Download The Eukaryotes: Fungi, Algae, Protozoa

11/21/2016
PowerPoint® Lecture
Presentations prepared by
Bradley W. Christian,
McLennan Community
College
CHAPTER
12
The
Eukaryotes:
Fungi, Algae,
Protozoa
© 2016 Pearson Education, Ltd.
Comparing Prokaryotic and Eukaryotic Cells: An
Overview (chapter 4)
Prokaryote
• One circular chromosome,
not in a membrane
• No histones
• No organelles
• Bacteria: peptidoglycan
cell walls
• Archaea: pseudomurein
cell walls
• Divides by binary fission
Eukaryote
• Paired chromosomes,
in nuclear membrane
• Histones
• Organelles
• Polysaccharide cell walls,
when present
• Divides by mitosis
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Figure 4.6 The Structure of a Prokaryotic Cell.
© 2016 Pearson Education, Ltd.
Figure 4.22a Eukaryotic cells showing typical structures.
IN PLANT AND
ANIMAL CELLS
IN PLANT CELL ONLY
Vacuole
Cell wall
Peroxisome
Magnetosomes
Nucleus
Nucleolus
Chloroplast
Rough
endoplasmic
reticulum
Smooth
endoplasmic
reticulum
Microtubule
Microfilament
IN ANIMAL CELL ONLY
Mitochondrion
Centrosome:
Centriole
Pericentriolar material
Plasma membrane
Ribosome
Lysosome
Basal body
Flagellum
Cytoplasm
Golgi complex
Idealized illustration of a composite eukaryotic cell, half plant and half animal
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Vacuole (plant and fungal cells)
The function and significance of vacuoles varies greatly according to the
type of cell in which they are present:
• Isolating materials that might be harmful or a threat to the cell
• Containing waste products and/or water in plant cells
• Maintaining internal hydrostatic pressure within the cell
• Maintaining an acidic internal pH
• Containing small molecules
• Exporting unwanted substances from the cell
• Allows plants to support structures such as leaves and flowers due to
the pressure of the central vacuole
• By increasing in size, allows the germinating plant or its organs (such
as leaves) to grow very quickly and using up mostly just water
• In seeds, stored proteins needed for germination are kept in 'protein
bodies', which are modified vacuoles
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Figure 4.22b Eukaryotic cells showing typical structures.
Nucleus
Vacuole
Mitochondrion
Chloroplast
Cell wall
Transmission electron micrograph of plant cell
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Flagella and Cilia
• Projections used for locomotion or moving
substances along the cell surface
• Flagella—long projections; few in number
• Cilia—short projections; numerous
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Figure 4.23a-b Eukaryotic flagella and cilia.
Flagellum
Cilia
Cilia
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Flagella and Cilia
• Both consist of microtubules made of the protein
tubulin
• Microtubules are organized as nine pairs in a ring,
plus two microtubules in the center (9 + 2 array)
• Allow flagella to move in a wavelike manner
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Figure 4.23c Eukaryotic flagella and cilia.
Plasma
membrane
Central
microtubules
Doublet
microtubules
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The Cell Wall and Glycocalyx
• Cell wall
• Found in plants, algae, and fungi
• Made of carbohydrates (cellulose—plants, chitin—fungi,
glucan and mannan—yeasts)
• Glycocalyx
• Carbohydrates bonded to proteins and lipids in the
plasma membrane
• Found in animal cells
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The Plasma (Cytoplasmic) Membrane
Learning Objective
4-15 Compare and contrast prokaryotic and
eukaryotic plasma membranes.
