Which statement correctly describes yeasts?

Microbiology is the branch of science that focuses on the study of microorganisms, which include bacteria, viruses, fungi, protozoa, and microscopic algae. These organisms are typically too small to be seen with the naked eye and require microscopes or other magnification tools for observation and analysis. Microbiology examines their structure, function, genetics, metabolism, and interactions with humans, animals, plants, and the environment. It also explores their roles in disease, industry, and ecology. Understanding microorganisms is essential for developing vaccines, antibiotics, and infection control measures, making microbiology a critical field in medicine and biology.

Gram-negative bacteria have a distinctive cell envelope composed of three key layers. The innermost layer is the cytoplasmic (inner) membrane, which regulates transport and maintains cellular integrity. Outside this is the periplasmic space, a gel-like area containing enzymes and proteins involved in nutrient processing and defense. The outermost layer is the outer membrane, which contains lipopolysaccharides (LPS) that contribute to the structural barrier, immune evasion, and pathogenicity. This multilayered structure differentiates gram-negative bacteria from gram-positive bacteria, which lack an outer membrane and have a much thicker peptidoglycan layer.