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 17th 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.
Cells, Cell Division & Protoctista (Protista) Laboratory
2.2
Lab #2 - Biological Sciences 102 – Animal Biology

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
A Eukaryotic Cell
may be seen in some protozoa.
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 only in 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
Cells, Cell Division & Protoctista (Protista) Laboratory
2.3
Lab #2 - Biological Sciences 102 – Animal Biology
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.
Cells, Cell Division & Protoctista (Protista) Laboratory
2.4
Lab #2 - Biological Sciences 102 – Animal Biology
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 bacteria are not
compartmentalized in different types of organelles. 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 colonial organisms with some
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.
Cells, Cell Division & Protoctista (Protista) Laboratory
2.5
Lab #2 - Biological Sciences 102 – Animal Biology
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, some form colonies), may
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
not
have
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”).
Cells, Cell Division & Protoctista (Protista) Laboratory
2.6
Lab #2 - Biological Sciences 102 – Animal Biology

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 and phylogenetic relationships.
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. About 7500 known different species. Examples:
Euglena, Trypanosoma, Diplonema
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. About 7000 known species. Examples: Volvox, Chlorella, Spirogyra, Ulva
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. About 2000 known species. Examples: Noctiluca, Ceratium, Gonyaulax
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 gameteproducing 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.) About 9000 different known
species. Examples: Paramecium, Colpoda, Tetrahymena, Stentor, Blepharisma, Epidinium, Vorticella,
Euplotes, Didinium
LAB PROCEDURE
NAME
LAB SCORE
Cells, Cell Division & Protoctista (Protista) Laboratory
2.7
Lab #2 - Biological Sciences 102 – Animal Biology
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….
Cells, Cell Division & Protoctista (Protista) Laboratory
2.8
Lab #2 - Biological Sciences 102 – Animal Biology
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?
Cells, Cell Division & Protoctista (Protista) Laboratory
2.9
Lab #2 - Biological Sciences 102 – Animal Biology
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?
Cells, Cell Division & Protoctista (Protista) Laboratory
2.10
Lab #2 - Biological Sciences 102 – Animal Biology
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 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.
You do not need to use Proto-Slo/Detain on the ameba slide preparation. Prepare a wet mount
of living Amoeba proteus and examine one under the 10X objective. Note the formation of the
lobose pseudopodium (=lobopodium) 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?

Do pseudopodia ever extend vertically as well as laterally?
Homework on Cell Division – due at the next lab meeting with this lab
Cells, Cell Division & Protoctista (Protista) Laboratory
2.11
Lab #2 - Biological Sciences 102 – Animal Biology
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
Cells, Cell Division & Protoctista (Protista) Laboratory
Lab #2 - Biological Sciences 102 – Animal Biology
METAPHASE
ANAPHASE
TELOPHASE
LABORATORY NOTES:
Mitosis
2.12