Question

List five differences between prokaryotes and eukaryotes.

Short answer

Prokaryotes are smaller, lack a nucleus, have smaller ribosomes, contain single circular chromosomes, and reproduce by binary fission. Eukaryotes are larger, have a nucleus, larger ribosomes, contain multiple linear chromosomes, and reproduce by mitosis or meiosis.

Step-by-step solution

- Define Prokaryotes

Prokaryotes are single-celled organisms that lack a membrane-bound nucleus and other membrane-bound organelles. Their DNA is found in a nucleoid region.

- Define Eukaryotes

Eukaryotes can be single-celled or multicellular organisms that have a membrane-bound nucleus and other organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus.

- Compare Cell Size

Prokaryotic cells are generally smaller, typically 0.1-5.0 micrometers in diameter, while eukaryotic cells are larger, usually 10-100 micrometers in diameter.

- Compare Genetic Material Organization

Prokaryotes have a single, circular chromosome that is located in a nucleoid region. Eukaryotes have multiple, linear chromosomes that are contained within a membrane-bound nucleus.

- Compare Ribosomes

Prokaryotic ribosomes are smaller (70S) compared to eukaryotic ribosomes (80S). The 'S' stands for Svedberg units, a measure of the rate at which particles sediment in a centrifuge.

- Compare Reproduction

Prokaryotes reproduce through binary fission, a simpler form of asexual reproduction. Eukaryotes reproduce either asexually through mitosis or sexually through meiosis.

- Compare Cellular Structure

Prokaryotes lack membrane-bound organelles, while eukaryotes have complex, membrane-bound organelles such as mitochondria, chloroplasts (in plants), and an endoplasmic reticulum.

Key concepts

Prokaryotes

Prokaryotes are simple, single-celled organisms. These cells do not have a membrane-bound nucleus or other membrane-bound organelles. Their genetic material is found in a region called the nucleoid. Examples of prokaryotes include bacteria and archaea. They are some of the oldest and most primitive forms of life on Earth, thriving in a variety of environments. They are essential in many ecological processes, such as the nitrogen cycle.

Eukaryotes

Eukaryotes can be either single-celled or multicellular. An important feature of eukaryotic cells is that they have a membrane-bound nucleus. This nucleus contains the cell’s genetic material. In addition to the nucleus, eukaryotic cells also have other membrane-bound organelles. These include mitochondria, the endoplasmic reticulum, and the Golgi apparatus. Organisms such as plants, animals, fungi, and protists are all eukaryotes. Eukaryotes have complex cellular structures that allow them to perform a variety of functions.

Cell Size

One of the main differences between prokaryotic and eukaryotic cells is their size. Prokaryotic cells are generally much smaller, with a diameter ranging from 0.1 to 5.0 micrometers. In contrast, eukaryotic cells are larger, usually between 10 and 100 micrometers in diameter. The larger size of eukaryotic cells allows them to have more complex structures and to accommodate various organelles that perform specific functions within the cell.

Genetic Material

The organization of genetic material is another significant difference between prokaryotes and eukaryotes. Prokaryotes have a single, circular chromosome located in the nucleoid region. This means that their DNA is not enclosed within a membrane. Eukaryotes, on the other hand, have multiple, linear chromosomes contained within a membrane-bound nucleus. Each eukaryotic chromosome is associated with histone proteins, which help in organizing and packing the DNA into chromatin. This complex structure allows for the regulation of gene expression and DNA replication.

Reproduction

Prokaryotes and eukaryotes also differ in their modes of reproduction. Prokaryotes reproduce asexually through a process called binary fission. During binary fission, the single chromosome is replicated, and the cell divides into two genetically identical daughter cells. Eukaryotes can reproduce both asexually and sexually. Asexual reproduction in eukaryotes occurs through mitosis, resulting in two genetically identical daughter cells. Sexual reproduction involves meiosis, which produces genetically diverse gametes. These gametes then fuse during fertilization to form a new organism with a combination of genetic material from both parents.