Title: Jack Sparrow Biochem / Biochemistry / Biochemistry Chapter 8
Tags: #JackSparrow::#B/B::#Biochemistry::#Chapter.8

Q: Describe the fluid mosaic model of the plasma membrane.
A: The fluid mosaic model states the plasma membrane is mostly a loose/fluid membrane that is studded and held together by proteins, cholesterols, and other groups.

Q: What is the glycoprotein coat?
A: The glycoprotein coat refers to sugar molecules attached to the exterior of the membrane.  The glycoprotein coat is important for cell recognition, signalling, and more.
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Q: What is the main purpose of the membrane?
A: To selectively regulate traffic into and out of the cell, whether it is chemical traffic through channel proteins or signal traffic through membrane receptors and other signal transduction machinery.

Q: Describe the diffusion of phospholipids in the membrane
A: The phospholipids that make up the membrane are always in flux and moving around.  They are constantly rotating and travelling laterally through the membrane.
Phospholipids can also flip their orientation in the membrane, but this is much less common.

Q: What is a lipid raft?
A: A lipid raft is a collection of similar lipids (usually sphingolipids and cholesterols) with or without associated proteins that serve as attachment points for other molecules.  These rafts often serve roles in signalling.

Q: What is a flippase?
A: A flippase is a specialized enzyme that helps phospholipids flip across the plasma membrane.

Q: How do unsaturated fatty acids affect the membrane?
A: Generally speaking, unsaturated fatty acids are not able to stack very well, which decreases their intermolecular forces.  Therefore, unsaturated fatty acids decrease the rigidity of the membrane and make it more flexible.

Q: How do saturated fatty acids affect the membrane?
A: Generally speaking, saturated fatty acids can stack well, which increases their intermolecular forces.  Therefore, saturated fatty acids increase the rigidity of the membrane and make it less flexible.\

Q: What is the difference between a micelle and a liposome?
A: Micelles are single-layered phospholipid vesicles while Liposomes are double layered phospholipid vesicles.

Q: What is a transmembrane protein?
A: A transmembrane protein is a protein that completely passes through the bilayer.

Q: What is an embedded protein?
A: An embedded protein is a protein that is in the bilayer, but only associates with the interior or exterior side of it.

Q: What is an integral protein?
A: An integral protein is a protein that associates with the inside of the plasma membrane.

Q: What is a peripheral protein?
A: A peripheral protein is a protein that associates with the periphery of the plasma membrane, usually by binding to lipid rafts or integral proteins.

Q: What is the role of gap junctions in the plasma membrane?
A: Gap Junctions allow for direct cell-cell communication and are often found in small bunches together.  They are also called connexons because they are composed of 6 molecules of connexin.

Q: What is the role of tight junctions in the plasma membrane?
A: Tight junctions prevent solutes from leaking into the space between cells by forming a tight seal between cells.

Q: What is the role of desmosomes in the plasma membrane?
A: Desmosomes bind adjacent cells by anchoring their cytoskeletions together.  Desmosomes are associated with intermediate filaments within the cells.

Q: What is the difference between primary active transport and secondary active transport?
A: Primary active transport is when an ATP molecule is used to directly power movement of molecules across a membrane.
Secondary active transport is when the release of energy of one molecule going down its concentration gradient is used to drive another molecule against its concentration gradient.

Q: What are the two types of secondary active transport?
A: 1.  Symporters
2.  Antiporters

Q: What is a symporter?
A: A symporter is a secondary active transport system that pushes both molecules in the same direction.

Q: What is an antiporter?
A: An antiporter is an active transport system that pushes molecules in opposite directions.

Q: What is endocytosis and what are the two types?
A: Endocytosis is when the cell membrane invaginates and engulgs material to bring it into the cell.
1.  Pinocytosis is endocytosis of fluid
2.  Phagocytosis is the endocytosis of solids.

Q: How is the process of endocytosis initiated?
A: Endocytosis is initiated through membrane receptors that bind with appropriate molecules and cause endocytosis to occur.

Q: The cell membrane is often compared to a [battery or capacitor?]
A: capacitor

Q: What are the main contributors to the resting membrane potential across any given cell membrane?
A: 1.  Sodium, Potassium, and Chloride leak channels
2.  Sodium Potassium Pump

Q: Describe the outer membrane of the mitochondria
A: The outer membrane is highly permeable due to many large pores that allow the passage of ions and small proteins.

Q: Describe the inner mitochondrial membrane.
A: The inner mitochondrial membrane is a selectively permeable membrane with cristae and important metabolic enzymes.

Q: What is paracellular transport?
A: Paracellular transport is when you move through a layer of cells by going through a space in between them.  This is what tight junctions protect against.