Chapter 4 Eukaryotic Cells and Microorganisms PDF

Because learning changes everything. ® Chapter 04 Eukaryotic Cells and Microorganisms Microbiology FUNDAMENTALS A Clinical Approach 2024 Release Marjorie Kelly Cowan, Heidi Smith © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior w...

Because learning changes everything. ® Chapter 04 Eukaryotic Cells and Microorganisms Microbiology FUNDAMENTALS A Clinical Approach 2024 Release Marjorie Kelly Cowan, Heidi Smith © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.  Learning Outcomes Section 4.1 1 1. Differentiate among the flagellar structures of bacteria, eukaryotes, and archaea. 2. List similarities and differences between eukaryotic and bacterial cytoplasmic membranes. 3. Describe the main structural components of a nucleus. 4. Diagram how the nucleus, endoplasmic reticulum, and Golgi apparatus act together with vesicles during the transport process. 5. Explain the function of the mitochondrion. © McGraw Hill, LLC 2  Learning Outcomes Section 4.1 2 6. Explain the importance of ribosomes, and differentiate between eukaryotic and bacterial types. 7. List and describe the three main fibers of the cytoskeleton. 8. Explain how endosymbiosis contributed to the development of eukaryotic cells. © McGraw Hill, LLC 3  Overview of the Eukaryotic Cell First primitive eukaryotes were likely single-celled and independent Over time cells aggregated, forming colonies Cells within colonies became specialized to perform a specific function Complex multicellular organisms evolved as individual cells lost the ability to survive separately from the intact colony © McGraw Hill, LLC 4  Structure of a Eukaryotic Cell Access the text alternative for slide images. © McGraw Hill, LLC 5  External Structures Appendages for Moving: Flagella and Cilia Eukaryotic flagella: Different from bacterial flagella About ten times thicker Structurally more complex Covered by an extension of the cell membrane Long, sheathed cylinder containing regularly spaced microtubules Eukaryotic cilia: Similar to flagella in structure, but are smaller and more numerous Found only in a single group of protozoa and certain animal cells © McGraw Hill, LLC 6  Microtubules in Flagella Regularly-spaced microtubules extend along the entire length of the flagellum Nine pairs of microtubules surround a single pair Known as the 9 + 2 arrangement Also present in cilia Aaron J. Bell/Science Source Flagella Cross-Section © McGraw Hill, LLC 7  The Glycocalyx An outermost layer that comes into direct contact with the environment Composed of polysaccharides Appears as: A network of fibers A slime layer A capsule Contributes to protection, adherence, and signal reception © McGraw Hill, LLC 8  Boundary Structures: The Cell Wall Protozoa and helminths do not have cell walls Cell walls of fungi: Rigid and provide structural support and shape Different in chemical composition from bacterial and archaeal cell walls Thick inner layer of polysaccharide fibers composed of chitin or cellulose Thin outer layer of mixed glycans © McGraw Hill, LLC 9  Cross-Sectional Views of Fungal Cell Wall Thomas Deerinck, NCMIR/Science Source Access the text alternative for slide images. © McGraw Hill, LLC 10  Boundary Structures: The Cell Membrane Typical bilayer of phospholipids in which protein molecules are embedded Contain sterols of various kinds: Relative rigidity give stability to the membrane Important in cells that do not have a cell wall Cytoplasmic membranes of eukaryotes have a similar function as those in bacteria and archaea, serving as selectively permeable barriers © McGraw Hill, LLC 11  Internal Structures: The Nucleus Most prominent organelle of eukaryotic cells Separated from the cell cytoplasm by an external boundary called the nuclear envelope: Composed of two parallel membranes (lipid-bilayers) separated by a narrow space Perforated with small, regularly spaced pores, formed at sites where the membranes unite Macromolecules migrate through the pores to the cytoplasm and vice versa © McGraw Hill, LLC 12  The Nucleus 1 Nucleolus: Found in the nucleoplasm Site for ribosomal RNA synthesis Collection area for ribosomal subunits Chromatin: Made of linear DNA and histone proteins Genetic material of the cell © McGraw Hill, LLC 13  