CHAPTER 5
...
The fluidity of biological membranes was proposed in the ___________ model
fluid mosaic
Which type of motion in a lipid bilayer is extremely slow?
Transverse diffusion of the lipids
Which statement does NOT accurately describe integral membrane proteins?
-Integral proteins typically have transmembrane a-helices or b-strands
-Integral proteins tend to aggregate in aqueous solution unless detergents are present
-Integral proteins typic
Integral proteins typically have covalently-bound lipids
What distinguishes lipid-linked proteins from peripheral proteins?
They are not released from the protein using mild conditions.
What is an example of nonmediated transport?
-simple diffusion
-facilitated diffusion
-passive transport
-active transport
-all of the above
simple diffusion
Which of the following channels open in response to an extracellular stimulus such as a neurotransmitter?
-mechanoselective channels
-ligand-gated channels
-signal gated channels
-voltage gated channels
-all of these are sensitive to an extracellular stim
ligand gated channels
What type of transporter moves two different molecules or ions in the same direction?
symporter
A sudden increase in the concentration of ____ causes the release of acetylcholine from the axon of a nerve cell
Ca2+
How does cAMP function as a second messenger?
cAMP is produced by adenylate cyclase in response to G-protein activation, it activates many enzymes through cAMP-dependent protein kinase, and it is eliminated through cAMP phosphodiesterase.
How do heterotrimeric G-proteins work?
Ligand binding to a receptor activates the G-protein, by allowing GTP to exchange for GDP at the alpha subunit, while the B and Y subunits dissociate.
A small molecule produced inside a cell in response to a hormone binding to its receptor is callen a(n)?
second messenger
Activation of a G protein in response to hormone binding requires binding of _____ to the ______ subunit.
GTP
a
What enzyme is activated by association with an active G protein?
adenylate cyclase
Ligand binding to a receptor tyrosine kinase causes ____ of the receptor which then _____ the next protein in the signaling pathway.
phosphorylation
phosphorylates
CHAPTER 6
...
Describe the glucoside structure?
Starting from oxygen in corner then to the right:
OCH3
H
H
OH
OH
H
H
OH
CH2OH
H
A saccharide that has a free aldehyde group is called a(n)?
reducing sugar
What carbon is the anomeric carbon?
The one that has 2 oxygens attached to it
In terms of structure, what is the main difference between a-amylose and cellulose?
Cellulose is formed by B-(1->4) glycosidic bonds, but a-amylose is formed by a-(1->4) glycosidic bonds.
Cellulose is ...
a linear polymer of glucose with B(1->4) linkages
What are epimers?
two sugars that differ only in the configuration around one carbon atom
In which reaction below is ATP required?
I. 1,3-Bisphosphoglycerate (BPG) --> 3-phosphoglycerate (3PG)
II. Glucose --> glucose-6-phosphate (G6P)
III. 2-Phosphoglycerate (2PG) --> 3-phosphoglycerate (3PG)
IV. Glycerol-3-phosphate (GAP) --> 1,3-Bisphosphogl
II only
In which reaction below is at least 1 NADH formed?
I. 1,3-Bisphosphoglycerate (BPG) --> 3-phosphoglycerate (3PG)
II. Glucose --> glucose-6-phosphate (G6P)
III. 2-Phosphoglycerate (2PG) --> 3-phosphoglycerate (3PG)
IV. Glyceraldehyde 3-phosphate (GAP) -->
IV only
What enzyme catalyzes the major regulatory step of glycolysis?
Phosphofructokinase
What is the name for the process that produces ATP from ADP in glycolysis?
substrate-level phosphorylation
What is the net energetic cost of converting two pyruvate to one glucose by gluconeogenesis in ATP equivalents?
6
Avidin, a protein intact in raw egg whites, prevents the absorption of biotin in the intestine resulting in biotin deficiency. Which of the following is affected in individuals who consume large amounts of raw egg?
Oxaloacetate --> phosphoenolpyruvate
1,3
Pyruvate --> Oxaloacetate
Where is gluconeogenesis most active?
liver
In skeletal muscle cells, oxidation of NADH generated from anaerobic glycolysis occurs during which of the following reactions?
pyruvate --> lactate
Fructose-2,6-bisphosphate is an activator of _______ and an inhibitor of _______
phosphofructokinase
fructose bisphosphatase
CHAPTER 7
...
What is the first compound that is oxidized in the citric acid cycle?
Isocitrate
What catalyzes a substrate-level phosphorylation reaction within the citric acid cycle?
Succinyl-CoA synthetase
What coenzyme is required by E1 of the pyruvate dehydrogenase complex for catalytic activity?
Thiamine pyrophosphate
In the net reaction of the citric acid cycle, what are the reactants?
3 NAD+
FAD
GDP
Pi
acetyl-CoA
How is flux throughout the citric acid cycle controlled?
At many points, including:
-control of citrate synthase
-control of isocitrate dehydrogenase
-control of alpha-ketoglutarate dehydrogenase
In the citric acid cycle, what reduced cofactors are derived from the oxidation of one molecule of acetyl CoA to two molecules of CO2?
3 NADH
1 QH2
Which of the following is an anaplerotic reaction that is often used in the cell?
-Conversion of pyruvate to acetyl-CoA
-Conversion of a-ketoglutarate to glutamic acid
-Conversion of citrate to oxaloacetate and acetyl-CoA
-Conversion of pyruvate to oxaloa
Conversion of pyruvate to oxaloacetate