Вопрос
Paper 6 1. Ziehl-Neelsen method, its principle, stages. Which properties ensure acid fastness of microorganism? 2. The main structures of prokaryotes. 3 characteristics of different pathogenic spirochetes . Medical significance of spirochetes. Morphology
Решения
4.2
(249 Голоса)
Олег
профессионал · Репетитор 6 лет
Ответ
1. The Ziehl-Neelsen method is a staining technique used to identify acid-fast bacteria. The principle of this method is to differentiate acid-fast bacteria from non-acid-fast bacteria based on their ability to retain the primary stain (carbol fuchsin) after being treated with an acid-alcohol solution. The stages of the Ziehl-Neelsen method are as follows: - Primary staining: The bacterial smear is stained with carbol fuchsin, a red dye. - Decolorization: The slide is treated with an acid-alcohol solution, which removes the primary stain from non-acid-fast bacteria. - Counterstaining: The slide is then stained with a secondary stain, such as methylene blue, which stains the non-acid-fast bacteria.The properties that ensure the acid-fastness of microorganisms are the high lipid content in their cell walls, particularly mycolic acids. These long-chain fatty acids create a waxy, hydrophobic barrier that prevents the primary stain from being easily removed during the decolorization step.2. Prokaryotes are single-celled organisms that lack a true nucleus and membrane-bound organelles. The main structures of prokaryotes include: - Cell wall: Provides structural support and protection. - Plasma membrane: Encloses the cell and regulates the movement of substances in and out. - Cytoplasm: The fluid medium within the cell where metabolic reactions occur. - Nucleoid: The region where the genetic material (DNA) is located. - Ribosomes: Sites of protein synthesis. - Flagella: Long, whip-like structures used for movement. - Pili: Hair-like structures used for attachment and conjugation.3. Spirochetes are a group of spiral-shaped bacteria. They have unique characteristics that distinguish them from other bacteria. Some of the characteristics of different pathogenic spirochetes include: - Treponema pallidum: The causative agent of syphilis, a sexually transmitted infection. - Borrelia burgdorferi: The causative agent of Lyme disease, transmitted through tick bites. - Leptospira interrogans: The causative agent of leptospirosis, transmitted through contaminated water or soil.The medical significance of spirochetes lies in their role in causing various diseases in humans. These diseases can range from sexually transmitted infections to vector-borne diseases and zoonotic diseases. Proper diagnosis and treatment of these diseases are essential for preventing complications and ensuring public health.