prelecture quizzes 12-18 (exam 2)

Which of the answers below best completes the following sentence: Although salts of fatty acids form micelles, phospholipids and glycolipids form bimolecular sheets because.... of the presence of two fatty acyl chains. water forms clathrate structures around fatty acid micelles. the association of phospholipids is entropically driven.

...of the presence of two fatty acyl chains

What are the overall oxidation states for glucose and pyruvate, respectively? 0 and +2 0 and 0 -1 and +2 -1 and +1 0 and +1

0 and +2

The three-dimensional structure of the potassium channel provided a rationale for the selectivity of potassium ions and the rejection of sodium ions. Which of the following is the basis for the ability of the potassium channel to discriminate between these two ions? - The opening of the channel is structurally arranged such that potassium ions can bind, but is too small for sodium ions. - A restriction in the channel allows for potassium ions to be re-solvated by protein backbone carbonyl groups but is too large to effectively resolvate sodium ions. - The sodium ion is too small to pass through the channel.

A restriction in the channel allows for potassium ions to be re-solvated by protein backbone carbonyl groups but is too large to effectively resolvate sodium ions

Which ONE of the following statements regarding the energy investment phase is FALSE? Cleavage occurs to maximize future energy yield. An induced fit helps hexokinase act on its substrate. A prior isomerization step helps aldolase act on its substrate. Two phosphorylations occur. ATP and NADH are consumed.

ATP and NADH are consumed

Blood glucose is high and insulin binds to a receptor on an adipose cell. Which ONE of the following things could occur in this cell because of phosphorylation that resulted ultimately from insulin signaling? - Recruitment and fusion of GLUT1 containing vesicles with the plasma membrane - Activation of pyruvate kinase by dephosphorylation - Activation of enzymes for fatty acid degradation - A rise in [F-2,6-BP] - Activation of hexokinase by phosphorylation

Activation of pyruvate kinase by dephosphorylation

You assay cell surface oligosaccharides from a blood sample. After determining the composition of the oligosaccharides relative to a reference monosaccharide, fucose, you conclude the donor is blood type B. What brought you to this conclusion? An abundance of unmodified glucose An abundance of unmodified galactose An abundance of N-acetylgalactosamine (GalNAc) Both galactose and GalNAc High levels of HbA1c

An abundance of unmodified galactose

You add a membrane impermeable reagent to a solution of intact erythrocytes. If a protein in the erythrocyte reacts with the reagent, what can you conclude about the membrane protein? It is a peripheral membrane protein. At least part of the protein is located on the outer face of the membrane. It is not a plasma membrane protein.

At least part of the protein is located on the outer face of the membrane

Which ONE of the following statements about phosphofructokinase and fructose-2,6-bisphosphate is TRUE? F-2,6-BP competes with substrate at the active site of PFK. Binding of F-2,6-BP to PFK shifts the enzyme toward the R state. Binding of F-2,6-BP to PFK shifts the enzyme toward the T state. F-2,6-BP competes with ATP and ADP for binding at an allosteric site. F-2,6-BP is elevated during insulin signaling, lowering activity of PFK.

Binding of F-2,6-BP to PFK shifts the enzyme toward the R state

Which one is a carbohydrate? C3H6O3 C2H5OH C3H5N2 C16H34O2 C2H6O2N

C3H6O3

An enzymatic weight-gain supplement claims to help users digest all carbohydrates in fruits and vegetables. What key enzyme would you hope to see on the label? Lactase Lipase Oligosaccharidase Amylase Cellulase

Cellulase

Which ONE of the following is DEPLETED from muscle during exercise? Creatine kinase Creatine phosphate Creatine ATP Pi

Creatine phosphate

Forming a glycosidic bond can be described generally as: Dehydration Dimerization Tautomerization Polymerization Hydrolysis

Dehydration

Your friend is training as a pastry chef and was excited to make a "healthy" cookie with oligosaccharides as a substitute for sugar. However, the cookies were dry and pale-looking. Why? - More alcohol on reducing sugars were available to undergo the Maillard reaction during baking - Fewer aldehydes on reducing sugars were available to undergo the Maillard reaction during baking - Oligosaccharides don't caramelize - Fewer aldehydes on nonreducing sugars were available to undergo the Maillard reaction during baking - More alcohol on nonreducing sugars were available to undergo the Maillard reaction during baking

