384 Exam 3

Put the following steps in the correct order describing inhibition of glutamine synthetase by a metabolite allosteric effector. A. Adenylation of glutamine synthetase. B. Glutamine binding to uridylyltransferase C. Deuridylation of glutamine synthetase adenylyltransferase -C,B,A -B,C,A -B,A,C -A,B,C

-B,C,A

Place the following steps describing receptor tyrosine kinase (RTK) signaling in proper order: phosphorylation of RTK cytoplasmic tails activation of downstream signaling pathways ligand binding, receptor dimerization, and kinase activation protein binding to RTK phosphotyrosines and phosphorylation of target proteins C, B, A, D C, D, A, B B, C, A, D C,A, D, B

-C, A, D, B

Place the following steps in proper order: A. phosphorylation of RTK cytoplasmic tails B. activation of downstream signaling pathways C. ligand binding, receptor dimerization, and kinase activation D. protein binding to RTK phosphotyrosines and phosphorylation of target proteins -B, C, A, D -C, B, A, D -A, B, C, D -C, A, D, B -C, D, A, B

-C, A, D, B

Put the following signal transduction pathway steps in the correct order: A.) upstream signaling protein B.) second messenger C.) receptor protein D.) first messenger E.) target proteins F.) downstream signaling protein -D,E,C,A,B,F -D,C,B,A,F,E -C,D,A,B,F,E -D,C,A,B,F,E

-D,C,A,B,F,E

The catalytic acitivity and/or conformational stability of this protein is likely dependent upon_____________of peripheral amino acid side chains. These side chains are expected to have a _______________ value.

-protonation -low pKa

Which of the following is the downstream signaling protein for the TRADD-associated complex in the cell survival path of TNF signaling? Choose one: A. NIK B. IKK C. TRAF2 D. RIP

B. IKK

Which of the following best describes the relationship among a subunit of the protein, metal cofactors, and ligands? Choose one: A. Metal ions and ligands interact with the protein in locations that are all quite distant from one another. B. Metal ions interact with one another within the protein at a distant location from the ligand interaction. C. A metal ion and ligand interact with the protein in locations proximal to one another. D. Ligands interact with one another proximally within the protein at a distant location from the metal ion interaction.

C. A metal ion and ligand interact with the protein in locations proximal to one another.

Which of the following can enter glycolysis without additional reactions? A. Both products from lactose after lactate treatment B. Both products from sucrose after sucrase treatment C. Both products from maltose after maltase treatment D. Glycerol

C. Both products from maltose after maltase treatment

Glucose and fructose are both C6H12O6. What is the structural difference between them? A.) Glucose is a linear molecule and fructose is a ring. B.) Glucose is found in the boat conformation and fructose is a chair conformation. C.) Fructose is a five-membered ring and glucose is a six-membered ring. D.) Glucose is a five-membered ring and fructose is a six-membered ring.

C.) Fructose is a five-membered ring and glucose is a six-membered ring.

Which one of the following processes occurs after activation of the PI-3K pathway by insulin signaling? A.) GTP binds to the Ras protein to promote glucose export B.) Rates of glycogen synthesis decrease to increase blood glucose C.) Glucose uptake increase and lower blood glucose levels. D.) Rates of glucose synthesis (gluconeogenesis) increase

C.) Glucose uptake increase and lower blood glucose levels.

What is the function of growth factor receptor-bound 2 (GRB2) protein in RTK signaling? A.) It is a tyrosine kinase protein that phosphorylates arginine residues in PI-3K and in phospholipase C. B.) It is an adaptor protein that binds to G proteins like Ras and GSa and also to MAPK, Raf, and ERK. C.) It is an adaptor protein that binds to phosphotyrosine residues in RTKs and also binds to GEF proteins. D.) It is an adaptor protein that binds to phosphoserine residues in IRSs and to GEF proteins like PI-3K. E.) It is a survival protein that binds to cysteine proteases and inhibits their auto-cleavage by TRADD.

C.) It is an adaptor protein that binds to phosphotyrosine residues in RTKs and also binds to GEF proteins.

Flux is defined as the rate at which __________is/are interconverted. A.) Minerals B.) Cells C.) Metabolites D.) Energy

C.) Metabolites

(a) Why is it critical for maintaining flux through the metabolic pathway that NADH be oxidized to NAD+, and (b) how is that done under anaerobic conditions in human cells? A.) NADH is required for the phosphofructokinase-1 reaction; by converting pyruvate to lactate. B.) NAD+ is required for the glyceraldehyde-3P dehydrogenase reaction; by converting pyruvate to acetate. C.) NAD+ is required for the glyceraldehyde-3P dehydrogenase reaction; by converting pyruvate to lactate.

C.) NAD+ is required for the glyceraldehyde-3P dehydrogenase reaction; by converting pyruvate to lactate.

Cultures of two different human cell types are exposed to the same steroid signaling molecule. Analysis of gene expression shows that only one of the cell types activated gene expression characteristic of the steroid signaling pathway. Which of the following is the most likely explanation for this difference? A.) Only one cell type contains the DNA sequences that the steroid receptor binds to. B.) Only one cell type phosphorylates the steroid ligand to activate it. C.) Only one of the cell type expresses the cognate steroid receptor D.) The steroid ligand can only cross the plasma membrane in one cell type.

C.) Only one of the cell type expresses the cognate steroid receptor

The a subunit of trimeric G proteins can function to A.) inhibit phosphodiesterase. B.) inhibit phospholipase A. C.) activate adenylate cyclase. D.) regulate ion channels.

C.) activate adenylate cyclase.

Why is fructose toxic to liver cells, but not muscle cells, in individuals with a defect in the enzyme aldolase B? A.) because liver cells lack the enzyme hexokinase, but not muscle cells, and depend on aldoase B to convert glucose to glucose 6-P in the glycolytic pathway. B.) because liver cells, not muscle cells, use up ATP converting fructose to fructose 6-P which cannot be further metabolized. C.) because liver cells, and not muscle cells, use up ATP converting fructose-1P, which cannot be further metabolized.

C.) because liver cells, and not muscle cells, use up ATP converting fructose-1P, which cannot be further metabolized.

