Ch05 Lecture

7/31/2019 Ch05 Lecture

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Chapter 5

Eukaryotic Cells andMicroorganisms

Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.


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Ancient Eukaryotes

3

Chloroplasts


Andrew Knoll

Cell wall

y.

Andrew Knoll

(a) (b)


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4

Eukaryotic Microbes


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5

The Eukaryotic Cell

Nuclearmembranewith pores

Nucleolus

Nucleus

Centrioles*

Microvilli/Glycocalyx

Rough endoplasmicreticulum withribosomes

MitochondrionCell wall*

Cell membrane

Golgi apparatus

Microtubules

Chloroplast*

*Structure not present in all cell types

Smoothendoplasmicreticulum

Lysosome

Microfilaments

Flagellum*



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Organization of the Eukaryotic Cell

6

Endoplasmic reticulumGolgi complexMitochondriaChloroplasts

AppendagesFlagellaCilia

GlycocalyxCapsulesSlimes

Cell wallCell/cytoplasmic membrane

Organelles

Cytoplasmic matrix

Externalorganelles andother structures

Boundary of cell

Nuclear envelopeNucleolusChromosomes

Nucleus

Internalorganelles andother contents

Microtubules

MicrofilamentsCytoskeleton

Ribosomes


Eukaryotic

cell


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External Structures Locomotor appendages: Flagella

Long, sheathed cylinder containing microtubules in a9+2 arrangement

Covered by an extension of the cell membrane

10X thicker than prokaryotic flagella

Function in motility

short

glycocalyxfringe

ciliarymembrane

singlet

B subfiberof doublet

outerdyneinarm

(a)


y .

Courtesy Richard Allen

CellMembrane

Courtesy Richard Allen

Microtubules

Cilium

bb

(b)

(c) Whips back and

forth and pushesin snakelikepattern

Twiddles

the tip

Lashes, grabs

the substrate,and pulls


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Micronucleus

Oral groove with gullet

Macronucleus

Contractile vacuole


External Structures Locomotor appendages: Cilia

Similar in overall structure to flagella, but shorterand more numerous

Found only on a single group of protozoa andcertain animal cells

Function in motility, feeding, and filtering

8(a) Power stroke Recovery stroke(b)


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External Structures Glycocalyx

An outermost boundary that comes into direct contactwith environment

Usually composed of polysaccharides Appears as a network of fibers, a slime layer or a

capsule Functions in adherence, protection, and signal reception Beneath the glycocalyx

Fungi and most algae have a thick, rigid cell wall Protozoa, a few algae, and all animal cells lack a cell

wall and have only a membrane


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Boundary of the Cell

Cell wall Rigid, provides structural support and

shape

Fungi have thick inner layer of

polysaccharide fibers composed of chitin orcellulose and a thin layer of mixed glycans

Algae varies in chemical composition;substances commonly found include

cellulose, pectin, mannans, silicon dioxide,and calcium carbonate


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Boundary of the Cell

Cytoplasmic (cell) membrane Typical bilayer of phospholipids and

proteins

Sterols confer stability

Serves as selectively permeable barrier intransport

Eukaryotic cells also contain membrane-

bound organelles that account for 60-80%of their volume


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Concept Check:

Which part of the Eukaryotic cell is responsible forcontacting the outside environment and signaling

between cells?

A. Flagella

B. Cell WallC. Glycocalyx

D. Cell Membrane

12


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Internal Structures

Nucleus Compact sphere, most

prominent organelle ofeukaryotic cell

Nuclear envelope

composed of twoparallel membranesseparated by a narrowspace and is perforatedwith pores

Containschromosomes

Nucleolus dark areafor rRNA synthesis and

ribosome assembly

Nuclearenvelope

Endoplasmic reticulum

Nuclearpore

Nucleolus

Chromatin

(a)

Don Fawcett/Visuals Unlimited

Nuclear pore

Nucleolus Nuclear envelope

(b)



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Nuclear changes during Mitosis

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Cleavage furrow

Chromatin

Nucleolus

Nuclear envelope

Cell membrane

Cytoplasm

Daughter cells

Interphase

Prophase

Chromosome

Earlymetaphase

Spindle fibers

Chromosome

Centromere

Metaphase

Early anaphase

Late anaphase

Early telophase

Telophase

Centrioles

1

2

3

4

5

6

7

8

(resting state priorto cell division)



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Internal Structures

Endoplasmic reticulum two types:

Rough endoplasmic reticulum (RER) originatesfrom the outer membrane of the nuclear envelope

and extends in a continuous network throughcytoplasm; rough due to ribosomes; proteinssynthesized and shunted into the ER for packagingand transport; first step in secretory pathway

