The cell is a functional unit of all living organisms. Cells have evolved into two fundamentally different types, eukaryotic and prokaryotic, which can be distinguished on the basis of their structure and the complexity of their organization. The simplest organisms which consist of one cell are called prokaryotes. More complex organisms are called eukaryotes and they consist of many cells. Objectives:
* Define the terms: Eukaryotes & Prokaryotes with examples * Explain the differences between Eukaryotic cells and Prokaryotic cells with particular reference to the characteristics of their: (Nucleus/nucleoid, DNA, Mitotic division, Chromosome number, Cell organelles, Size of Ribosomes, Cell wall structure and composition, Peptidoglycan, Cell membrane, Motility) * List the functions of different cell organelles in eukaryotic and prokaryotic cells Prokaryotes:
Prokaryotes are single-celled organisms that lack a nucleus and other internal compartments. Early prokaryotes lived at least 3.5 billion years ago and for nearly 2 billion years, prokaryotes were the only organisms on Earth. Bacteria and algae are two examples of prokaryotes. Characteristics of Prokaryotic Cells:
Figure 1: Prokaryotic Cell
Prokaryotic cells, shown in figure 1, are primarily distinguished by the fact that they lack a membrane-bound nucleus. The genetic material is a single, circular molecule of loosely organized DNA (deoxyribonucleic acid). It is often located in the nucleoid, an irregularly-shaped region within the cell of prokaryotes which has nuclear material without a nuclear envelope and where the genetic material is localized. The cytoplasm of a prokaryotic
cell includes everything inside its membrane. The enzymes and ribosomes are free to move around the cytoplasm because there are no internal structures that divide the cell into compartments. Without separate compartments to isolate materials,...