Cryopreservation: Preserving Germplasm at Very Low Temperatures

Introduction:
Cryopreservation is a technique used to preserve germplasm, which includes plant seeds, animal embryos, sperm, and eggs, at extremely low temperatures. By cooling these biological materials to temperatures well below freezing, their metabolic processes are effectively halted, allowing them to be stored for extended periods without damage or degradation. The preservation of germplasm via cryopreservation is crucial for various fields such as agriculture, human fertility, and conservation biology.

The Ideal Temperature for Cryopreservation:
The ideal temperature for cryopreservation depends on the type of germplasm being preserved. However, for most applications, the commonly used temperature is -196 degrees Celsius. This temperature is achieved using liquid nitrogen, which has a boiling point of -196 degrees Celsius. At this extremely low temperature, biological activities essentially cease, preventing the deterioration of the stored germplasm.

Options:
(a) -121°C
(b) -196°C
(c) 0°C
(d) -101°C

Correct Answer:
The correct answer is (b) -196°C.

Explanation:
Cryopreservation requires temperatures lower than the freezing point of water (-0°C) to prevent the formation of ice crystals. Ice crystals can damage cells and tissues, leading to cell death and loss of viability. Liquid nitrogen, with its temperature of -196°C, provides the necessary conditions for successful cryopreservation.

Benefits of Cryopreservation:
1. Long-term storage: Germplasm can be stored for extended periods, allowing genetic resources to be preserved for future use.
2. Genetic diversity conservation: Cryopreservation enables the storage of a wide range of genetic materials, maintaining genetic diversity and preventing the loss of rare or endangered species.
3. Disease control: Cryopreservation can be used to preserve germplasm from animals or plants that are susceptible to diseases, mitigating the risk of extinction or loss of valuable genetic traits.
4. Assisted reproductive technologies: Cryopreservation of sperm, eggs, and embryos allows for artificial insemination, in vitro fertilization, and other assisted reproductive techniques, aiding in human fertility treatments and livestock breeding programs.

In conclusion, cryopreservation involves the preservation of germplasm at extremely low temperatures, typically -196°C using liquid nitrogen. This technique has numerous applications in agriculture, conservation biology, and human fertility. By storing genetic resources, cryopreservation ensures the preservation of biodiversity and facilitates advancements in various fields.