Cell Cycle and DNA Replication: How Does DNA Replicate in Preparation for Cell Division?
What Is the Cell Cycle?
Cells are structural and functional units of organisms.
All cells contain DNA, which encodes all the genetic information of an organism.
The DNA in each cell can be transmitted to future generations, that is, the genetic material is heritable.
There are different ways to describe and classify organisms. For example:
Unicellular organisms versus multicellular organisms: Unicellular organisms are composed of just one cell, whereas multicellular organisms are composed of many cells.
Prokaryotes versus eukaryotes: Prokaryotes (such as bacteria) lack nuclear membranes and are unicellular. Eukaryotes contain nuclear membranes and are often multicellular organisms, although most protists and certain fungi are unicellular.
Some unicellular organisms live together, forming colonies, but each cell in the colony is independent, carrying out its own life processes.
Multicellular organisms contain specialized (differentiated) cells that perform specific functions.