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Three types of lipids correct answer: storage lipid(fat), structural lipids(membrane) and signaling lipids(hormaones) storage lipids are correct answer: triacyl glyceride structural lipids include correct answer: phospholipid, sphingolipid, glycolipids and steroids signaling lipids include correct answer: eicosonoids and steroids what are the core building blocks of lipids correct answer: fatty acids a fatty acyl chain is _ if it contains only single bonds, but _ if it has one or more double bonds correct answer: saturated, unsaturated Saturated Fatty acid adopt _ conformation correct answer: anti, trans Double bonds in fatty acids are _ conformation correct answer: cis, gauche the melting temp _ with increase in carbon and _with increase with double bond correct answer: increase, decrease
Fatty acids are stored as _ correct answer: triacylglycerols The 2 types of triacylglycerol are: correct answer: simple (same tail length)and mixed (different tail length and can be saturated or unsaturated) In membranes fatty acids are attached to correct answer: polar head groups1) glycerophosholipids 2) sphingolipids 3) glycoshpingolipids to make a glycerophosholipid fatty acids are esterfied at the correct answer: 1,2 position of the sn-glycerol-3-phosphate List the neutral phospholips correct answer: 1)phosphotidilcholine and phosphotidilethanolamine In sphingolipids, the structure is based of of_ and fatty acids are attached by what kind of likage? correct answer: sphingosine, amide linkage. The polar head groups are esterfied How can cholesterol modulate membrane fluidity? correct answer: 1) Disrupt packing of hydrocarbon tails
- Slow motion of hydrocarbon tails The two types of signalling lipids come from: correct answer:
- steroids-precursor for animal lipids 2)phospholipids-the break down of certain structural lipids by hydrolyzing phospholipase, can cause chemical signals.
Types of membrane proteins correct answer: peripheral, integral(goes all the way through the membrane) Peripheral membrane proteins adhere to the membrane through correct answer: non covalent interactions peripheral membrane proteins can removed using correct answer: mild disruption( high salt or small change in pH) How does salt removeperipheral membrane protein correct answer: high salt concentration gets in between the ioninc/ hydrogen interactons of proteins to the membrane by sheilding. How does pH remove peripheral proteins correct answer: It disrupts ionic interactions and hydrogen bonds by protonating/deprotonating ionizable groups Amphipathic alpha helix have 2 faces the_ and the . Their signature amino acid sequence is correct answer: polar and non- polar. Polar AA-Polar AA-NPAA-NP AA-P AA-P AA Integral membrane proteins require conditions to remove them like_ correct answer: harsh conditions like detergents or organic solvents What are the types of integral membrane proteins correct answer: 1) Type 1-Single pass-NH3+ outside
- Type 2- Single pass-NH3+ inside
- Type 3-Multi pass-sinlge proteins 4)Type 4-Single pass-Multiple proteins
How can you tell whether a region of the cell is facing the extracellular side? correct answer: the membrane is lined with lots of sugars involved in functions like cell-cell communication The function of the intracellular facing region of the membrane proteins is to correct answer: Transmit the signals from the outside bacteria rhodopsin purple colour arises from a retinal molecule bound via correct answer: Schiff base linkage to Lys light induces a _ isomerization in the retinal correct answer: cis- trans isomerization. goes from trans to cis retinal isomerization triggers correct answer: proton release. the proton moves faster in retinal due to correct answer: proton hopping how does proton hopping occur correct answer: - The schiff base is deprotonated so it reaquires it proton from asp 96 -Asp 96 takes a proton from cytosol then gives it up the reprotonation of glu 204-Glu194 pair. -system is ready for another round of photon-proton pumping What is the Beta Barrel sequence motif correct answer: P AA- NP AA-P AA-N AA What is the schematic model of glycophorin A correct answer: - It's an integral membrane protein with thecarboxyl terminal
the active site of lysozyme has 2 key residues correct answer: Glu35 and Asp 52which is deprotonated Enzymes can be modified using correct answer: 1) Substrate Availability and supply 2)covalent modifications, 3)Allosteric control
- zymogen, proenzymes- ex trypsinogen-inactive enzyme precursos which when activated positivley regulate themselvs the disease gout is caused by the lack in negative feedback in correct answer: ribose-5-phosphate geting posphorylated by atp hydrolysis What assumptions are made by the michaelis menten eqn correct answer: 1) Assumes the formation of an enzyme substrate comple E+s=ES---> P 2)Assumes the the ES complex is in rapid equilibrium with free enzyme
- break down of ES to product is slower than ES formation and ES---> E+S Michaelis menten eqns correct answer: 1) Rate of P production v=k2[ES]
- Rate of ES formation v=k1[E][S]
- Rate of ES breakdown v=[ES](k-1 +k) Km=[K-1 +K2]/K
What is Km correct answer: -constant derived from rate constant small Km means correct answer: higher affinity for substrate binding RNA cleavage by RNAse mechanism correct answer: 1-His carries out a nucleophilic attack on the oh of a RNA, which deprotonates His 2- the phosphate in the phosphdiester linkage has 5 bonds. Lys 41 stabilizes 3- the molecule is cleavedreleasing a phosphate tetramer with a deprotonated o 4-His119 nucleophilic attacks a water molecule which deprotonates another O2 in phosphate. Phosphate attacks the proton on his 12, deprotonating it 5- the enzyme is now reset for another cleavage. Mechanism of lysozyme cleavage correct answer: 1) MyrNac undergoes a conformational change when it enters the active site(D).
- Glu35 whichis protnated at ph5 acts as an acidic catalyst donating a proton to the oxygen involved in glycosidic bond between D and E residues.
- the portion of substrate bound to site E difuses out of the cleft and is replaced by water
- Asp 52 which is negatively charged at ph5 forms a strong ion pair with the unstable oxocarbocation -strong like a covslent bond
- A proton from H2O is transferred to the conjugat base of Glu35-glu gets a proton back-the resulting ion adds to the
