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126 Cards in this Set
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Saturated FA Properties |
Reason: No double bonds > Stronger IMF Properties: High melting point |
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Unsaturated FA properties |
Reason: Double bonds > Weaker IMF Properties: Low melting point |
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What increases fluidity |
# double bonds (unsaturations) |
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Examples saturated and unsaturated |
Saturated: butter (more solid) Unsaturated: oil (more fluid like) |
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Which of the following is not a polymer? a. Polysaccharide b. Nucleic acids c. Lipids d. Polypeptides |
c. Lipids |
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Functions fats |
Energy storage: 9 cal/g (carb 4 cal / g) Cushion vital organs: kidneys embedded in adipose tissue Insulation (polar and marine animals have thick subcutaneous fat layer for insulation) |
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Which organ embedded in adipose tissue? a. Liver b. Kidney c. Heart d. Stomach e. Large intestines f. Brain |
b. Kidney. The kidney is embedded in adipose tissue for cushioning of vital organs. |
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What determines characteristics of FA? |
# C and # unsaturations |
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Most common type fat |
TG |
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Structure TG |
Glycerol backbone, esterified to 3 FA FA structure: Unsaturated or saturated # C |
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What gives a phospholipid hydrophilic properties, hydrophobic? |
PO43- (phosphate head) Tail (hydrophobic) |
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Properties phospholipid Location |
Glycerol backbone: > esterified to 2 FA (hydrophobic part) > esterified to 1 PO43- (hydrophilic part) (via attached to -OH of third C of glycerol) Properties of : PO43: Hydrophilic head interacting with water Hydrophobic tail: Avoid water > Thus consdiered amphipathic Location: cell membrane |
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How to show properties phospholipid |
Micelle Phospholipid > showing amphipathic properties phospholipid |
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Steroid (structure, function, pathologies, location) |
Focus on cholsterol as basic steroid. 4 Fused rings (3 6-C, 1 5-C) 1 -OH > Hydrophilicty Function: > Component of animal cell membranes (stabilizing cell membrane) > Precusor for other steroids synthesis > Form bile acids (Biological 'detergents' which solubilize fats) Pathophysiology: > High levels cholesterol contribute to atherosclerosis Location: Reaches across half of the bilayer |
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How does cholesterol span across the bilayer? a. 1/8 b. 1/4 c. 1/3 d. 1/2 bilayer e. Spans compeltely across |
Reaches across half the bilayer d. 1/2 bilayer |
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bile acids (function, structure) |
Biological detergents, which solubilize fats Structure: Cholesterol |
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Cholesterol in the membrane |
Interspersed in membrane Well within the phospholipid, spanning 1/2 the membrane Polar heads always point towards hydrophilic heads of phospholipid |
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Cell membrane (structure, function) |
Structure: Fluid mosaic of: Phospholipids Lipids Proteins (can be spanning entire as integral proteins) Carbohydrates (found outside (charged)) Function: Semipermeable barrier |
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Which is not in cell membranes? a. Phospholipids b. Nucleic acids c. Lipids d. Proteins e. Carbohydrates |
b. nucleic acids. |
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Reasons asymmetry of cell membranes |
Has proteins (integral proteins spanning throughout) Has carbohydrates on exterior (b/c charged) |
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Properties cell membrane |
Asymmetric Fluid Mosaic: different components: > phospholipid > lipid > protein > carbohydrate |
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Movement in C/M |
Proteins: little to no Phospholipids molecules: Lateral migration > 22 um/sec Flip flop > Rarely > Reason: Hydrophilic head of molecule must cross hydrophobic core of the membrane Rotation along axis > Fast |
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Tm relation to phospholipids |
More unsaturations: lower Tm in melting and freezing b/c more kinks (weaker IMF) More saturations: Increased Tm in melting and freezing b/c less kinks (stronger IMF) |
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Impact of cholesterol on changing temperatures |
Cholesterol will adapt based on changing temperature.
