as glycogen, whereas, plants store theirs as starch. -Animal cells lack the cell walls that characterize plant cells. Also, animals have unique types of intercellularjunctions. -Also unique among animals are two types of tissues responsible for impulse conduction and movement: nervous tissue and muscle tissue.

2. Distinguish between radial and bilateral symmetry. Radial symmetry characterizes a body shaped like a pie or a barrel, with many equal parts radiating outward like the spokes of a wheel; present in cnidarians and echinoderms. Bilateral symmetry characterizes a body form with a central longitudinal plane that divides the body into two equal but opposite halves.

3. Outline the major phylogenetic branches of the animal kingdom, which are based upon grade of organization; symmetry and embryonic germ layers; absence or presence of a body cavity; and protostome-deuterostome dichotomy. 1) The Parazoa-Eumetazoa are sponges that lack true tissues. Also called parazoa. 2) The Radiata-Bilateria Split have been divided according to symmtery. Radial symmetry includes jellydishes, hydras, etc. and are collectively known as Radiata. These have a top, a bottom, a 'mouth', and an aboral side but no real head or end. The other division consists of animals with bilateral symmtery. These have a dorsal side, ventral side, a head and and an anterior. These are known as Bilateria. 3) The Acoelmate-Coelmate Split includes those without a body cavity which usually dont have a blood vascular system and those with a body cavity, the coelmates. These do have vasucular systems and organs as opposed to the former. 4) The Protosome - Deuterostome Split are a further division of the coelmate phyla. These can be classified as protosomes or deuterostomes. They differ in cleavage, blastopore fate, and coelom formation.

4. Distinguish among acoelomate, pseudocoelomate and coelomate. Acoelomates are triplobastic animals with solid bodies, that is without a cavity between gut and outer body wall. Pseudoceolomates are animals with a body cavity but the cavity is not completely lined by tissue derived from mesoderm. Coelmates are animals with a true coelm, a fluid-filled body cavity completely lined by tissue derived from mesoderm.