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The Plasma (Cytoplasmic) Membrane
• Similar in structure to prokaryotic cell membranes
• Phospholipid bilayer
• Integral and peripheral proteins
• Differences in structure
• Sterols—complex lipids
• Carbohydrates—for attachment and cell-to-cell
recognition
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The Plasma (Cytoplasmic) Membrane
• Similar in function to prokaryotic cell membranes
• Selective permeability
• Simple diffusion, facilitated diffusion, osmosis, active
transport
• Differences in function
• Endocytosis—phagocytosis and pinocytosis
• Phagocytosis: pseudopods extend and engulf particles
• Pinocytosis: membrane folds inward, bringing in fluid
and dissolved substances
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Cytoplasm
Learning Objective
4-16 Compare and contrast prokaryotic and
eukaryotic cytoplasms.
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Cytoplasm
• Cytoplasm: substance inside the plasma and
outside the nucleus
• Cytosol: fluid portion of cytoplasm
• Cytoskeleton: made of microfilaments and
intermediate filaments; gives shape and support
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Ribosomes
Learning Objective
4-17 Compare the structure and function of
eukaryotic and prokaryotic ribosomes.
© 2016 Pearson Education, Ltd.
Ribosomes
• Sites of protein synthesis
• 80S
• Consists of the large 60S subunit and the small 40S
subunit
• Membrane-bound: attached to endoplasmic reticulum
• Free: in cytoplasm
• 70S
• In chloroplasts and mitochondria
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Check Your Understanding
ü Identify at least one significant difference between
eukaryotic and prokaryotic flagella and cilia, cell
walls, plasma membranes, and cytoplasm.
4-13–4-16
ü The antibiotic erythromycin binds with the 50S
portion of a ribosome. What effect does this have
on a prokaryotic cell? On a eukaryotic cell?
4-17
© 2016 Pearson Education, Ltd.
Organelles
Learning Objectives
4-18 Define organelle.
4-19 Describe the functions of the nucleus,
endoplasmic reticulum, Golgi complex,
lysosomes, vacuoles, mitochondria,
chloroplasts, peroxisomes, and centrosomes.
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The Nucleus
• Nucleus
• Double membrane structure (nuclear envelope) that
contains the cell's DNA
• DNA is complexed with histone proteins to form
chromatin
• During mitosis and meiosis, chromatin condenses into
chromosomes
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Figure 4.24 The eukaryotic nucleus.
Nuclear
pores
Nuclear
envelope
Nucleolus
Chromatin
Ribosome
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Endoplasmic Reticulum
• Folded transport network
• Rough ER: studded with ribosomes; sites of
protein synthesis
• Smooth ER: no ribosomes; synthesizes cell
membranes, fats, and hormones
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Figure 4.25 Rough endoplasmic reticulum and ribosomes.
Rough ER
Ribosomes
Cisterna
Smooth ER
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Figure 4.25b Rough endoplasmic reticulum and ribosomes.
Rough ER
Ribosomes
Cisterna
Smooth ER
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Golgi Complex
• Transport organelle
• Modifies proteins from the ER
• Transports modified proteins via secretory
vesicles to the plasma membrane
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Figure 4.26 Golgi complex.
Transport vesicle
from rough ER
Cisternae
Transfer
vesicles
Secretory
vesicle
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Mitochondria
• Double membrane
• Contain inner folds (cristae) and fluid (matrix)
• Involved in cellular respiration (ATP production)
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Organelles
• Lysosomes
• Vesicles formed in the Golgi complex
• Contain digestive enzymes
• Vacuoles
• Cavities in the cell formed from the Golgi complex
• Bring food into cells; provide shape and storage
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Figure 4.27 Mitochondria.
Outer
membrane
Inner
membrane
Crista
Matrix
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Chloroplasts
• Locations of photosynthesis
• Contain flattened membranes (thylakoids) that
contain chlorophyll
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Figure 4.28 Chloroplasts.
Chloroplast
Thylakoid
Granum
Membranes
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Figure 4.28b Chloroplasts.
Chloroplast
Thylakoid
Granum
Membranes
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Organelles
• Peroxisomes
• Oxidize fatty acids; destroy H2O2
• Centrosomes
• Networks of protein fibers and centrioles
• Form the mitotic spindle; critical role in cell division
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© 2016 Pearson Education, Ltd.
