Available under Creative Commons-ShareAlike 4.0 International License.
- Figure 13.12 A
- B
- A
- D
- A
- C
- B
- D
- C
- C
- B
- C
- C
- Antibiotics kill bacteria that are sensitive to them; thus, only the resistant ones will survive. These resistant bacteria will reproduce, and therefore, after a while, there will be only resistant bacteria, making it more difficult to treat the diseases they may cause in humans.
- Remind them of the important roles prokaryotes play in decomposition and freeing up nutrients in biogeochemical cycles; remind them of the many prokaryotes that are not human pathogens and that fill very specialized niches.
- Eukaryote cells arose through endosymbiotic events that gave rise to energy-producing organelles within the eukaryotic cells, such as mitochondria and plastids. The nuclear genome of eukaryotes is related most closely to the Archaea, so it may have been an early archaean that engulfed a bacterial cell that evolved into a mitochondrion. Mitochondria appear to have originated from an alpha-proteobacterium, whereas chloroplasts originated from a cyanobacterium. There is also evidence of secondary endosymbiotic events. Other cell components may have resulted from endosymbiotic events.
- Plasmodium parasites infect humans and cause malaria. However, they must complete part of their life cycle within Anopheles mosquitoes, and they can only be transmitted to humans via the bite wound of a mosquito. If the mosquito population were decreased, then fewer Plasmodium would be able to develop and be transmitted to humans, thereby reducing the incidence of human infections with this parasite.
- The trypanosomes that cause this disease are capable of expressing a glycoprotein coat with a different molecular structure with each generation. Because the immune system must respond to specific antigens to raise a meaningful defense, the changing nature of trypanosome antigens prevents the immune system from ever clearing this infection. Massive trypanosome infection eventually leads to host organ failure and death.
- Dermatophytes that colonize skin break down the keratinized layer of dead cells that protects tissues from bacterial invasion. Once the integrity of the skin is breached, bacteria can enter the deeper layers of tissues and cause infections.
- 1864 reads