What effect do elevated levels of ATP have on glycolysis? A.) increase the concentration of glucose entering glycolysis B.) increase the affinity of PFK-1 for fructose-6-P and increase the rate of the pathway C.) decrease the affinity of PFK-1 for fructose-6-P and slow rate of the pathway D.) increase the concentration of PFK-1 in the R-state

C.) decrease the affinity of PFK-1 for fructose-6-P and slow rate of the pathway

Which of the following best defines substrate-level phosphorylation? A.) ndirect transfer of a Pi to glucose B.) indirect transfer of a Pi to an ATP C.) direct transfer of a Pi to an ADP D.) removal of a Pi from ATP

C.) direct transfer of a Pi to an ADP

Which of the following is the correct net reaction for glycolysis? A.) glucose + 2 ATP 2 lactate + 2 ADP + 2 Pi B.) glucose + 2 ADP + 2 Pi + 2 NAD+ 2 pyruvate + 2 ATP + 2 NADH + 4 H+ C.) glucose + 2 ADP + 2 Pi + 2 NAD+ 2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2H2O D.) glucose + 2 ADP + 2 Pi 2 CH3CH2OH + 2 CO2 + 2 ATP

C.) glucose + 2 ADP + 2 Pi + 2 NAD+ 2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2H2O

List three ways in which flux is controlled through glycolysis. A.) regulation of glucokinase, fructokinase, and number of intermediates B.) regulation of glucokinase, PFK-1, and concentration of glucose C.) regulation of glucokinase, PFK-1, and supply and demand of intermediates D.) regulation of aldolase, PFK-1, and supply and demand of intermediates

C.) regulation of glucokinase, PFK-1, and supply and demand of intermediates

A plot of vo versus [S] for aspartyl transcarbamoylase displays three sigmoidal lines. If the line in the middle represents the enzyme activity in the absence of any allosteric effectors, then the line to the __________ represents the enzyme in the __________ when bound to __________. none of these answers are correct. A.) left; T state; GTP B.) right; R state; CTP C.) right; T state; CTP D.) left; R state; GTP

C.) right; T state; CTP

Muscle relaxation in response to neuronal stimualtion and nitric oxide signaling would be reduced if a(n) ______________was present. A.) inhibitor of acetylcholine esterase B.) stimulator of guanylate cyclase C.) stimulator of cGMP phosphodiesterase D.) inhibitor of protein kinase A

C.) stimulator of cGMP phosphodiesterase

An inhibitor that binds only to the ES complex and not free enzyme is known as a(n) ___________ inhibitor. A.) mixed B.) irreversible C.) uncompetitive D.) competitive

C.) uncompetitive

Why would mutation of a tyrosine residue to glutamate in the intracellular portion of a growth factor receptor lead to increased tumor formation? Choose one or more: A. A receptor with a glutamate in place of a tyrosine is a "phosphomimetic." That is, the protein mimics the phosphorylated state of tyrosine. B. Loss of the tyrosine would mean phosphorylation would not occur, thus blocking the inhibiting action of these receptors. C. Unlike tyrosine, a glutamate will leave the receptor "constitutively" active and no longer responsive to the phosphatases that shut off such signaling. D. This amino acid substitution would convert the protein from poorly water soluble to charged and water soluble.

C.Unlike tyrosine, a glutamate will leave the receptor "constitutively" active and no longer responsive to the phosphatases that shut off such signaling.

What advantage is there to phosphoglycerate kinase having an open and closed protein configuration? A.) changing of the configuration of the enzyme makes the reaction exergonic. B.) It allows water to be trapped in the active site along with the substrate C.) It forces covalent bonding of the substrate to the enzyme active site. D.) The induced-fit mechanism maximizes accessibility of active site without sacrificing hydrophobic environment

D.) The induced-fit mechanism maximizes accessibility of active site without sacrificing hydrophobic environment

The GS-alpha subunit of trimeric G proteins can function to A.) inhibit phosphodiesterase B.) inhibit phospholipase A C.) regulate ion channels D.) activate adenylate cyclase

D.) activate adenylate cyclase

In which of the following glycolytic pathway reactions is ATP phosphoryl transfer energy required to drive the reaction in the forward direction? A.) 2-Phosphoglycerate → 3-phosphoglycerate B.) glucose-6-phosphate → fructose-6-phosphate C.) 1,3-Bisphosphoglycerate → 3-phosphoglycerate D.) glucose → glucose-6-phosphate

D.) glucose → glucose-6-phosphate

When compared with the T state of aspartate transcarbamoylase, the R state A.) has dissociated into two C3R3 complexes. B.) has substrate bound in the ATP binding site. C.) is bound to CTP. D.) has greater separation of the catalytic subunits.

D.) has greater separation of the catalytic subunits.

Acetylcholinesterase is an important enzyme in the nervous system. Acetylcholinesterase activity is blocked by the nerve agent sarin gas, which forms a covalent bond with a Ser in the active site of the enzyme. Sarin gas is a(n) A.) allosteric effector B.) competitive inhibitor C.) reversible inhibitor D.) irreversible inhibitor

D.) irreversible inhibitor

If GRB2 were truncated so that the N-terminal domain was missing, the truncated protein would be unable to bind the A.) proline-rich sequence of the IRS protein. B.) protein-rich sequence of the RTK substrate. C.) phosphorylated Tyr of the SOS protein. D.) none of these answers are correct. E.) phosphorylated Tyr of the RTK substrate.

D.) none of these answers are correct.

Put a number in the box to correctly match with each letter on the reaction coordinate diagram. ( GRAPH PICTURE) 1. Substrate 2. Product 3. Transition state 4. Uncatalyzed activation free energy 5. Catalyzed activation free energy 6. Overall free energy change D ____ F ____ B ____ C ____ E ____ A____

D.)_6__ F.)__5__ B.)__3__ C.)__1__ E.)_4__ A.) __2__

Predict which bond of a target protein would be cleaved by caspase 3 executioner enzyme. (PICTURE) A.) 3 B.) none of these bonds. C.) 1 D.) 2 E.) 4

E.) 4

Choose the ONE statement that BEST describes what the actual change in free energy (deltaG) tells you about an enzymatic reaction, which cannot be determined by the standard free energy (deltaGº') change. A.) The direction of the reaction at equilibrium. B.) The direction of the reaction at 1M substrate concentration at pH7. C.) The actual change in free energy = 0, so it does not tell you anything. D.) The temperature of the reaction at 1 atmosphere pressure. E.) The direction of the reaction under steady state conditions. F.) The spontaneity of the reaction in the presence of an inhibitor.

E.) The direction of the reaction under steady state conditions.

An estrogen-dependent breast cancer cell line is grown in a medium that contains estrogen. Cell proliferation is monitored over time. In a separate experiment, the cell line is grown in a medium that lacks estrogen but includes bisphenol A, a compound found in polycarbonate plastics. When monitored, cell proliferation is higher than in the presence of estrogen. A possible explanation of these results is that bisphenol A A.) inhibits the binding of estrogen to the estrogen receptor. B.) it stimulates aquaporin function. C.) inhibits adenylate cyclase. D.) is toxic to the cell line. E.) is an agonist of the estrogen receptor.

E.) is an agonist of the estrogen receptor.

