The cell is the most basic and fundamental building block of life on Earth that undergoes cell growth and cell division to replicate itself. The cell consists of a cell wall and a protective semipermeable membrane, protecting the cytoplasm of the cell along with the cell nucleus. They are classified as prokaryote that has no cell nucleus and Eukaryote that have one.

Frequently Asked Questionsedit

Where did the first cell come from?edit

As of today, there are no answers for the actual mechanism of abiogenesis. There are several hypotheses that advocate that the first cell or protocell could have been formed out of a primordial RNA world.[1][2]

What is the source of energy for a cell?edit

The energy of the cell comes from an organelle called mitochondrion, which produces ATP by glycolysis. ATP breaks down to ADP by hydrolysis, losing a phosphate group and thus releasing and energy.


How cells interact with the surroundings and receive chemical signals?edit

The outer plasma membrane of a cell is a semipermeable membrane that has many protein receptors embedded in it. When a signaling protein binds to these receptors, they change shape and initiate a particular chemical reaction that is attributed to it. There are also receptors found inside the cytoplasm that works the same way.


  1. Schrum, J. P., Zhu, T. F., & Szostak, J. W. (2010). The Origins of Cellular Life. Cold Spring Harbor Perspectives in Biology, 2(9), a002212. http://doi.org/10.1101/cshperspect.a002212
  2. Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. The RNA World and the Origins of Life. Available from: https://www.ncbi.nlm.nih.gov/books/NBK26876/