TopHat and Quiz Questions (copy)

Which of the following is most likely true about oligonucleotide, pACGUAC?

A: the nucleotide at the 3' end has a phosphate at its 3' hydroxyl
B: the nucleotide at the 3' end is a purine
C: the nucleotide at the 5' end has a 5' hydroxyl
D: the nucleotide at the 5' end has a phosphate on its 5' hydroxyl

D: the nucleotide at the 5' end has a phosphate on its 5' hydroxyl

Which of the following is true about properties of fatty acids?

A: are highly oxidized storage forms of hydrocarbons
B: can be branched or unbranched
C: never exceed 20 carbons in length, by definition

B: can be branched or unbranched

Which of the following fatty acids is less stable?

A: 18:3 (delta sup9,12)
B: 18:3 (delta sup9,12,15)

A: 18:3 (delta sup9,12)

T/F: melting point decreases as the number of double bonds increases in fatty acid

true

- a parent compound or compounds of sphingolipids

A: phospholipases are
B: glycerol-3-phosphate
C: sphingomyelinds are
D: ceramides are

D: ceramides are

Which statement regarding cholesterol is false?

A: It is the precursor for steroid hormones
B: It is the precursor for bile acids
C: It is usually not a component of eukaryotic membranes
D: It has a hydrophilic functional group

C: It is usually not a component of eukaryotic membranes

Membrane lipids do not include:

A: glycerophospholipids
B: triacylglycerols
C: sphingolipids
D: glycolipids

B: triacylglycerols

Which statement is false?

A: phosphorylated derivatives of phosphatidylinosital regulate cell structure and metabolism
B: Extracellular signals activate a specific phospholipase C in the membrane, which hydrolyzes PIP2 to release two products that act as intracellular messengers
C: PIP3 is a potent regulator of protein kinases

C: PIP3 is a potent regulator of protein kinases

A novel subclass of thromboxane was discovered in lipids isolated from a newly discovered poison dart from the Amazon valley. What unique structural feature is likely present in these lipids?

A: four conjugated double bonds
B: a six membered ring
C: a long chain alcohol bound to a double ring
D: fiver membered ring

B: a six membered ring

What product of the preparatory phase of glycolysis is required, but at twice the concentration, as a reactant in the payoff phase?

A: dihydroxyacetone phosphate
B: NAD+
C: ADP

C: ADP

How is glucose kept inside the cell, against a concentration gradient?

A: glucose is kept inside the cell by active transport pumps
B: glucose is kept inside the cell by conversion to glucose 6 phosphate
C: glucose is kept inside the cell through rapid conversion to pyruvate
D: there are no glucose transporters to pump glucose out of the cell

B: glucose is kept inside the cell by conversion to glucose 6 phosphate

How is glucose 6 phosphate prevented from leaving the cell?

A: It is prevented from leaving by active transport pump
B: there are no phospho-glucose specific transporters
C: glucose 6 phosphate is rapidly converted to fructose 6 phosphate

B: there are no phospho-glucose specific transporters

How are glycolysis, ethanol fermentation, and lactate fermentation all related?

A: all are regulated by the ATP/ADP mass action ratio
B: all three produce CO2
C: all can proceed in the absence of oxygen
D: all require pyruvate

C: all can proceed in the absence of oxygen

The reaction catalyzed by glyceraldehyde 3 phosphate dehydrogenase oxidizes an aldehyde group. How does this reaction conserve much of the free energy of oxidation?

A: through the formation of a carboxylic acid
B: through the formation of an acyl phosphate
C: through the formation of a carbon carbon bond
D: through the formation of ATP

B: through the formation of an acyl phosphate

Which sugar cannot be fed into the glycolytic pathway?

A: sucrose
B: mannose
C: glycogen
D: cellulose

D: cellulose

Which enzyme is specific to the gluconeogeneic pathway?

A: glucose 6 phosphatase
B: pyruvate carboxylase
C: PEP carboxykinase
D: all of the answers are correct

D: all of the answers are correct

Which carbons of the original glucose are phosphorylated in the two molecules of glyceraldehyde 3 phosphate?

A: C1 and C2
B: C3 and C4
C: C1 and C6
D: C1 and C4

C: C1 and C6

Which reaction of glycolysis includes substrate level phosphorylation, a very different mechanisms that oxidative phosphorylation?

A: hexokinase
B: phosphoglycerate kinase
C: phosphofrutokinase-1
D: pyruvate kinase

B: phosphoglycerate kinase

Which of these enzymes catalyzes a reversible reaction in glycolysis under typical cellular conditions?

A: phosphofructokinase-1
B: pyruvate kinase
C: hexokinase

A: phosphofructokinase-1

Which compound does not appear in the overall reaction for glycolysis?

A: 2 pyruvate
B: fructose 6 phosphate
C: 2 ATP
D: 2 NADH

B: fructose 6 phosphate

Which of the following statements is true of galactosemia?