The Nucleus 2 Jose Luis Calvo/Shutterstock Access the text alternative for slide images. © McGraw Hill, LLC 14  Internal Structures: Endoplasmic Reticulum A series of membrane tunnels used in transport and storage Rough endoplasmic reticulum (R E R): Allows transport materials from the nucleus to the cytoplasm and to the cell’s exterior Ribosomes attached to its membrane surface hence its ‘rough’ appearance Smooth endoplasmic reticulum (S E R): Closed tubular network without ribosomes Functions in nutrient processing and in synthesis and storage of nonprotein macromolecules such as lipids © McGraw Hill, LLC 15  Rough Endoplasmic Reticulum Don W. Fawcett/Science Source Access the text alternative for slide images. © McGraw Hill, LLC 16  Internal Structures: Golgi Apparatus The site in the cell in which proteins are modified and then sent to their final destinations Consists of several flattened, disc-shaped sacs called cisternae Always closely associated with the endoplasmic reticulum: Transitional vesicles from the endoplasmic reticulum are picked up at the face of the Golgi apparatus Proteins are modified within the cisternae by the addition of polysaccharides and lipids Condensing vesicles pinch off of the Golgi apparatus and are then conveyed to lysosomes or transported outside the cell © McGraw Hill, LLC 17  Golgi Apparatus EM Research Services/Newcastle University Access the text alternative for slide images. © McGraw Hill, LLC 18  Nature’s Assembly Line Nucleus, endoplasmic reticulum, and Golgi apparatus: A segment of DNA containing the instructions for producing a protein is copied into RNA, and this RNA transcript is passed out through the nuclear pores directly to the ribosomes on the endoplasmic reticulum Specific proteins on the R E R are deposited in the lumen and transported to the Golgi apparatus Proteins in the Golgi apparatus are chemically modified and packaged into vesicles to be used by the cell © McGraw Hill, LLC 19  The Transport Process Access the text alternative for slide images. © McGraw Hill, LLC 20  Vesicles Lysosomes: Bud off the Golgi apparatus as a vesicle Contain a variety of enzymes involved in the intracellular digestion of food particles and protection against invading microorganisms Participate in the removal of cell debris in damaged tissue Vacuoles: Membrane-bound sacs containing fluids or solid particles to be digested, excreted, or stored Found in phagocytic cells in response to food and other substances that have been engulfed Contents of a food vacuole are digested through a merger of a vacuole with a lysosome © McGraw Hill, LLC 21  Origin and Action of Lysosomes in Phagocytosis Access the text alternative for slide images. © McGraw Hill, LLC 22  Mitochondria 1 Generate energy for the cell Composed of a smooth, continuous outer membrane with an inner folded membrane Folds on the inner membrane are called cristae: Hold the enzymes and electron carriers of aerobic respiration Extracts chemical energy contained in nutrient molecules and stores it in the form of high-energy molecules, or ATP © McGraw Hill, LLC 23  Mitochondria 2 Mitochondria are unique organelles Divide independently of the cell Contain circular strands of DNA Have bacteria-sized 70 S ribosomes These characteristics led scientists to hypothesize that mitochondria evolved from bacterial cells following an interaction between bacteria and an archaea-like cell © McGraw Hill, LLC 24  Mitochondria 3 Science History Images/Alamy Stock Photo Access the text alternative for slide images. © McGraw Hill, LLC 25  Chloroplasts Found in algae and plant cells Capable of converting energy from sunlight into chemical energy through photosynthesis Produce oxygen gas as a by-product of photosynthesis Resemble mitochondria but are larger, contain special pigments, and are more varied in shape © McGraw Hill, LLC 26  Ribosomes Distributed throughout the cell: Scattered freely in the cytoplasm and cytoskeleton Attached to the rough endoplasmic reticulum Appear inside mitochondria and chloroplasts Multiple ribosomes are often found arranged in short chains called polyribosomes (polysomes) Size and structure: Large and small subunits of ribonucleoprotein Eukaryotic ribosome is 80 S, a combination of 60 S and 40 S subunits © McGraw Hill, LLC 