Smooth endoplasmic reticulum (SER) closedtubular network without ribosomes; functions innutrient processing, synthesis, and storage of lipids


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Rough endoplasmic reticulum

16

(a)

(b)

(c)

RER membrane

mRNARibosome

Protein beingsynthesized

Small subunit

Large subunit

Cisterna

Polyribosomes

Polyribosomes

Cisterna

Nuclear envelopeNuclear pore



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Internal Structures

Golgi apparatus

Modifies, stores, andpackages proteins

Consists of a stack offlattened sacs calledcisternae

Transportvesicles

Endoplasmicreticulum

Condensingvesicles

Cisternae



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Internal Structures

Transport Processes

Transitional vesiclesfrom the ER containingproteins go to the Golgi

apparatus formodification andmaturation

Condensing vesiclestransport proteins toorganelles or secretoryproteins to the outside

nucleus RER Golgi vesicles secretion 18

Ribosomeparts

Cell membrane

Secretory vesicle

Secretion by exocytosis

Nucleus

Roughendoplasmicreticulum

Transitionalvesicles

Golgiapparatus

Condensingvesicles

Nucleolus



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Internal Structures Lysosomes

Vesicles containingenzymes that originate fromGolgi apparatus

Involved in intracellulardigestion of food particles

and in protection againstinvading microbes

Vacuoles Membrane bound sacs

containing particles to bedigested, excreted, or stored

Phagosome vacuole merged with a

lysosome

Food vacuole

Lysosome

Merger oflysosome

and vacuole

Phagosome

Digestion

Digestive vacuole

Engulfmentof food

Formation of foodvacuole

Golgi apparatus

Food

particle

Lysosomes

Cell membrane

Nucleus



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Inner membrane

CircularDNA strand

Matrix

Cristae

(a) Outer membrane

70S ribosomes

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Internal Structures Mitochondria

Function in energyproduction

Consist of an outermembrane and an

inner membrane withfolds called cristae

Cristae hold theenzymes and electroncarriers of aerobicrespiration

Divide independentlyof cell

Contain DNA and

prokaryotic ribosomes

Cristae

(darker lines)

Matrix(lighter spaces)

(b) Don Fawcett/Visuals Unlimited



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Internal Structures

Chloroplast Convert the energy of

sunlight into chemicalenergy throughphotosynthesis

Found in algae andplant cells

Outer membranecovers inner

membrane folded intosacs,thylakoids,stacked into grana

Primary producers oforganic nutrients for

other organisms

70S ribosomes

CircularDNA strand

Granum Thylakoids

Chloroplast envelope(double membrane)

Stroma matrix



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Internal Structures

Ribosomes Composed of rRNA and proteins

Scattered in cytoplasm or associated with RER

Larger than prokaryotic ribosomes Function in protein synthesis

RER membrane

mRNARibosome

Protein beingsynthesized

Small subunit

Large subunit

Cisterna



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Cellmembrane

Ribosomes

Roughendoplasmicreticulum

Microtubule

Microfilaments

Mitochondrion

(a) 23

Internal Structures Cytoskeleton

Flexible framework of proteins, microfilaments andmicrotubules form network throughout cytoplasm

Involved in movement of cytoplasm, amoeboidmovement, transport, and structural support

(b)Courtesy of Life Technologies, Carlsbad, CA



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24

Comparing Prokaryotes, Eukaryotes & Viruses


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Concept Check:

The Eukaryotic organelle that is responsible for transportingvesicles inside the cells is the

A. Golgi

B. Smooth Endoplasmic Reticulum

C. Rough Endoplasmic Reticulum

D. Nucleus

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Phylogenetic Relationships between Eukaryotes

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Naegleria

Euglena

Zea (corn)

Eukarya

(a)

EVOLUTIONAR

YADVANCEMENTOFTHEEUKARYO

TES

Animals

True Fungi

(Eumycota)

Plants

Stramenopiles

(formerly

heterokonts

or chrysophytes)

Golden-brown and

yellow-green algaXanthophytes

Brown algaeDiatoms

Water molds

(Oomycota)

Ciliates

Colponema

DinoflagellatesHaplosporidia

Apicomplexans

Entamoebids

AmoeboflagellatesKinetoplastidsEuglenids

Parabasilids (Trichomonas)