Fungi
Learning Objectives
12-1 List the defining characteristics of fungi.
12-2 Differentiate asexual from sexual reproduction,
and describe each of these processes in fungi.
12-3 List defining characteristics of the four phyla of
fungi.
12-4 Identify two beneficial and two harmful effects
of fungi.
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Fungi
• Mycology: the study of fungi
• Chemoheterotrophs
• Decompose organic matter
• Aerobic or facultative anaerobic
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Table 12.1 Selected Features of Fungi and Bacteria Compared
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Vegetative Structures
• Molds and fleshy fungi
• The fungal thallus (body) consists of hyphae filaments;
a mass of hyphae is a mycelium
• Septate hyphae: contain cross-walls
• Coenocytic hyphae: do not contain septa
• Vegetative hyphae obtain nutrients while aerial hyphae
are involved with reproduction
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Figure 12.2 Characteristics of fungal hyphae.
Cell wall
Pore
Nuclei
Spore
Septum
Septate hypha
Coenocytic hypha
Growth of a hypha from a spore
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Trichoderma transformation
• Protoplast formation
• Transformation
• Cultivation
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Figure 12.3 Aerial and vegetative hyphae.
Aerial hyphae
Vegetative hyphae
Aerial hyphae
Aspergillus niger
A. niger on agar
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Vegetative Structures
• Yeasts
• Nonfilamentous and unicellular
• Budding yeasts divide unevenly
• Fission yeasts divide evenly
• Dimorphic fungi
• Yeastlike at 37 C and moldlike at 25 C
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Figure 12.4 A budding yeast.
Bud
Parent cell
Bud scar
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Figure 12.5 Fungal dimorphism.
Yeastlike growth
Moldlike growth
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Life Cycle
• Fungi reproduce sexually and asexually via the
formation of spores that detach from the parent
and germinate into a new mold
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Life Cycle
• Asexual spores
• Produced via mitosis and cell division; formed by the
hyphae of one organism
• (Seuraavia ei tarvitse osata)
• Conidiospore: not enclosed in a sac
• Arthroconidia: fragmentation of septate hyphae
• Blastoconidia: buds of the parent cell
• Chlamydoconidium: spore within a hyphal segment
• Sporangiospore: enclosed in a sac
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Figure 12.6 Representative asexual spores.
Arthroconidia
Conidia
Pseudohypha
Conidiophore
Conidia are arranged in
chains at the end of an
Aspergillus niger conidiophore.
Blastoconidia
Fragmentation of hyphae
results in the formation of
arthroconidia in Ceratocystis ulmi.
Blastoconidia are formed
from the buds of a parent cell
of Candida albicans.
Sporangiospores
Chlamydoconidium
Sporangiophore
Chlamydoconidia are thick-walled
cells within hyphae of this Candida
albicans.
Sporangiospores are formed
within a sporangium of Rhizopus
stolonifer.
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Life Cycle
• Sexual spores
• Fusion of nuclei from two opposite mating strains
• Three phases of sexual reproduction:
• Plasmogamy: haploid donor cell nucleus (+) penetrates
cytoplasm of recipient cell (−)
• Karyogamy: + and − nuclei fuse and form diploid zygote
• Meiosis: diploid nucleus produces haploid nuclei
(sexual spores)
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Nutritional Adaptations
• Grow better at pH of 5
• Grow in high sugar and salt concentration;
resistant to osmotic pressure
• Can grow in low moisture content
• Can metabolize complex carbohydrates
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Ascomycota
• Sac fungi; septate hyphae
• Teleomorphic fungi
• Produce sexual and asexual spores
• Some are anamorphic
• Lost ability to sexually reproduce
• Produced asexually: conidiospore
• Produced sexually: ascospore
• Nuclei morphologically similar or dissimilar fuse in a
saclike ascus
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Figure 12.9 The life cycle of Talaromyces, an ascomycete.
