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BSC 2010 Lecture Notes - Lecture 5: Peripheral Membrane Protein, Lipid Bilayer, Transmembrane Protein

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School
University of Florida
Department
Biology - Biological Sciences
Course
BSC 2010
Professor
Cuddy Katrina

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Document Summary

Concept 5. 1 biological membranes have a common structure and. Membranes may differ in lipid composition as there are many types of phospholipids. Two important factors in membrane fluidity: lipid composition types of fatty acids can increase or decrease fluidity, temperature membrane fluidity decreases in colder conditions. Biological membranes contain proteins, with varying ratios of phospholipids. Peripheral membrane proteins lack hydrophobic groups and are not embedded in the bilayer. Integral membrane proteins are partly embedded in the phospholipid bilayer. Anchored membrane proteins have lipid components that anchor them in the bilayer. Proteins are asymmetrically distributed on the inner and outer membrane surfaces. A transmembrane protein extends through the bilayer on both sides, and may have different functions in its external and transmembrane domains. Some membrane proteins can move within the phosopholipid bilayer, while others are restricted. Proteins inside the cell can restrict movement of membrane proteins, as can attachments to the cytoskeleton.

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Related Questions

Hybridomas are the useful result of a fusion between _______________ and _________________ to obtain hybrid cells that can proliferate and produce _________________ against specific ________________.
myeloma cells; B lymphocytes; monoclonal antibodies; epitopes
myeloma cells; T lymphocytes; polyclonal antibodies; antigen
T lymphocytes; B lymphocytes; monoclonal antibodies; antigen

T lymphocytes; B lymphocytes; polyclonal antibodies; epitopes
With respect to mammalian cell culture, which of the following statements is true?
Media used for cell growth contain proteases and a divalent cation chelator to help cells adhere to the surface.
During the establishment of a cell line, senescence is the last stage of the cell's life.
Rodent cells cultures undergo spontaneous transformation with similar frequency to human cell cultures.
Embryonic cell lines do not undergo senescence nor do they have a finite life span.
Epithelial cells have distinct surfaces. Which of these surfaces tends to be involved in secreting proteins out of the cell and into the bloodstream?
apical
basal
All of the answers are correct.
lateral
Which of the following is NOT true of phospholipid bilayers?
Phospholipid bilayers separate the cell from the exterior environment as well as from compartments within the cell.
The interior of phospholipid bilayers is a highly hydrophobic environment.
Membrane budding requires transient breakages in the bilayer membrane.
The chemical properties of phospholipids lead to the spontaneous formation of bilayers.
Which of the following is true regarding membrane proteins?
All peripheral membrane proteins contact the lipid bilayer by covalent attachment to the hydrophilic head groups on membrane lipids.
Beta strands can assemble into a membrane-spanning barrel structure.
Lipid-anchored membrane proteins always face the cell exterior.
A protein with six hydrophobic helices is most likely a lipid-anchored membrane protein.
Which of the following statements is NOT true?
The three types of lipid anchors responsible for tethering proteins to the bilayer are acylation, prenylation, and ubiquitinylation.
Movement of lipids from the cytoplasmic to the exoplasmic leaflet of the membrane bilayer requires specialized transport proteins called flippases.
Glycoproteins are the basis for blood type compatibility between donor and receiver.
Glycoproteins are always oriented so that the carbohydrate moieties are exoplasmic.


Which of the following Scientist(s) described the contemporary“fluid- mosiac”model of the plasma Membrane
Davson and Nicholson
Nicholson and Danielle
Singer and Davson
Nicholson and Singer
Answer:_________________________________________________________________

________________________________________________________________________



The “fluid-mosaic” model of the PM differ from the first proposedmodel in that:
The first model did not have cholesterol
The first model was devoid of some lipids
The first model was devoid of some proteins
The first mode was devoid of some carbohydrates
Answer:_________________________________________________________________

________________________________________________________________________


Which is most likely to be a membrane receptor protein?
A glycosylated protein containing three hydrophobic regions
A glycosylated protein devoid of hydrophobic regions
A protein containing hydrophobic regions but devoid of sugars
A glycosylated protein devoid of hydrophilic regions
Answer:_________________________________________________________________

________________________________________________________________________


Which secondary structures of proteins are formed within thePM?
Alpha-pleated sheets
Beta-pleated sheets
Alpha-helicies
Beta-helicies
Answer:_________________________________________________________________

________________________________________________________________________

Intergal proteins project
entirely outside of the bilayer on the extracellular surface
entirely through the membrane having N- and C- terminusexposed.
entirely outside of the bilayer on the cytoplasmic surface
outside bilayer but covalently linked to lipids withinmembrane
Answer:_________________________________________________________________

________________________________________________________________________




Which is the driving force which maintains the lipid bilayer?
Van der waals forces
Hydrophobic interactions
Hydrophilic interactions
Ionic interactions
Answer:_________________________________________________________________

________________________________________________________________________

What affect do lipids with double bonds in their nonpolar tailshave on the integrity of the PM?
They increase the fluidity of the PM
They decrease the fluidity of the PM
They allow more lipids to pack tighter in the membrane
They cause the membrane to become less stable
Answer:_________________________________________________________________

