Textbook Question
With respect to their solubility in water, substances with nonpolar covalent bonds are__________, while substances with polar covalent and ionic bonds are__________.
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2. Cell Chemistry & Cell Components
Introduction to Chemical Bonding
Multiple Choice
In the context of cell communication, which stain is used to stain the background in the capsule stain?
A
India Ink
B
Methylene Blue
C
Crystal Violet
D
Safranin
Verified step by step guidance1
Understand the purpose of a capsule stain: Capsule staining is used to visualize the capsule of bacteria, which is a protective layer that surrounds the cell wall. The capsule is often not stained by conventional methods, so special techniques are used.
Identify the role of the background stain: In capsule staining, the background is stained to create contrast, allowing the capsule to appear as a clear halo around the stained cell.
Review common stains used in microbiology: India Ink is a common choice for capsule staining because it provides a dark background, making the capsule visible as a clear area. Methylene Blue, Crystal Violet, and Safranin are typically used for other types of staining, such as Gram staining.
Consider the properties of India Ink: India Ink is a colloidal suspension of carbon particles that does not penetrate the capsule, thus staining the background and leaving the capsule clear.
Conclude the selection of the stain: Based on the properties and purpose of the stains, India Ink is the correct choice for staining the background in capsule staining, as it highlights the capsule effectively.
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