A: results from defective or absent lactase in the intestine
B: is a disorder that affects how the body processes a simple sugar called galactose
C: the ability to metabolize galactose results in galactosemia

B: is a disorder that affects how the body processes a simple sugar called galactose

Which nucleotide is required for glycogen synthesis?

A: GTP
B: UTP
C: cAMP
D: ATP

B: UTP

Glyconeogenesis:

A: begins the production of a new glycogen molecule with the reactions of glycogenin
B: involves the action of glycogen debranching enzyme
C: involves transfer of glucose from CDP glucose to a nonreducing end of glycogen
D: only occurs in the liver and muscle

A: begins the production of a new glycogen molecule with the reactions of glycogenin

In muscle, what are two allosteric activators of glycogen phosphorylase?

A: Mg2+ and ATP
B: Ca2+ and AMP
C: AMP and glucose
D: cAMP and acetyl-CoA

B: Ca2+ and AMP

Which vitamin is a coenzyme to the pyruvate dehydrogenase (PDH) complex?

A: pantothenate
B: thiamine pyrophosphate
C: niacin
D: riboflavin
E: all of the answers are correct

E: all of the answers are correct

Which two chemical mechanisms change to acetyl-CoA in the pyruvate dehydrogenase complex?

A: dehydrogenation and oxidation
B: decarboxylation and condensation
C: condensation and dehydrogenation
D: dehydrogenation and decarboxylation

D: dehydrogenation and decarboxylation

What is the advantage to having an enzyme complex, as in pyruvate dehydrogenase (PDH) complex?

A: multiple steps can be regulated at one point
B: products do not need to diffuse to become substrates for the next enzymatic reaction
C: products cannot be scavenged by other enzymes or pathways
D: conservation of energy drives the reactions
E: all of the answers are correct

E: all of the answers are correct

The citrate synthase step of the citric acid cycle:

A: is freely reversible under physiological conditions
B: does not involve ATP hydrolysis
C: is considered to be both the first and last step of the cycle

B: does not involve ATP hydrolysis

Which statement regarding isocitrate dehydrogenase is false?

A: in eukaryotes, there is an NAD+ dependent form in mitochondria and an NAD+ independent form found in both mitochondria and cytosol
B: it catalyzes a reversible reaction under physiological conditions
C: it catalyzes an oxidative decarboxylation

B: it catalyzes a reversible reaction under physiological conditions

Which enzyme of the citric acid cycle is capable of a substrate level phosphorylation?

A: citrate synthase
B: aconitase
C: succinate dehydrogenase
D: isocitrate dehydrogenase
E: succinyl CoA synthetase

E: succinyl CoA synthetase

Which citric acid cycle reaction produces FADH2?

A: succinyl CoA synthetase
B: aconitase
C: a-ketoglutarate dehydrogenase complex
D: isocitrate dehydrogenase
E: succinate dehydrogenase

E: succinate dehydrogenase

Which statement regarding the citric acid cycle is false?

A: The PDH complex is considered to be an enzyme of the citric acid cycle
B: succinate dehydrogenase is an integral membrane protein
C: for the complete conversion of glucose to CO2, approximately 32 ATP can be synthesized

A: The PDH complex is considered to be an enzyme of the citric acid cycle

The conversion of 1 mol of fructose 1,6 bisphosphate to 2 mol of pyruvate by the glycolytic pathway results in a net formation of:

A: 1 mol of NAD+ and 2 mol of ATP
B: 1 mold NADH and 1 mol ATP
C: 2 mol of NAD+ and 4 mol of ATP
D: 2 mol of NADH and 2 mol ATP
E: 2 mol of NADH and 4 mol of ATP

E: 2 mol of NADH and 4 mol of ATP

Which of the following glycolytic steps does not most likely occur between glyceraldehyde 3 phosphate and 3 phosphoglycerate?

A: ATP synthesis
B: catalysis by phosphorylation kinase
C: oxidation of NADH and NAD+
D: the formation of 1,3 bisphosphoglycerate
E: utilization of Pi

NOT A: ATP synthesis, Quizlet says C: oxidation of NADH and NAD+

Which of the following statements is not true concerning glycolysis in anaerobic muscle?

A: fructose 1,6 bisphosphate is one of the enzymes of the pathway
B: it is an endergonic process
C: it results in net synthesis of of ATP
D: it results in synthesis of NADH
E: its rate is slowed by a high [ATP]/[ADP] ration

B: it is an endergonic process

Which of these cofactors participates directly in most of the oxidation-reduction reactions in the fermentation of glucose to lactate?

A: ADP
B: ATP
C: FAD/FADH2
D: glyceraldehyde 3 phosphate
E: NAD+/NADH

E: NAD+/NADH

Which of the following enzymes is used in both glycolysis and gluconeogenesis?

A: 3 phosphoglycerate kinase
B: glucose 6 phosphae
C: phosphofructokinase 1
D: the conversion of pyruvate to lactate

A: 3 phosphoglycerate kinase

Which statement about carbohydrate metabolism is false?