Conidium germinates
to produce hyphae.
Conidia are released
from conidiophore.
Asexual
reproduction
Ascospore germinates
to produce hyphae.
Vegetative mycelium grows.
Ascus opens to
release ascospores.
Sexual
reproduction
Hypha produces
conidiophore.
Meiosis then
mitosis.
Ascus
Karyogamy.
Conidia
Plasmogamy.
Ascospore
Conidiophore
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Basidiomycota
• Club fungi; septate hyphae
• Produced asexually: conidiospores
• Produced sexually: basidiospores
• Formed externally on a base pedestal called a
basidium
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Figure 12.10 A generalized life cycle of a basidiomycete.
Hyphal fragment breaks off
vegetative mycelium.
Fragment grows
to produce new
mycelium.
Basidiospore
germinates
to produce
hyphae.
Basidiospores are
discharged.
Basidiospores
mature.
Basidium
Asexual
reproduction
Sexual
reproduction
Vegetative
mycelium
grows.
Plasmogamy
.
Basidiospores are
formed by meiosis.
Fruiting structure
("mushroom")
develops.
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Fungal Diseases
•
•
•
•
•
•
Mycosis: fungal infection
Systemic mycoses: deep within the body
Subcutaneous mycoses: beneath the skin
Cutaneous mycoses: affect hair, skin, and nails
Superficial mycoses: localized (e.g., hair shafts)
Opportunistic mycoses: fungi harmless in
normal habitat but pathogenic in a compromised
host
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Economic Effects of Fungi
• Saccharomyces cerevisiae: e.g. bread, wine,
hepatitis B vaccine
• Trichoderma: e.g. cellulose (and other enzymes)
• Coniothyrium minitans: kills fungi on crops
• Paecilomyces: kills termites
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Lichens
Learning Objectives
12-5 List the distinguishing characteristics of
lichens, and describe their nutritional needs.
12-6 Describe the roles of the fungus and the alga
in a lichen.
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Lichens
• Mutualistic combination of a green alga (or
cyanobacterium) and fungus
• Thallus (body) of lichens are made of:
• Medulla—hyphae grown around algal cells
• Rhizines (holdfasts)—hyphae projections below the
body
• Cortex—protective coating over the algal layer
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Figure 12.11a Lichens.
Fruticose
Foliose
Crustose
Three types of lichens
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Figure 12.11b Lichens.
Fungus
Alga
Cortex
Algal
layer
Medulla
Fungal
hyphae
Cortex
Rhizine
Lichen thallus
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Lichens
• Alga produces and secretes carbohydrates;
fungus provides holdfast
• Economic importance
• Dyes
• Antimicrobial (Usnea)
• Food for herbivores
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Algae
Learning Objectives
12-7 List the defining characteristics of algae.
12-9 Identify two beneficial and two harmful effects
of algae.
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Algae
•
•
•
•
Not a taxonomic group
Unicellular or filamentous photoautotrophs
Lack roots, stems, and leaves
Mostly aquatic
• Water is necessary for growth and reproduction
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Characteristics of Algae
• Locations depend on nutrient availability,
wavelengths of light, and surfaces to attach
• Thallus: body of multicellular algae
• Consists of holdfasts, stipes, and blades
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Figure 12.12a Algae and their habitats.
Sublittoral
zone
SURFACE
Green algae,
cyanobacteria,
euglenoids
Unicellular green algae,
diatoms, dinoflagellates
Red
LAND
Multicellular
green algae
Brown algae
Orange
Photic zone
Littoral
zone
Yellow
Violet
Blue
Red algae
Algal habitats
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Characteristics of Algae
• All reproduce asexually
• Multicellular algae can fragment or reproduce
sexually via alternation of generations
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Selected Phyla of Algae
• Green algae
•
•
•
•
•
Cellulose cell walls
Unicellular or multicellular
Chlorophyll a and b
Store starch
Gave rise to terrestrial plants
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Figure 12.13 Green algae.
