In this lesson, we will cover:
The cell is the basic unit of life. The cell theory, set forth in the 1850's, says that:
Cells are 90% water. The rest of the present molecules are:
By elements, a cells composition is:
Eukaryotes could be said to have a more complex form than that of prokaryotes. Eukaryotes have a nucleus and membraned-bound organelles, while prokaryotes do not. The DNA of prokaryotes floats around the cell, while the DNA of eukaryotes is trapped in the nucleus. On the average, eukaryote cells are ten times larger than prokaryote cells. The DNA of eukaryotes is much more complex than that of prokaryotes. Prokaryotes have a cell wall made up of peptidoglycan, a large polymer consisting of amino acids and sugar. Many kinds of eukaryotic cells also have cell walls, but none are made of peptidoglycan. Prokaryotes and eukaryotes have many similarities, also.
That's it! You have made it through lesson 1, an introduction to cells. If you want to proceed to the next lesson, first take the lesson 1 quiz.