The activity of phosphofructokinase-1 is regulated based on the energy charge of the cell. Sort the phrases to correctly describe the role of ADP and ATP in this regulation. High or Low. -ATP bound to effector site -[ADP]/[ATP] <1 -Affinity for F6P decreased -Predominant form is T-state -[ADP]/[ATP] >1 -ADP bound to effector site -Predominant form is R-state -Affinity for F6P increased

High: ATP bound to effector site [ADP]/[ATP] <1 Affinity for F6P decreased Predominant form is T-state Low: [ADP]/[ATP] >1 ADP bound to effector site Predominant form is R-state Affinity for F6P increased

The second messenger cyclic AMP (cAMP) is synthesized from ATP by the activity of the enzyme adenylate cyclase. Cyclic AMP, in turn, activates proteins kinase A (PKA), which is responsible for most of the effects of cAMP within the cell. Determine the correct steps in the activation of PKA, and then number them in the correct order (1-5), starting after the adenylyl cylcase reaction. _____Two cAMP molecules bind to each PKA regulatory subunit. _____ Cytosolic cAMP concentration increases. _____ The regulatory subunits move out of the active sites of the catalytic subunits, and the R2C2 complex dissociates. _____Each regulatory subunit is activated as the two cAMP molecules are released. ______ The free catalytic subunits interact with proteins to phosphorylate Ser or Thr residues.

___2__Two cAMP molecules bind to each PKA regulatory subunit. ___1__ Cytosolic cAMP concentration increases. ___3__ The regulatory subunits move out of the active sites of the catalytic subunits, and the R2C2 complex dissociates. __5___Each regulatory subunit is activated as the two cAMP molecules are released. __4____ The free catalytic subunits interact with proteins to phosphorylate Ser or Thr residues

You have a mystery hormone (agonist), and to test the nature of the agonist you add it to a dish of cultured liver cells. Shortly afterward you observe an increase in protein kinase activity. In a second experiment, you find the kinase is inhibited if you add an adenylate cyclase inhibitor to the cells prior to adding your mystery agonist. Which kind of receptor system is the agonist signaling through? Choose one: A. GPCR B. ion channel C. steroid hormone receptor D. protein tyrosine kinase receptor

A. GPCR

Which of the following statements correctly describe the properties of glucose and fructose? Choose one or more: A. Glucose can form furanose and pyranose ring structures, while fructose can only form a furanose ring. B. Glucose and fructose are both hexose sugars. C. Glucose and fructose are both reducing sugars. D. Glucose is found in at least three common disaccharides found in nature, while fructose is a component of only one.

A. Glucose can form furanose and pyranose ring structures, while fructose can only form a furanose ring. B. Glucose and fructose are both hexose sugars. D. Glucose is found in at least three common disaccharides found in nature, while fructose is a component of only one.

Along with other similar symptoms, both deficiencies can also result in reduced lactate levels during exercise. In order to distinguish between these two disorders, a physician could test the patient's lactate levels during exercise before and after administering glycerol. What would be the expected results if this test were performed? Choose one or more: A. Lactate levels would be low after intense exercise and would increase after glycerol was administered if the patient has a deficiency in muscle phosphofructokinase-1. B. Lactate levels would be low after intense exercise and would not increase after glycerol was administered if the patient has a deficiency in lactate dehydrogenase. C. Lactate levels would be low after intense exercise and would not increase after glycerol was administered if the patient has a deficiency in muscle phosphofructokinase-1. D. Lactate levels would be low after intense exercise and would increase after glycerol was administered if the patient has a deficiency in lactate dehydrogenase.

A. Lactate levels would be low after intense exercise and would increase after glycerol was administered if the patient has a deficiency in muscle phosphofructokinase-1. B. Lactate levels would be low after intense exercise and would not increase after glycerol was administered if the patient has a deficiency in lactate dehydrogenase.

Consider two reactions. Reaction 1 (P → Q) has ΔG = 2.3 kJ/mol. Reaction 2 (Q → R) has ΔG = 12.3 kJ/mol. Which reaction is more likely to require coupling to ATP or the equivalent in order to be spontaneous under cellular conditions? A. Reaction 2 (Q → R). This reaction is nonspontaneous and operates far from equilibrium in the cell. It will not be able to proceed as written in the cell without coupling to a process with a large negative free energy change (such as ATP hydrolysis). B. Neither reaction will require ATP or the equivalent to become spontaneous in the cell. The fluctuations in the actual concentrations of substrates and products present in the cell will always allow a reaction that is nonspontaneous to become spontaneous eventually. C. Both reactions will require ATP or the equivalent to proceed under cellular conditions because both reactions are nonspontaneous and are the same distance from equilibrium in the cell. D. Reaction 1 (P → Q). This reaction is nonspontaneous and operates far from equilibrium in the cell. It will not be able to proceed as written without coupling it to a process with a large free energy change (such as ATP hydrolysis).

A. Reaction 2 (Q → R). This reaction is nonspontaneous and operates far from equilibrium in the cell. It will not be able to proceed as written in the cell without coupling to a process with a large negative free energy change (such as ATP hydrolysis).

Rosiglitazone is an antidiabetic drug meant to target adipose cells, enhancing insulin effects. The drug mimics the fatty acid metabolites that bind to a nuclear receptor found mostly in fat, liver, and a few other tissues. Cortisone is a type of glucocorticoid mimic that binds to a nuclear receptor, activating the receptor's transcriptional regulatory function. The ligand-activated receptor binds coregulatory proteins, and the protein complex targets gene transcription involved with inflammation. Which of the following statements about these two drugs best describe their mechanism of action? Choose one or more: A. Rosiglitazone will bind to its receptor (peroxisome proliferator-activated receptor), and the receptor-ligand complex can bind to the RXR receptor in a head-to-tail fashion. B. Receptor dimers with bound cortisone bind to the DNA target using a zinc finger to bind to an inverted repeat that must be at least partially palindromic to be recognized. C. Zinc fingers bind at the top of rosiglitazone receptor dimers as a stabilizer, allowing the alpha helical recognition strand to bind into the minor groove of the target DNA. D. Cortisone and rosiglitazone form heterodimers with the receptor in a head-to-tail fashion to regulate gene activity.

A. Rosiglitazone will bind to its receptor (peroxisome proliferator-activated receptor), and the receptor-ligand complex can bind to the RXR receptor in a head-to-tail fashion. B. Receptor dimers with bound cortisone bind to the DNA target using a zinc finger to bind to an inverted repeat that must be at least partially palindromic to be recognized.

Observe the ribbon structure of pepsin. To do this, click the green-outlined box at the bottom of the player. Green x's will appear over your selection. Then go to the dropdown menu and on the "Display" line, click the "Toggle Ribbon for selection" icon. Then click the "Toggle CPK for selection" icon to remove the space-filling display. To remove the green x's, click "Clear Selection" on the "Misc" line of the dropdown menu. (PICTURE) Determine the relative proportions of secondary and quaternary structure(s). What best describes these structures? Choose one: A. The major secondary structures are beta sheets, and there is no quaternary structure. B. The major secondary structures are alpha helices, and there is quaternary structure. C. The major secondary structures are beta sheets, and there is quaternary structure. D. The major secondary structures are alpha helices, and there is no quaternary structure.

