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