| A | B |
|---|
| virus | a strand of nucleic acid encased in a protein coat that can infect cells and replicate within them |
| capsid | a protein sheath that surrounds the nucleic acid core in a virus |
| envelope | outer layer covering the capsid of many kinds of viruses |
| glycoprotein | protein with carbohydrate molecules attached |
| icosahedron | a shape with 20 triangles and 12 corners |
| bacteriophage | virus that infects bacteria |
| pathogen | a disease-causing agent |
| antibody | defensive protein released by B cells in response to a foreing substance in the body |
| reverse transcripts | enzyme in a retrovirus that manufactures DNA complementary to the virus' RNA |
| retrovirus | virus that uses reverse transcripts to transcribe DNA from an RNA template |
| bacillus | rod-shaped bacterial cell |
| coccus | spherical-shaped bacteria cell |
| spirillum | spiral-shaped bacteria cell |
| capsule | a gelatinous outer layer enclosing many bacterial cell walls |
| gram-positive | designates a bacterium that retains the Gram stain |
| gram-negative | designates a bacterium that does not retain the Gram stain |
| endospore | dormant cell enclosed by a tough coating that is highly resistant to environmental stress |
| pili | short, thick outgrowth of a bacterium that allows it to attach to another bacterium |
| heterocyst | thick-walled, cyanobacterial cell with enzymes that fix nigrogen gas (N2) into ammonia (NH3) |
| nitrification | formation of nitrates by the oxidation of ammonia |
| tuberculosis | disease of the respiratory tract caused by the bacterium Mycobacteriukm Tuberculosis |
| antibiotic | substance used as a drug to kill bacteria |