With increasing temperature, cholesterol makes fluid less fluid > by restraining the movement of phospholipids) With decreasing temperature, cholesterol makes more fluid > by hindering the closing packing of phospholipids and lowering the critical membrane making it harder to become solid and remains fluid |
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Components C/M |
Mosaic structure: Proteins > Integral membrane protein > Peripheral membrane proteins (via weak electrostatic forces) > also contribtues to assymetry Carbohydrates > found outside > contribuets asymmetry Lipids Glycoprotiens Lipoproteins ECM elements Cytoskeleton |
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Types proteins in c/M (structure, properties, location) Functions of these proteins |
Integral membrane proteins: Hydrophilic on outside areas Hydrophobic on inside areas Location: Span the hydrophobic interior of the membrane several times Function: Commonly function as ion channels b/c span Peripheral membrane proteins: Hydrophilic on outside areas No hydrophobic interior areas (thus no inside only on peripheries) Location: Loosely bound to the surface of the membrane |
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What forms ion channels? |
integral membrane proteins (with hydorphobic interior and hydrophilic exterior) |
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Properties of peripheral proteins |
Loosely bound to surface of membrane: Frequently exposed to parts of integral proteins Not embedded in lipid bilayer |
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Does integral membrane proteins span C/M only once? T/F |
False Integral membrane proteins can span multiple times across C/M |
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Functions of membrane proteins |
Receptor, i.e receptors for Cytokines (signal transduction) Active and facilitated passive transport Membrane enzymes > Transferases > Hydrolases > Oxidoreductase Cell adhesion molecules > Cell cell identification and interactions >> Selectins, integrins |
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Function membrane carbohydrates |
Markers that distinguish cells, including infectious agents, such as bacteria >Application: Markers for antibodies Adhesion between cells (cell-cell interaction) |
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Factors contributing membrane asymmetry |
Integral proteins Carbohydrates (on exterior surface) |
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Where are carbohydrates located |
reSTRICTED TO THE EXTERIOR Surface |
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Role ER in membrane asymmetry |
Builds plasma membrane Delivers PM in reversed orientation to its place of destiny > Molecules that start on inside face of ER end up on outside face of PM ER determines asymmetrical distribution of proteins, lipids, carbohydrates |
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How does PM deliver PM?
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In reversed orientation to its place of destiny Via: molecules starting on inside face of ER ending up on outside face of PM |
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Result flippase |
> ATP hydrolysis for flip flop > Multi drug resistance in which ATP hydrolysis pumps drugs out of cell membrane > Cancer > Chemo |
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Types transport |
Passive transport: > Simple diffusion > Osmosis (flow of higher concentration H2O (low conc. solute to lower concentration H2O (High conc. solute)) > Facilitated diffusion - carrier proteins > Facilitated diffusion - ion channels (* different from physiology) Active transport: > Primary AT (Using ATP) > Secondary AT (Using energy via the downhill passive transport of another molecule) i.e: Na+/Glucose, Na+/AA Secondary AT symporters > Endocytosis >> Ex: phagocytosis via macrophages > Exocytosis: Reverse process via secretion of enzymes, hormones, NT (Ach) |
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Types osmolarities of RBC and effects |
290 mosM: normal 150 mOsM: 50% HEMOLYSIS Lower tonicity: rapid hemolysis < 50 mOsM: Compeltel hemolysis |
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Effect of RBC in: 1. 150 mosm 2. less than 50 mosm 3. 290 mosM.
a. Nothing b. Some hemolysis c. 50% Hemolysis d. Complete hemolysis |
1. c. 50% hemolysis 2. d. Compete hemolysis 3. a. Nothing |
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Effect of rbc at 150 mosm |
50% hemolysis |
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Effect rbc at < 50 mosm |
Complete hemolysis |
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Effect RBC at 290 mosm |
Nothing |
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Slightl decrease < 290 mosm RBC |
Beginning water enter |
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Importance RBC? |
An osmometer that can measure swelling. |
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Facilitated diffusion property |
Method: No energy/ATP needed ** Down conc. gradient Types transporters: Transport proteins > Ion channels (different physiology) > Carrier proteins |
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Different simple ad facilitatetd difusion on graph |
Simple diffusion: straight lienar non saturable Facilitated diffusion: Michaelis menten like (Hyperbolic) with maximum VMax b/c of saturation of carrier proteins, i.e: in permease |
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What is Km? Description, and units * |
The concentration of [S] at which Vmax is 1/2* Units: milli molar (mM) * |
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Active ion pumps (Result mechanism) |
Using ATP hydrolysis to pump ions against a concentration gradient. |
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Function biological membranes |
