Bacterial Cell Structures: Capsule and Cytoplasmic Membrane

Practice questions covering the functions of bacterial capsules and the structure and function of the cytoplasmic membrane based on lecture notes.

What are the three primary functions of the bacterial capsule?

1. Protection (prevents drying out), 2. Immune evasion (stops phagocytosis), and 3. Attachment (helps bacteria stick to surfaces and forms biofilms).

How does the capsule contribute to immune evasion?

It acts as an "invisible slime shield" that stops phagocytosis, meaning immune cells cannot "eat" the bacteria.

What is the main structure of the cytoplasmic (plasma) membrane?

The phospholipid bilayer.

What are the two types of proteins found in the cytoplasmic membrane?

Integral (transmembrane) proteins, which go through the membrane, and peripheral proteins, which are attached to the surface.

What are the primary functions of the cytoplasmic membrane?

It controls what enters and leaves the cell, handles the transport of nutrients and waste, and maintains internal balance.

What is the key idea behind a semi-permeable membrane?

Only certain molecules can pass through it.

How does the fluid mosaic model describe the plasma membrane?

"Fluid" means it is flexible, like a moving sea, and "Mosaic" means there are many proteins mixed in, appearing like floating proteins.