Question

How much is the size of typical bacteria? (a) \(1-2 \mu \mathrm{m}\) (b) \(10-20 \mu \mathrm{m}\) (c) \(10-20 \mathrm{~mm}\) (d) \(1-2 \mathrm{~mm}\)

Short answer

The typical size of bacteria is 1-2 µm, so the correct answer is (a).

Step-by-step solution

Discard the large sizes

Bacteria are generally microscopic and therefore too small to measure in millimeters (mm), as the eye cannot see such tiny organisms. This means we can safely discard options (c) and (d) which suggest that bacteria are 10-20mm and 1-2mm respectively, as they are too large.

Evaluate the remaining sizes

Now we have to pick between options (a) and (b), which suggest that bacteria measure 1-2µm and 10-20µm respectively. The average bacteria size is typically about 1 micron in diameter, which corresponds to one thousandth of a millimeter. This fact aligns with the values given in option (a).

Key concepts

Microscopic Organisms

Microscopic organisms, commonly known as microbes, include a vast array of organisms such as bacteria, viruses, protozoa, and fungi that are not visible to the naked eye. To visualize these minute life forms, specialized microscopes are essential. They range in size from a few micrometers, like most bacteria, to several millimeters, in the case of some parasites and fungi.

Understanding the size of these organisms is crucial in fields such as microbiology and medicine, where distinguishing between different types of cells and identifying pathogens is often based on their size and shape. For instance, bacteria sizes typically fall into the 1-2 µm (micrometers) range for diameter or length, making them one of the smallest cellular organisms, while eukaryotic cells, such as human cells, are usually much larger, generally around 10-100 µm. This significant size difference helps in differentiating bacteria from other cells under the microscope during diagnostic procedures.

Measurement in Microbiology

Measurement in microbiology is an essential skill for understanding the scale and impact of microbial organisms. Given that microbes are not within the detectable range of the human eye, which can typically see objects down to about 0.1mm, microbiologists use units like the micrometer (\(1 \text{µm} = 10^{-6} \text{m}\)) and the nanometer (\(1 \text{nm} = 10^{-9} \text{m}\)) to measure these tiny entities.

When measuring bacteria, the most common metric used is the micrometer. The size of a typical bacterial cell, as outlined in the given exercise, is around 1-2 µm. It's essential to note that this measurement is not only helpful for identification but also for understanding the bacterial cell's structural components and its ability to pass through filters or invade biological tissues. High-resolution tools such as electron microscopes can even measure structures within the bacteria in nanometers, providing insight into the intricate details of microbial life.

NEET Biology Preparation

NEET (National Eligibility cum Entrance Test) is a highly competitive exam for students aspiring to enter medical fields in India. Biology is a substantial part of the NEET syllabus, and it includes topics like microbiology and the study of bacteria. A strong grasp of the size and scale of bacteria and other microorganisms is crucial for NEET biology preparation.

For those preparing for NEET, a thorough understanding of how bacteria are measured is fundamental. Remembering that most bacteria range from 1-2 µm in size could aid in solving multiple-choice questions efficiently. It's vital to conceptualize this size difference as it relates to infection, treatment, and prevention strategies in medical science – concepts that are all within the NEET biology curriculum. Students can practice with exercises similar to the textbook solution provided to familiarize themselves with the types of questions that may appear on the exam, and thereby enhance their readiness for tackling questions about microbial measurement in biology.