Problem 70 - Objective Biology for NEET

Question

Which is the elongated tubular structure made of special protein on the surface of bacterial cell? (a) Flagella (b) Fimbriae (c) Pilli (d) All of these

Step-by-Step Solution

Answer

The elongated tubular structure on the surface of a bacterial cell made of special protein is Flagella.

Step 1: Recognise the given options

The given choices are Flagella, Fimbriae, Pilli, and all of these. These are all structures found on the surface of bacterial cells.

Step 2: Match the description with the options

The description is for an elongated, tubular structure made of special protein. Flagella matches this description since they are long, filamentous, thread-like structures protruding from the cell surface. Fimbriae and Pilus (pl. Pili), do match some aspects of the description but they are not considered as elongated tubular structure, instead they are often short and thin.

Step 3: Make a Decision

Since the description matches only one of the options, the answer would be Flagella. Although all given choices are structures found on bacterial cells made of protein, 'All of these' would be incorrect because not all options are described as elongated and tubular. A flagella is referred to as elongated and tubular structure.

Key Concepts

Flagella

The flagella are akin to the propellers of a boat, enabling bacteria to navigate through their aquatic environments. In essence, these are long, spiral filaments that stretch out from the cell body. Composed primarily of a special protein called flagellin, they are remarkable for their whip-like movement that propels the organism.

The flagella's movement is powered by a motor protein located in the cell wall and membrane, which spins the flagella much like a boat's propeller. This structure is not only crucial for mobility but also plays a role in bacterial attachment to surfaces and in some cases are important for the infectivity of pathogenic bacteria.

Biological Significance of Flagella

Bacteria use their flagella for a myriad of purposes, including but not limited to locomotion. They can move towards nutrients or away from danger in a process known as 'chemotaxis.' Understanding this structure thoroughly is essential as it can shed light on bacterial behavior and their survival mechanisms.

Bacterial Surface Proteins

Bacteria are enveloped in a diverse array of proteins that serve as the interface between the organism and its environment. These proteins perform a vast range of functions, including facilitating attachment to host tissues during infection, protecting against the host's immune system and even participating in nutrient acquisition.

The surface proteins, like those found in the flagella and pili or fimbriae, can be variable within bacterial populations, thus allowing bacteria to adapt to different niches or evade immune detection. A profound understanding of bacterial surface proteins is fundamental in developing antimicrobial agents and vaccines.

Importance in Medicine

For medical students and researchers, knowledge of these proteins is critical, as they often contain antigens that can be targeted by the immune system or by medications. Moreover, understanding how these proteins function can also inform the treatment and prevention strategies for bacterial infections.

Biology NEET exam

For students preparing for the National Eligibility cum Entrance Test (NEET), which is paramount for admissions into medical courses in India, mastering topics like bacterial structures becomes indispensable. The exam evaluates a student's knowledge across various biological concepts, and understanding the intricate details of entities such as flagella and bacterial surface proteins can fetch valuable points.

NEET aspirants are encouraged to delve deep into characteristics, functions, and roles of bacterial structures in both health and disease. Utilizing resources that provide clear explanations and solutions, like the ones presented here, can significantly enhance one's studying effectiveness.

Tips for NEET Preparation

Consistent practice with a focus on conceptual clarity, frequent self-assessment, and a robust study plan are key strategies for success on this exam. Addressing any gaps in knowledge promptly is crucial to build a strong foundation for the Biology NEET exam.