BIOC405 MIDTERM2 EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
Lipid molecules are said to be amphipathic, meaning that:
they have a dual nature with part of the molecule being hydrophobic and the other part
hydrophilic.
Unsaturated fatty acids generally have double bonds that are in the cis, rather
than the trans, configuration. One of the consequences of this is
a 30° bend in the molecule
Which of the following lipids is used for energy storage?
triacylglycerols
Compared to olive oil, you would expect beef fat to have a higher proportion of:
long-chain saturated fatty acids.
The basic building blocks that make up glycosphingolipids include all of the
following except:
glycerol
After the removal of all sugar units from a ganglioside, what molecule remains?
a ceramide
What is the structure of the steroid nucleus common to all sterols?
It consists of four fused rings, three with six carbons and one with five
added more carbons to unsaturated fatty acid:
,increases melting point (london dispersion become stronger w/ more carbons), need
more energy to break these interactions
double bonds in saturated fatty acids:
cis double bond REDUCES melting temp (kinking molecule prevents it from being able
to pack together)
(introducing double bonds reduces MP)
lipids
any various substances that: are soluble in nonpolar organic solvents (chloroform or
ether)
usually insoluble in water, along with proteins and carbohydrates constitute the principal
structural components of living cells
hardest waxes:
more packing, longest fatty acid chain, highest MP, means its more solid wax
which of the following components are part of structure of cardiolipin
fatty acid, glycerol, phosphate
clostridium psychrophilic is a species of extremophilic bacteria that thrives at low
temperatures. how would you expect their membranes to differ from ordinary
bacteria?
shorter, more unsaturated lipids
two FRAP experiments are run:
a) lipid headgroups are fluorescently labeled
b) membrane proteins are explicitly labelled
which is correct?
, the recovery time will be longer for proteins
what readily pass through membrane?
small, nonpolar molecules, gases
what is correct about aquaporin-1?
is c4- tetramer has 4 channels where water can come in
at high levels of water flux, it will show saturation behavior
transporters that do not undergo large-scale conformational change as part of
their transport mechanism
potassium ion channel KcsA, aquaporin
the sodium calcium (Na+/Ca2+) exchanger is used to remove calcium from cells.
It pumps:
3 Na+ ions inside the cell down a concentration gradient
1 Ca2+ ion outside the cell against a concentration gradient
what type of transporter is this?
secondary active antiporter
a mutant variant of GPCR alpha chain is found that hydrolyze GTP twice as fast
as the wile-type variant. What is true for a single cycle of activity?
the mutant GPCR will produce less cAMP compared to wild-type
considering the insulin receptor, what is true?
insulin is a primary messenger, while PIP3 is a second messenger
Although salts of fatty acids form micelles, phospholipids and glycolipids form
bimolecular sheets because
of the presence of two fatty acyl chains
WITH COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
Lipid molecules are said to be amphipathic, meaning that:
they have a dual nature with part of the molecule being hydrophobic and the other part
hydrophilic.
Unsaturated fatty acids generally have double bonds that are in the cis, rather
than the trans, configuration. One of the consequences of this is
a 30° bend in the molecule
Which of the following lipids is used for energy storage?
triacylglycerols
Compared to olive oil, you would expect beef fat to have a higher proportion of:
long-chain saturated fatty acids.
The basic building blocks that make up glycosphingolipids include all of the
following except:
glycerol
After the removal of all sugar units from a ganglioside, what molecule remains?
a ceramide
What is the structure of the steroid nucleus common to all sterols?
It consists of four fused rings, three with six carbons and one with five
added more carbons to unsaturated fatty acid:
,increases melting point (london dispersion become stronger w/ more carbons), need
more energy to break these interactions
double bonds in saturated fatty acids:
cis double bond REDUCES melting temp (kinking molecule prevents it from being able
to pack together)
(introducing double bonds reduces MP)
lipids
any various substances that: are soluble in nonpolar organic solvents (chloroform or
ether)
usually insoluble in water, along with proteins and carbohydrates constitute the principal
structural components of living cells
hardest waxes:
more packing, longest fatty acid chain, highest MP, means its more solid wax
which of the following components are part of structure of cardiolipin
fatty acid, glycerol, phosphate
clostridium psychrophilic is a species of extremophilic bacteria that thrives at low
temperatures. how would you expect their membranes to differ from ordinary
bacteria?
shorter, more unsaturated lipids
two FRAP experiments are run:
a) lipid headgroups are fluorescently labeled
b) membrane proteins are explicitly labelled
which is correct?
, the recovery time will be longer for proteins
what readily pass through membrane?
small, nonpolar molecules, gases
what is correct about aquaporin-1?
is c4- tetramer has 4 channels where water can come in
at high levels of water flux, it will show saturation behavior
transporters that do not undergo large-scale conformational change as part of
their transport mechanism
potassium ion channel KcsA, aquaporin
the sodium calcium (Na+/Ca2+) exchanger is used to remove calcium from cells.
It pumps:
3 Na+ ions inside the cell down a concentration gradient
1 Ca2+ ion outside the cell against a concentration gradient
what type of transporter is this?
secondary active antiporter
a mutant variant of GPCR alpha chain is found that hydrolyze GTP twice as fast
as the wile-type variant. What is true for a single cycle of activity?
the mutant GPCR will produce less cAMP compared to wild-type
considering the insulin receptor, what is true?
insulin is a primary messenger, while PIP3 is a second messenger
Although salts of fatty acids form micelles, phospholipids and glycolipids form
bimolecular sheets because
of the presence of two fatty acyl chains