A. The major secondary structures are beta sheets, and there is no quaternary structure.

The standard free energy change of phosphate hydrolysis is shown below for several molecules in the glycolytic pathway. MoleculeΔG˚ (kJ/mol) Phosphoenolpyruvate−61.91 1,3-Bisphosphoglycerate−49.4 ATP → ADP + Pi−30.5 Fructose-6-phosphate−15.9 Glucose-6-phosphate−13.8 Which statement explains why glucose phosphorylation could not occur without ATP investment? A. Without ATP investment, one or both of the substrates would need to exceed the solvent capacity of the cell for glucose phosphorylation to occur. B. Without ATP investment it would be impossible to regulate the entry of glucose into glycolysis. C. Without ATP investment, glucose would not become "trapped" in the cell and could easily be transported out as blood glucose levels decrease. This transport would reduce the amount of glucose available for some organs. D. Without ATP investment in stage I of glycolysis, the concentration of ATP would become too high and would inhibit phosphofructokinase, leading to inhibition of the entire glycolytic pathway.

A. Without ATP investment, one or both of the substrates would need to exceed the solvent capacity of the cell for glucose phosphorylation to occur.

If phosphofructokinase experienced a mutation that interfered with substrate binding, then what other enzyme is going to be most immediately impacted in terms of accessing substrate? Choose one:. A. aldolase B. glucolactonase C. hexokinase. D. fumarase

A. aldolase

Which of the following statements is true concerning the role of cGMP in vasodilation? Choose one: A. cGMP is a secondary messenger that acts on protein kinase G. B. Sildenafil prolongs NO-mediated vasodilation by stimulating production of cGMP. C. Increased cGMP leads to increased NO, which serves as a secondary messenger for vasodilation. D. Vasodilation is increased by increased activity of cGMP phosphodiesterase.

A. cGMP is a secondary messenger that acts on protein kinase G.

Kinase enzymes phosphorylate other proteins and enzymes. This is a common mechanism of covalently modifying enzymes in order to control their catalytic efficiency. Which of the following amino acids is not targeted for phosphorylation by kinases? A. leucine B. threonine C. serine D. tyrosine

A. leucine

Sucrose, maltose, and lactose are common dietary disaccharides. Their monosaccharide components are substrates for the glycolytic pathway, but some must participate in additional reactions before they can act as substrates for a glycolytic enzyme. As a result, all do not enter glycolysis at the same step. In muscle cells, which enzyme would act as the rate-limiting step to regulate entry of products from all three dietary disaccharides into glycolysis? A. phosphofructokinase-1 B. hexokinase C. aldolase D. phosphoglucose isomerase

A. phosphofructokinase-1

Which of the following correctly describes the biochemistry of the amino acids at the termini of pepsin? Choose one: A. two nonpolar amino acids at the N-terminus and one polar amino acid at the C-terminus B. three polar amino acids at the N-terminus and one charged amino acid at the C-terminus C. three charged amino acids at the N-terminus and two polar amino acids at the C-terminus D. two charged amino acids at the N-terminus and two nonpolar amino acids at the C-terminus

A. two nonpolar amino acids at the N-terminus and one polar amino acid at the C-terminus

Individuals with a deficiency in the aldolase B enzyme have a condition known as hereditary fructose intolerance. The metabolic intermediate that accumulates in the liver as a result of this deficiency can have an indirect, activating effect on hepatic glucokinase. The blood glucose levels in these individuals Choose one: A. would be lower than normal due to the increased reaction rate of glucokinase. B. would be higher than normal due to the increased reaction rate of glucokinase. C. would be lower than normal due to the increased concentration of glucokinase. D. would be higher than normal due to the increased concentration of glucokinase.

A. would be lower than normal due to the increased reaction rate of glucokinase.

How can an extracellular signal be amplified a million-fold inside a cell? Choose the ONE correct answer. A.) Activation of a single receptor can result in the production of 100 second messengers. Each of these second messengers can activate an enzyme that can act on 100 target enzymes. Each target enzyme can act on 100 other targets. 100 X 100 X 100 = 1,000,000 B.) Each extracellular ligand activates 100 receptor molecules sequentially. These activated receptor molecules dissociate into 100 second messengers. Each of these second messengers can activate an enzyme that can act on 100 target enzymes. 100 X 100 X 100 = 1,000,000 C.) Each extracellular ligand activates 100 receptor molecules sequentially. These activated receptor molecules each result in the production of 100 second messengers. Each of these second messengers can activate an enzyme that can act on 100 target enzymes. 100 X 100 X 100 = 1,000,000 D.) Activation of a single receptor can result in the production of 100 second messengers. Each of these second messengers can catalyze 100 reactions on target enzymes. Each target enzyme can act on 100 other targets. 100 X 100 X 100 = 1,000,000

A.) Activation of a single receptor can result in the production of 100 second messengers. Each of these second messengers can activate an enzyme that can act on 100 target enzymes. Each target enzyme can act on 100 other targets. 100 X 100 X 100 = 1,000,000

Caspases (cysteine-aspartate proteases) function as "executioners" in the cell death pathway. Choose THREE reasons why it makes sense that they function in this role rather than some other biomolecule. A.) Caspases are enzymes that function catalytically and therefore can do a lot of damage in a very short amount of time B.) Caspases are rapidly produced by the ribosome after the signal for cell death is received. C.) Caspases have longer stability in the cell than most proteins, since they are readily refolded by chaperones. D.) Caspases must be activated by proteolytic cleavagge to convert the inactive zymogen to the active form-this provides a means to control caspase activity by initiating the cleavage reaciton. E.) Caspases have preferred substrate recognition sites for cleavage, and therefore can preferentially degrade other proteins

A.) Caspases are enzymes that function catalytically and therefore can do a lot of damage in a very short amount of time D.) Caspases must be activated by proteolytic cleavagge to convert the inactive zymogen to the active form-this provides a means to control caspase activity by initiating the cleavage reaciton. E.) Caspases have preferred substrate recognition sites for cleavage, and therefore can preferentially degrade other proteins

Caspases (cysteine-aspartate proteases) function as "executioners" in the cell death pathway. Choose THREE reasons why it makes sense that they function in this role rather than some other biomolecule. (2 ANSWERS) A.) Caspases have preferred substrate recognition sites for cleavage, and therefore can preferentially degrade other proteins B.) Caspases must be activated by proteolytic cleavagge to convert the inactive zymogen to the active form-this provides a means to control caspase activity by initiating the cleavage reaciton. C.) Caspases have longer stability in the cell than most proteins, since they are readily refolded by chaperones. D.) Caspases are enzymes that function catalytically and therefore can do a lot of damage in a very short amount of time E.) Caspases are rapidly produced by the ribosome after the signal for cell death is received.