A: The overall strategy for metabolizing the common monosacharides is to convert them into glycolytic intermediates
B: Galactose metabolism requires a nucleotide
C: mannose is phosphorylated by hexokinase
D: galactosemia results from defective or absent lactase in the intestine

D: galactosemia results from defective or absent lactase in the intestine

Glycerophospholipids do not contain:

A: fatty acids
B: ester linkages
C: glycerol
D: a mono or disaccharide

D: a mono or disaccharide

Where do we store triacylglycerol (triglyceride)?

A: in the lumen of the ER
B: in the mitochondria
C: in the lipid droplet
D: in the nucleus

C: in the lipid droplet

Which statement is false?

A: Naturally occurring fatty acids usually have an even number of carbons
B: wax esters contain long chain fatty acids and long chain alcohols
C: triacylglycerols are polar due to their ester functional groups
D: the number of C-C double bonds in a fatty acids affects its melting point

C: triacylglycerols are polar due to their ester functional groups

Which statement regarding linoleic acid (18:2(delta sup 9,12)) is false?

A: It has one carboxylic acid functional group
B: it has two double bonds
C: it has 20 carbons
D: it has C-C double bonds between carbons 9 and 10

C: it has 20 carbons

Which of the following biomolecules is an allosteric activator of BOTH citric acid cycle and glycolysis pathways?

A: ATP
B: NAD+
C: ADP
D: Citrate
E: NADH

C: ADP

The glyoxylate cycle is remarkably similar to the citric acid cycle but differs in several important ways. Which important molecule is conserved by by the glyoxylate cycle but NOT the citric acid cycle?

A: acetyl-CoA
B: malate
C: citrate
D: carbon dioxide
E: NADH

D: carbon dioxide

Which of the below is not required for the oxidative decarboxylation of pyruvate from acetyl-CoA?

A: ATP
B: CoA-SH
C: FAD
D: Lipoic acid
E: NAD+

A: ATP

Which of the following biochemical conversion would lead to the production of GTP via substrate level phosphorylation in the citric acid cycle?

A: citrate to isocitrate
B: fumarate to malate
C: malate to oxaloacetate
D: succinate to fumarate
E: succinyl-CoA to succinate

E: succinyl-CoA to succinate

Which of the following can most likely inhibit citrate synthase and the NAD+ specific isocitrate dehydrogenase (IDH) of the citric acid cycle?

A: acetyl-CoA and fructose 6 phosphate
B: AMP and/or NAD+
C: AMP and/or NADH
D: ATP and/or NAD+
E: ATP and/or NADH

NOT C: AMP and/or NADH, Quizlet says E: ATP and/or NADH

Which of the following does NOT occur during the citric acid cycle?

A: formation of a-ketoglutarate
B: generation of NADH and FADH2
C: net synthesis of oxaloacetate from acetyl-CoA
D: oxidation of acetyl-CoA

NOT A: formation of a-ketoglutarate, Quizlet says C: net synthesis of oxaloacetate from acetyl-CoA

Which of the following molecules is NOT an intermediate of the citric acid cycle?

A: acetyl-CoA
B: citrate
C: oxaloacetate
D: succinyl-CoA
E: a-ketoglutarate

A: acetyl-CoA

Which of the following statements is/are true about the regulation of glucose metabolism through glycolysis and the citric acid cycle?

A: High ADP levels stimulate glycolysis and the citric acid cycle
B: High NADP levels inhibit glycolysis and the citric acid cycle
C: High citrate levels inhibit glycolysis
D: all of the answers are correct

D: all of the answers are correct

Which statement regarding the citric acid cycle is false?

A: The PDH complex is considered to be an enzyme of the citric acid cycle
B: Succinate dehydrogenase is an integral membrane protein
C: For the conversion of glucose to CO2, approximately 32 ATP can be synthesized
D: Decarboxylation of pyruvate takes place on the thiamine pyrophosphate (TPP) of pyruvate dehydrogenase (E1) of the pryuvate dehydrogenase reaction

A: The PDH complex is considered to be an enzyme of the citric acid cycle

- is required as a cofactor for the conversion of succinate to fumarate in the citric acid cycle

A: ATP
B: biotin
C: FAD
D: NAD+
E: NADP+

C: FAD

The glycosaminoglycan hyaluronan:

A: is a homopolysaccharide
B: is a much shorter polymer than heparin
C: consists of alternating residues of D-glucuronic acid and N-acetylglucosamine

C: consists of alternating residues of D-glucuronic acid and N-acetylglucosamine

Which of the following is NOT a main component of ECM?

A: proteoglycan aggregates
B: collagen fibers
C: elastin
D: heparinase

D: heparinase

The biochemical property of lectins that is the basis for most of their biological effects is their ability to bind to:

A: specific ligands
B: specific oligosaccharides
C: specific peptides
D: specific DNA

B: specific oligosaccharides