Cells, Cell Division & Protoctista (Protista) Laboratory - Biosciweb.net

Cells, Cell Division & Protoctista (Protista) Laboratory 2.1 

Lab #2 - Biological Sciences 102 – Animal Biology 

This lab is designed to review some basic aspects of cell structure, function and division in the 

context of the group of single-celled organisms known as protozoa. The following is a basic 

review of cell theory. Many of the organelles (outside of the cell nucleus) are too small to see 

well even with a light microscope at high power, but you should think about the protozoa in the 

context that one cell is all they are, so literally these organelles are their “organs”. These 

organelles can only be clearly viewed using an electron microscope. Refer to the microscopy 

homework assignment regarding concepts related to electron microscopy. 

‣ A BRIEF HISTORY OF THE CELL THEORY 

• All living things are composed of cells and cells are in turn composed of large and small 

molecules which are in turn made up of atoms. 

• Early in the 17 th century, Galileo Galilei (of Astronomy fame) arranged two glass lenses 

within a cylinder and used it to look at an insect and later described the stunning 

geometric patterns of its tiny eyes. While Galileo was not a biologist, he was one of the first 

scientists to record a biological observation made through a microscope. 

• In the late 1600’s, Anton van Leeuwenhoek, a Dutch shopkeeper who had great skill in 

constructing lenses invents one of the first microscopes and uses it to look at scrapings of 

tartar from his own teeth, pond water and many other samples. In his studies (using a very 

primitive microscope by today’s standards), he observed “many very small animalcules, the 

motions of which were very pleasing to behold”. He observed diverse protoctistans, sperm 

and even bacteria – an organism so small it would not be seen again for another two 

centuries. 

• In 1665, the Curator of Instruments for the Royal Society in England, Robert Hooke, was 

at the forefront of microscopic study. When Hooke first turned a microscope to thinly 

sliced cork from a mature tree, he observed tiny compartments (formed from the plant cell 

walls). He gave them the latin name, cellulae, meaning small rooms and thus coined the 

term “cell”. 

• In 1820, Robert Brown, a botanist, using an improved microscope with better optics 

noticed an opaque spot in a variety of cells which he called a nucleus. 

• By 1839 Theodor Schwann (a German zoologist) and Matthias Schleiden (a German 

botanist) formulated the idea that tissues are composed of discrete units or cells which 

could divide. 

• In 1858, Rudolph Virchow, a german pathophysiologist states: 

"Every animal appears as a sum of vital units each of which bears in itself the complete 

characteristics of life" 

‣ The basic tenets of the cell theory are: 

1. All living things are made of cells. 

2. Cells only arise from pre-existing cells by division. 

(spontaneous generation does not occur) 

3. Cells are made of similar molecules with similar characteristics and biochemistry. 

• In single-celled organisms, nutrients, fluids, and other materials diffuse or are 

transported into and out of the cell membrane.



• In order for a multi-cellular organism to communicate with itself and pass nutrients from 

one cell to another, materials and fluids need to be able to pass from one part of the body 

to another. Multi-cellular organisms may only take up nutrients, oxygen, and fluids and 

dispose of carbon dioxide and waste products through certain specialized tissues and 

organs. 

• In multi-cellular organisms, cells are further organized and integrated together to form 

tissues. In many organisms, tissues are organized into organs and organ systems. 

• For instance, humans are multi-cellular and made up of around 100 trillion cells 

(depending on their size) of over 200 different types. 

‣ CELL STRUCTURE AND FUNCTION 

• organelle = a compartmentalized structure with a specialized 

function in a cell. 

Note that most of these organelles are only found in eukaryotic cells. 

Prokaryotic cells (bacteria) lack a membrane bound cell nucleus and 

organelles. As noted below, each cell type (plant, animal, fungal, or 

protist) does not necessarily have every organelle. Some of these 

organelles would not be found in a typical animal cell, but they 

may be seen in some protozoa. 

A Eukaryotic Cell 

Please refer to Chapter 3 in the Hickman text for illustrations and further information 

regarding the table below. 

