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60 Cards in this Set

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Fatty Acids
major fuel for the body, precursor for lipids
Are fatty acids hydrophibic or hydrophillic?
They are amphipathic, carboxyl group at one end and hydrocarbon chain at other
Where fatty acids are found?
Fatty acids are rarely found in blood or in cells, in blood bound to albumin, in cells bound to proteins or exist as acetyl-CoA
Unsaturated Fatty Acids
Acids that have one or more double bond
What is another name for triglycerides?
Triacylglycerols, neutral fats
What is the structure of a triglycerol?
Triglycerol has a glycerol backbone in which all three hydroxyl groups are esterified with a fatty acid.
Are triglycerides hydrophobic or hydrophillic?
Hydrophobic, tend to associate into large anhydrous oil drops
What are phospholipids?
Amphipathic molecules, primary building block of membrane
What is structure of a phospholipid?
Two alcohols linked together by a phosphodiester bond
Sphingolipid
structural part of the membrane,contains sphingosine, long chain amino alcohol and serine
Sphingosine
one amino group and 2 hydroxyls, amino group is linked via amide bond to long chain saturated fatty acid
what is the relationship between enzyme concentration and velocity
more enzyme faster reaction
What is Km and what does it show?
Km = [S] at 1/2 Vmax, shows affinity for substrate
At low concentrations, what does low Km mean? high?
low Km - more effective, high Km less effective
what is kcat?
It is the rate constant of the reaction when enzyme is saturated with sbstrate
What does kcat/Km show?
catalytic efficiency
What reactions do not follow Michaelis-Menten equation?
Multisubstrate(ox-red, transferase), multistep reaction, nonhyperbolic reaction(multiple active sites)
If reaction is nonhyperbolic, what shape does the curve have?
Sigmoidal, due to cooperativity
Describe competitive inhibition
Inhibitor and substrate compete for binding in enzyme active site, inhibitor usually resembles substrate in shape and size
How does competitive inhibition affect Km?
Increases
How does it affect Vmax and Kcat?
stays same
What does low inhibition K means?
Inhibitor tightly bound to enzyme
Mixed inhibition
Vmax decreases, Km may increase or decrease
Noncompetitive inhibition
Km is not affected, Vmax and Kcat decrease, irreversible
Is Na concentration greater iside of the cell or outside?
Greater outside then inside
Is K concentration greater inside or outside?
Greater inside then outside
Glycerophospholipids
Glycerol backbone, 2 fatty acids and phosphate derivative
What kind of lipids form bilayers
glycerophospholipids
Are glycerophospholipids hydrophobic or hydrophilic
Amphipathic
Melting point of bilayer
Temperature of transition from solid state to fluid state
Describe solid phase of bilayer
acyl chains pack together in van der Waals contact
Describe fluid phase of bilayer
Methylene groups of acyl chains rotate freely
What is the relationship between chain length in saturated fatty acids and melting temp
Melting point inreases with increased chain length because surface for van der Waals increases
What is the relationship between unsaturation and melting point
more unsaturation - lower temp, double bonds kink, pack less efficiently
Cholesterol and membrane fluidity
Cholesterol can both increase membrane fluidity by preventing close packing or decrease it due to rigid planar system
Raft?
cholesterol+sphingolipid
Movement from one leaflet into another
transverse diffusion, flip flop
Is this a favorable movement?
no, thermodynamically unfavorable but assisted with enzymes translocases
Movement within one leaflet
Lateral diffusion
Which is faster transverse or lateral diffusion?
Lateral - fast, transverse - very slow
Intrinsic Protein (integral)
Portion of structure is fully buried into lipid bilayer
Peripheral Protein(extrinsic)
On the surface, interact with heads
Lipid Linked Protein
hydrophobic tail inside
What kind of transporters are Na and K and why
passive, move down concentration gradient , dont need energy
Uniport definition and example
moves single substance at a time, ex - glucose
symport definiiton
transport two different substances across membrane in same direction
antiport
transport two different substances in opposite directions.
What suppports Na K outside/inside concentrations
Na, K ATPase
What drives energetically unfavorable transport of Na and K
converting ATP to ADP and Pi
Protein Primary structure
Sequence of amino acids
Protein Secondary structure
Localized conformation of polypeptide backbone
Tertiary structure
Three dimensional structure of an entire polypeptide including side chains
Quaternary structure
Spatial arrangement of polypeptide chains in a protein with multiple subunits
What drives formation of Secondary structure
H bonding and steric strain
Name examples of 2 structure
alpha helix and b sheet
Parallel beta sheet
neighboring strands run in the same direction
Antiparallel beta sheet
neighboring strands in opposite directions
Fractional Saturation
y= MbO2/Mb+MbO2, or pO2/K+pO2
Bohr effect
When pH decreases, affinity of hemoglobin for O2 decreases
BPG
binds to deoxyhemoglobin, but not oxyhemoglobin, reduces oxygen affinity stablizing deoxy conformation