Review Questions
4. The first forms of life on Earth were thought to be_________.
- single-celled plants
- prokaryotes
- insects
- large animals such as dinosaurs
5. Microbial mats __________.
- are the earliest forms of life on Earth
- obtained their energy and food from hydrothermal vents
- are multi-layered sheets of prokaryotes including mostly bacteria but also archaea
- all of the above
6. The first organisms that oxygenated the atmosphere were
- cyanobacteria
- phototrophic organisms
- anaerobic organisms
- all of the above
7. Halophiles are organisms that require________.
- a salt concentration of at least 0.2 M
- high sugar concentration
- the addition of halogens
- all of the above
8. Many of the first prokaryotes to be cultured in a scientific lab were human or animal pathogens. Why would these species be more readily cultured than non-pathogenic prokaryotes?
- Pathogenic prokaryotes are hardier than non-pathogenic prokaryotes.
- Non-pathogenic prokaryotes require more supplements in their growth media.
- Most of the necessary culture conditions could be inferred for pathogenic prokaryotes.
- Pathogenic bacteria can grow as free bacteria, but non-pathogenic bacteria only grow as parts of large colonies.
9. The presence of a membrane-enclosed nucleus is a characteristic of ________.
- prokaryotic cells
- eukaryotic cells
- all cells
- viruses
10. Which of the following consist of prokaryotic cells?
- bacteria and fungi
- archaea and fungi
- protists and animals
- bacteria and archaea
11. The cell wall is ________.
- interior to the cell membrane
- exterior to the cell membrane
- a part of the cell membrane
- interior or exterior, depending on the particular cell
12. Organisms most likely to be found in extreme environments are ________.
- fungi
- bacteria
- viruses
- archaea
13. Prokaryotes stain as Gram-positive or Gram-negative because of differences in the cell _______.
- wall
- cytoplasm
- nucleus
- chromosome
14. Pseudopeptidoglycan is a characteristic of the walls of ________.
- eukaryotic cells
- bacterial prokaryotic cells
- archaean prokaryotic cells
- bacterial and archaean prokaryotic cells
15. The lipopolysaccharide layer (LPS) is a characteristic of the wall of ________.
- archaean cells
- Gram-negative bacteria
- bacterial prokaryotic cells
- eukaryotic cells
16. Which of the following elements is not a micronutrient?
- boron
- calcium
- chromium
- manganese
17. Prokaryotes that obtain their energy from chemical compounds are called _____.
- phototrophs
- auxotrophs
- chemotrophs
- lithotrophs
18. Ammonification is the process by which _____.
- ammonia is released during the decomposition of nitrogen-containing organic compounds
- ammonium is converted to nitrite and nitrate in soils
- nitrate from soil is transformed to gaseous nitrogen compounds such as NO, N2O, and N2
- gaseous nitrogen is fixed to yield ammonia
19. Plants use carbon dioxide from the air and are therefore called _____.
- consumers
- producers
- decompos