BIOL 2730 — Lab 2 Exercise 5: Microbiology of Pond Water

Comprehensive practice flashcards covering Exercise 5: Microbiology of Pond Water — Protozoa, Algae, and Cyanobacteria, including procedural questions, core concepts, laboratory report topics, and figure identifications.

What is the purpose of Exercise 5?

To study the diverse organisms that can occur in pond water, including protozoa, algae, and cyanobacteria, and identify/categorize them.

What type of specimen is examined in Exercise 5?

Pond water prepared as wet mounts on microscope slides.

Where in a pond water bottle should the pipette be inserted to obtain the maximum number of organisms?

Into the bottom of the pond water bottle; fewer organisms occur at mid-depth.

What should be used to remove filamentous algae?

Forceps.

Which objective should you focus with first when examining pond water?

The low-power objective.

What should you reduce to provide better contrast when examining pond water?

The illumination, using the iris diaphragm.

What should you do when you find an organism of interest?

Switch to the high-dry objective and adjust the illumination appropriately.

Where should you look for help identifying pond-water organisms?

Figures 5.2–5.7 and their accompanying text.

What should you do with your pond-water observations?

Record them on the Laboratory Report.

What are protozoa described as in the manual?

Protists, historically meaning “first animals.”

What major cellular characteristic distinguishes protozoa/algae from cyanobacteria in this exercise?

Protozoa and algae are eukaryotic; cyanobacteria are prokaryotic.

Why are modern genetic analyses important for classifying these organisms?

Morphological characteristics alone cannot reliably determine evolutionary relationships; molecular genetics helps establish taxonomic and evolutionary relationships.

What are the three broad organism categories studied in Exercise 5?

Protozoa, algae, and cyanobacteria.

What domains contain the organisms discussed in Exercise 5?

Protozoa and algae are eukaryotic and occur in Eukarya; cyanobacteria are prokaryotic and occur in Bacteria.

What is one similarity between algae and plants?

Both have photosynthetic pigments and can carry out photosynthesis.

What is one difference between algae and plants?

Algae are generally simpler/smaller and less complex in structure than land plants.

What is a pseudopodium?

A temporary cytoplasmic extension used by amoeboid organisms for movement and for capturing/surrounding food.

What are the three mechanisms of motility displayed by protozoa?

Flagella, cilia, and pseudopodia.

How do cilia function in ciliates?

They beat in a coordinated fashion to move the cell and also help direct food toward the cell mouth.

What are the four major protozoan groups listed in the classification table?

Diplomonads and parabasalids; euglenozoans; alveolates; and amoebozoans.

What are diplomonads characterized by?

Two nuclei and organelles called mitosomes that lack electron transport and Krebs cycle components.

What disease is caused by Giardia?

Giardiasis; Giardia is a diplomonad associated with contaminated water from lakes and streams.

What are parabasalids characterized by?

A parabasal body associated with the Golgi apparatus and a lack of mitochondria; they obtain energy anaerobically.

What disease is caused by Trichomonas vaginalis?

Trichomoniasis, a sexually transmitted disease.

What are euglenozoans?

A diverse group of protists including kinetoplastids and euglenids; they have a unique crystalline rod associated with their flagella.

What are kinetoplastids characterized by?

A single large mitochondrion containing a kinetoplast, a large mass of DNA.

Name two human diseases associated with kinetoplastids in the manual.

African sleeping sickness caused by Trypanosoma brucei and leishmaniasis caused by Leishmania species.

What are alveolates characterized by?

They have sacs called alveoli associated with the cytoplasmic membrane.

What are the three alveolate groups discussed?

Ciliates, dinoflagellates, and apicomplexans.

What are ciliates characterized by?

Two kinds of nuclei—micronuclei and macronuclei—and cilia used for motility.

What is the function of the micronucleus in ciliates?

It contains genes involved in sexual reproduction.

What is the function of the macronucleus in ciliates?

It contains genes encoding functions associated with cellular activities.

What is the 9 + 2 arrangement mentioned for cilia?

Cilia are short hairlike structures with the same microtubule arrangement as flagella: a $9 + 2$ arrangement of microtubules.

What are dinoflagellates characterized by?

Two flagella of different lengths; the flagella can cause the cell to whirl or spin.

What is a 'red tide'?

A bloom of dinoflagellates associated with red coloration caused by xanthophyll pigments; some blooms can poison humans and kill fish.

What toxin does Gonyaulax produce according to the manual?

Saxitoxin, a neurotoxin associated with dizziness, numbness of lips, and difficulty breathing.

What are apicomplexans?

Obligate parasites of animals and humans that contain apicoplasts and lack photosynthetic pigments.

Name three diseases caused by apicomplexans mentioned in the manual.

Malaria (Plasmodium), toxoplasmosis (Toxoplasma gondii), and coccidiosis (Eimeria).

What structures do apicomplexans produce that facilitate transmission?

Resistant stages called sporozoites.

How do gymnamoebas move and feed?

They use pseudopodia for amoeboid movement and for engulfing food by phagocytosis.

What is Entamoeba histolytica?

A human intestinal pathogen that causes amoebic dysentery.

How is Entamoeba histolytica transmitted?

By fecal contamination of water and food.

