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