General Biology:
* Biology: The study of living organisms
* Biochemistry: The chemistry of living organisms
* Biophysics: The physics of living organisms
* Biotechnology: The use of living organisms or their products in technology
* Bioethics: The ethical implications of biological research
* Biogeography: The study of the geographical distribution of living organisms
* Biodiversity: The variety of life on Earth
* Biomass: The total mass of living organisms in a given area
* Biosphere: The part of Earth where life exists
* Bioaccumulation: The increase in concentration of a substance in an organism over time
* Biomagnification: The increase in concentration of a substance in organisms at higher trophic levels
Medical:
* Biopsy: The removal of a small sample of tissue for examination
* Biofeedback: A technique that allows people to monitor and control physiological responses
* Biomedical: Relating to both biology and medicine
* Biopsyche: The mental and emotional aspects of living organisms
* Biohazard: A biological substance that poses a threat to health
* Biometric: Relating to the measurement of biological characteristics
Other:
* Bionic: Relating to the use of artificial devices to replace or enhance biological functions
* Biofuel: Fuel derived from organic matter
* Biodegradable: Capable of being broken down by living organisms
* Biometric: Relating to the measurement of biological characteristics
* Bioluminescence: The emission of light by living organisms
This list is not exhaustive, but it gives you a good starting point. You can find many more words with the root "bio" by browsing dictionaries and scientific journals.