Fewer aldehydes on reducing sugars were available to undergo the Maillard reaction during baking

Insulin secreting beta cells in the pancreas use specialized forms of which two proteins? (Choose ONE answer) GLUT and creatine kinase Hexokinase and lactate dehydrogenase GLUT and hexokinase Hexokinase and enolase Hexokinase and creatine kinase

GLUT and hexokinase

Both liver and pancreatic beta cells express a pair of proteins whose cooperation helps the cell perform unique functions with regard to glucose. Which ONE of the following lists that pair of proteins? GLUT2, PFK-2/FBPase-2 GLUT3, glucokinase GLUT3, PFK-2/FBPase-2 glucokinase, PFK-2/FBPase-2 GLUT2, glucokinase

GLUT2, glucokinase

Which ONE of the following lists the products of glycolysis in the CORRECT order? - Glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate, 1,3-bisphosphoglycerate, glyceraldehyde-3-phosphate, 3-phosphoglycerate, 2-phosphoglycerate, phosphoenolpyruvate, pyruvate - Glucose-6-phosphate, fructose-1,6-bisphosphate, fructose-6-phosphate, glyceraldehyde-3-phosphate, 1,3-bisphosphoglycerate, 3-phosphoglycerate, 2-phosphoglycerate, phosphoenolpyruvate, pyruvate - Glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate, 1,3-bisphosphoglycerate, 3-phosphoglycerate, 2-phosphoglycerate, glyceraldehyde-3-phosphate, phosphoenolpyruvate, pyruvate - Glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate, glyceraldehyde-3-phosphate, 1,3-bisphosphoglycerate, 2-phosphoglycerate, 3-phosphoglycerate, phosphoenolpyruvate, pyruvate - Glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate, glyceraldehyde-3-phosphate, 1,3-bisphosphoglycerate, 3-phosphoglycerate, 2-phosphoglycerate, phosphoenolpyruvate, pyruvate

Glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate, glyceraldehyde-3-phosphate, 1,3-bisphosphoglycerate, 3-phosphoglycerate, 2-phosphoglycerate, phosphoenolpyruvate, pyruvate

Which of the following glycolytic enzymes does NOT use substrate level phosphorylation? (Choose ALL that apply.) Glyceraldehyde-3-phosphate dehydrogenase Pyruvate kinase Phosphoglycerate kinase Hexokinase Phosphofructokinase

Glyceraldehyde-3-phosphate dehydrogenase Hexokinase Phosphofructokinase

The 3 irreversible steps of glycolysis have which of the following features in common? I. They have a large negative ΔG II. They have a large positive ΔG III. They consume ATP IV. They are catalyzed by kinases II and IV only I only II, III, and IV only I and IV only I, III, and IV only

I and IV only

Which of the following would be expected to lower the Tm for a phospholipid bilayer the most? - In a membrane composed of phospholipids made from saturated 18-carbon fatty acyl chains, replacing them with saturated 16-carbon fatty acyl chains. - Replacing a phosopholipid containing unsaturated fatty acids with one containing saturated fatty acids of the same length. - Replacing a cis bond in a monounsaturated fatty acid with a trans bond. - Replacing a mono-unsaturated 16-Carbon fatty acids in phospholipids with mono-unsaturated 18-Carbon fatty acids.

In a membrane composed of phospholipids made from saturated 18-carbon fatty acyl chains, replacing them with saturated 16-carbon fatty acyl chains

Which of the following is NOT true of ion channels? - Movement of ions through ion channels is more rapid than through pumps or secondary transporters. - Ion channels are gated, only being opened in response to specific signals. - Ion channels are continually open while pumps or secondary transporters depend on an energy source to open and allow the flow of ions.

Ion channels are continually open while pumps or secondary transporters depend on an energy source to open and allow the flow of ions

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. It consists of five fused rings, three with six carbons and two with five. It consists of three fused rings, two with six carbons and one with five. It consists of five fused rings, four with six carbons and one with five.