A.) Caspases have preferred substrate recognition sites for cleavage, and therefore can preferentially degrade other proteins B.) Caspases must be activated by proteolytic cleavagge to convert the inactive zymogen to the active form-this provides a means to control caspase activity by initiating the cleavage reaciton.

Below is shown the structure of a homodimer of the GR DNA-binding domain. Four areas are highlighted. Which is most likely to interact with DNA? (PICTURE) A.) D B.) A and C C.) A D.) B E.) C

A.) D

What characteristic is true for both RTKs and GPCRs? A.) The receptor undergoes a conformational change on activation. B.) The receptor transmits ions. C.) The receptor binds to intracellular proteins only when activated. D.) When activated, the receptor has enzymatic activity.

A.) The receptor undergoes a conformational change on activation.

An enzyme undergoes a mutation that causes it to lose the ability to be regulated via phosphorylation. Which of the following mutations may lead to this loss of regulation? Assume that the overall structure is not altered by the mutation. A.) Tyr mc080-3.jpg Phe B.) Ser mc080-4.jpg Tyr C.) Thr mc080-2.jpg Ser D.) Ser mc080-1.jpg Thr

A.) Tyr Phe

A ligand binds to a transmembrane protein. This causes a conformational change in the protein that is detected by an intracellular protein. The intracellular protein is an enzyme that adds phosphate groups to target proteins. The phosphorylated proteins cause a physiological change within the cell. This is an example of A.) a signal transduction pathway. B.) chemotaxis. C.) an allosteric inhibition pathway. D.) homeostasis. E.) a metabolic pathway.

A.) a signal transduction pathway

Why is it critical to glucose homeostasis that glucokinase has a low affinity for glucose with regard to insulin release from the pancreas? A.) because increased glucose concentrations in the blood lead to increased rates of metabolic flux through the glycolytic pathway, which is required for insulin release. B.) because increased glucose concentrations in the blood lead to decreased rates of metabolic flux through the glycolytic pathway, which is required for insulin release. C.) Because maximal saturation of the glucokinase active site occurs when blood glucose levels are low, resulting in increased insulin at high glucose concentrations.

A.) because increased glucose concentrations in the blood lead to increased rates of metabolic flux through the glycolytic pathway, which is required for insulin release.

If a mutation occurred in SODD that prohibited its interaction with the DD of TNF receptor, the TNF receptor would A.) bind TRADD, even in the absence of TNF-. B.) bind CASP 8 directly. C.) no longer form a trimer. D.) bind NFκB, even in the absence of TNF-. E.) no longer be able to release TNF-.

A.) bind TRADD, even in the absence of TNF-.

Metabolism is best defined as a collection of A.) biochemical reactions that convert chemical energy into work. B.) biochemical reactions that convert mechanical work into energy. C.) enzymes that convert metabolites into pathways D.) cellular processes that activate cell division

A.) biochemical reactions that convert chemical energy into work.

Which of the following list includes ONLY first messengers? A.) cortisol, insulin, prostaglandins B.) cytochrome c, insulin, estrogen receptor C.) Ca2+, testosterone, protein kinase A D.) insulin, glucagon, glucose E.) nitric oxide, estradiol, heme

A.) cortisol, insulin, prostaglandins

Acetylcholinesterase is an important enzyme in the nervous system. Acetylcholinesterase activity is blocked by the nerve agent sarin gas, which forms a covalent bond with a Ser in the active site of the enzyme. Sarin gas is a(n) A.) irreversible inhibitor. B.) allosteric effector. C.) competitive inhibitor. D.) allosteric activator.

A.) irreversible inhibitor.

Review the figure below. Shared intermediates are used so effectively in coupled reactions because they (PICTURE) A.) limit product diffusion and allow intermediates to channel from one enzyme to the next. B.) decrease the value of Q. C.) allow products to diffuse through membrane to increase concentration gradient. D.) increase the value of .

A.) limit product diffusion and allow intermediates to channel from one enzyme to the next.

For the following reaction A→ B, if at equilibrium > 0, what can be said about the directionality of the reaction? A.) strongly favored in the reverse direction B.) Not enough information is given. C.) strongly favored in both directions D.) strongly favored in the forward direction

A.) strongly favored in the reverse direction

Caffeine leads to a vasoconstriction, raises the epinephrine levels, and increases nervous signaling. A metabolite of caffeine blocks phosphodiesterase. What is the most likely impact of caffeine on cell signaling? A. Caffeine directly binds and activates the protein kinases which signal the described effects, enhancing the effects of caffeine. B. Inhibition of the phosphodiesterase results in an elevated cAMP levels and PKA activation, leading to increased glycogen breakdown and increased phosphorylation of events controlling the physiology of caffeine addiction. C. The vascular effects of caffeine are long term, indicating a steroid-enhanced activity supported by loss of phosphodiesterase action. D. Phosphodiesterase leads to increased PIP2 breakdown, inhibiting Akt signaling. This alters the glycogen metabolism and glucose uptake in the liver after caffeine ingestion.

B. Inhibition of the phosphodiesterase results in an elevated cAMP levels and PKA activation, leading to increased glycogen breakdown and increased phosphorylation of events controlling the physiology of caffeine addiction.

Which of the following is not a parameter that governs the cell-specific physiological responses controlled by nuclear receptors? Choose one: A. Localized bioavailability of ligands B. Organism-wide expression of coregulatory proteins C. Differential accessibility of target gene DNA sequences D. Cell-specific expression of nuclear receptors

B. Organism-wide expression of coregulatory proteins

A pH/enzyme activity curve is shown above. Which of the following pairs of amino acids would be likely candidates as catalytic groups? (GRAPH) A.) Glu and Lys B.) His and Cys C.) His and Lys D.) Asp and His E.) His and His

B.) His and Cys

Name the following disaccharide using the common name and the descriptive nomenclature. A.) Maltose; Glc (a1-4) Glc B.) Lactose; Gla (B1->4) Glc C.) Sucrose; Glc (a1-B2) Glc D.) Lactose; Glc (a1->2) Glc

B.) Lactose; Gla (B1->4) Glc

An enzyme undergoes a mutation that causes it to lose the ability to be regulated via phosphorylation. Which of the following mutations may lead to this loss of regulation? Assume that the overall structure is not altered by the mutation. A.) Thr-->Ser B.) Tyr--> Phe C.) Ser--> Thr D.) Ser--> Tyr

B.) Tyr--> Phe

The Lineweaver-Burk plot shows data obtained for an enzyme in the absence and presence of a noncompetitive inhibitor. If the [I] is increased significantly in the experiment, the Vmaxapp would __________ and the Kmapp would __________. (PICTURE GRAPH) A.) stay the same; decrease B.) decrease; stay the same C.) decrease; decrease D.) stay the same; stay the same

B.) decrease; stay the same

Caspase 3 is responsible for A.) activating caspase 8. B.) degrading key regulatory molecules. C.) phosphorylating Fas. D.) dephosphorylating FasL.

