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61 Cards in this Set
- Front
- Back
lipids |
water insoluble molecules that are highly soluble in organic solvents |
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Lipids are sometimes used to |
store energy |
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Lipids are |
key components of membrans |
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Lipids do not form |
polymers |
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lipids are |
non covalent assemblies |
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Five classes of lipids |
Free Fatty Acids Triacyglycerols Phospholipids Glycolipids Steroids |
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Explain Free Fatty Acids |
This simplest type of lipid is most commonly used as a fuel. Fatty acids vary in hydrocarbon chain length, which has important ramifications when they are used as fuels and as components of membrane lipids |
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Explain triacyglycerols |
this class of lipid is the storage form of fatty acids |
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Explain phospholipids |
these membrane lipids consist of fatty acids attached to a scaffold that also bears a charged phosphoryl group, creating a macromolecule with a polar head and nonpolar tail. |
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Explain glycolipids |
these lipids are bound to carbohydrates and are important membrane constituents |
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Explain steroids |
these lipids differ from the other classes in that they are polycyclic hydrocarbons. Steroids function as hormones that control a variety of physiological functions. The most common steroid is cholesterol, another vital membrane component. |
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Fats or Fatty Acids |
chains of hydrogen bearing carbon atoms which terminate with carboxcylic acid groups. |
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Two key roles of fatty acids |
fuels and as building blocks for membrane lipids |
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Why are fats good fuels |
because they are more reduced than carbohydrates |
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What does it mean to be a saturated fatty acid |
to only contain single bonds |
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unsaturated fatty acids |
contain one or more double or triple bonds |
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18:2 means |
there are 18 single bonds and 2 double bonds |
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Fatty acid carbon atoms are usually numbered starting at |
the carboxyl terminus or at the terminal carbon |
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Carbon atoms 2 and 3 are often referred to as |
alpha and beta |
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The last carbon atom in the chain is usually a |
methyl carbon atom |
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The last carbon is called the |
omega carbon atom (w) |
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What symbol represents a double bond |
delta followed by a superscript |
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Fatty acids in biological systems usually contain |
an even number of carbon atoms, typically between 14 and 24. With 16 and 18 being the most common |
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configuration of most double bonds in most unsaturated fatty acids is |
cis |
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properties of fatty acids and of lipids are dependent on |
the chain length and degree of unsaturation |
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unsaturated fatty acids have (blank) boiling points than saturated fatty acids of the same length |
lower |
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What does a cis bond NOT allow |
tight packing |
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The lack of tight packing limits |
van der waals forces between chains and lowers the melting temperature |
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short chain length makes for a (blank) boiling point |
lower |
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too much saturated and trans-unsaturated fats are correlated with |
high blood levels of cholesterol and cardiovascular disease |
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certain cis polyunsaturated fats are essential in our diets because |
we cannot synthesize them ourselves. Example would be (Omega)-3 fatty acids |
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Omega 3 fatty acids |
polyunsaturated fatty acids common in cold water fish such as salmon. Vegatable oils as well |
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the concentration of free fatty acids in cells or the blood is low because |
free fatty acids are strong acids |
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Fatty acids required for energy generation are stored as |
triacyglycerols |
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How are triacyglycerols formed |
by the attachment of three fatty acid chains to a glycerol molecule |
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tricyglycerols are hydro |
phobic. This means they are stored in a nearly anhydrous form. |
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Polar carbohydrates bind to |
water molecules |
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a gram of nearly anhydrous fat stores more than |
6 times as much energy as a gram of hydrated glycogen |
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major site of tricyglycerol accumulation |
adipose tissue |
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three major kinds of membrane lipids |
phospholipids, glycolipids, and cholesterol |
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Four components of a phospholipid |
on or more fatty acids a platform to which the fatty acids are attached a phosphate an alcohol attached to the phosphate |
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possible platforms for phospholipids |
glycerol a three carbon alcohol sphingosine or more complex alcohol |
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esterification |
fatty acids are attached to a glycerol through ester linkages |
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https://memorize.com/membrane-lipids-proteins-and-carbohydrates/emmurphy11 |
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sphingolipids |
phospholipids built on a sphingosine backbone |
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sphingosine |
an amino alcohol that contains a long, unsaturated hydrocarbon chain |
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glycolipids |
sugar containing lipids that play a role in cell - cell interations |
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the simplist glycolipid |
cerebroside |
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glycolipids are oriented in an |
asymmetric fashion in membranes with the sugar residues always on the extracellular side of the membrane |
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steroids |
function as powerful hormones that facilitate the digestion of lipids in the diet are are key membrane constituents |
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steroids exhibit a |
cyclical rather than a linear structure |
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explain the steroid nucleus |
all steroids have a tetracyclohexane ring structure. this consists of three cyclohexane rings and cyclopentane ring joined together |
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what is the most common steroid
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cholesterol
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sterol |
steroid with an alcohol functional group |
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cholesterol is important in |
maintaining proper membrane fluidity |
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free cholesterol does not exist |
outside of membranes and is esterfied to a fatty acid for storage and transport |
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membrane lipids are |
amphipathic molecules containing both hydrophilic and hydrophobic moiety |
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the polar head is |
hydrophilic |
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some proteins are modified by the covalent attachment of |
hydrophobic groups |
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Triacyglycerols are stored in |
anhydrous form |
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