Chapter 3 True/ False
1) The counterstain used in the Gram stain is a basic dye.
Answer: TRUE
2) In a completed Gram stain, gram-negative bacteria are colorless.
Answer: FALSE
3) In a completed Gram stain, gram-positive bacteria are purple.
Answer: TRUE
4) If acid-fast bacteria are stained with the Gram stain, they will stain gram-negative.
Answer: FALSE
5) The limit of resolution of the compound microscope illuminated with visible light is approximately 0.2 μm.
Answer: TRUE
6) Both phase-contrast microscopy and differential interference contrast microscopy are used to
view the internal structures of cells without staining.
Answer: TRUE
7) Cells viewed in darkfield microscopy appear similar to those stained with the negative stain.
Answer: TRUE
8) The capsules and flagella of bacteria can be observed in gram-stained smears.
Answer: FALSE
9) The greater resolution of the electron microscope compared to the compound microscope is due to the longer wavelengths of the electrons used to examine specimens.
Answer: FALSE
10) Scanned probe microscopy is used to examine fine detail of molecular complexes, such as blood clots, or molecules, such as DNA.
Answer: TRUE