There are four major classes of lipoproteins: chylomicrons, VLDL, LDL, and HDL. This classification is based on the relative content of the five major constituents of lipoproteins: cholesterol, cholesteryl esters, phospholipids, proteins, and triacylglycerols.  Blank #1: Which of the five constituents listed above would be found in the inner core of lipoproteins? List all that apply, separated by commas. Blank #2: Which of the five constituents listed above would be found at the surface of lipoproteins? List all that apply, separated by commas. Blank #3: Which lipoprotein carries cholesteryl esters to the liver for excretion, LDL or HDL? Blank #4: The surface of lipoproteins is a monolayer and not a bilayer because ___________.

Below is a diagram of the cell wall of a Gram-negative bacteria.  Blank #1: What type of molecule is A? Be specific (for example: glycerophospholipid) Blank #2: What is the effect of molecules like A in our bodies? Blank #3: What type of molecule is B? Be specific (for example: glycerophospholipid)   Gram-negative bacteria are particularly difficult to treat because their cells are shielded by a double-membrane envelope, which constitutes a formidable barrier to antibiotics. In class we discussed both lysozymes and penicillin as antibiotics that are ineffective against Gram-negative bacteria. Use blanks 4 and 5 to give a detailed explanation of how each of these antibiotics act to kill Gram-positive bacteria, and why that is not possible in Gram-negative bacteria. Blank #4: Lysozyme Blank #5: Penicillin

Blanks #1 through #5: Complete hydrolysis of the lipid below gives which five molecules? List one molecule per blank. Describe specific fatty acids by their delta nomenclature (e.g. 18:2 delta 4, 7 fatty acid).  Blank #6: The unsaturated fatty acid is an omega        fatty acid Blank #7: Is this lipid likely to be part of the inner or outer leaflet of the plasma membrane?   In response to certain hormonal signals, phospholipase A2 hydrolyzes the unsaturated fatty acid (arachidonic acid) from the lipid above. Arachidonic acid then serves as a precursor to various eicosanoids. These include prostaglandins (such as PGE2, PGI2), thromboxane A2 (TXA2), and leukotriene A (see the diagram below).  Blank #8: Non-steroidal anti-inflammatories (NSAID’s) such as aspirin or ibuprofen reduce pain and inflammation, cause bleeding, but have no effect on smooth muscle contraction. Explain this statement by describing how NSAID’s impact the formation of various molecules in the diagram above. 

Below are oxygen binding curves for myoglobin and hemoglobin.  Blank #1: Which of the curves shows cooperative binding of O2, myoglobin or hemoglobin? Blank #2: Which has a lower P50 value, myoglobin or hemoglobin? Blank #3: What is the approximate P50 value for myoglobin, with units? Blank #4: At high O2 pressures, both myoglobin and hemoglobin have comparable O2 affinities. In the tissues, however, where the oxygen pressure is much lower, hemoglobin has a much _______ (higher/lower) affinity for O2 than myoglobin, allowing it to ______(release/absorb) O2 ______(to/from) myoglobin.  Consider the inhibitors CO and CO2. Blank #5: Myoglobin is inhibited by ______ (CO only, CO2 only, or both CO and CO2) Blank #6: Hemoglobin is inhibited by ______ (CO only, CO2 only, or both CO and CO2)  

Blank #1: The molecule below is a ________ Blank #2: The hydrophobic region of this molecule is an oxidized form of _________ Blank #3: The ionic/hydrophilic region of this molecule is ___________, which has condensed with the molecule in blank #2 Blank #4: Explain how this amphiphilic molecule aids in digestion. Blank #5: In addition to aiding in digestion, hepatic synthesis of this molecule is the major route used by your body to ____________.   

Match the number on each structure with the correct statement. 

Below is a disaccharide. The sugar on the right is allose.  Blank #1: What kind of glycosidic bond is represented here? (for example: beta 1 -> 6) Blank #2: What is the stereochemical relationship between allose and glucose? (enantiomers, epimers at C-? , diastereomers with more than one different chiral C, structural isomers, different molecules)   The disaccharide above condenses with other sugars to give the branched polysaccharide below.  Blank #3: Which is (are) the reducing end(s) of this polysaccharide? (A, B, and/or C) Blank #4: Which is (are) beta 1->6 glycosidic bond(s)? (1, 2, 3, and/or 4) Blank #5: Is this likely to be an energy storage or structural polysaccharide? Explain why. Blank #6: What is the benefit of having branch points? Blank #7: Give two additional examples of branched polysaccharides.

Membrane lipids in tissue samples obtained from different parts of a reindeer’s leg have different fatty acid compositions. (2 pts each, 6 pts) Blank #1: Relative to the membrane lipids from tissues near the upper leg, how are the membrane lipids near the hooves, which are often sunk in snow, different (length and saturation of fatty acids)?  Blank #2: Explain how the length of fatty acids chosen in blank #1 helps the deer maintain the correct level of fluidity in the membranes from cells in the hooves. Blank #3: Explain how the degree of saturation/unsaturation of fatty acids chosen in blank #1 helps the deer maintain the correct level of fluidity in the membranes from cells in the hooves.

The structure of one of the enantiomers of psicose is shown below.  Blank #1: Is this the D or L enantiomer of psicose? Blank #2: Define psicose in terms of the number of carbons and its carbonyl functional group (for example, aldopentose).  Blank #3: What is the stereochemical relationship between psicose and fructose, assuming they are both D? (enantiomers, epimers at C-? , diastereomers with more than one different chiral C, structural isomers, different molecules) Blank #4: Write the letter of the cyclic structure shown below that corresponds to a-D-psicose.  Blank #5: Is this a reducing sugar? (yes/no) Blank #6: Does picose undergo mutarotation? (yes/no)  

Into which group would you place a photosynthetic organism that lacks a nucleus and has a thin peptidoglycan wall surrounded by an outer membrane?