protistaandsimplemetazoa

THE UNIVERSITY OF ARIZONA

Biology 182 Spring 1998 Section #9,#13
Lab Notes A.K. Huxley

PROTISTA AND SIMPLE METAZOA
I. Eukaryotic Cell Structure (Kingdoms: Protista, Fungi, Plantae, and Animalia)

A. bilipid cellular and nuclear membrane
B. membrane-bound internal organelles - organelles are sequestered packages with complex biochemical reactions, examples

1. mitochondria function to produce energy, ATP, through cellular respiration
2. plastids, such as chloroplasts, function to convert light energy into sugar and oxygen
3. endoplasmic reticulum allows for storage, export of synthesized proteins
4. golgi apparatus function to export synthesized proteins

C. endoymbiotic organisms - mitochondria, chloroplasts, flagella?, cilia?

II. Levels of Organization

A. Chemical level

1. elements form molecules
2. four classes of molecules that form living organisms

a. protein to build structure, muscle, hair, nail
b. carbohydrates for energy, cell receptors
c. lipids for energy, cell and organelle membranes
d. DNA to allow for protein synthesis and cell duplication

B. Cellular level

1. Cell is the structural and functional unit of an organism, Is one cell alive?
2. Types of cellular organisms

a. single-celled organisms interact directly with environment

1. cell receives all nutrients from environment by process of diffusion
2. cell asexually reproduces by binary fission

b. multi-celled organisms are differentiated and specialized cells interact with the environment

1. differentiated cells have specialized functions, such as receive nutrients from the environment
2. division of the soma and germ line for sexual reproduction

3. Differentiated cells have organelles, which have specific functions

a. mitochondria

1. powerhouses of the cell and function in energy production called adenosinetriphosphatase through the process of oxidative phosphorylation
2. endosymbiote, once considered to be a separate organism that was incorporated into a primordial cell; has its own DNA and replicates on its own

b. DNA - deoxyribonucleic acid

1. functions to store the genetic code for two purposes:

a) cell duplication

1) mitosis is the process of producing two identical daughter cells from a precursor cell for the replacement of somatic (general body) cells
2) some cells are no longer capable of undergoing mitosis and are referred to as post-mitotic cells, examples include neurons (nerve cells) and muscle

b) protein synthesis for the production of two types of proteins:

1) structural proteins produce collagen, elastin and other proteins that form structure in the body
2) regulatory proteins that control the timing, shape, growth, and development of the organism, and are referred to as homeotic genes

c. RNA - ribonucleic acid

1. functions in protein synthesis by two processes:

a) transcription in which mRNA copies DNA, sNRP's edit the message, and mRNA carries the message to the cells cytoplasm
b) translation is which the mRNA joins to rRNA and tRNA carries the appropriate amino acid for the formation of peptide bonds

d. endoplasmic reticulum

1. series of cysterns that aids in the synthesis and storage of newly formed proteins; same as Nissl substance in the neuron

e. golgi apparatus

1. receives packaged protein from the golgi apparatus and excretes the proteins into the extracellular matrix

f. lysosome

1. small vesicles that contain proteolytic enzymes that digest cellular debris
2. enzymes are produced through the process of protein synthesis and aid in cell death, apoptosis

g. cytoskeletal elements

1. proteins that provide structural support to the cell, aid in cell division, aid in transportation of materials within the cell, and ameboid movement of the cell
2. three proteins or combinations thereof provide these functions

a. microfilaments - actin
b. microtubules - tubulin
c. intermediate filaments - several proteins

C. Tissue Level

1. Tissues are groups of differentiated cells that function together

a. there are four general tissue types

1. epithelium - forms skin, linings of body
2. muscle - cardiac, skeletal, smooth
3. connective - cartilage, bone, blood, adipose
4. nervous - neurons, neuroglia

D. System Level

1. Several related layers of tissue with a common function, such as the alimentary canal

E. Organismal Level

1. Whole organism is a combination of all of these systems

III. Protists

A. Unicellular Eukaryotes
B. Characteristics

1. Presence of flagella
2. Gamete production
3. Contractile vacuoles to take in and remove water
4. Food vacuoles to take in food

C. Chart

1. Animal Like Protists (Protozoans)

a. Phylum Zoomastigophora - considered ancestral to other protists, contains flagella for locomotion; many live as parasites, in inside termites, responsible for sleeping sickness, giardiasis and trichomoniasis

