Tetrahymena Experiment

Amazing Essays
Tetrahymena contractions with different solutions

Purpose: How fast will the Tetrahymena contractile vacuole contract in different solutions?

Introduction: In this experiment, the organism that is used are the Tetrahymena. The Tetrahymena has a contractile vacuole that protects them from absorbing too much water, causing cytolysis, in which a cell swells up and could result in explosion of the cell. The contractile vacuole expands when water enters it and contracts to release water to maintain equilibrium and to regulate the concentration of water within the cell. The Tetrahymena is placed in different solutions with different concentrations of solute (salt) to see the rate of how fast and how slow the contractile vacuole will move in these
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Materials: Microscope, glass slides, coverslips, lens paper, Tetrahymena culture, 20 µL micropipette, Detain©, timer, calculator, Neff (growth medium), distilled water, 50 mM salt water, 500 mM salt water

Procedure: Follow the given procedure.

Variables: The independent variable are the different solutions, and the dependent variable is the rate of vacuole contractions. The control variables are the time, the amount of each solution, and the measurements of the solutions.

Safety:
Do not touch the tip of the micropipettes
Do not spill the Tetrahymena
Do not touch the Tetrahymena
Keep the Tetrahymena culture closed when is it not in use
Be careful to not break the glass slides
Wash hands after experiment

Results and Analysis:

NEFF
Distilled Water
50 mM NaCI
500mM
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The rate of how fast and slow contractile vacuole contracts in the Tetrahymena depends on what osmosis pressure it is in. The tetrahymena fills up with water and then contracts right before it bursts. Osmosis occurred in this experiment which affected the rate at which contractile vacuole contracts in the Tetrahymena. In a hypertonic solution, such as 500mM NaCI, water is already leaving the cell due to osmosis, a type of diffusion of water going from a high concentration to a low concentration or concentration gradient. Since the water is already leaving the cell, the contractile vacuole in the Tetrahymena does not need to work as hard to get water out of it. Therefore, when the Tetrahymena is placed in a higher concentration of a solute solution, its contractile vacuole will contract at a slower rate. In a hypotonic solution, such as distilled water, water is entering the cell due to osmosis. Since more water is entering the cell, the Tetrahymena needs to work harder to get water out of its cell to keep the water level constant, so they will contract faster. Therefore, when the Tetrahymena is placed in a solution with a lower concentration of solute, its contractile vacuole will contract faster. With the Tetrahymena is contracting faster, it shows that the distilled water has an effect on the rate of contracts. The contractile vacuole is very important for osmoregulation in Tetrahymena and

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