Quiz 9
_____________ this is the number of carbons is most common fatty. __________ transport systems confer this important property on membranes
16 - 18 , Selective permeability
Which of the following four fatty acids has the lowest melting point? 1. CH3CH2CH2CH2CH2COOH 2.CH3CH2CH2CH2CH2CH2CH2CH2CH2COOH 3.CH3CH2CH2CH2CH2CH2CH2COOH 4. CH3CH=CHCH2CH2COOH
4
Which of the following groups is not present in a phosphatidic acid?
Choline
What does amphipathic mean?
Having both hydrophilic and hydrophobic regions
How does cholesterol affect membrane fluidity?
It tends to decrease the fluidity
how do the membranes of archaea differ from bacteria and eukaryotes?
The lipids do not contain a carboxylic acid ester, but instead have an ether link to the glycerol the alkyl chains are branched the stereochemistry of the central carbon of glycerol is inverted
Which of the following is not a characteristic of most fatty acids?
Two carboxyl (-COOH) groups, one at each end
Which of the following membranes would be the most rigid?
a bilayer made of lipids with saturated 18 carbon-fatty acids
Carbohydrates residues attached to the membrane lipids are
always positioned on the extracellular side of the membrane
________________- this is a term applied to molecules that have both hydrophilic and hydrophobic moieties. ____________ contain a double bond three carbons from distal end of the fatty acid
amphipatic, w-3 fatty acids
_____________ in addition to phospholipids and glycolipids, this is a major type of membrane lipid. _______________ these membrane components contain carbohydrates
cholesterol, gycolipids
In phosphoglycerides, the fatty acids are linked to the glycerol backbone by the ________ linkages. ______________ is a membrane lipid composed of sphingosine, fatty acid, and a simple sugar
ester, cerebroside
Which of the following molecules is not amphipathic?
glucose
With what compound are fatty acids reacted to make a fat or oil?
glycerol
What characteristic is most used to define lipids?
solubility
Glycolipids are characterized by containing the following non-lipid component:
sugars
How does the presence of cis double bonds in fatty acids affect membrane fluidity?
they tend to decrease the fluidity
The distribution of lipids in membranes is
uneven, with bulkier molecules on the exterior
What force(s) stabilize(s) the lipid bilayers?
van der waals interaction and electrostatic and hydrogen bonding between the polar heads and surrounding water