ORGANELLE NAME 

Cell Membrane 

Cell Wall 

Cytoplasm 

Nucleus 

Rough Endoplasmic 

Reticulum 

Smooth Endoplasmic 

Reticulum 

Golgi Apparatus 

DESCRIPTION OF ORGANELLE 

separates cell from other cells and from the environment in which 

the cells exist; helps regulate what is transported into and out of the 

cell (for all cells); formed of a phospholipid bilayer, proteins, 

glycolipids, glycoproteins and cholesterol in animal cells 

maintains cell shape and provides skeletal support for the cell and 

the entire organism in the case of multicellular organisms such as 

plants; helps in the binding of the cell to other tissues; 

found in plants, fungi, and some protists only – not in animal cells 

the semifluid medium between the cell membrane and all of the 

organelles in a cell; found in all cells 

a membrane bound compartment with pores (small holes) where the 

eukaryotic cell's genetic material (DNA) is stored, copied and used to 

make RNA; found in all eukaryotic cells 

a network of interconnected membranous sacs in a eukaryotic cell 

that is studded with ribosomes that make proteins which will 

become part of the cell membrane or proteins that will be secreted 

from the cell; found in all eukaryotic cells 

a network of interconnected membranous tubules in a eukaryotic 

cell that contains specific enzymes; the smooth ER lacks ribosomes 

but it is important for the synthesis of special molecules such as the 

lipids which make up most of the cell membranes and steroids; 

found in all eukaryotic cells 

stacks of membranous sacs containing special enzymes that modify, 

store and ship products from the ER to the cell membrane or other 

parts of eukaryotic cells; found in all eukaryotic cells



Lysosomes 

Vacuoles 

Chloroplasts 

Mitochondria (plural) 

Mitochondrion (singular) 

Cytoskeleton 

Microfilaments 

about 7-8 nanometers 

in diameter 

Intermediate filaments 

about 10-13 nanometers 

in diameter 

Microtubules 

about 25 nanometers 

in diameter 

Centriole 

Cilia (plural) 

Cilium (singular) 

Flagella (plural) 

Flagellum (singular) 

Pili 

an organelle that contains enzymes that digest food and wastes in 

eukaryotic cells; found in animal cells, not plant cells 

a membrane enclosed sac that has diverse functions in eukaryotic 

cells, but is often used to store substances inside the cell; the 

central vacuole in plant cells stores water and has diverse roles in 

reproduction, growth, and development of the plant (not animals) 

an organelle that is enclosed by two membranes (an inner and an 

outer membrane); chloroplasts absorb sunlight and use it to make 

food molecules (sugars) by photosynthesis 

(not found in animal cells) 

an organelle that is enclosed by two membranes (an inner and an 

outer membrane); a eukaryotic organelle that plays important roles 

in cellular respiration; mitochondria produce ATP which is the fuel 

the cell uses for its various activities; found in all eukaryotic cells 

a network of small fibers that provides structural support and 

directs transport and movement of organelles within a eukaryotic 

cell; the cytoskeleton is formed of three different sized protein fibers: 

microfilaments, intermediate filaments and microtubules 

the thinnest of the three main kinds of protein fibers that make up 

the cytoskeleton; microfilaments are solid rods made of a the 

protein called actin; microfilaments help some cells change shape 

the middle sized of the three main kinds of protein fibers that make 

up the cytoskeleton; intermediate filaments are made of fibrous 

proteins 

the thickest of the three main kinds of protein fibers that make up 

the cytoskeleton; microtubules are hollow tubes made of proteins 

called tubulins; flagella, cilia and the spindle fibers used in cell 

division are made of microtubules. 