Diplomonads (Giardia)Oxymonads

Microsporidia

Metazoa

MyxozoaChoanoflagellates

Zygomycota

Kingdom Animalia

Kingdom Eumycota

Kingdom Plantae

Kingdom ProtistaDivision Chlorophyta

Division Rhodophyta

Division Chrysophyta

Division PhaeophytaDivision Bacillariophyta

Division Euglenophyta

Phylum Sarcomastigophora

Phylum Ciliophora

Division Pyrrophyta

Phylum Apicomplexa

Traditional Kingdoms

and Subcategories

Taxonomy Based on mRNA Analysis

Ascomycota

Basidiomycota

Chytridiomycota(chytrids)

Land plantsGreen algae

Cryptomonads

Red algae

Alveolates

Entamoebae

Universal

Ancestor

Lack

mitochondria


(b)


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Survey of Eukaryotic Microbes

Fungi

Algae

Protozoa

Parasitic worms


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Kingdom Fungi 100,000 species divided into 2 groups:

Macroscopic fungi (mushrooms, puffballs, gillfungi)

Microscopic fungi (molds, yeasts)

Majority are unicellular or colonial; a few havecellular specialization

George Barron, University of Guelph, CANADA



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Microscopic Fungi Exist in two morphologies:

Yeast round ovoid shape, asexual reproduction

Hyphae long filamentous fungi or molds

Some exist in either formdimorphic

characteristic of some pathogenic molds

Septum

Dr. Judy A. Murphy, San Joaquin Delta College, Department of Microscopy, Stocton, CAJanice Carr/CDC



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Fungal Nutrition

All are heterotrophic Majority are harmless

saprobes living off deadplants and animals

Some are parasites, livingon the tissues of otherorganisms, but none areobligate

Mycoses fungalinfections

Extremely widespreaddistribution in manyhabitats

(a)

(b)

Kathy Park Talaro

New Zealand Dermatological Society


F l O i ti


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Fungal Organization

Yeast soft, uniform texture and appearance

Reproduce through an asexual process called budding

Janice Carr/CDC

Fungal (Yeast) Cell(a)

Ribosomes

Mitochondrion


Nucleus

Nucleolus

Cell membrane

Golgi apparatus

Cell wall

Storage vacuole

Bud scarBud


Bud

Nucleus Bud scars

Pseudohypha(c)

(b)

F l O i i


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Septa

Septate hyphae

Nucleus

NucleiSeptum with pores

As in Penicillium As in Rhizopus

Nonseptate hyphae


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Fungal Organization

Filamentous fungi mass of hyphae called

mycelium;cottony, hairy, or velvety texture Hyphae may be divided by cross wallsseptate

Vegetative hyphae digest and absorb nutrients

Reproductive hyphae produce spores for reproduction

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Fungal Reproduction Primarily through spores formed on reproductive

hyphae Asexual reproduction spores are formed through

budding or mitosis; conidia or sporangiospores

George Barron, University of Guelph, CANADA

(a) Vegetative Hyphae (b) Reproductive Hyphae

Surfacehyphae

Submergedhyphae

Hypha

Germ tube

Rhizoids

Spore

Substrate

Spores

(c) Germination


(d)

T f A l M ld S


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Types of Asexual Mold Spores

ArthrosporesChlamydospores Phialospores

Porospore

Microconidia

Macroconidia

Sporangiophore

Sporangiospore

Columella

Sporangium

1

4 5

1

2

2 3

ConidiaSporangiospore

Sterigma

Conidiophore

Blastospores

(a) (b)



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Fungal Reproduction

Sexual reproduction spores are formedfollowing fusion of two different strains andformation of sexual structure

Zygospores, ascospores, and basidiospores

Sexual spores and spore-forming structuresare one basis for classification


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Formation of zygospores

Sporangium

Stolon

Rhizoid

+ Strain

Sporesgerminate.

Germinatingzygospore

Strain

Mature zygospore

Zygote

Asexual Phase

Sexual Phase


Production of ascospores


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Production of ascospores

Ascospores

Asci

Fruitingbody

Cup fungus

Antheridium (male)

+ Hypha

Ascogonium(female)

Sterile hyphae

Ascogenoushyphae

Hypha


Zygote nucleithat undergo meiosis

prior to formationof asci

Formation of basidiospores in a mushroom


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Formation of basidiospores in a mushroom

Pair of nuclei fuseto form diploid nucleus.

Basidium

Portion of gillcovered withbasidia

Cap

Gill

Annulus

Stalk

+ Basidiospore

Button

Basidiospore

Basidium

Diploid nucleusundergoes meiosisto produce fourhaploid nuclei.

