Experiment 3 Phagocytosis in Tetrahymena sp. Group #3 Cua, Patricia Nicole De Castro, Armand Joseph Dela Cruz, Bernadette Diomampo, Hazelie
INTRODUCTION Endocytosis The process by which cells absorb molecules (such as proteins) by engulfing them. Types of Endocytosis : Phagocytosis and Pinocytosis.
Pinocytosis The process by which a cell takes in extracellular fluid by the invagination of the cell membrane. A pocket then forms and pinches off to form a vesicle, which subsequently ruptures, releasing its contents into the cytosol. It is nonspecific in the substances that it transports.
Phagocytosis The cellular process of engulfing solid particles by the cell membrane to form an internal phagosome by phagocytes and protists. Engulfs whole particles, which are later broken down by enzymes and absorbed into the cells. Involved in the acquisition of nutrients for some cells, and, in the immune system, it is a major mechanism used to remove pathogens and cell debris.
Tetrahymena sp. A free-living unicellular eukaryote. A ciliate considered to be the most highly developed protozoan, because it possesses specialized organelles that perform each of the cell functions. Commonly found in freshwater and even hot springs. Possess rapid adaptation machineries to regulate biological processes including cell division, conjugation and cell death against intracellular and extracellular stresses.
Why use Tetrahymena sp. in observing Phagocytosis? They are easily obtained, cultured and manipulated. Phagocytosis can be observed under the microscope. Food vacuoles can be readily observed.
Objectives To observe the phagocytosis process of Tetrahymena sp. The experiment aims to observe the phagocytosis of Chlorella sp. and the scrapings of graphite by Tetrahymena sp.
Materials Tetrahymena cell suspension Chlorella sp. culture Microscope Slides and cover slips Micropippetors and tips Graphite shavings from pencil Razor blade/cuttter
Methods On a slide, a drop of Tetrahymena sp. was put. Then, a cover slip was put on the slide. On the microscope, the slide with the Tetrahymena sp. was observed. A drop of Chlorella sp. was added at the side of the cover slip to allow the alga to move beneath the cover slip. After doing this, the slide was viewed on the microscope and the phagocytosis of Chlorella sp. by Tetrahymena sp. was observed. In another slide, a drop of Tetrahymena sp. was put. With the use of a razor blade, the graphite from the lead of the pencil was scrapes and was allowed to fall on the drop of the Tetrahymena sp. culture. A cover slip was placed above and the slide was observed under the microscope.
Result and Discussion In unstained Tetrahymena sp., the most conspicuous structures are the food vacuoles. When a hungry Tetrahymena sp. encounters food, they use their cilia to sweep into the cell’s buccal cavity. Food vacuole number and formation depends on how much food eaten by the Tetrahymena.
Pathway of Endocytosis Movement of food to the buccal cavity is accomplished by cilia. Food Vacuole Formation Pinocytic vacuoles enters the food vacuole, takes the excess water and then leaves the food vacuole. Lysosomes transport enzymes to the food vacuoles so food particles undergo digestion. Once the nutrients has been absorbed, waste exits the vacuole.
Table of Results
Tetrahymena and Chlorella It is a genus of single-celled green algae, belonging to the phylum Chlorophyta. It is spherical in shape, about 2 to 10 μm in diameter, and is without flagella. It is a complete protein source for Tetrahymena sp.
Tetrahymena sp. and Graphite An allotrope of carbon It is used in pencils, where it is commonly called lead. Food formation was decreased in number compared with chlorella. It inhibits ciliary action which also inhibits feeding and the rate of food vacuole formation.
Conclusion Based on the experiment conducted the average food vacuole formed in Tetrahymena sp. is higher when fed in Chlorella sp. than in graphite. Because Chlorella sp. is complete protein source and also packed with calories, fat, and vitamins.