A structure in an animal cell, composed of cylinders of microtubule 

triplets arranged in a 9 + 0 pattern; an animal cell usually has a 

pair of centrioles which are involved in cell division (not in plants) 

a short cellular appendage that has a 9 + 2 arrangement of 

microtubules covered by the cell membrane; the cilia beat back and 

forth in synchrony to propel the cell or to move material outside the 

cell; not present in all eukaryotic cells 

a long cellular appendage that has a 9 + 2 arrangement of 

microtubules covered by the cell membrane; the flagellum moves 

back and forth to propel the cell forward; animal cells such as 

sperm and some protists have eukaryotic flagella, some bacteria 

have prokaryotic flagella of a different molecular structure; 

not found in plants 

short projections on the surface of bacterial cells that help the 

bacteria attach to other surfaces or other cells (bacteria only) 

Most animal cells (eukaryotes) contain: a nucleus, rough endoplasmic reticulum, ribosomes, 

smooth endoplasmic reticulum, peroxisomes, mitochondria, a cytoskeleton, a plasma (cell) 

membrane, Golgi apparatus, lysosomes, centrioles; some animal cells possess a flagella or cilia, 

but many do not possess a flagella or cilia. 

Most plant cells (eukaryotes) contain: a nucleus, a cell wall, a central vacuole, chloroplasts, 

peroxisomes, mitochondria, a plasma (cell) membrane, a cytoskeleton, Golgi apparatus, smooth 

endoplasmic reticulum, ribosomes, & rough endoplasmic reticulum.



Most bacterial cells (prokaryotes) contain: a nucleoid region (where DNA is found), 

ribosomes, a plasma (cell) membrane, a capsule, some bacteria have a cell wall, pili or flagella, 

but many do not. Note that the chemical reactions that occur in a bacteria are not 

compartmentalized in different types of organelles, that is, bacteria (prokaryotes) lack 

organelles. 

• Organelles found in animal cells, but not found in plant cells = lysosomes, flagella, 

centrioles 

• Organelles found in plant cells, but not found in animal cells = cell wall, chloroplasts, 

central vacuole 

Etymology (word origin) of eukaryote and prokaryote 

“eu” = true (from Greek) 

“pro” = earlier than or before (from Greek) 

“kary” =a nut; the nucleus of a cell (from Greek for nut or kernel) 

eukaryote = “true nucleus” 

prokaryote = “before nucleus” 

• eukaryotic cell = a type of cell that has a membrane enclosed nucleus and other 

membrane enclosed organelles described above. All organisms except bacteria are 

composed of eukaryotic cells. All members of the Domain Eukarya which includes the 

Kingdoms Protoctista (Protista), Fungi, Plantae, and Animalia are comprised of eukaryotic 

cells. The first eukaryotic cells evolved around 1.7 billion years ago and are typically more 

than 10 times larger than prokaryotic cells with cell sizes of 10 to 30 micrometers (microns) 

for animal cells and 10 to 100 micrometers (microns) for plant cells. 

• prokaryotic cell = a bacterial cell; a type of cell lacking a membrane enclosed nucleus 

and other membrane-enclosed organelles; found only in members of the Domain Archaea 

and Prokarya (Bacteria) (Kingdom Monera in Whittaker’s 5 kingdom system); prokaryotic 

cells were the first type of cell to evolve 3.5 to 4 billion years ago with average sizes typically 

1 to 10 micrometers (microns). 

Kingdom Protoctista versus Kingdom Protista 

General classification has seen marked changes since the mid-70s to the present. The term 

protista is still used in many schemes for classification. Protozoa was once considered a single 

phylum in the Kingdom Protista. Now considered to consist of at least 29 to 45 phyla within 

what used to be 3 different kingdoms (now the Kingdom Protoctista by some authors). Many 

taxonomists consider it best to group the different groups as different phyla. 

Margulis and Schwartz promote the term protoctista because protista denotes only organisms 

which are unicellular. The protoctista scheme contains many multi-cellular organisms with 

tissue specialization. The protista system places several of the protoctistan phyla into the 

plant and fungi kingdoms. For introductory students, protista and protoctista are 

basically interchangeable terms with both referring to the unicellular eukaryotic 

organisms (some of which form colonies) 

According to the system used for classification by Lynn Margulis and Karlene Schwartz, 

members of the protoctista are identified primarily by exclusion from all the other kingdoms. 

• Animals develop from a blastula. 

• Plants develop from an embryo. 

• Fungi develop from spores, and lack flagella and cilia 

• Monerans (prokaryotes) lack a membraned nucleus.