B.) degrading key regulatory molecules.

In the following series of reactions, what is the shared intermediate? (PICTURE) A.) glucose-6-P B.) fructose-6-P C.) ATP D.) fructose-1,6-P E.) Pi

B.) fructose-6-P

Which reaction in glycolysis is a redox reaction? A.) 2-phosphoglycerate mc075-3.jpg phosphoenolpyruvate B.) glucose mc075-2.jpg glucose-6-P C.) glyceraldehyde-3-P mc075-1.jpg 1,3-bisphosphoglycerate D.) fructose-6-P mc075-4.jpg fructose-1,6-BP

B.) glucose mc075-2.jpg glucose-6-P

To produce 4 ATP requires 122 kJ/mol. Which reactions in the glycolytic pathway produce enough energy to be able to overcome this deficit? A.) hexokinase, aldolase, and pyruvate kinase B.) hexokinase, phosphofructokinase-1, and pyruvate kinase C.) hexokinase, enolase, and glyceraldehyde-3P dehydrogenase D.) enolase, aldolase, and pyruvate kinase

B.) hexokinase, phosphofructokinase-1, and pyruvate kinase

Let's get warmed up to revisit bioenergetics, which we covered in Module 1, and see if you can remember how equilibrium relates to spontaneity of a reaction written from left to right. In the reaction A→ B, what can be said about the directionality of the reaction if when starting with equal concentratios of A and B at time zero (T0), you find that at equilibrium 30 minutes (T30) later, that [B] >> [A]? A.) not enough information is given B.) strongly favored in the forward direction C.) strongly favored in the reverse direction D.) strongly favored in both directions

B.) strongly favored in the forward direction

When protein kinase A (PKA) is inactive, which of the following is true? A.) cAMP is bound to the catalytic site to inhibit the regulatory subunit B.) the intrinisic pseudosubstrate peptide is bound to the active site C.) ATP is bound to the regulatory subunit to inhibit subunit dissociation D.) the regulatory subunit has cyclic GMP bound in place of cyclic AMP

B.) the intrinisic pseudosubstrate peptide is bound to the active site

Which human disease states are treated by glucocorticoids based on the anti-inflammatory response of cells to glucocorticoid treatment? Choose the three most common (use a Google search). A.) Prostate Cancer B.) Obesity C.) Dermatitis D.) Gout E.) Asthma F.) Stress G.) insomnia H.) ophidiophobia I.) arthritis

C.) Dermatitis E.) Asthma I.) arthritis

Long-term activation by nuclear receptors differs from the more transient membrane receptor signaling for what reason? Choose one: A. Receptor-mediated signaling takes longer to reverse the phosphorylation caused by kinases, while nuclear protein expression is much faster. B. It takes longer for the steroid to diffuse through the cell, while membrane receptor ligands do not require translocation into the cell. C. Long-term activation occurs by nuclear receptors activating sets of genes, while membrane receptors involve small second messenger molecules responding quickly, as their signaling occurs by activation of kinases, phosphatases, and other enzymes already expressed in the cell. D. Steroid receptors are antagonistic to most GPCR signaling.

C. Long-term activation occurs by nuclear receptors activating sets of genes, while membrane receptors involve small second messenger molecules responding quickly, as their signaling occurs by activation of kinases, phosphatases, and other enzymes already expressed in the cell.

The spontaneous direction of a metabolic reaction is dictated by the ratio of substrate and products under equilibrium conditions (K) and under cellular conditions (Q). Compare the two reactions A→B and C→D. For A→B, ΔG˚ = -13 kJ/mol. For C→D, ΔG˚ = 3.5 kJ/mol. The cellular concentrations are as follows: [A] = 0.050 mM, [B] = 4.0 mM, [C] = 0.060 mM, and [D] = 0.010 mM. Which statement below correctly describes the relationship between Q and K for both reactions? Are these reactions spontaneous as written under cellular conditions? A. Q < K for A→B; Q > K for C→D. A→B will be spontaneous at those substrate and product concentrations; C→D will be nonspontaneous. B. Q > K for A→B; Q < K for C→D. A→B will be nonspontaneous at those substrate and product concentrations; C→D will be spontaneous. C. Q < K for both reactions. Both are spontaneous at those concentrations of substrate and product. D. Q > K for both reactions. Both are nonspontaneous at those concentrations of substrate and produ

C. Q < K for both reactions. Both are spontaneous at those concentrations of substrate and product.

The reaction mechanism of glyceraldehyde-3-phosphate dehydrogenase is shown below. (PICTURE) Glyceraldehyde-3-phosphate dehydrogenase catalyzes the phosphorylation of glyceraldehyde-3-phosphate, but unlike other glycolytic reactions, it does not require energy investment from ATP. This reaction occurs in two stages: oxidation/reduction and phosphorylation. Why is the oxidation/reduction reaction necessary to make phosphorylation favorable? Choose one: A. The oxidation/reduction reaction is necessary to oxidize phosphate, allowing addition to the substrate. B. The oxidation/reduction reaction is for the substrate to bind to the enzyme. C. The oxidation/reduction reaction is necessary to form an intermediate with a large free energy of hydrolysis. D. The oxidation/reduction reaction is necessary to produce NADH, which is required for ATP synthesis.

