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(11 cards)
What is the primary function of the cell membrane?
Control movement of substances in and out the cell
The cell membrane also regulates cell-cell interaction and acts as an interface between the cytoplasm and the external environment. Also, recognition via receptors, antigens
How is the cell membrane visualized?
Not visible by light microscope, seen only by E/M
E/M refers to electron microscopy.
What is the thickness of the cell membrane?
7.5nm thick
This thickness contributes to its trilaminar structure.
Describe the trilaminar structure of the cell membrane.
Two thin, dense lines and a light line in between
The entire structure is called a unit membrane.
What are the two components of the unit membrane?
- Inner leaflet
- Outer leaflet
The inner leaflet corresponds to the inner cytoplasmic dense line, and the outer leaflet corresponds to the outer dense line.
What is each leaflet of the cell membrane composed of?
A single layer of phospholipids and associated proteins
These components are crucial for membrane functionality.
What are the two parts of a phospholipid molecule?
- Polar hydrophilic head
- Two long non-polar hydrophobic fatty acyl tails
The polar head is at the surface, while the hydrophobic tails are oriented toward the center.
What is the composition of the polar head of a phospholipid?
Composed of glycerol, to which other molecules are attached
The structure of the polar head influences membrane properties.
What are integral proteins?
Proteins that span the entire lipid bilayer
Integral proteins can form channels and carrier proteins.
What are peripheral proteins?
Proteins attached to the cytoplasmic aspect of the lipid bilayer
Peripheral proteins play roles in signaling and structural support.
What types of channels do integral proteins form?
- Ion channels
- Carrier proteins
These proteins facilitate the passage of specific ions and molecules across the cell membrane.