Signal transduction: Needed for function hormones, cytokines that have receptors and do not enter (water soluble/non lipophilic) Transport Nerve conductance Generation and maintenance of electrochemical potential |
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Use generation and maintenance of electrochemical ptoential |
The concentration diff |
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Na+/K+ ATPase result What is it? |
3 nA+ out 2 K+ in A form of primary active transport |
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LDL receptor result |
LDL receptor (LDL-R) Participates in endocytosis of LDL cholesterol |
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Rationale for Na+/K+ atpase transfer of Na+ out, K+ in |
atomic weight na+ compared to k+ plays a role in why 3 Na+ goes out and 2K+ in And K+ more abundant and wants to get rid of more |
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Types cotransport (secondary AT) |
Symporter: both molecules both in same directiON Antiport: both molecules move in opposite directions |
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Secondary atp principles |
Conformational change Indirectly linked to ATP hydrolysis Location: Types such as glucose/na+ sympmort on apical side. |
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Does a conformational change result in Sec. AT? |
Yes. |
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What side is glucose-na+ symport protein on Na+/k+ atpase? |
Glucose-na: Apical. Na+/K+: Basolateral |
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Sides of Sec. AT and Fac. T for glucose? |
SAT: Apical symporter of Na+/glucose FT: Basolateral (down) via glucose going down concentration gradient of glucose |
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Gramicidin A (Result mechanism) |
Result: Active against gram positive cocci Mechanism: deplete cell of necessary cations Considerations: Topocal infections, not internal infections b/c its effect on our RBC can cause hemolysis and faster than effect on abcteria |
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Types ligand gating |
Voltage gated: Electrical potential difference causes nerve pulse transmission Ligand gated: Noncovalent bond of chemical lgiand, Ach, causes conformational change Mechanically gated: Allosteric change in channel. |
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What is the most important single factor to organize molecules of living matter into complex structural entities such as cellular plasma membranes or organelles?H |
Hydrophobic effect also: formation of detergent micelles |
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Composition of lipid in cellular plasma and organelle membranes |
40-80% lipid |
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What is the most prevalent lipid in cell membranes? |
phospholipids |
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What type of molecule is cholesterol? a. polar b. nonpolar c. amphipathic Reason? |
c. Amphipathic hydrophobic layer: planaer steroid ring polar layer: -OH group |
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location of plasma membrane cholesterol. |
Polar region near phosphate head Nonpolar steroid ring near hydrophilic lipid tails |
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Methods of phospholipid movement in membranes. Describe them. |
Rapid rotation around central long axis Move laterally (1x10^-8 cm2/s) Flip and flop > slow process, but can be facilitated with proteins |
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Difference between integral and peripheral membrane proteins. |
Integral: Have polar heads near ECM and cytosol Has non-polar tails in the interior of C/M > Dissolve using detergent Peripheral: Have only polar regions on polar head > Dissolved by shifting the the ionic strength of pH of the aqueous solution |
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Contributions to asymmetry in C/M |
Peripheral proteins Carbohydrate portion of glycolipids cause asymmetrical orientation |
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Effect of failure of Na+/K+ ATPase |
Cell may swell or shrink |
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1. Cells placed into 290 mOsm. What will happen? 2. Cells placed in 150 mOsM. whAT WILL Happen? 3. Cells placed in 50 mOsM. What will happen? a. some water will flow in b. 50% cells undergo hemolysis c. 100% cells undergo hemolysis d. some water will flow out e. moderate crenation f. complete crenation g. nothing |
1. g. since isotonic 2. b. since hypotonic enough for 50% cellular hemolysis 3. c. since too hypotonic and compelte 100% hemolysis |
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A facilitated transporter is now active for glucose.. what will happen? |
Glucose flow down its concentration gradient with assistance of protein (carrier), but then saturation will eventually be reached at Vmax. Values: Km = substrate concentration [S] at which 1/2 Vmax Vm = maximum enzyme activity |
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Know the structural components of the cell membrane |
All biological membranes basically made of phospholipid bilayer May include: - Lipids such as steroids - Proteins - Carbohydrates - Glycolipids - Glycoproteins |
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All biological membranes must contain which of the following? a. steroids b. phospholipid bilayer c. protein d. carbohydrates e. glycolipids f. glycoproteins |
b. phospholipid bilayer All biological membranes made basically of phospholipid bilayer, others are optional. |
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What do all lipids have in common? |
Low or no affinity for water. |