Soil,plantlitter


Basidiospore


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Fungal Classification

Kingdom Eumycota is subdivided into several phylabased upon the type of sexual reproduction:

1. Phylum Zygomycota zygospores; mostlysporangiospores and some conidia

2. Phylum Ascomycota ascospores; conidia

3. Phylum Basidiomycota basidiospores; conidia

4. Phylum Chytridomycota flagellated spores

5. Fungi that produce only Asexual Spores (Imperfect)

Di it f F i


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Chytrid cells

Diatom cell

10.0 mm

Diversity of Fungi

40

Kathy Park Talaro George Barron, University of Guelph, CANADA George Barron, University of Guelph, CANADA

Gregory M. Filip Joyce E. Longcore, University of Maine



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Fungal Identification

Isolation on specific media Macroscopic and microscopic observation of:

Asexual spore-forming structures and spores

Hyphal type Colony texture and pigmentation

Physiological characteristics

Genetic makeup


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Roles of Fungi

Adverse impact Mycoses, allergies, toxin production

Destruction of crops and food storages

Beneficial impact

Decomposers of dead plants and animals

Sources of antibiotics, alcohol, organic acids,vitamins

Used in making foods and in genetic studies

Human Fungal Infections


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Human Fungal Infections


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Concept Check:

Fungi are generally classified according to their

A. Type of sexual spore

B. Type of asexual spore

C. Type of hyphae

D. Type of habitat

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The Protists

Algae - eukaryoticorganisms, usuallyunicellular and colonial,that photosynthesize

with chlorophyll a Protozoa - unicellular

eukaryotes that lacktissues and share

similarities in cellstructure, nutrition, lifecycle, and biochemistry


EVOLUTIONARY

ADVANCEMENTOFTHEEUKARYOTE

S

Animals

True Fungi

(Eumycota)

Plants

Stramenopiles

(formerly

heterokonts

or chrysophytes)

Golden-brown and

yellow-green algaXanthophytes

Brown algaeDiatoms

Water molds(Oomycota)

Ciliates

Colponema

Dinoflagellates

Haplosporidia

Apicomplexans

Entamoebids

Amoeboflagellates

KinetoplastidsEuglenids

Parabasilids (Trichomonas)

Diplomonads (Giardia)Oxymonads

Microsporidia

Metazoa

Myxozoa

Choanoflagellates

Zygomycota

Kingdom Animalia

Kingdom Eumycota

Kingdom Plantae

Kingdom Protista

Division Chlorophyta

Division Rhodophyta

Division Chrysophyta

Division PhaeophytaDivision Bacillariophyta

Division Euglenophyta


Phylum Ciliophora

Division Pyrrophyta

Phylum Apicomplexa

Traditional Kingdoms

and Subcategories

Taxonomy Based on mRNA Analysis

Ascomycota

BasidiomycotaChytridiomycota

(chytrids)

Land plantsGreen algae

Cryptomonads

Red algae

Alveolates

Entamoebae

UniversalAncestor

Lack

mitochondria



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Algae

Photosynthetic organisms Microscopic forms are

unicellular, colonial,filamentous

Macroscopic forms arecolonial and multicellular

Contain chloroplasts withchlorophyll and otherpigments

Cell wall

May or may not haveflagella

Ribosomes

Flagellum

Cytoplasm

Nucleus

Nucleolus

Golgi

apparatus

Cell membrane

Mitochondrion

Starch vacuoles

Cell wall

Chloroplast

Algal Cell(a)

(b)

Jan Hinsch/Photo Researchers, Inc



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Algae

Most are free-living infresh and marine waterplankton

Provide basis of food webin most aquatic habitats

Produce large proportionof atmospheric O2

Dinoflagellates can causered tides and give off

toxins that cause foodpoisoning withneurological symptoms


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Classified according to types of pigments and cell wall Used for cosmetics, food, and medical products

Algae Classification


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Protozoa

Diverse group of 65,000 species Vary in shape, lack a cell wall

Most are unicellular; colonies are rare

Most are harmless, free-living in a moist habitat

Some are animal parasites and can be spread byinsect vectors

All are heterotrophic lack chloroplasts

Cytoplasm divided into ectoplasm and endoplasm Feed by engulfing other microbes and organic

matter


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Protozoa

Most have locomotorstructures flagella, cilia,or pseudopods

Exist as trophozoitemotile feeding stage

Many can enter into adormant resting stagewhen conditions areunfavorable for growth andfeedingcyst

All reproduce asexually,mitosis or multiple fission;many also reproducesexuallyconjugation

Trophozoiteis reactivated.

