biol 201 chp 2 introduction to protozoa
DESCRIPTION
This is a lecture presentation for my BIOL 201 Invertebrate Zoology students on Chapter 2: Introduction to Protozoa (Invertebrate Zoology 7E by Ruppert, Fox, Barnes, 2004). Rob Swatski, Assistant Professor of Biology, Harrisburg Area Community College - York Campus, York, PA. Email: [email protected] visit my website, BioGeekiWiki, for more biology learning resources: http://robswatskibiology.wetpaint.comVisit my Flickr photostream for anatomy model photographs! http://www.flickr.com/photos/rswatski/Thanks for looking!TRANSCRIPT
BIOL 201: Invertebrate Zoology
Chapter 2: Introduction to Protozoa
Rob SwatskiAssistant Professor of Biology
HACC-York
Eukaryotes
Domain Eukarya
Protozoa are animal-like
protists
Classification continually
changes
Membrane-bound nucleus
& organelles2
Protozoa
Most unicellular
Some colonial (ancestors of
plants & animals)
Most motile
Incredible diversity
3
Eukaryotic Cells
Diversity of specialized organelles
Cell membrane & cytoplasm
Double-membranednucleus,
mitochondria, & chloroplasts
Internal membrane system
4
5
Cytoplasm
Fluid enclosed by cell
membrane
Ectoplasm: outer, stiff
portion
Endoplasm: inner, fluid
portion6
Cell Membrane
Phospholipidbilayer with
proteins
Barrier to the external
environment
Selective passage of molecules
Glycocalyx
Endocytosis & exocytosis
7
8
Internal Membrane
System
Compartmentalizes the cell
Endoplasmic reticulum (ER)
Golgi bodies
Lysosomes
9
10
Cytoskeleton
Cytoskeleton
3-D network of protein fibers
Microfilaments(actin)
Microtubules
Dynamic
11
12
Microfilaments
Microtubules13
Functions of the Cytoskeleton
Cell motility: cilia, flagella, pseudopodia
Maintains cell shape
Regulates cell division
Vesicular transport
14
15
Cell Motility
Motor molecules (dynein) change shape in the presence of ATP
Dynein arms grab, move, & release outer
MT’s
MT doublets flex, bending cilium or
flagellum
Treadmilling
16
17
18
Cilia & FlagellaBoth made of MT core (axoneme) sheathed by plasma membrane
(9x2)+2 MT arrangement
Arises from & anchored to cell by basal body (9x3)+0
Motor protein (dynein) drives
bending movement
Cilia
Many
Short
Sweep materials across
cell (oar-like)
Flagella
Fewer
Long
Move entire cell (whip-like)
19
20Cilia
Cilia
21
22
Basal body
Cilium or Flagellum
(9x2)+2
23
Flagella
24
Base-to-tip wave propagation
Longitudinal forces provide forward thrust
Flagellarpropulsion 25
Ciliarypropulsion Metachronal waves
26
27
Cell motility using actin
Pseudopodia
Used for locomotion, feeding, & endocytosis
Dynamic disassembly & assembly of actin
Ectoplasm (gel) converted into
endoplasm (fluid)
Contractile ectoplasm provides force to move
cytoplasm forward
28
29Amoeboid movement
30
Protozoan Physiology
Same rules as in metazoans
Environmental effects may be
more significant
Ectothermic
Large surface area-to-volume ratio
31
Uptake By Cells
Endocytosis: extracellular uptake
Micropinocytosis: water, ions, small
molecules
Macropinocytosis: proteins &
macromolecules
Phagocytosis: bacteria & protozoans
in food vacuoles
32
33
34Micropinocytosis
35Macropinocytosis
36
Phagocytosis
Intracellular Digestion
Engulfment(phagocytosis): food vacuoles fuse with
lysosomes
Intracellular Digestion: mechanical/chemical
Absorption into cytoplasm: products are metabolized or stored
Elimination of indigestible material via
exocytosis37
Cell Circulation
Cytoplasmiccirculation needed in
larger cells
Streaming: directional transport within cell
or pseudopodium
Shuttling: the movement of vesicles
along a MT
Cyclosis: flow travels in a circuit
(Paramecium)38
39
Endosymbiosis
Heterotrophs often form mutualistic symbioses
with autotrophs
Zoochlorellae: photosynthetic symbiontssuch as unicellular green
algae or diatoms
Zooxanthellae: photosynthetic symbiontssuch as nonmotile yellow or brown dinoflagellates
Evolutionary value
40 Stentor
41
Zoochlorellae (in Paramecium bursaria)
42
Zoochlorellae(in giant green sea anemone)
43
Zooxanthellae (in coral)
44
Endosymbiosis
45
Creditsby Rob Swatski, 2010
http://robswatskibiology.wetpaint.com
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