All remaining organisms are placed into the Kingdom Protoctista. They are aquatic, living in 

saltwater, freshwater, and of the watery tissues of other organisms. There are many protozoan 

parasites of both invertebrates and vertebrates. Depending on the source the Kingdom 

Protoctista is now considered to consist of at least 29 to 45 phyla within what used to be 3 

different kingdoms. 

General Characteristics of Protoctistans (Protistans) 

1. unicellular eukaryotes (some multinucleate, a few loosely multicellular), not all have 

mitochondria (microspores, many flagellates). 

2. up to about 400 micrometer in size (some larger) 

3. all have at least one nucleus 

4. most are free living, but many parasitic forms including entire phyla 

5. motile by a variety of mechanisms but also several non-motile taxa 

6. many have cyst stages secreted by trophic or spore stages 

cysts/spores have four basic functions: 

• protect against unfavorable conditions 

• serve as sites for multiplication 

• assist in attachment to surfaces such as hosts 

• transmission stage from host to host 

7. all types of nutrition are exhibited by the Kingdom. 

• autotrophs: photosynthesis 

• heterotrophs (holozoic vs. saprozoic) 

• phagocytosis: ingestion of solid particles (e.g., bacteria) 

• pinocytosis: same as phagocytosis but intake of liquid 

• saprozoic or saprotrophy: diffusion or active transport across membrane 

Characteristics of “Protozoa” = Protoctistans with animal cell characteristics 

The protozoa are a diverse assemblage of unicellular eukaryotic organisms having at 

least two animal-like properties: (1) absence of a cell wall and (2) presence of at least one 

motile stage in the life cycle. All functions of life are performed within the limits of a one cell 

membrane. Although protozoans have no organs or tissues, there is division of labor within the 

cytoplasm, where various complex organelles are specialized to carry out specific tasks. These 

organelles tend to be more specialized than those of an average cell of a multicellular organism, 

functioning as skeletons, locomotory systems, sensory systems, conduction mechanisms, 

defense mechanisms, and contractile systems. 

Protozoa are often called "simple" organisms. However, many are quite complex. Ciliates, for 

example, are not only the most complex of protozoans but also the most elaborately organized 

of all known cells. Protozoans are widespread ecologically, being found in fresh, marine, and 

brackish water and in moist soils. Some are free-living; others live as parasites or in some 

other symbiotic relationship. 

The protozoa are an artificial assemblage of organisms placed together for convenience. 

Traditionally, four main groups of protozoa have been recognized: flagellates, amebas, spore 

formers, and ciliates. These were assembled in a single phylum, Protozoa, within the kingdom 

Animalia. A revision adopted by the Society of Protozoologists in 1980 recognized seven 

separate phyla. However, more recent DNA sequence analyses of genes have shown that the 

protozoa represent numerous clades of varying evolutionary relationships. For example, 

ameboid organisms (formerly Sarcodina) fall into numerous lineages with undetermined 

associations. Nevertheless, the amebas comprise recognizable morphological groups, which we 

collect for convenience into the informal heading "Ameobas." (or “Amebas”).



• Modern taxonomists now reject the term protozoa as an invalid 

taxonomic group. 

TAXONOMIC CLASSIFICATION OF THE “PROTOZOAN” PROTOCTISTANS 

The following is a condensed Linnaean classification of the protozoan groups as 

presently recognized. 

Amebas = about 12,000 different known species; locomotion by pseudopodia; body naked or 

with external or internal test or skeleton; asexual reproduction by fission; sexuality, if present, 

associated with flagellated (rarely ameboid) gametes; most free-living, some parasitic. Several 

groups of uncertain affinities. 

Rhizopodans Locomotion by lobopodia, filopodia (thin pseudopodia that may branch but 

do not rejoin), or by cytoplasmic flow without forming discrete pseudopodia. (The 

rhizopodans are divided among several clades.) Examples: Amoeba, Endamoeba, Difflugia, 

Arcella, Chlamydophrys. 

Granuloreticulosans Locomotion by reticulopodia (thin pseudopodia that branch and 

often rejoin). Includes foraminiferans. Examples: Globigerina, Vertebralima. 

Actinopodans Locomotion by axopodia (long, slender pseudopodia). Includes radiolarians. 