Trophozoite(active, feeding stage)

Cell rounds up,loses motility.

Cyst wallbreaks open.

Mature cyst(dormant, resting stage)

Early cyst wallformation



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Protozoan Identification Classification is difficult because of diversity

Simple grouping is based on method of motility,reproduction, and life cycle

1. Mastigophora primarily flagellar motility, someflagellar and amoeboid; sexual reproduction

2. Sarcodina primarily amoeba; asexual by fission;most are free-living

3. Ciliophora cilia; trophozoites and cysts; most arefree-living, harmless

4. Apicomplexa motility is absent except malegametes; sexual and asexual reproduction; complexlife cycle all parasitic

Mastigophora


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Mastigophora

Protozoan Cell(a)

Cell membrane

Glycocalyx

Ribosomes

Mitochondrion


NucleusPellicle

Nucleolus

Cell membrane

Golgi apparatus

Water vacuole

Centrioles

Flagellum


(b)Janice Carr/CDC


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Sarcodina

53

Nucleus

Food vacuoles

ContractilevacuolesPseudopods(a) (b)

David Patterson/MBL/Biological Discovery in Woods Hole


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Ciliophora

54

(a)

Oral ciliain groove

Gullet

Food

vacuoles

Macronucleus

Micronucleus

Watervacuole

Eric Russell, BioMEDIA ASSOCIATES


Yuuji Tsukii, Protist Information Server

(b)


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Apicomplexa

55

(a)

Cytostome(mouth)

Foodvacuole


Nucleus

Cell membrane

Mitochondrion

Cytostome Food vacuoles Nucleus

(b)Michael Riggs et al, Infection and Immunity, Vol. 62, #5, May 1994, p. 1931

ASM


Pathogenic Protozoa


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Pathogenic Protozoa

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Important Protozoan Pathogens

Pathogenicflagellates Trypanosomes

Trypanosoma

T. bruceiAfricansleeping sickness

T. cruziChagasdisease; SouthAmerica

(a) InfectiveTrypanosome

(b) Mode ofinfection

Cycle inthe Wild

Reduviidbug

Cycle inHuman

Dwellings




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Infective amoebas Entamoeba

histolytica amebicdysentery; worldwide

58

Cysts infood, water

(a)

Trophozoitesreleased

(b)

Largeintestinesite ofinfection

Eaten

Food,water Feces

Cysts exitMature cysts

Smallintestine

Maturetrophozoites

Stomach

(c)

(d)



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Concept Check:

Which of the following descriptions is true of both Algaeand Protozoa?

A. They are both photosynthetic

B. They are both always unicellular

C. They both contain mitochondria

D. They are both heterotrophs

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Parasitic Helminths

Multicellular animals, organs for reproduction,digestion, movement, protection

Parasitize host tissues

Have mouthparts for attachment to or

digestion of host tissues Most have well-developed sex organs that

produce eggs and sperm

Fertilized eggs go through larval period in or

out of host body


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Major Groups of Parasitic Helminths

1. Flatworms flat, no definite body cavity;digestive tract a blind pouch; simple excretoryand nervous systems

Cestodes (tapeworms)

Trematodes or flukes, are flattened, nonsegmentedworms with sucking mouthparts

2. Roundworms (nematodes) round, acomplete digestive tract, a protective surface

cuticle, spines and hooks on mouth; excretoryand nervous systems poorly developed

Helminth Classification and


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Helminth Classification and

Identification

Classify according to shape, size, organ development,presence of hooks, suckers, or other special structures, modeof reproduction, hosts, and appearance of eggs and larvae

Identify by microscopic detection of worm, larvae, or eggs

Esophagus

Ventralsucker

Cuticle

Uterus

Testes

(b)(a)

Scolex

Cuticle

Proglottid

Fertile eggsImmature eggsSuckers

Pharynx

Intestine

Vas deferens

Ovary

Seminalreceptacle

Excretory

bladder

Oral sucker


Distribution and Importance of


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Distribution and Importance ofParasitic Worms

Approximately 50 species parasitize humans

Distributed worldwide; some restricted to certaingeographic regions with higher incidence in

tropics

Acquired through ingestion of larvae or eggs infood; from soil or water; some are carried by

insect vectors Afflict billions of humans

Lifecycle of the Pinworm


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Lifecycle of the Pinworm

Cross-infection

Self-

infection

Fertileegg

FemaleAnus

Copulatory

spicule

MaleEggs

Mouth

Cuticle Mouth

Autoinoculation



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Concept Check:

Helminths are in the Domain ________ and

in the Kingdom ___________.

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