Chapter 5 - Phospholipids Flashcards
What are in Phospholipid sheets?
Two fatty acids attached to a glycerol backbone with the third space linked to a phosphorylated molecule.
What is the structure of a phospholipid?
Contains a polar head (Phosphate Group) and a nonpolar tail (fatty acid). Globular proteins are inserted into the lipid bilayer. Nonpolar segments are with the nonpolar interior while the polar portions protrude out.
What is the main component of cell membranes?
Phospholipid bilayer
What is used to transport and communicate across the membrane?
Transmembrane proteins
What reinforces the membrane’s shape and anchoring?
Interior protein network
What contains glycoproteins and glycolipids?
Cell-surface markers
What is the difference and the same between a glycoprotein and a glycolipid?
Both are modified within the Golgi complex and have a sugar chain attached (polysaccharide). A glycoprotein is a protein and a glycolipid is a fat.
What fills the space between the phospholipid?
Cholesterol
How does a phospholipid form?
Polar water molecules repel the long nonpolar tails of the phospholipids while seeking partners for hydrogen bonding. The tails face each other so they do not encounter water.
Why does a phospholipid form?
It is spontaneous driven by the tendency of water molecules to form the maximum number of hydrogen bonds.
What holds the membrane together?
Hydrogen bonds
What makes a lipid bilayer stable?
Water’s affinity for hydrogen bonding never stops
What can alter the degree of fluidity of the plasma membrane?
This can be altered by either changing the fatty acid composition, the amount of cholesterol, and changes in the environment like temperature.
What are transporters?
Allows only selective solutes to enter or leave the cell through channels of carriers composed of proteins.
What are enzymes?
Biological catalyst, usually a protein that increases rate of specific reactions without being consumed in the reaction.
What are cell-surface identity markers?
A combination of cell-surface proteins and glycoproteins that carry markers that identify them to other cells.
What are cell-surface receptors?
Receptor proteins that detect chemical messages which are anchored to the cell’s surface.
What are cell-to-cell adhesion proteins?
Uses specific proteins to glue themselves to one another.
What are cytoskeleton anchors?
Surface proteins that interact with other cells are firmly anchored to the cytoskeleton of the cell interior by linking proteins.
What is the hydrophobic region of a transmembrane protein that anchors it in the membrane?
Transmembrane domain - Often composed of alpha helixes but sometimes utilizes beta pleated sheets that form a barrel which opens at both ends called a pore.
What does the pore allow to pass?
The openings allow polar water molecules to pass through the membrane.
What is the net movement of dissolved molecules or other particles from a region of high concentration to low concentration?
Diffusion
What is carrier-assisted diffusion called?
Facilitated diffusion
What allows the diffusion of K+, NA+, or CA2 across the membrane and has an aqueous channel?
Ion Channels
