Why are yeast cells frequently used as host organisms for gene cloning and recombinant DNA experiments?

Introduction / Context:
In genetic engineering and biotechnology, researchers must choose suitable host cells in which to clone and express foreign genes. Yeast, especially Saccharomyces cerevisiae, is a common eukaryotic host. This question asks why yeast cells are frequently used, testing your understanding of their unique advantages in cloning experiments.

Given Data / Assumptions:

• Several statements describe properties of yeast cells and their use in cloning.

• Only one option correctly summarises why yeast is a popular host.

• We assume familiarity with the difference between prokaryotic and eukaryotic cells.

• Yeast combines features of simple culture and eukaryotic cell biology.

Concept / Approach:
Yeast cells are eukaryotic but unicellular, making them easier to grow in large numbers, similar to bacteria. They possess membrane bound organelles and can perform post translational modifications similar to higher eukaryotes, which is important for proper folding and function of many proteins. Yeast can also maintain plasmids or artificial chromosomes. These qualities make yeast an excellent compromise host when a eukaryotic system is needed but higher multicellular organisms would be too complex or slow to handle.

Step-by-Step Solution:
Step 1: Recognize that as eukaryotes, yeast cells have a nucleus, endoplasmic reticulum, Golgi apparatus, and other organelles, allowing them to process proteins more like animal or plant cells do. Step 2: Understand that yeast grows quickly in simple media, allowing large scale cultures similar to bacterial cultures. Step 3: Yeast can maintain plasmid like elements and artificial chromosomes, which can carry cloned genes. Step 4: Because yeast is eukaryotic, it can carry out post translational modifications that bacteria often cannot, making it useful for producing functional eukaryotic proteins. Step 5: Evaluate the options: the correct statement should mention their eukaryotic nature and ease of use. Step 6: The statement that they are simple eukaryotic cells that combine ease of culture with eukaryotic features captures this idea accurately.

Verification / Alternative check:
Biotechnology textbooks often describe yeast as a model eukaryotic organism for molecular biology. They highlight its ability to replicate plasmids, its rapid growth, and its eukaryotic cell machinery. Yeast is used in producing vaccines and recombinant proteins. These references agree that yeast is chosen because it combines eukaryotic features with practical advantages such as ease of culture, backing up the correct option.

Why Other Options Are Wrong:

Because they do not have any plasmids: This is incorrect; yeast can carry plasmids or similar elements used in cloning.

Because only yeast cells allow any gene to be cloned: Many genes can be cloned in bacterial, yeast, or mammalian cells; yeast is not the only option.

Because they easily form colonies but cannot express eukaryotic genes: Yeast can express eukaryotic genes and is often chosen for that reason.

Because they are prokaryotic cells similar to bacteria: Yeast are eukaryotic, not prokaryotic; this statement is factually wrong.

Common Pitfalls:
Some students mistakenly classify yeast as bacteria because both are unicellular and grow quickly. Others focus only on colony formation and overlook the importance of eukaryotic cellular machinery. To avoid these errors, remember that yeast belongs to the fungi kingdom and has a nucleus and other organelles, which makes it valuable for expressing complex eukaryotic proteins in a reasonably simple lab system.

Final Answer:
Yeast cells are frequently used as cloning hosts Because they are simple eukaryotic cells that combine ease of culture with eukaryotic features.