Problem: What sorts of properties and behaviors are
associated with the euglena?
Objectives: Upon the completion of this lab activity the student will be able to:
1. make a wet mount of the euglena and get these organisms
in focus using the compound microscope.
2. describe the shape of this organism and its means of locomotion.
3. describe and discuss the structure and function of several organelles
in the euglena.
Materials: compound microscope, slides with a cover slips,
methyl cellulose (optional),
separate cultures containing euglena
Procedure:
1. Using a medicine dropper or a pipette, place a drop of water
containing the
euglena culture on to a clean microscope slide.
2. Most Protists such as the euglena are capable of very rapid motion.
If it
is available, use a drop of methyl cellulose to
slow the paramecia.
.
3. Add a cover slip to this drop of euglena-containing water. Find a
euglena
and attempt to get one in focus. You may not want
to look for these using
intense lighting so it may be helpful to partially
close your diaphragm.
4. Make a drawing of your euglena in conclusion question # 1 exactly as
it appears under the
microscope.
Conclusion Questions: Please answer the questions which follow.
Use complete sentences to respond where it is appropriate.
1. Draw your euglena as you actually saw it under the light
microscope (either low or high power).
Link to an actual
euglena image
2. Draw and label an idealized diagram of a euglena.
Download euglena
image
3. How does the euglena move? Explain fully!!
What are the structures called that
the euglena uses for locomotion?
4. How does the streamlined shape of the euglena appear
to aid its motion and function?
5. List the function of the following structures in the
euglena:
(a.) flagellum
(b.) eyespot
6. What is meant by the terms autotroph and heterotroph?
7. The euglena acts as an autotroph in the daylight and acts
like a heterotroph in
the darkness. Explain the
difference between these two different methods of
nutrition in the euglena.
8. Explain how the euglena undergoes asexual
reproduction and what this
process is specifically
called.
9. Name 1 animal-like characteristic of the euglena AND 1 plant-like
characteristic of the euglena.
10. The euglena is classified as a Protist. What
characteristics are shared by all Protists?
11. Relate the function of the following Protist structures to human
organs with
similar functions:
(a.) nucleus
(b.) contractile vacuole
(c.) food vacuole
Base your answers to questions 12 and 13 on
the information below and on your
knowledge of biology.
A biology student was given three unlabeled jars of pond water
from the same source, each containing a different type of mobile unicellular
organism: euglena, ameba, and paramecium. The only information
the student has is that the ameba and paramecium are both heterotrophs
and the euglena can be either heterotrophic or autotrophic, depending on its
environment.
12. State one
way the euglena’s two methods of
nutrition provide a survival advantage
the other unicellular organisms do not
have.
Circle the number of the choice which is the correct answer to the following
question.
13. Which procedure and resulting observation would help
identify the jar that contains the euglena?
(1) Expose only one side of each jar to light. After 24 hours, only in the jar
containing
euglena will most of organisms be seen on the darker side of the jar.
(2) Expose all sides of each jar to light. After 48 hours, the jar with the
highest dissolved
carbon dioxide content will contain the euglena.
(3) Over a period of one week, determine the method of reproduction used by each
type of organism. If mitotic cell division is observed, the jar will contain
euglena.
(4) Prepare a wet-mount slide of specimens from each jar and observe each slide
with
a compound light microscope. Only the euglena will have chloroplasts.
