Computational biology is a rapidly expanding and cutting edge field that seeks to apply computer science, statistics and applied mathematics to biological problems. This can take the form of data analysis (bioinformatics), molecular modeling (genomics, proteomics, molecular visualisation), and prediction and simulation (molecular dynamics, gene prediction, protein structure prediction). It's a vague field and it provides an interdisciplinary approach to solving questions and problems in the biological sciences. Below is just a sampling of the kinds of problems and approaches in computational biology.
1) Bioinformatics. Statistics, probability and applied mathematics have been used to a huge degree in molecula biology and proteomics. One of the most famous examples was the human genome project, which took advantage of great computer processing power to sequence the human genome. Sequence alignments allow scientists to compare DNA, RNA and protein sequences to find homology and predict the presences of motifs, genes, structures and even build phylogeny trees that model evolutionary trends.
2) Biophysics. The realms of biochemistry, biophysics and structural biology have seen huge gains thanks to computational techniques. Molecular dynamics is the use of Newtonian physics to simulate the movement and interactions of molecules. This allows scientists with just a crystal structure of their molecule to try to gather some information on some of the physical properties of the molecule.
3) Modeling and Visualization. One of the most important aspects of scientific research is the ability to related information to others. Being able to visualize systems or model molecules is rapidly growing field. Many times, this visualization work is related to similar fields that are trying to predict the structure of RNA or protein molecules.
4) Systems biology. Computational biology and statistical analysis are being use more every year to create system models to show the flux of important molecules in a biological system. Metabolomics and proteomics researchers use these techniques to estimate how the body or more specific organ systems take raw materials and produce important system intermediates.
While this was just a sampling of the world of computational biology, it is easy to see how large the field is. It encompasses many interdisciplinary fields and uses many techniques to solve biological problems.