Problem 73 - Objective Biology for NEET

Question

What is the size of ribosomes? (a) \(10-20 \mu \mathrm{m}\) (b) \(15-20 \mathrm{~nm}\) (c) \(10-20 \mathrm{~nm}\) (d) \(15-20 \mathrm{~cm}\)

Step-by-Step Solution

Answer

The size of ribosomes is usually between \(10-20 \mathrm{~nm}\), thus the correct option is C.

Step 1 Recall the size of ribosomes

Recall the approximate size of ribosomes from knowledge of cell biology. Ribosomes are tiny cellular structures, whose size is usually in the range of nanometers (nm).

Step 2 Match the recall with the options

Determine the option that falls within the range of sizes that ribosomes can be. We knew that ribosomes' size is measured in nanometers (nm). Looking at the options, only options B and C mention the size in nanometers. Then choose the correct range from these two options.

Step 3 Choose the correct answer

Now, choose the correct range. The size of ribosomes is usually between 10 and 20 nm. Thus, the correct answer is option C.

Key Concepts

Understanding Cell Biology

Cell biology is the study of the structure, function, and behavior of cells, which are the basic units of life. Within these microscopic compartments, various activities are carried out that are essential for the survival of living organisms. The pivotal functions of the cell include replication, energy conversion, and the production of molecular building blocks which cells use to grow and maintain their structure.

Ribosomes, for example, are key cellular machines that facilitate protein synthesis by decoding the genetic information carried in messenger RNA (mRNA). This process of translation is crucial for the creation of proteins that carry out a multitude of functions within the biological systems. Ribosomes can be found floating freely in the cytoplasm or attached to another cellular structure called the endoplasmic reticulum, helping create a diverse range of proteins.

Nanometers in Cell Biology

A nanometer (nm) is a unit of measurement in the metric system that is equal to one billionth of a meter, or approximately the size of ten hydrogen atoms laid out in a line. In cell biology, measuring in nanometers is essential because it allows scientists to quantify and discuss the incredibly small structures that are fundamental to cellular function, such as ribosomes.

When we refer to ribosomes measuring between 10 and 20 nanometers, we're appreciating just how small these structures are. To put it in perspective, a sheet of paper is about 100,000 nanometers thick. It is this extraordinary scale that necessitates the use of high-resolution microscopy techniques, like electron microscopy, to visualize these small wonders of our biology.

Cellular Structures: The Role of Ribosomes

Cellular structures, including ribosomes, are specifically designed units within a cell that have distinct functions. The complexity of a cell lies not just in its multitude of structures, but also in their size, shape, and intricate interactions to sustain life. Ribosomes are no exception; they are tiny yet vital components.

Ribosomes consist of two subunits, one small and one large, each comprising its own ribonucleic acid (rRNA) and protein content. In eukaryotic cells, ribosomes are about 20 nm in diameter. Conversely, in prokaryotic cells, they are slightly smaller. A deeper understanding of the structure and function of ribosomes has broad implications, including insights into antibiotic mechanisms, which often target bacterial ribosomes, leaving human ribosomes unaffected due to subtle structural differences.