1. Sleeping Sickness - caused by Trypanosoma gambiense parasite carried by the Testis Fly, it is recognizable by the immune system since it changes so quickly and causes death in the individuals infected. The areas of the world inflicted with this parasite are uninhabitable.

b. Phylum Rhizopoda - Sarcodina - contain pseudopodia for movement; such as ameba in ameboid movement
c. Phylum Ciliophora - named by the presence of cilia for movement and feeding, examples include Paramecium
d. Phylum Apicoplexa - Sporozoa - produce spores; live in host as parasite an produce spores

1. Malaria

a. Caused by a parasite called Plasmodium (genus) and vivax/falciparum/malariae/ovale (species), Plasmodium falciparum is the most virulent of these forms, the parasite is carried by the female Anopheles mosquito in the salivary glands.
b. Great apes are thought to have originally carried the parasite and with the introduction of agriculture into overlapping habitats and the decline of the apes niche, humans were infected.
c. Malaria is characterized by the introduction of the parasite into the individual, after 5-11 days, the parasites infect the RBC's and proliferate. When the parasite reproduces and leaves the RBC, the cell lyses. When this occurs, there is increased load on the spleen, which will grow in size (splenomegaly) and overload the liver to break down RBC's, which leads to a build-up of pigment by-products. This condition is called Black-Water Fever and is diagnosed by urine the color of coca-cola and feces the color of chalk. After time, the condition causes headaches, nausea, convulsions and death.

2. Fungus-like Protists

a. Characteristics

1. Alternation of generations with a definable sporophyte (2N) and gametophyte (1N) generation
2. Lack chitin in cell wall
3. Have flagella in some stage of life cycle
4. Lack dikaryotic stage in life cycle

b. Phylum Acrasiomycota - Gymnomycota - slime mold that lives as amoeba, then under environmental stress such as lack of bacteria, comes together to form pseudoplasmodium that will form spores, or macrocysts that will form a giant cell to undergo meiosis.

3. Plant-like Protists (Algae)

a. Characteristics

1. Use photosynthesis as the primary source of energy, so they contain chloroplast

b. Phylum Euglenophyta contain both flagella and chloroplast
c. Phylum Pyrrophyta contain chlorophyll pigments responsible for the "Red Tide"; produce a neurotoxin that can kill other organisms; stored in shell fish
d. Phylum Chrysophyta are called golden-brown algae

IV. Simple Metazoa (Animals)

A. Multicellular Eukaryotes - multicellularity allows for specialization of cells and tissues to increase adaptive fitness of the organism; lack of cell walls; protostomes first mouth; deuterostomes second mouth

1. Cellular Level of Organization - cells perform functions to maintain the organism; that act as separate units in the organism, as demonstrated by the reassociation of sponge cells if separated

a. Phylum Porifera - sponges that remain sessile, attached to a site, asymmetric body plan

2. Tissue Level of Organization - two or more cell types that function together as specialized tissues to maintain the organism

a. Characteristics

1. Diploblastic - two embryonic cell layers
2. No enclosed body cavity
3. Radial symmetry - any plane will give same parts on each side
4. Contain Nematocysts, which are stinging structures

b. Phylum Cnidaria - hydras, jellyfish, sea anemones, corals

1. phylum characterized by radial symmetry (unequal divisions if cut in any plane)
2. contains no true embryonic dermis, rather epidermis, mesoglia and gastrodermis

3. Organ Level of Organization - two or more tissue types that function together to form a definable shape to maintain the individual; bilateral symmetry at some stage of the life cycle; and embryonic mesoderm between ectoderm and endoderm

a. Phylum Platyhelminthes/Phylum Acoelomates - flatworms - lack a body cavity, and system to distribute nutrients

1. Turbellarians, such as Planaria, that contain eyespots and developed digestive systems
2. Cestodes, such as tapeworms, that act as parasites
3. Trematodes, such as flukes, that also act as parasites

b. Phylum Pseudocoelomates - roundworms - contain a fluid-filled cavity derived from the blastocoel that acts to distribute nutrients

1. Phylum Nematoda - Nematodes are small worms that are located throughout the world, parasitic intestinal worm Ascaris, lays eggs that pass through the intestinal tract and out the feces to hands or soil, originally thought to have come from pigs (i.e. zoonoses); Trichinella spiralis is a nematode that is ingested from uncooked, contaminated pork

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Angie K. Huxley, Doctoral Candidate, Department of Anthropology

AHUXLEY@u.arizona.edu