27  The Cytoskeleton 1 Functions: Anchoring organelles Moving RNA and vesicles Permitting shape changes and movement Three main types of cytoskeletal elements: Actin filaments: long, thin protein strands Intermediate filaments: ropelike structures Microtubules: long, hollow tubes © McGraw Hill, LLC 28  The Cytoskeleton 2 defun/Getty Images Access the text alternative for slide images. © McGraw Hill, LLC 29  Components and Characteristics of Each Organism Type Function or Structure Characteristic Bacterial/ Archaeal Cells Eukaryotic Cells Viruses Genetics Nucleic acids + + + Chromosomes + + − True nucleus − + − Nuclear envelope − + − Reproduction Mitosis − + − Production of sex cells +/− + − Binary fission + + − Biosynthesis Independent + + − Golgi apparatus − + − Endoplasmic reticulum − + − Ribosomes + + − Respiration Mitochondria − + − Photosynthesis Pigments +/− +/− − Chloroplasts − +/− − Motility/locomotor Flagella +/− +/− − structures Cilia − +/− − Shape/protection Membrane + + +/− (called “envelope” when present) Cell wall + +/− − (have capsids instead) Glycocalyx +/− +/− − Complexity of function + + +/− Size (in general) 0.5–3 μm 2–300 μm 0.2 μm © McGraw Hill, LLC 30  Endosymbiosis Access the text alternative for slide images. © McGraw Hill, LLC 31  Concept Check 1 Which of the following characteristics is evidence that mitochondria evolved from bacterial cells? A. Circular chromosome B. Bacteria-like ribosomes C. Capable of independent division D. All of the choices are correct. © McGraw Hill, LLC 32  Concept Check 2 Which of the following organelles is responsible for protein modification and distribution in the cell? A. Nucleus B. Golgi apparatus C. Endoplasmic reticulum D. Mitochondrion E. Ribosome © McGraw Hill, LLC 33  Learning Outcomes Section 4.2 9. List two detrimental and two beneficial activities of fungi (from the viewpoint of humans). 10. List three general features of fungal anatomy. 11. Differentiate among the terms heterotroph, saprobe, and parasite. 12. Explain the relationship between fungal hyphae and the production of a mycelium. 13. Describe two ways in which fungal spores arise. © McGraw Hill, LLC 34  Fungal Cells 2 basic cell forms: Yeasts: Round to oval shape Asexual reproduction, budding Hyphae: Long, threadlike cells found in the bodies of filamentous fungi Pseudohyphae are chains of yeast cells Some fungal cells are considered dimorphic and can take either form, depending on growth conditions © McGraw Hill, LLC 35  Hyphae of Molds Dr. Judy A. Murphy (a-b) Access the text alternative for slide images. © McGraw Hill, LLC 36  Fungi and Human Disease 1 Nearly 300 species of fungi can cause human disease Three types of fungal disease in humans: Community-acquired infections caused by environmental pathogens Hospital-associated infections caused by fungal pathogens in clinical settings Opportunistic infections caused by low-virulence species infecting already-weakened individuals © McGraw Hill, LLC 37  Fungi and Human Disease 2 Harmless spores can cause opportunistic infections in AIDS patients Fungal cell walls give off chemical substances that can trigger allergies Toxins produced by poisonous mushrooms can induce neurological disturbances and even death Aspergillus flavus synthesizes a poison called aflatoxin, potentially lethal to animals who eat contaminated grain © McGraw Hill, LLC 38  Agricultural Impact of Fungi A number of species are pathogenic to corn and grain: Reduces crop production Can cause disease in domestic animals consuming contaminated feed crops Fungi rot fresh produce during shipping and storage: 40% of yearly fruit crop is consumed by fungi © McGraw Hill, LLC 39  Benefits of Fungi Play an essential role in decomposing organic matter and returning minerals to the soil Form stable associations with plant roots and increase their ability to absorb water and nutrients Fungi have been engineered to produce large quantities of antibiotics, alcohol, organic acids, and vitamins Some fungi are eaten or used to provide flavoring to food © McGraw Hill, LLC 40  Fungal Nutrition All fungi are heterotrophs: they acquire nutrients from a wide variety of organic substrates Saprobes: fungi that acquire nutrients from the remnants of dead plants and animals in soil or aquatic