Chp 3 Cell Mem. & Envelope Flashcards
What is the fundamental unit of life?
The cell.
What are cells capable of?
Growing, reproducing, responding, and metabolizing.
What is a small living entity?
Single-celled microorganisms.
What is a key structural feature of prokaryotic cells?
They lack a nucleus.
Which cells are larger: prokaryotic or eukaryotic?
Eukaryotic cells.
What organisms are included in eukaryotic cells?
Algae, protozoa, fungi, animals, and plants.
What is the function of the cell envelope?
Provides structure, protects from osmotic forces, aids in attachment, resists drugs, and allows import & export of materials.
What are the main components of the prokaryotic cell envelope?
Cytoplasmic membrane, cell wall, outer membrane, and S-layers.
Why is the cell wall important for bacteria?
It prevents cell lysis and maintains shape and rigidity.
What is the structure of a bacterial cytoplasmic membrane?
A phospholipid bilayer with embedded proteins.
What does the fluid mosaic model describe?
The movement of proteins and lipids within the cell membrane.
What is the hydrophilic region of the phospholipid bilayer composed of?
Glycerophosphate and other functional groups.
What is the first step in Gram staining?
Apply crystal violet dye.
What happens during the decolorization step in Gram staining?
The outer lipid layer of Gram-negative bacteria is stripped, releasing the dye.
What is the counterstain used in Gram staining?
Safranin.