(The actinopodans are divided among several clades.) Examples: Actinophrys, Clathrulina. 

Phylum Euglenozoa (yu-glen-a-zo'a) (Gr. eu-, good, true, + glime, cavity, socket, + zoon, 

animal). Movement by flagella; cortical microtubules. Examples: Euglena, 

Trypanosoma. About 7500 known different species. 

Phylum Chlorophyta (klor-of'i-ta) (Gr. chloros, green, + phyton; plant). Unicellular and 

multicellular algae; photosynthetic chlorophyll pigments, flagella of equal length and 

smooth, mostly free-living photo autotrophs. Example: Volvox. About 7000 known species. 

Phylum Dinoflagellata (dy'no-fla-jel-at'a) (Gr. dinos, whirling, + flagellum, little whip). 

Typically with two flagella, one transverse, one trailing; body usually grooved 

transversely and longitudinally, each groove containing a flagellum; chromoplasts bearing 

chlorophyll; free-living, planktonic, parasitic, or mutualistic. Examples: Noctiluca, Ceratium, 

Gonyaulax. About 2000 known species. 

Phylum Apicomplexa (a'pi-com-plex'a) (1. apex, tip, + complex, twisted around, + a, suffix). 

Characteristic set of organelles (apical complex) at anterior end in some stages; cilia and 

flagella usually absent; all species parasitic; about 5500 known species. 

Class Gregarinea (gre-ga -ryn' e-a) (1. gregarius, belong to a herd or flock). Mature 

gamete-producing individuals large, extracellular; gametes usually alike in shape and 

size; parasites of digestive tract or body cavity of invertebrates; life cycle with one host. 

Examples: Monocystis, Gregarina. 

Class Coccidea (kok-sid'e-a) (Gr. kokkos, kernel, grain). Mature gamete-producing 

individuals small, typically intracellular; parasites mostly of vertebrates. 

Examples: Plasmodium, Toxoplasma, Eimeria. 

Phylum Ciliophora (sil-i-of' o-ra) (1. cilium, eyelash, + Gr. phora, bearing). Cilia or ciliary 

organelles present in at least one stage of life cycle; usually two types of nuclei; binary 

fission across rows of cilia; budding and multiple fission also occur; sexuality involving 

conjugation, autogamy, and cytogamy; heterotrophic nutrition; mostly free-living; contractile 

vacuole typically present. (This is a very large group, now divided into three classes and 

numerous orders.) Examples: Paramecium, Colpoda, Tetrahymena, Stentor, Blepharisma, 

Epidinium, Vorticella, Euplotes, Didinium; about 9000 different known species.



LAB PROCEDURE 

NAME: 

LAB SCORE: 

Refer to chapter 3 in the Hickman text for illustrations and photos of 

Protozoa. 

Phylum Euglenozoa 

Your instructor will review and demonstrate how to properly prepare a wet mount. 

Obtain a compound microscope and prepare a wet-mount of Euglena sp. using Proto-Slo. 

(Make a thin ring of Proto-Slo on the slide, add a drop of the culture in the center of the ring, 

and carefully add the cover slip.) Examine the preparation under 10X magnification and 

then under 40X magnification. 

• After observing Euglena sp. for a few minutes, answer these questions: 

• What adjectives would you use to describe the movements 

• Can you see the flagellum Does the movement appear to correlate to the presence of 

flagella At which “end” (anterior or posterior) of the cell are the flagella found 

• Do Euglena push or pull themselves with their flagella 

Sketch a Euglena below and label it with the following structures (you may not clearly see all 

of these with your microscope so you can use a textbook or internet picture to assist you): 

• cell nucleus 

• cell membrane 

• red eyespot (or stigma) 

• chloroplasts 

• contractile vacuole 

• flagella



Hypermastids – the organisms in termites that actually “eat” wood…. 

Historically, hypermastids were classified as flagellates in the Phylum Sarcomastigophora, 

Subphylum Mastigophora (flagellates), Order Hypermastigida (many flagella). Today many 

taxonomists do not recognize the Phylum Sarcomastigophora as a valid taxonomic group. 