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Which correctly describes lipids? a. lipids are macromolecules b. lipids are the third larger macromolecule c. lipids have a moderate level of affinity for water due to some hydrophilicity d. lipids have low or no affinity for water |
d. lipids have low or no affinity for water |
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Which is the smallest macromolecule? a. nucleic acids b. proteins c. lipids d. polysaccharides |
c. lipids Lipids are macromolecules that do not include polymers, but smaller than true macromolecules |
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Which describes a lipid? a. micromolecule b. macromolecule c. polymer |
b. macromolecule |
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What do lipids mostly consist of? a. fatty acids b. glycerol backbone c. hydrocarbons d. phosphate heads e. steroid chains |
c. hydrocarbons Consist mainly of hydrocarbons |
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What are the 3 classes of lipids? |
Fats Steroids Phospholipids |
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Which of the following is not considered a class of lipid according to slide 5 ? a. fat b. steroid c. wax d. phospholipid |
c. wax Rest considered lipids according to slide 5 |
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Describe Fat |
Triglyceride 1 glycerol esterified via dehydration reaction (removing 3 H2O) to 3 FA Properties FA: Long linear unbranched carbon skeleton 16 or 18 carbon atoms Carboxyl group (hydrophilic): head Long hydrocarbon tail |
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What are responsibile for FA hydrophobicity? |
C-H bonds |
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WHAT IS AN ESTER BOND IN FA? |
Bond between OH and COOH. |
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What determines characteristics of FA? |
Length # and location of double bonds |
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Which of the following causes hydrocarbon tails to pack together? a. saturated fats b. unsaturated fats c. cholesterol d. glycoproteins |
a. saturated fats cause hydrocarbon tails to pack together |
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Which of the following causes hydrocarbon tails to have a high melting point? a. saturated fats b. unsaturated fats c. cholesterol d. glycoproteins |
a. saturated fats cause hydrocarbon tails to pack together |
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What has an important influence on membrane fluidity at different temperature? |
Unsaturated fats |
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What has an important influence on membrane fluidity at different temperature? a. saturated fats b. unsaturated fats c. cholesterol d. glycoproteins e. glycolipids |
b. unsaturated fats Unsaturated fats have an important influence on membrane fluidity at difference temperatures. |
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Properties fat |
Energy storage (1g fat 9kcal/g) Cushion for vital organs > kidneys are embedded in adipose tissue (fat) Insulation |
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Which organ is embedded in fat? a. brain b. liver c. kidneys d. pancreas e. stomach f. SI g. LI |
c. kidneys |
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How are phospholipids differ from fats? |
Only 2 FA, third FA replaced by phosphate group |
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Properties of phospholipids |
Hydrohphobic (hydrocarbon tail) Hydrophilic pO43- head When water added: Micelle/phospholipid bilayer orientatoin via: > Phosphate heads face water > Nonpolar tails away from water |
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What causes heart arrhythmia? |
Malfunction of gap junctions |
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How do heart cells beat in coordination? |
After they touch each other and gap junctions connect the cytoplasms of adjacent touching cells. |
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Heart cells are placed near one another, but do not touch. w hat will happen? a. beat in coordination b. beat independently c. beat at times in coordination and times independently. d. beat as one heart |
b. beat independently Separated myocyte beat but without coordinatino if they do not touch each oth er. They will only beat in coordination if they contain gap junctions and touch one another |
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What is responsible or light absorption in theh eye? a. bacteriorhodopsin b. retinal c. a 7 alpha helical protein |
b. retinal |
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What describes retinal? a. a 7 alpha helical protein that spans the bilayer b. a light driven proton pump protein c. an aldehyde of vitamin A that absorbs light |
c. |
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What is rhodopsin
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A 7 alpha helical protein spanning the bilayer which is a light driven proton pump |
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What describes the structure of steroids? a. 6 hexose rings b. 2 hexose rings and 2 pentose rings c. 3 hexose rings and 1 pentose rings d. 3 hexose rings and 2 pentose rings e. 3 pentose rings and 1 hexose ring |
c. 3 hexose rings and 1 pentose ring |
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Function steroids? Structure steroids |
Function: Precursor for other steroid synthesis Bad: > may promote atherosclerosis Precursor bile Essential component of most membranes Structure: 4 rings (3 hexose, 1 pentose) Reaches across 1/2 of the membrane |
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Which of the following functions in the stabilization of the membrane? a. saturated fatty acids b. unsaturated fatty acids c. cholesterol d. glycoproteins e. glycolipids |