Flagella
Mitosis
Meiosis
Zygote
formation
Growth
Eyespot
Nucleus
Asexual
reproduction
Sexual
reproduction
Stored
starch
Chloroplast
Fertilization
Cell
wall
Gamete formation
Multicellular green alga (Ulva)
Growth
Life cycle of a unicellular green alga (Chlamydomonas)
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Roles of Algae in Nature
• Fix CO2 into organic molecules
• Produce 80% of Earth's O2
• Algal blooms are increases in planktonic algae
that can result in toxin release or die and consume
oxygen
• Oil production
• Symbionts of animals
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Protozoa
Learning Objectives
12-10 List the defining characteristics of protozoa.
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Protozoa = Alkueläimet
•
•
•
•
Unicellular eukaryotes
Inhabit water and soil
Animal-like nutrition
Complex life cycles
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Characteristics of Protozoa
• Require a large supply of water
• Many have an outer protective pellicle, requiring
specialized structures to take in food
• Ciliates wave cilia toward mouthlike cytosome
• Amebae phagocytize food
• Food is digested in vacuoles and wastes
eliminated through an anal pore
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Figure 12.18 Members of the super kingdom Excavata.
1st–3rd
flagella
Nucleus
Cyst
Oral groove
4th flagellum
Food vacuole
Chilomastix. This flagellate, found in the
human intestine, may be mildly pathogenic.
The cysts can survive for months outside a
human host. The fourth flagellum is used to
move food into the oral groove, where food
vacuoles are formed.
Giardia
trophozoites. The
trophozoite of this intestinal parasite
has eight flagella and two prominent
nuclei, giving it a distinctive
appearance.
Giardia cyst.
The Giardia cyst
provides protection from the
environment before it is ingested
by a new host.
Flagella
Chloroplasts
Eye
spot
Undulating
membrane
Axostyle
Trichomonas vaginalis. This
flagellate causes urinary and genital
tract infections. Notice the small undulating
membrane. This flagellate does not have a cyst stage.
Flagella
Euglena. Euglenoids are autotrophs. Semirigid
rings supporting the pellicle allow Euglena to
change shape.
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Amebae
• Move by extending pseudopods
• Entamoeba histolytica—causes amebic dysentery
• Acanthamoeba—infects corneas and causes
blindness
• Balamuthia—granulomatous amebic encephalitis
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Figure 12.19 Amebae.
Food vacuole
Pseudopods
Nucleus
Amoeba proteus
Red blood cells
Nucleus
Entamoeba histolytica
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Apicomplexa
• Plasmodium—causes malaria
• Sexually reproduces in the Anopheles mosquito
• A mosquito injects a sporozoite into its bite, and the
sporozoite undergoes schizogony in the liver;
merozoites are produced
• Merozoites infect red blood cells, forming a ring stage
inside the cell
• Red blood cells rupture, and merozoites infect new red
blood cells
• Which medical condition protects from malaria?
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Figure 12.20 The life cycle of Plasmodium vivax, the apicomplexan that causes malaria.
Infected mosquito bites
human; sporozoites migrate
through bloodstream to
liver of human.
Sporozoites in
salivary gland
Resulting sporozoites
migrate to salivary
glands of mosquito.
Sporozoites undergo
schizogony in liver cell;
merozoites are produced.
Zygote
Sexual
reproduction
In mosquito's
digestive tract,
gametocytes
unite to form
zygote.
Merozoites released
into bloodstream
from liver may infect
new red blood cells.
Female
gametocyte
Asexual
reproduction
Male
gametocyte
Male
Gametocytes
Merozoite develops
into ring stage in
red blood cell.
Intermediate
host
Another mosquito bites
infected human and
ingests gametocytes.
Ring stage grows and
divides, producing
merozoites.
Female
Merozoites are released when
red blood cell ruptures; some
merozoites infect new red blood
cells, and some develop into male
and female gametocytes.
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