C. The oxidation/reduction reaction is necessary to form an intermediate with a large free energy of hydrolysis.

Select only one of the four identical subunits of the protein by clicking one of the green-outlined boxes next to a subunit listed along the bottom of the player. When the subunit is selected, it will be covered with green x's. Next, change the display of the selected subunit to ribbon structure by clicking the dropdown menu in the upper right corner and then clicking "Toggle Ribbon for selection" on the Display line. Click "Toggle CPK for selection" to remove the space-filling display. To remove the green x's, click "Clear Selection" on the Misc line. Determine the secondary structure(s) that is/are exhibited in this polypeptide. (PICTURE) Choose one: A. alpha helices only B. beta sheets only C. both alpha helices and beta sheets D. no alpha helices and no beta sheets

C. both alpha helices and beta sheets

Even in the presence of a properly signaling TNF receptor signaling pathway that involves FADD and TRADD, breast cancer cells do not undergo apoptosis in response to TNF-alpha, allowing tumors to grow and metastasize. A close inspection shows that one protein is no longer expressed in these cells. The addition of TNF-alpha leads to TRADD and FADD complexes but does not lead to cell death. Procaspase 3 is expressed and functioning. A western blotting analysis shows that NFkB is expressed, and other studies show that the protein is functioning properly in these cells. What is the most likely cause of resistance to cell death by TNF-alpha in breast cancer cells? Choose one: A. loss of NFkB interacting p50 B. inactivation of IKK kinases C. loss or mutational inactivation of caspase 8 D. overexpression of CASP3

C. loss or mutational inactivation of caspase 8

Which two of the following compounds are used to produce ATP by substrate-level phosphorylation in glycolysis? A.) 3-phosphoglycerate B.) fructose 1,6 BP C.) 1,3 Biphosphoglycerate D.) phosphoenolpyruvate E.) glucose 6P F.) 2-phosphoglycerate G.) dihydroxyacetone phosphate

C.) 1,3 Biphosphoglycerate D.) phosphoenolpyruvate

Predict how oxygen transport is affected in individuals with a hexokinase deficiency as a result of decreased flux through the glycolytic pathway. A.) 2,3 BPG-levels are reduced leading to lower oxygen affinity and reduced oxygen transport to the tissues.\ B.) 2,3 BPG levels are increased leading to higher oxygen affinity and increased oxygen transport to the tissues. C.) 2,3 BPG levels are reduced leading to higher oxygen affinity and reduced oxygen transport to the tissues. D.) 2,3-BPG levels are reduced leading to higher oxygen affinity and increased oxygen transport to the tissues.

C.) 2,3 BPG levels are reduced leading to higher oxygen affinity and reduced oxygen transport to the tissues.

Predict how oxygen saturation would be affected if an individual has defective hexokinase enzymes A.) 2,3-BPG levels are reduced and oxygen binding decreases. B.) 2,3-BPG levels are elevated and oxygen binding decreases. C.) 2,3-BPG levels are reduced and oxygen binding increases. D.) 2,3-BPG levels are elevated and oxygen binding increases.

C.) 2,3-BPG levels are reduced and oxygen binding increases.

Which statements below describe three regulatory mechanisms in the glycolytic pathway? (More than one answer is correct). A.) Glucokinase is activated by insulin signaling in liver cells. B.) ADP is an allosteric inhibitor of phosphofrucktokinase-1. C.) ATP is an allostertic inhibitor of phosphofructokinase-1. D.) ATP is an allosteric inhibitor of pyruvate kinase. E.) Fructose 1,6 Bisphosphate is an allosteric activator of pyruvate kinase F.) Hexokinase is activated by increasing glucose concentrations in the blood. G.) Fructose 2,6-Bisphosphate is an allosteric activator of phosphofructokinase-1.

C.) ATP is an allostertic inhibitor of phosphofructokinase-1 E.) Fructose 1,6 Bisphosphate is an allosteric activator of pyruvate kinase G.) Fructose 2,6-Bisphosphate is an allosteric activator of phosphofructokinase-1.

When ATCase is in the __________ state it indicates that ____________ is bound, and that ATCase is ______________ regulated. A.) R; CTP; up B.) T; ATP; up C.) R; ATP; down D.) T; CTP; down

D.) T; CTP; down

Sort the following statements into the appropriate bin, considering if they apply to competitive, uncompetitive, or mixed inhibitors. -Does not affect the vmax of the reaction -Binds to the active site of an enzyme -Higher concentrations of substrate can reduce the effect of the inhibitor. -The y-axis intercept of the Lineweaver-Burk plot remains the same with or without this inhibitor. -Does not bind to the free enzyme -Increasing inhibitor concentration decreases both the vmax and the Km. -Does not bind to the active site of an enzyme, but can bind to the free enzyme or the enzyme-substrate complex

Competitive Inhibitor: -Does not affect the vmax of the reaction -Binds to the active site of an enzyme -Higher concentrations of substrate can reduce the effect of the inhibitor. -The y-axis intercept of the Lineweaver-Burk plot remains the same with or without this inhibitor. Uncompetitive Inhibitor: -Does not bind to the free enzyme -Increasing inhibitor concentration decreases both the vmax and the Km. Mixed Inhibitor: -Does not bind to the active site of an enzyme, but can bind to the free enzyme or the enzyme-substrate complex

Which amino acid is NOT a target for kinases? Choose one: A. Thr B. Tyr C. Ser D. Asp

D. Asp

One subtype of breast cancer involves the human epidermal growth factor receptor 2 gene (EGF receptor). One in every five breast cancers has a mutation in this gene. Understanding that this is a growth factor receptor gene, which of the answer choices best describes how this type of cancer develops? Choose one: A. Mutations that block the receptor from functioning will block cell growth, indicating that this is a loss-of-function gene. B. Mutations in the intracellular domain of the receptor will cause Akt to bind without further signaling and regulation of cell apoptotic processes. C. Interactions of the mutated receptor, which activates protein kinases, will not impact tumor growth because the ligand cannot bind to the receptor. D. Mutations that activate the kinase portion of the receptor result in a receptor that is constantly phosphorylated. This causes constitutive activation of downstream signaling and the resulting cell growth and proliferation.

D. Mutations that activate the kinase portion of the receptor result in a receptor that is constantly phosphorylated. This causes constitutive activation of downstream signaling and the resulting cell growth and proliferation.

Which of the following is not a primary mechanism used to regulate the catalytic efficiency of enzymes? Choose one: A. proteolytic processing B. covalent modification C. binding of regulatory molecules D. RNA synthesis

D. RNA synthesis

Lysophosphatidic acid (LPA) is a water-soluble phospholipid derivative found in blood serum, where it binds to receptors throughout the body, inducing cell growth and other effects. This is an example of what kind of signaling system? Choose one: A. exocrine B. autocrine C. paracrine D. endocrine

D. endocrine

Substrate binding to phosphoglycerate kinase induces a conformational change from an open to a closed complex. This conformational change is necessary to form a hydrophobic environment within the active site. A hydrophobic environment is necessary for optimal activity of phosphoglycerate kinase Choose one: A. for both substrates to bind to the active site. B. for the positioning of the substrates within the active site. C. to prevent early release of the substrates before the reaction is complete. D. to prevent hydrolysis of 1,3-bisphosphoglycerate.

D. to prevent hydrolysis of 1,3-bisphosphoglycerate.

-Why are Ras mutations so prevalent in certain types of cancers? A.) Because a tumor suppressor mutations In Ras require only one mutation to be a gain of function oncongene activation. B.) Because dominant mutations block signaling pathways that are required for cell growth, and thereby lead to a loss of function oncongene activation. C.) Because a recessive mutation in Ras requires two mutations to cause a gain of function oncongene activation. D.) Because a dominant mutation in Ras requires only one mutation to be a gain of function oncongene activation.

