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Biology 224 Liberty University (Dr. Brophy) Chapter 5
Terms in this set (80)
_____________________ are Amphipathic.
Each phospholipid layer is called a_______________
Cannot pass hydrophobic membrane center.
Can generally diffuse through membranes.
__________________________ are embedded in Phospholipid bilayer.
Protein content of membranes varies from ____________ times more Lipid molecules than Protein molecules.
Less closely associated with the membrane.
Peripheral Membrane Proteins
Loosely bound to the membrane.
Peripheral Proteins are bound by what bonds?
Hydrogen or Ionic Bonds
What are Peripheral Proteins bound to?
Transmembrane Proteins or the Heads of Phospholipids
The exposed portions of Peripheral Proteins are usually ____________ for binding.
More closely associated with the membrane.
Integral Membrane Proteins
Exposed portions are usually__________________for binding.
What are two types of binding in Integral Membrane Proteins?
________________________________transverse the membrane with domains forming a-helices.
Transmembrane Proteins are bound to the __________________.
Have a lipid covalently attached to the Protein.
Phospholipids in the membrane are not covalently bound.
Phospholipids are not free to move between leaflets.
Since Phospholipids are not free to move between leaflets, a special protein ________________ is needed to do this using the energy from__________________.
The most common Phospholipids have an even number of ___________________(18-20).
What are the factors affecting membrane fluidity?
- fewer hydrophobic interactions (higher fluidity)
- shorter hydrocarbon chains
-more unsaturated hydrocarbon chains
- more cholesterol will make membrane more fluid at low temperatures, less fluid at higher temperatures.
Carbohydrates in membranes occur only as _____________ and _______________.
Glycolipids and Glycoproteins
_____________________________occur in the exterior leaflet of t he Plasma Membrane.
What does Glycolipids and Glycoproteins function as in the Plasma Membrane?
antigens, identifying the cells of organisms(cell surface recognition).
_____________________ shields the cell from the immune system of other cells.
How are Phospholipids synthesized?
by the smooth ER and inserted into the membrane.
What allows Phospholipids to be spread throughout the Endomembrane System?
The membranes of what are connected by vesicles?
Can extract a lipid from one membrane, diffuse through the Cytoplasm, and insert it into any other membrane.
Lipid Exchange Proteins
The _____________________and ____________________synthesize various types of lipids then transferred to other organelles by Lipid Exchange Proteins.
Most Transmembrane Proteins are synthesized where?
___________________________ are left in the ER membrane as they are synthesized, forming Transmembrane Proteins.
Hydrophobic a helices
From the ER, Proteins can be moved to other membranes by _________________.
Where does Glycosylation of Proteins occur in Membrane Synthesis?
Where are Oligosaccharides synthesized?
In the Lumen of the ER on a Dolichol lipid.
Where are Oligosaccharides transferred during membrane synthesis?
as a unit to the R/Side group of an Asparagine amino acid on the protein.
In the ________________, an Oligosaccharide chain can be synthesized and transferred to the Oxygen of a _____________________or ____________________amino acid.
Golgi, Serine or Threonine
Proteoglycans are often secreted from the cell to help form the __________________.
Proteoglycans are also components of _______________.
Molecules are passed through membranes, by either ________________or___________________transport.
passive or active
simple and facilitated diffusion; down/with concentration gradient
up/against concentration gradient; requires ATP
Passive Transport does not require the input of outside energy.
What does passive transport depend on?
the Kinetic Energy of the solute molecule
energy in motion
All molecules are in constant motion.
the net movement of a substance from an area of high concentration to an area of low concentration.
When can passive diffusion occur?
for nonpolar molecules diffusing through the phospholipid bilayer, or through channel or carrier proteins.
What are the respiratory gases that are the primary examples of molecules that move by Passive Diffusion through Membranes?
Oxygen, Nitrogen and Carbon Dioxide
Passive Diffusion is due to what?
What does the rate of diffusion depend upon?
Diffusion over short distances is very effective.
What is Facilitated Diffusion?
The diffusion of macromolecules and polar molecules through membranes using proteins.
In facilitated diffusion, the proteins may be described as what?
channel or carrier/transporter proteins
What are Channel Proteins?
transmembrane proteins that form channels through the membrane through which certain molecules can diffuse.
_________________Proteins may be gated and only transport when the "gate" is opened.
_______________________ channels open when a signal molecule (ligand) is bound.
____________channels open when a membrane is depolarized, by a change in the electrical charge across the membrane.
___________________Proteins bind the solute which is then carried through the membrane, usually by a conformational change in the protein.
transports one solute molecule.
transports two in same direction.
transports two in different directions.
What is the definition of Primary Active Transport?
the transport of a substance, with a pump, against its concentration gradient with the direct expenditure of energy.
In Primary Active Transport, what is often the energy source used?
What is an example of Primary Active Transport with the use of ATP?
Sodium Potassium pump
Puming two_____________at uneven rates results in an electrical charge across the ______________________________.
cations, plasma membrane
the diffusion of water through a semipermeable membrane.
What is the name of the pores in which water diffuses?
Where are Aquaporins found?
plant cells, kidney cells, and RBCs of animals.
What are the three conditions (solutions) in which a cell may be placed?
the same solute concentration and water as the cell, cell volume does not change.
solution has a higher solute concentration than the cell(less water), so cell looses volume
solution has a lower solute concentration (more water) than cell, so cell gains volume.
Brings large sized materials into cells using Vesicles formation.
____________________ uses receptors to concentrate materials before bringing them in.
In Endocytosis, after the vesicle imports material from outside the cell, it can fuse with a _____________________________.
In Endocytosis, __________________ are digested to monomers before they are transported to the cytoplasm.
What is the function of Exocytosis?
discards materials from cells using vesicles.
What adds phospholipids to Plasma Membrane?