c. steroids |
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Which of the following contributes to atherosclerosis in high levels? a. saturated fatty acids b. unsaturated fatty acids c. cholesterol d. glycoproteins e. glycolipids |
c. cholesterol |
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Cholesterol travels how far across the c/m? |
Reaches across half of the membrane |
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Structure steroids. |
4 rings (3 hexose rings, 1 pentose ring) 1 of the 3 hexose rings have a double bond. |
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Do steroids have to have a double bond? |
Yes on 1 of the hexose rings (3 hexose rings, 1 pentose ring) |
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What describes steroids overall? a. hydrophobic b. hydrophilic c. amphipathic Why? |
c. amphipathic Hydrophobic 4 carbon rings and hydropilic Polar -OH on the ring |
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Describe movement of phospholipids |
Overall: move randomly Migration rate: 22 um/s Types movement: LateraL (fast) Rotation (fast0 Rarely flip flop (require proteins) |
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Role of ER in membrane asymmetry |
Plasma membrane build by ER The eR then determines asymmetric distirbution of proteins, lipids, and carbs |
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Which of the following determines asymmetrical distribution of proteins, lipids, and carbohydrates on P/M? a. Rough ER b. Smooth eR c. Golgi Apparatus d. Mitochondria e. P/M |
a. Rough ER Not only does the RER synthesize P/M, it also determines asymmetrical distribution of the proteins, lipids, and carbs in the P/M |
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Which of the following synthesizes the P/M? a. Rough ER b. Smooth eR c. Golgi Apparatus d. Mitochondria e. P/M |
a. Rough eR |
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Factors affecting membrane fluidity. Describe. |
3 factors: temperature A saturation or unsaturation Cholesterol Temperature: Membrane fluid until critical temp, Tm, reached at which the membrane solidifies. But the temperature of solidification depends on unsaturated hydrocarbon tails. With unsaturated hydrocarbon tails, we have kinking which weakens IMF and thus lower temperature required (# Unsaturations decrease solidifying temeprature of membrane) Cholesteorl: Increase temp, less fluid Low temp, more fluid Thus, cholesterol lower critical temp (temp solidification of phospholipids) |
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Describe protein mobility. Compare to phospholipid mobility. |
Slower than phospholipids Reason: Proteins larger Immobile by virtue of their attachment to cytoskeleton |
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1. What causes proteins to be immobile? 2. What causes their movement to be much slower? a. large b. electrostatic forces ebtween their AA c. attachment to cytoskeleton d. They are not, they are quite mobile |
1. c. 2. a. |
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Describe membrane carbohydrates |
Branched oligosaccharides Short with < 15 monosaccharides Oligosaccharides can form > glycoproteins (via covalent binding to proteins) > glycolipids (via covalent bonding to lipids) Function: > adhesion > cell-cell interaction |
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Function LDL receptor |
Endocytosis of LDL molecules |
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Where does the AP start? |
Axon hillock |
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What is the myelin sheath made of? |
Cholesterol H2O Lipid: glycolipid-galactocerebroside Protein: glycoprotein proteolipid |
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Lipid component of myelin? a. cholesterol b. glycolipid-galactocerebroside c. glycoprotein proteolipid d. phospholipid |
b. glycolipid-galactocerebroside |
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Protein component of myelin? a. cholesterol b. glycolipid-galactocerebroside c. glycoprotein proteolipid d. phospholipid |
c. glycoprotein proteolipid |
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Protien component myelin? |
glycoprotein proteolipid |
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Lipid component myelin? |
Glycolipid-galactocerebroside |
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How is bacteriorhodopsin grown? |
Low levels O2, 4 M NaCl |
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How is bacteriorhodopsin grown? a. high levels o2, 0 M NaCl b. high levels o2, 4 M NaCl c. low levels o2, 0 M NaCl d. low levels o2, 4 M NaCl e. low levels O2, 8 M NaCl F. HIGH levels o2, 8 M NaCl |
d. low levels o2, 4 M NaCl |
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Which describes peripheral membrane proteins?** Location Bond Function Properties |
On the peripheries, usually associated with integral Not in interior Loosely attached to membranes via electrostatic interactions Properties: easily released with high salt solution Involved in eTC |
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Which describes integral membrane proteins?** |
Solbulization requires disruption via detergent Usually span Asymmetry required for most functions > cell surface > transport |
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which of the following is incorrect? a. Ach receptor only contains L amino acids b. Asymmetry is not required for most functions in integral membrane proteins c. Bacteriorhodopsin is grown with low O2 and 4 M NaCl d. Detergent is not required to disrupt peripheral proteins, only salt. |
b. false. Explanation: a. correct b: not correct, asymmetry is required for most functions especially in integral membrane: i.e: cell surface markers, transport proteins c: correct d: correct |