What organisms are included in the stramenopiles discussed in this exercise?

Oomycetes (water molds), diatoms, golden algae, and multicellular phaeophytes/seaweeds.

What is distinctive about unicellular stramenopiles?

They have flagella with short, hairlike extensions.

What is a diatom frustule?

The external cell wall of a diatom, composed of silica.

What are the two halves of a diatom frustule called?

The epitheca and hypotheca.

How do the two halves of a diatom frustule fit together?

The epitheca fits over the hypotheca, like a box with a lid.

What are areolae in diatoms?

Pores in the frustule that function as passageways for gases and nutrients.

What happens to the diatom frustule after the organism dies?

It remains and can accumulate as diatomaceous earth.

What is a common use of diatomaceous earth mentioned in the manual?

As a polishing abrasive, including in some toothpaste applications.

What gives many golden algae their golden/brown color?

The carotenoid fucoxanthin.

How can some golden algae obtain food without photosynthesis?

Some are chemoorganotrophs and obtain food from transported organic compounds across the cytoplasmic membrane.

What are algae?

A diverse group of organisms that obtain carbon through oxygenic photosynthesis; water is split and oxygen is produced.

What photosynthetic pigments do algae possess according to the manual?

Pigments such as chlorophyll and carotenoids that harvest light energy.

How can algae be organized structurally?

Microscopic algae can occur as unicellular forms, filaments, or colonies.

How can many unicellular algae move?

By means of flagella.

How can many unicellular algae reproduce?

By asexual and sexual mechanisms.

What are red and green algae?

Red algae belong to the rhodophytes and green algae belong to the chlorophytes.

What pigment is responsible for the red coloration of red algae in the manual?

Phycoerythrin, a phycobiliprotein.

What pigments do unicellular green algae contain?

Chlorophyll a and b.

What do unicellular green algae store as an energy reserve?

Starch granules.

What is Chlamydomonas?

An example of a unicellular green alga shown in Figure 5.4.

What are the desmids?

A unique group of green algae whose cells consist of two halves (semicells) separated by a constriction called the isthmus.

What is a pseudo-filament?

A filament-like form produced by some desmids such as Desmidium, as described in the manual.

What were cyanobacteria formerly called?

Blue-green algae.

Why are cyanobacteria not algae?

They are prokaryotic bacteria, not eukaryotic algae.

When did cyanobacteria first appear on Earth according to the manual?

About $2.7$ billion years ago.

Why were cyanobacteria important to the evolution of life on Earth?

They carried out oxygenic photosynthesis and released oxygen into the atmosphere, helping shift Earth toward an oxygen-rich environment.

How did cyanobacteria contribute to the development of aerobic life?

Accumulation of oxygen allowed aerobic bacteria and eukaryotic organisms requiring oxygen for respiration to develop.

What is one hypothesis about cyanobacteria and chloroplasts?

Evidence suggests cyanobacteria may have invaded a primitive cell and established an endosymbiotic relationship, giving rise to chloroplasts in algae and plants.

Where can cyanobacteria occur?

In many environments, including aquatic habitats such as oceans, lakes, and streams, from the tropics to the poles.

What additional light-harvesting pigments are associated with cyanobacteria?

Phycobiliproteins.

Identify Protozoa Figure 5.2, illustration 1.

Heteromita

Identify Protozoa Figure 5.2, illustration 2.

Cercomonas

Identify Protozoa Figure 5.2, illustration 3.

Codonella

Identify Protozoa Figure 5.2, illustration 4.

Prorodonopsis

Identify Protozoa Figure 5.2, illustration 5.

Trichomonas

Identify Protozoa Figure 5.2, illustration 6.

Amoeba

Identify Protozoa Figure 5.2, illustration 7.

Mayorella

Identify Protozoa Figure 5.2, illustration 8.

Dileptus

Identify Protozoa Figure 5.2, illustration 9.

Paramecium

Identify Protozoa Figure 5.2, illustration 10.

Lacrymaria

Identify Protozoa Figure 5.2, illustration 11.

Loxodes

Identify Protozoa Figure 5.2, illustration 12.

Loxodes

Identify Protozoa Figure 5.2, illustration 13.

Blepharisma

Identify Protozoa Figure 5.2, illustration 14.

Coleps

Identify Protozoa Figure 5.2, illustration 15.

Codosiga

Identify Protozoa Figure 5.2, illustration 16.

Stentor

Identify Protozoa Figure 5.2, illustration 17.

Vorticella

Identify Protozoa Figure 5.2, illustration 18.

Carchesium

Identify Protozoa Figure 5.2, illustration 19.

Zoothamnium

Identify Protozoa Figure 5.2, illustration 20.

Stylonychia

Identify Protozoa Figure 5.2, illustration 21.

Onychodromus

Identify Protozoa Figure 5.2, illustration 22.

Histriculidium

Identify Protozoa Figure 5.2, illustration 23.

Euplotes

Identify Protozoa Figure 5.2, illustration 24.

Didinium

Identify Figure 5.3, illustration 1.

Euglena

Identify Figure 5.3, illustration 2.

Euglena

Identify Figure 5.3, illustration 3.

Phacus

Identify Figure 5.3, illustration 4.

Phacus