Final answer:
The question deals with the use of glycerin and glycol percentages in the freezing of semen and/or cells to ensure they are adequately protected from freezing damage. Glycerin at 3-10% concentration is commonly used in sperm cryopreservation, with the mixing temperature being critically controlled. Ethylene glycol is also used as a cryoprotective agent in various applications, like antifreeze solutions.
Step-by-step explanation:
The subject of the question is related to the process of freezing semen and how certain agents like glycerin and glycol are used to protect it from freezing. In semen freezing, a concentration of 3-10% glycerol is used, with an indication that spermatozoa survival is better when the glycerol is mixed with semen at 5°C. This is essential to prevent damage to the spermatozoa, which can occur if glycerol is added at higher temperatures. The method of adding glycerol to the semen in fractions at controlled temperatures ensures an optimal freezing process.
When freezing with glycerol, cells in Eagle's medium containing 5% glycerol undergo a slow temperature decrease until they reach -25°C before being stored in liquid nitrogen at -196°C. This gradual decline in temperature is critical to the preservation of the cells.
Additionally, ethylene glycol is mentioned as an example of a cryoprotective agent used in commercial antifreezes. A water solution containing ethylene glycol can lower the freezing point of the solution, thereby protecting vehicle radiators from the effects of freezing temperatures.