D.) Because a dominant mutation in Ras requires only one mutation to be a gain of function oncongene activation.

Which protein is part of the TNF receptor-activated programmed cell death signaling pathway? A.) TRAF2 B.) IKK C.) NFkB D.) FADD

D.) FADD

Glucose and fructose are both C6H12O6. What is the structural difference between them? A.) Glucose is a linear molecule and fructose is a ring. B.) Glucose is a five membered ring and fructose is a six membered ring. C.) Glucose is found in the boat conformation and fructose is a chair conformation. D.) Fructose is a five-membered ring and glucose is a six-membered ring.

D.) Fructose is a five-membered ring and glucose is a six-membered ring.

Which of the following statements is true of procaspase 8? A.) It is phosphorylated and activated by IKK B.) It cleaves and activates procaspase 3 C.) It is cleaved by TRADD and binds to p65 D.) It is activated by autocleavage

D.) It is activated by autocleavage

A new protein is discovered that contains a pleckstrin homology domain. Which of the following is likely to bind to the protein? A.) PI-3K B.) IP3 C.) Ca2+ D.) PIP3

D.) PIP3

Match the terms with the appropriate definition. Oncogene, Dominant Mutation, Recessive Mutation, Tumor Suppressor. -The mutant form of a normal gene that now has the ability to induce cell growth and cause cells to become cancerous -A somatic mutation that is gain-of-function or acts antagonistically to the wild-type allele. -A somatic mutation that results in the loss of a function. Both gene copies must be mutated to see the effect. -A gene whose function is to limit cell growth or tumor behavior. Both copies must be mutated to see the full effect

Oncogene: The mutant form of a normal gene that now has the ability to induce cell growth and cause cells to become cancerous Dominant Mutation: A somatic mutation that is gain-of-function or acts antagonistically to the wild-type allele Recessive Mutation: A somatic mutation that results in the loss of a function. Both gene copies must be mutated to see the effect Tumor Suppressor: A gene whose function is to limit cell growth or tumor behavior. Both copies must be mutated to see the full effect

While glucagon (a peptide) and epinephrine (a tyrosine derivative) are very different agonists, both signal through GPCR systems. Some of the components of the pathways are unique, while other signaling components are shared between both systems. Place each item in the appropriate category: glucagon and epinephrine shared, glucagon independent, or epinephrine independent. -cAMP signaling pathways -Gsa activation -Adenylate cyclase activation -Net accumulation of glucose -Peptide binding to GPCR receptor -Gqa activation -Activation of phospholipase C -Ligand binding to adrenergic receptor

Shared: cAMP signaling pathways Gsa activation Adenylate cyclase activation Net accumulation of glucose Glucagon Independent: Peptide binding to GPCR receptor Epinephrine Independent: Gqa activation Activation of phospholipase C Ligand binding to adrenergic receptor

Put the following glycolytic reactions in the correct order. Only 8 of the 10 reactions are listed, so the answer should be the relative order of the reactions. Note that the answer is graded as an "all or nothing" question, meaning the order must be correct to earn 1 point. _____A redox reaction utilizing inorganic phosphate and a coenzyme. _____Phosphorylation reaction generating a hexose sugar. _____A substrate level phosphorylation reaction generating the ATP needed to replace the ATP investment in stage 1. _____Substrate level phosphorylation reaction generating a net yield in ATP for the glycolytic pathway. ____Cleavage reaction converting a diphosphate sugar into two monophosphate metabolites. _____A dehydration reaction generating a high energy phosphorylated compound. _____Phosphorylation reaction converting a hexose monophosphate into a hexose bisphosphate. _____An isomerization reaction converting an aldose sugar into a ketose sugar.

_5__A redox reaction utilizing inorganic phosphate and a coenzyme. __1__ Phosphorylation reaction generating a hexose sugar. __6__ A substrate level phosphorylation reaction generating the ATP needed to replace the ATP investment in stage 1. __8__ Substrate level phosphorylation reaction generating a net yield in ATP for the glycolytic pathway. __4__ Cleavage reaction converting a diphosphate sugar into two monophosphate metabolites. __7__ A dehydration reaction generating a high energy phosphorylated compound. __3__ Phosphorylation reaction converting a hexose monophosphate into a hexose bisphosphate. __2__ An isomerization reaction converting an aldose sugar into a ketose sugar.

For the cAMP-mediated pathway, identify the following components: 1. cAMP 2. Adenylate cyclase 3. Protein kinase A (PKA) 4. Glucose mobilization 5. diacylglycerol (DAG) 6. phospholipase C (PLC) 7. protein kinase C (PKC) 8. Glucose storage (as glycogen) _______Kinase ______Second messenger ______Second messenger produced by ______Result

__3___Kinase __2___ Second Messenger ___1___ Second Messenger produced by __4___ Result

The phosphoinositide-3 kinase (PI-3K) pathway is activated by insulin signaling in liver cells. Number the following statements 1-10 to order the sequence of events that lead to glucose uptake and glycogen synthesis in response to insulin signaling. The abbreviations for each signaling component of the pathway are defined in Section 8.3 of the textbook. ____PDK1 and Akt bind to PIP3 in the plasma membrane via PH domains. ______Akt is phosphorylated and activated by the PDK1 serine/threonine kinase activity. ______Insulin receptor phosphorylates IRS proteins on tyrosine residues. ______Increased rates of glucose uptake and glycogen synthesis lower blood glucose. ______Akt dissociates from PIP3 and phosphorylates downstream target proteins. ______IRS proteins bind to phosphotyrosines in the insulin receptor via PTB domains. ______Insulin receptor autophosphorylates tyrosine residues in the cytoplasmic tail. ______PI-3K binds to phosphotyrosines on IRS proteins via SH2 domains ______PI-3K phosphorylates PIP2 to generate PIP3. ______Insulin binds to the insulin receptor and activates its intrinsic kinase activity.

__7__PDK1 and Akt bind to PIP3 in the plasma membrane via PH domains. __8__Akt is phosphorylated and activated by the PDK1 serine/threonine kinase activity. __4__Insulin receptor phosphorylates IRS proteins on tyrosine residues. __10__Increased rates of glucose uptake and glycogen synthesis lower blood glucose. __9__Akt dissociates from PIP3 and phosphorylates downstream target proteins. __3__IRS proteins bind to phosphotyrosines in the insulin receptor via PTB domains. __2__Insulin receptor autophosphorylates tyrosine residues in the cytoplasmic tail. _5__PI-3K binds to phosphotyrosines on IRS proteins via SH2 domains __6__PI-3K phosphorylates PIP2 to generate PIP3. _1__Insulin binds to the insulin receptor and activates its intrinsic kinase activity.