habitats Parasites: fungi that grow on the bodies of living animals or plants, although very few require a living host Fungi penetrate the substrate and secrete enzymes that reduces it to small molecules that can be absorbed Fungi are often found in nutritionally poor or adverse environments, and those with high salt or sugar content They can digest a wide array of organic substrates such as rubber, petroleum products, wood, and hair. © McGraw Hill, LLC 41  Morphology of Fungi 1 Cells of most microscopic fungi grow in loose associations or colonies Colonies of yeasts are much like bacteria: they have a soft, uniform texture and appearance Colonies of filamentous fungi are noted for the striking cottony, hairy, or velvety texture © McGraw Hill, LLC 42  Morphology of Fungi 2 Mycelium: the woven, intertwining mass of hyphae that makes up the body or colony of a mold Septa: the nature of the septa varies from solid partitions with no communication between the compartments to partial walls with small pores that allow the flow of organelles and nutrients between adjacent compartments: Nonseptate hyphae consist of one, long, continuous cell Vegetative hyphae are responsible for the visible mass of growth that appears on a substrate Reproductive, or fertile, hyphae produce spores © McGraw Hill, LLC 43  Microscopic Morphology of Yeasts Steve Gschmeissner/Science Photo Library/Getty Images Access the text alternative for slide images. © McGraw Hill, LLC 44  Reproductive Strategies and Spore Formation Most can propagate by the outward growth of existing hyphae or by fragmentation Spores: Primary reproductive mode of fungi Can be dispersed through the environment by air, water, and living things Will germinate upon finding a favorable substrate and produce a new fungus colony in a short time © McGraw Hill, LLC 45  Types of Asexual Mold Spores (Ghosted background image) ©Kathy Park Talaro Access the text alternative for slide images. © McGraw Hill, LLC 46  Asexual Spore Formation Sporangiospores: formed by successive cleavages within a saclike head called a sporangium, which is attached to a stalk, the sporangiophore Conidiospores or conidia: free spores not enclosed by a spore-bearing sac © McGraw Hill, LLC 47  Sexual Spore Formation Mixing of DNA from two parent fungi creates offspring with combinations of genes different from that of the parents Variations lead to potentially advantageous adaptations Sexual spores vary from simple fusion of fertile hyphae of two different strains, or as a complex union of male and female structures © McGraw Hill, LLC 48  Concept Check 3 From which sources can fungi derive nutrients? A. Dead plants and animals B. Living tissues C. Rubber D. Petroleum products E. All of the choices are correct. © McGraw Hill, LLC 49  Learning Outcomes Section 4.3 14. Describe the protozoan characteristics that illustrate why protozoa are informally placed into a single group. 15. List three means of locomotion exhibited by protozoa. 16. Explain why a cyst stage might be useful to a protozoan. 17. Give an example of a disease caused by each of the four types of protozoa. © McGraw Hill, LLC 50  The Protozoa Name comes from the Greek for “primitive animals” About 12,000 species of single-celled creatures Most are harmless, free-living inhabitants of water and soil A few species are pathogens responsible for hundreds of millions of infections each year © McGraw Hill, LLC 51  Protozoan Form and Function 1 Single cells containing all of the major eukaryotic organelles Cytoplasm divided into two parts: Ectoplasm: clear outer layer involved in locomotion, feeding, and protection Endoplasm: granular inner region housing the nucleus, mitochondria, and food and contractile vacuoles © McGraw Hill, LLC 52  Protozoan Form and Function 2 Some organelles act as a primitive nervous system to coordinate movement Can move through fluids by means of pseudopods (“false feet”) Cell membrane regulates food, wastes, and secretions Cell shape can remain constant (as in most ciliates), or change constantly (as in amoebas) Size of most protozoans range from 3 to 300 μm: Giant amoebas and ciliates range from 3 to 4 mm © McGraw Hill, LLC 53  Nutritional and Habitat Range Heterotrophic, require food in a complex organic form Free-living species