Teacher and Student Guides

The phagocytosis lab uses Tetrahymena to investigate the processes of ingestion, phagocytosis, and vacuole formation in cells, and the effects of various factors on these physiological processes. Students monitor vacuole development during feeding using digital cameras to record the data, learning microscopy and data collection and analysis as an integral part of the exercise. Students can look at feeding preferences, including live vs. dead food, big vs. small food, organic vs. inorganic material. The lab can be combined with a consideration of mutational effects by incorporating the use of mutants unable to eat for various reasons, e.g., mutants that fail to form mouths at certain temperatures, or mutants with swimming defects that are unable to efficiently filter food from the water. The lab can also be used to address other issues like pollution and toxicology, and can be combined with labs addressing the effects of cigarette smoke and alcohol.

Normal Tetrahymena feeding on ink particles. Each black spot is a separate food vacuole.
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Relevant Concepts

Cellular Energetics; Chemistry of Life; Energy Transfer; Structural similarity between Single cell and Multicellular Organisms; Relationship of Structure to Function.

Next Generation Science Standards Relationships

High School:

HS-LS1-7 Use a model to illustrate that cellular respiration is a chemical process whereby the bonds of food molecules and oxygen molecules are broken and the bonds in new compounds are formed resulting in a net transfer of energy.

HS-LS2-3 Construct and revise an explanation based on evidence for the cycling of matter and flow of energy in aerobic and anaerobic conditions.

Middle School:

MS-LS1-1 Conduct an investigation to provide evidence that living things are made of cells, either one cell or many different numbers and types of cells.

MS-LS1-2 Develop and use a model to describe the function of a cell as a whole and ways parts of cells contribute to the function.

MS-LS1-7 Develop a model to describe how food is rearranged through chemical reactions forming new molecules that support growth and/or release energy as this matter moves through an organism.

MS-LS2-3 Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.

Elementary School:

1-LS1-1 Use materials to design a solution to a human problem by mimicking how plants and/or animals use their external parts to help them survive, grow, and meet their needs.

4-LS1-1 Construct an argument that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction.

4-LS1-2 Use a model to describe that animals’ receive different types of information through their senses, process the information in their brain, and respond to the information in different ways.

5-LS2-1 Develop a model to describe the movement of matter among plants, animals, decomposers, and the environment. 

3-LS4-2 Use evidence to construct an explanation for how the variations in characteristics among individuals of the same species may provide advantages in surviving, finding mates, and reproducing. 


●Hoffmann EK, Rasmussen L, Zeuthen E. 1974. Cytochalasin B: aspects of phagocytosis in nutrient uptake in Tetrahymena. J.Cell.Sci. 15 (2):403-406.

●Jacobs ME, DeSouza LV, Samaranayake H, Pearlman RE, Siu KW, Klobutcher LA. 2006. The Tetrahymena thermophila phagosome proteome. 5 (12):1990-2000.

●Orias E and Rasmussen L. 1979. Dual capacity for nutrient uptake in Tetrahymena. V. Utilization of amino acids and proteins. J.Cell.Sci. 36:343-353.

●Pinheiro MD, Power ME, Butler BJ, Dayeh VR, Slawson R, Lee LE, Lynn DH, Bols NC. 2007. Use of Tetrahymena thermophila to study the role of protozoa in inactivation of viruses in water. Appl.Environ.Microbiol. 73 (2):643-649.

●Rasmussen L and Orias E. 1975. Tetrahymena: growth without phagocytosis. Science 190 (4213):464-465.

●Silberstein GB, Orias E, Pollock NA. 1975. Mutant with heat-sensitive capacity for phagocytosis in tetrahymena: isolation and genetic characterization. Genet.Res. 26 (1):11-19.

●Skriver L and Nilsson JR. 1978. The relationship between energy-dependent phagocytosis and the rate of oxygen consumption in Tetrahymena. J.Gen.Microbiol. 109 (2):359-366.

●Suhr-Jessen PB and Orias E. 1979. Mutants of TETRAHYMENA THERMOPHILA with Temperature-Sensitive Food Vacuole Formation. I. Isolation and Genetic Characterization. Genetics 92 (4):1061-1077.

●Williams NE, Tsao CC, Bowen J, Hehman GL, Williams RJ, Frankel J. 2006. The actin gene ACT1 is required for phagocytosis, motility, and cell separation of Tetrahymena thermophila. 5 (3):555-567.

See our glossary for the terms used in the modules.