Some hypermastids are now classified by taxonomists into the Phylum Axostylata due to the 

presence of an axostyle made of microtubules. These are symbiotic flagellates found in the 

intestines of termites, cockroaches and woodroaches. Hypermastids have many, many 

flagella and aid their hosts in the digestion of cellulose (wood). 

View the slide of hypermastids on the screen demo setup by your instructor at the front 

of the room. 

A termite 

A termite mound 

Answer these questions: 

• What type of symbiotic relationship occurs between hypermastids and a termite 

• How does the insect benefit these flagellates 

• How do the flagellates benefit the host insect 

• How does a young termite become infected (infaunation) with hypermastids



Phylum Ciliophora 

Make a thin circle of Proto-Slo on a slide and add a drop of culture containing Paramecium 

caudatum. Carefully add the coverslip and examine the preparation under the 10X 

objective. Then view with the 40X objective. 

Sketch a Paramecium below and label it with the following structures (you may not clearly see 

all of these with your microscope so you can use a textbook or internet picture to assist you): 

• cilia 

• oral groove 

• contractile vacuoles 

• cytostome (mouth) 

• cytopharynx 

• food vacuoles 

• macronucleus 

• micronucleus 

Answer these questions: 

• Do the paramecia swim in straight lines 

• Does it spin on an axis as it moves 

• Does it have a definite anterior (front) end 

• Can Paramecium swim backwards (reverse its direction) 

• How does Paramecium deal with a barrier (such as edge of coverslip or strand of hair or 

cotton) Is its body flexible enough to bend or to squeeze through tight places



Amoebas 

Amebas may be naked or enclosed in a shell. 

Naked amebas, which include the genera Amoeba 

and Pelomyxa, live in both fresh water and 

seawater and in soil. They are bottom dwellers and 

must have a substratum on which to glide. 

Amoeba proteus is a freshwater species that is 

usually found in slow-moving or still-water 

ponds. They are often found on the underside 

of lily pads and other water plants. They feed 

on algae, bacteria, protozoa, rotifers, and other 

microscopic organisms. 

Prepare a wet mount of living Amoeba proteus and examine one under the 10X objective. 

Note the formation of the lobose pseudopodium (=Iobopodium) and the “protoplasmic 

streaming” leading to its extensions. Amoeba should be viewed in a thin depression slide 

with a coverslip or by placing short lengths of hair on each side of the coverslip, otherwise as 

the water evaporates the amebas will be crushed by the coverslip. 

• Regarding the endoplasm and ectoplasm, using the aid of your textbook or the 

internet, write a brief description and draw a diagram to show the formation of a 

pseudopodium by an amoeba. This involves some important molecular biology 

that utilizes some of the same proteins found in animal muscle tissue that 

allows for muscle contraction. Be sure to include the names of these proteins in 

your description. 

• Your instructor will show you a living amoeba and video of amoeba on the screen 

at the front of the room. 

Observe the amebas and answer these questions: 

• Can you observe the change from endoplasm to ectoplasm Is one darker 

• Does an amoeba have an anterior (front) and posterior (back) side 

• Does the amoeba move steadily in one direction 

• Does more than one pseudopodium ever start to form at once 

• Tap the coverslip gently with the tip of a pencil. Does the amoeba respond 

• Do pseudopodia ever extend vertically as well as laterally



Homework on Cell Division – due at the next lab meeting with this lab 

Using the internet, textbook, lab manual and discussions with your classmates, answer 

the following questions. 

1. List four differences between mitosis and meiosis. 

1. 

2. 

3. 

4. 

2. In what organ(s) of a multicellular animal does meiosis take place. 

3. Meiosis forms sperm and egg (ova) cells. Regarding sexual reproduction in animals, 

why is it important that sperm and egg cells are formed by meiosis and not mitosis. 

4. Briefly list what occurs in a cell during each of the following phases of mitosis. 

PROPHASE 

METAPHASE 

ANAPHASE 

TELOPHASE



LABORATORY NOTES: 

Mitosis

Cells, Cell Division & Protoctista (Protista) Laboratory - Biosciweb.net

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