Chapter 8: Biological Membranes Flashcards
Fatty acids are ____________ ________ that contain a ____________ chain and terminal ________ group.
carboxylic acids; hydrocarbon; carboyxl
____________ fatty acids are regarded as “healthier” fats because they tend to have one or more ________ bonds and exist in ________ form at RT.
unsaturated; double; liquids
Unsaturated fatty acids impart ____________ to the membrane because they cannot stack well and are liquids.
fluidity
Saturated fattty acids are the main components of animal fats and tend to exist as ________ at RT.
solids
By substituting one of the fatty acid chains of triacylglycerol with a phosphate group, a polar head group joins the nonpolar tails, forming a ________________.
glycerophospholipid (commonly known as a phospholipid)
Phospholipids spontaneously assemble into ________ or ____________ due to hydrophobic interactions.
micelles, liposomes
____________ not only regulates membrane fluidity, but it is also necessary in the synthesis of all ________, which are derived from cholesterol.
cholesterol, steroids
While cholesterol stabilizes adjacent phospholipids, it also occupies space between them. Why?
To prevent the formation of crystal structures in the membrane and increase fluidity
________ proteins are associated with only the interior or exterior surface of the cell membrane.
embedded
Cell-cell junctions are generally comprised of ________ ____________ ____________ (CAM), which are proteins that allow cells to recognize each other and contribute to proper cell differentiation and development.
cell adhesion molecules
____ ________ allow for direct cell-call communication and are often found in small bunches together. Gap junctions are also called ____________ and are formed by the alignment/interaction of pores composed of six molecules of ________.
gap junctions; connexons; connexin
________ ____________ prevent solutes from leaking into the space between cells via a paracellular route. They are found where?
tight junctions; epithelial cells
____________ bind adjacent cells by anchoring to their cytoskeletons.
desmosomes
Desmosomes are formed by interactions between ____________ proteins associated with ____________ ____________ inside adjacent cells.
transmembrane; intermediate filaments
Spontaneous processes that do not require energy (____________ delta G) proceed through ________ transport.
negative; passive
Nonspontaneous processes not requiring energy (____________ delta G) proceed through ________ transport.
positive; active
____________ diffusion is simple diffusion for molecules that are impermeable to the membrane. They require ________ proteins.
facilitated; carrier
________ active transport uses ATP or another energy molecule to power transport. ____________ active transport, also known as, ________ transport.
primary; secondary, coupled
When both particles flow the same direction across the membrane, it is termed ____________.
symport
When particles flow in opposite directions, it is called ________.
antiport
____________ occurs when the cell membrane invaginates and engulfs material to bring it into the cell.
endocytosis
____________ is the endocytosis of fluids and dissolve particles, whereas ____________ is the ingestion of large solids like bacteria.
pinocytosis, phagocytosis
Invagination is initiated and carried out by ________-________ proteins, most notably clathrin.
vesicle-coating
____________ occurs when secretory vesicles fuse with the membrane, releasing material from inside the cell to the extracellular environment.
exocytosis
Maintaining membrane potential requires energy because ions may passively diffuse through the cell membrane over time using ________ channels. Therefore, an ion transporter or pump such as the ________-____________ pump regulates the concentration of intracellular and extracellular Na+ and K+ ions.
leak; sodium-potassium
The Na+/K+ ATPase maintains a low concentration of sodium ions and high concentration of potassium ions intracellular by pumping ____ Na+ ions for every ____ K+ ions pumped in. This removes ____ positive charge from the intracellular space of the cell to maintain the negative resting potential.
3, 2, 1
