Question

A typical prokaryotic cell __________________ compared to a eukaryotic cell. a. is smaller in size by a factor of 100 b. is similar in size c. is smaller in size by a factor of one million d. is larger in size by a factor of 10

Short answer

A typical prokaryotic cell is smaller in size than a eukaryotic cell by a factor of 10 (on average).

Step-by-step solution

Understand the terms prokaryotic and eukaryotic cells

Prokaryotic cells are simple, single-celled organisms that lack a nucleus and membrane-bound organelles, e.g., bacteria and archaea. In contrast, Eukaryotic cells are more complex, containing a nucleus and membrane-bound organelles, and can be single-celled or part of multicellular organisms, like plants and animals.

Compare the size of prokaryotic and eukaryotic cells

Generally, prokaryotic cells are smaller than eukaryotic cells. Prokaryotic cells have an average size of 1-10 micrometers in diameter, whereas eukaryotic cells range from 10-100 micrometers in diameter.

Identify the correct option

Based on the size difference described in Step 2, we can see that: a. is smaller in size by a factor of 100: This option exaggerates the size difference between prokaryotic and eukaryotic cells. The actual size difference is smaller. b. is similar in size: This option is incorrect, as prokaryotic cells are generally smaller than eukaryotic cells. c. is smaller in size by a factor of one million: This option greatly exaggerates the size difference and is incorrect. d. is larger in size by a factor of 10: This option is also incorrect, as prokaryotic cells are smaller, not larger, than eukaryotic cells. Based on this information, we now have the correct answer: A typical prokaryotic cell is smaller in size than a eukaryotic cell by a factor of 10 (on average).

Key concepts

Prokaryotic Cells

Prokaryotic cells are the earliest, most primitive forms of life on Earth. They are simple, single-celled organisms lacking a nucleus or any membrane-bound organelles such as mitochondria or chloroplasts. Instead, they have a nucleoid, a region where their genetic material, composed of a single circular DNA molecule, is located. This simplicity makes prokaryotes highly efficient and adaptable, allowing them to thrive in various environments. Typical examples include bacteria and archaea.
Key features of prokaryotic cells:

• Lack of nucleus: Genetic material is not enclosed within a membrane.
• Smaller size: Generally ranges between 1-10 micrometers in diameter.
• Survive in extreme conditions: Many can live in high temperatures, salinity, or acidity.

Eukaryotic Cells

Eukaryotic cells are characterized by their complex structure, which includes a well-defined nucleus surrounded by a nuclear membrane. They also contain other membrane-bound organelles such as mitochondria, which are crucial for energy production; chloroplasts, found in plants and some algae, which are essential for photosynthesis; and the endoplasmic reticulum and Golgi apparatus, which are involved in protein and lipid processing. Eukaryotic cells can be part of single-celled or multicellular organisms like fungi, plants, and animals.
Characteristics of eukaryotic cells include:

• Contain a nucleus: A double-membraned structure that holds the cell's DNA.
• Generally larger in size: Ranges from 10-100 micrometers in diameter.
• Ability to form complex and organized life forms: Found in humans, animals, plants, fungi, and protists.

Cell Size Comparison

Understanding the size difference between prokaryotic and eukaryotic cells is crucial for cell biology. Prokaryotic cells, like bacteria, are generally much smaller than eukaryotic cells. Typically, prokaryotic cells measure between 1 and 10 micrometers in diameter. In contrast, eukaryotic cells, such as those of plants and animals, range from 10 to 100 micrometers. This difference is significant because it reflects the amount of internal complexity and specialized functions that eukaryotic cells can support.
The comparison in size impacts:

• Metabolic Rate: Small size in prokaryotes often leads to faster metabolic rates relative to their volume.
• Complexity: Eukaryotic cells have more room for organelles and metabolic processes, making them capable of more complex functions.
• Adaptability: Smaller prokaryotic cells can proliferate rapidly, adapting quickly to environmental changes.

In summary, the size difference between these cell types is a fundamental aspect of their functional capabilities and evolutionary adaptations.