scavenge dead plant or animal debris or graze on bacteria and algae Some have special feeding structures, such as oral grooves Some absorb food directly through the cell membrane Pathogenic species may live on the fluids of their host, such as plasma and digestive juices, or actively feed on tissues Main limiting factor is availability of moisture Predominant habitats are fresh and marine water, soil, plants, and animals Can survive in extremes of temperature and pH © McGraw Hill, LLC 54  Life Cycles Trophozoite: the motile feeding stage requiring ample food and moisture to stay active Cyst: Dormant, resting stage when conditions in the environment become unfavorable Resistant to heat, drying, and chemicals Can be dispersed by air currents Important factor in the spread of disease © McGraw Hill, LLC 55  General Life Cycle of Protozoa Dr. Stan Erlandsen/CDC Access the text alternative for slide images. © McGraw Hill, LLC 56  Life Cycles and Transmission Some protozoan groups exist only in the trophozoite phase Many alternate between the trophozoite and cyst stage, depending on the habitat Trichomonas vaginalis, a common STD, does not form cysts and must be transmitted by intimate contact Entamoeba histolytica and Giardia lamblia form cysts and are readily transmitted in contaminated water and foods © McGraw Hill, LLC 57  Reproduction All protozoa reproduce by relatively simple, asexual mitotic cell division or multiple fission Sexual reproduction also occurs in most protozoa: Ciliates participate in conjugation in which two cells fuse and exchange micronuclei This results in new and different genetic combinations that can be advantageous in evolution © McGraw Hill, LLC 58  Major Pathogenic Protozoa 1 Amoeboid Protozoa Disease Reservoir/Source Entamoeba histolytica Amoebiasis (intestinal and other Humans, water, and food symptoms) Naegleria, Acanthamoeba Brain infection Water Ciliated Protozoa Disease Reservoir/Source Balantidium coli Balantidiosis (intestinal and other Pigs, cattle, primates symptoms) Flagellated Protozoa Disease Reservoir/Source Giardia lamblia Giardiasis (intestinal distress) Animals, water, and food Trichomonas vaginalis Trichomoniasis (vaginal symptoms) Human Trypanosoma brucei, T. Trypanosomiasis (intestinal distress Animals, vector-borne cruzi and widespread organ damage) Leishmania donovani, L. Leishmaniasis (either skin lesions or Animals, vector-borne tropica, L. brasiliensis widespread involvement of internal organs) © McGraw Hill, LLC 59  Major Pathogenic Protozoa 2 Apicomplexan Protozoa Disease Reservoir/Source Plasmodium vivax, P. Malaria (cardiovascular and Human, vector-borne falciparum, P. Malariae other symptoms) Toxoplasma gondii Toxoplasmosis (flulike Animals, vector-borne illness or silent infection) Cryptosporidium Cryptosporidiosis (intestinal Water, food and other symptoms) Cyclospora cayetanensis Cyclosporiasis (intestinal Water, fresh produce and other symptoms) Amoeboid Protozoa Ciliated Protozoa Flagellated Apicomplexan Using Pseudopods (Ciliophora) Protozoa Protozoa–Nonmotile (Sarcodina) (Mastigophora) (Sporozoa) Stephen Durr (Amoeba proteus); J. R. Factor/Science Source (Balantidium coli); Dr. Stan Erlandsen/CDC (SEM of Trichomonas vaginalis. Magnification-9,000×); IMA/BSIP SA/Alamy Stock Photo (SEM of Toxoplasma gondii. Magnification not available) Access the text alternative for slide images. © McGraw Hill, LLC 60  Concept Check 4 The active, feeding, and motile stage of the protozoan life cycle is the blank stage. A. cyst B. endospore C. trophozoite D. merozoite E. All of the choices are correct. © McGraw Hill, LLC 61  Learning Outcomes Section 4.4 18. List the two major groups of helminths, and provide examples representing each body type. 19. Summarize the stages of a typical helminth life cycle. © McGraw Hill, LLC 62  The Helminths Include tapeworms, flukes, and roundworms Adult specimens are usually large enough to be seen with the naked eye Not all flatworms and roundworms are parasites; many live free in soil and water Disease-causing helminths spend part of their lives in the gastrointestinal tract © McGraw Hill, LLC 63  Flatworms and Roundworms Flatworms (phylum Platyhelminthes): Very thin, often segmented body plan Divided into cestodes (tapeworms) and trematodes (flukes) Roundworms (phylum Aschelminthes): Also called nematodes Elongated, cylindrical, unsegmented body Helminths’ microscopic eggs and larvae are transmitted and can cause disease similar to microbes © McGraw Hill, LLC 64  Pathogenic Flatworms Dorling Kindersley/Alamy Stock Photo (a); Jubal Harshaw/Shutterstock (b) Access the text alternative for slide images. © McGraw Hill, LLC 65  Pathogenic Roundworm CDC Access the text alternative for slide images. © McGraw Hill, LLC 66  General Worm Morphology Multicellular animals that are equipped to some degree with organs and organ systems In pathogenic helminths, the most developed organ is the reproductive tract The digestive, excretory, nervous, and muscular systems are more rudimentary © McGraw Hill, LLC 67  Life Cycles and Reproduction 1 Complete life cycle includes the fertilized egg, larval, and adult stages Adults derive nutrients and reproduce sexually in a host’s body Nematodes: sexes are separate and different in appearance Trematodes: sexes can be separate or hermaphroditic (have both male and female sex organs) Cestodes: generally hermaphroditic © McGraw Hill, LLC 68  Life Cycles and Reproduction 2 Helminth life cycle: Must transmit an infective form (egg or larva) to the body of another host The host in which the larva develops is known as the intermediate (secondary) host Adulthood and mating occur in the definitive (final) host Transport host is an intermediate that experiences no parasitic development Sources for human infection are contaminated food, soil, and water or infected animals © McGraw Hill, LLC 69  Examples of Helminths and How They Are Transmitted Common Name Disease or Host Requirement Spread to Humans By Worm Roundworms—Nematodes Intestinal Nematodes Infective in egg (embryo) stage: Ascaris lumbricoides Ascariasis Humans Fecal pollution of soil with eggs Enterobius vermicularis Pinworm Humans Close contact Infective in larval stage: Trichinella spiralis Trichina worm Pigs, wild mammals Consumption of meat containing larvae Tissue Nematodes Burrowing of larva into tissue Onchocerca volvulus River blindness Humans, black flies Fly bite Dracunculus medinensis Guinea worm Humans and Ingestion of water containing Cyclops Cyclops (an aquatic invertebrate) Flatworms—Trematodes Schistosoma japonicum Blood fluke Humans and snails Skin penetration of larval stage Flatworms—Cestodes Taenia solium Pork tapeworm Humans, swine Consumption of undercooked or raw pork Diphyllobothrium latum Fish tapeworm Humans, fish Consumption of undercooked or raw fish © McGraw Hill, LLC 70  Egg Laying Fertilized eggs: Released to the environment Provided with a protective shell and extra food to aid their development into larvae Vulnerable to heat, cold, drying, and predators Certain helminths can lay from 200,000 to 25 million eggs a day to assure successful completion of their life cycle © McGraw Hill, LLC 71  A Helminth Cycle: The Pinworm 1 Example: Enterobius vermicularis: Pinworm Common infestation of the large intestine Range from 2 to 12 mm long with a tapered, curved cylindrical shape Cause enterobiasis (rarely serious) © McGraw Hill, LLC 72  A Helminth Cycle: The Pinworm 2 Life cycle: Microscopic eggs are swallowed: picked up from another infected person or objects they have touched Eggs hatch in the intestine Larvae mature into adults within 1 month Male and female worms mate Female migrates to the anus to deposit eggs Intense itching ensues Scratching spreads the eggs © McGraw Hill, LLC 73  Life Cycle of the Pinworm Olga Enger/Shutterstock Access the text alternative for slide images. © McGraw Hill, LLC 74  Distribution and Importance of Parasitic Worms About 50 species of helminths cause disease in humans Distributed in all areas of the world Higher incidence in tropical areas Yearly estimate of cases is in the billions and are not confined to developing countries Conservative estimate of 50 million helminth infections in North America alone © McGraw Hill, LLC 75  Concept Check 5 Adulthood and mating of helminths occurs in the blank. A. larvae B. intermediate host C. cyst D. definitive host E. egg © McGraw Hill, LLC 76  End of Main Content Because learning changes everything. ® www.mheducation.com © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.