________________________________________________________________________

As the fluidity of the PM increases, what happens to theentropy?
increases
decreases
stays the same
none of the above
Answer:_________________________________________________________________

________________________________________________________________________


The consistency of membranes at various temperatures can beunderstood using the Margarine and Butter analogy. Butter containslonger saturated chains of fat derived from animals while Margarinecontains short polyunsaturated fats derived from corn oil. Whentaken directly from the refrigerator, Margarine can be spread withease while the Butter does not. What conclusion should you drawregarding how the composition of membrane lipid regulate thefluidity of the PM?
Longer chains exhibit more double bonds and increases contact oflipids
Longer chain exhibit fewer double bonds and increases contact oflipids
Shorter chains exhibit more double bonds and increases contact oflipids
Shorter chains exhibit more double bonds and increases contact oflipids
Answer:_________________________________________________________________

_____________________________________________________________________
Which PM lipid covalently anchors proteins?
Phosphoglycerides
Sphingolipids
Cholesterol
Triglycerides
Answer:_________________________________________________________________

________________________________________________________________________

Which PM lipid is the least amphipathic?
Phosphoglycerides
Sphingolipids
Cholesterol
Triglycerides
Answer:_________________________________________________________________

________________________________________________________________________


Which of the following is not a function of the PM?
Signal Transduction
Energy Transduction
Regulates which molecules enters and exits cell
Site of Biochemical events such as production ofmacromolecules
Answer:_________________________________________________________________

________________________________________________________________________

Which two PM phospholipids have negative charges?
Phosphatidylcholine and Phosphatidylethanolamine
Phosphatidylethanolamine and Phosphatidylserine
Phosphatidylinositol and Phosphatidylserine
Phosphatidylserine and Phosphatidylcholine
Answer:_________________________________________________________________

________________________________________________________________________

Which PM lipid is the only true glycolipid?
Phosphatidylcholine
Phosphatidylethanolamine
Sphingolipid
d. Cholesterol
Answer:_________________________________________________________________

________________________________________________________________________


Which is NOT a function of the Plasma Membrane
It serves as a barrier allowing all molecules to enter cell
It serves as a site for energy and signal transductions
It is composed of lipids, proteins, and carbohydrates
It compartmentalizes the cells
Answer:_________________________________________________________________

________________________________________________________________________


Cholesterol, which is not present in bacteria, controls the PMfluidity of animal cells. Which is the CORRECT orientation of thehydroxyl group of the four-member ring of cholesterol in thePM.
The hydroxyl group is oriented inside the membrane
The hydroxyl group is oriented toward the cytoplasm
The hydroxyl group is oriented toward other cholesterolmolecules
The hydroxyl group is oriented toward the membrane surface
Answer:_________________________________________________________________

_____________________________________________________________________
PM carbohydrates are oriented:
Inside the membrane
Toward the cytoplasm
Toward other carbohydrate molecules
Away from the cytoplasm and inside organelles
Answer:_________________________________________________________________

________________________________________________________________________



Sugars constituents various on red blood cells depending on bloodtype, why would giving someone the wrong blood type be fatal?
Blood groups differ in the levels of hemoglobin they carry
The body would view the sugars as antigens and form antibodiesagainst them.
Because of the incompatible sugar arrangement, the blood would notflow to the heart properly.
The foreign sugar sequences will attack to the sugar sequences onnormal cells.
Answer:_________________________________________________________________

________________________________________________________________________


NaCl most likely get into cells by which of the followingmethods?
Diffusion
Facilitated Transport
Osmosis
Active Transport
Answer:_________________________________________________________________

________________________________________________________________________


Sufferers of type II diabetes (adult onset) have normal insulinlevels but no target cell response due to deficiency in receptorsfor insulin. Which type of transport is missing?
Diffusion
Facilitated Transport
Osmosis
Active Transport
Answer:_________________________________________________________________

________________________________________________________________________

The movement of molecules against a gradient refers to which typeof transport?
Diffusion
Facilitated Transport
Osmosis
Active Transport
Answer:_________________________________________________________________

________________________________________________________________________


Which is the correct exchange of sodium and potassium in the Na/Kpump of cells?
three sodium for three potassium
two sodium for three potassium
three sodium for two potassium
two sodium for one potassium
Answer:_________________________________________________________________

________________________________________________________________________


This type of transport is important to cells because they receivetheir oxygen and rid themselves of carbon dioxide by thismethod:
Diffusion
Facilitated Transport
Osmosis
Active Transport
Answer:_________________________________________________________________

________________________________________________________________________

Maintaining membrane fluidity is important to cells because?
Cells are able to maintain proper function at differenttemperatures
Cells can break down membranes lipids very quickly when energy isneeded
Larger molecules can pass through the membrane when fluidity isincreased
The membrane fluidity helps to maintain the positions ofglycoproteins and glycolipids
Answer:_________________________________________________________________

________________________________________________________________________

Scientists agreed that the plasma membrane was the site ofbiochemical events when peroxide was broken to produce bubblescontaining?
water
hydrogen
oxygen
carbon dioxide

Answer:_________________________________________________________________

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