It consists of four fused rings, three with six carbons and one with five

Which ONE of the following statements about acetaldehyde is FALSE? It can be made by the enzyme pyruvate decarboxylase. It can be made by the enzyme alcohol dehydrogenase. It can be made by the enzyme aldehyde dehydrogenase. It is not metabolized in patients with autobrewery syndrome. It is removed from cells using NAD+.

It is not metabolized in patients with autobrewery syndrome

Lactate dehydrogenase can use ____ to oxidize ____ O2, pyruvate NAD+, pyruvate O2, lactate NADH, lactate NAD+, lactate NADH, pyruvate

NAD+, lactate

As molecules move through glycolysis, the carbons from glucose generally become more: Reduced Dephosphorylated Energetic Oxidized Phosphorylated

Oxidized

Which ONE of the following statements about ATP hydrolysis is NOT CORRECT? The liberated phosphate is stabilized by resonance. Relief of charge repulsion is a partial driving force for the reaction. Phosphoester bonds hold most of the energy. The overall reaction is exergonic.

Phosphoester bonds hold most of the energy

The liver uses several specialized enzymes. Which of the following enzymes is used ONLY by the liver? GAPDH Hexokinase GLUT2 Phosphofructokinase-2/fructose bisphosphatase-2 Phosphofructokinase-1

Phosphofructokinase-2/fructose bisphosphatase-2

A monosaccharide is to a _____ what a(n) _____ is to a protein. Polysaccharide, domain Polysaccharide, amino acid Polysaccharide, peptide Disaccharide, amino acid Disaccharide, domain

Polysaccharide, amino acid

Which of the following is true? In cellular membranes, the composition of both sheets that make up a lipid bilayer are at equilibrium. In cellular membranes, lipid rafts are primarily composed of cholesterol and peripheral membrane proteins. Proteins can be anchored to cellular membranes by post-translational modification with fatty acids. Within a eukaryotic cell, the composition of all cellular membranes are essentially the same.

Proteins can be anchored to cellular membranes by post-translational modification with fatty acids

Which of the following is NOT a role of carbohydrates? - Providing physical cell support & structure - Oxidation to make ATP - Cell-cell signaling - Modifying proteins - Storing genetic information

Storing genetic information

In active transport systems, what is the difference between symporters and antiporters? - Symporters allow the same molecule to be moved in both directions while antiporters allow it to move in only one direction. - Symporters use the energy from one molecule moving down its concentration gradient to drive the movement of a second molecule in the same direction against its concentration gradient while antiporters drive the movement in the opposite direction. - Symporters use the energy from one molecule moving down its concentration gradient to drive the movement of a second molecule in the opposite direction against its concentration gradient while antiporters drive the movement in the same direction. - No answer text provided.

Symporters use the energy from one molecule moving down its concentration gradient to drive the movement of a second molecule in the same direction against its concentration gradient while antiporters drive the movement in the opposite direction

After a period of time, Gα ceases to stimulate adenylyl cyclase. Why? - Gα is phosphorylated which enables it to re-associate with the βγ subunits. - GTP displaced GDP and enables the G-protein to re-associate with the βγ subunits. - The G-protein's GTPase activity removes a phosphate; Gα bound to GDP then reassociates with the βγ subunits.

The G-protein's GTPase activity removes a phosphate; Gα bound to GDP then reassociates with the βγ subunit

Which ONE of the following CORRECTLY states why liver and pancreatic beta cells use the pair of proteins named in question 5? - They allow the cell to sense and/or release phosphorylated glucose without committing it to glycolysis. - They bring in a steady stream of glucose and trap it there to fuel glycolysis. - They allow the cell to bring in glucose in response to insulin signaling. - They bring in large amounts of glucose when blood glucose is high and trap it there to fuel glycolysis. - They allow the cell to sense and/or release glucose without committing it to glycolysis.

They allow the cell to sense and/or release glucose without committing it to glycolysis

Which of the following is true about motion of membrane lipids? - They can move most rapidly when in the gel phase. - Lateral diffusion is catalyzed by flippase proteins. - To increase the fluidity of membranes at low temperatures, cells synthesize phosholipids with longer, more saturated fatty acids and fewer unsaturated fatty acids. - Transbilayer diffusion involves the transfer of lipids from one face of the bilayer to another.

Transbilayer diffusion involves the transfer of lipids from one face of the bilayer to another

Unsaturated fatty acids generally have double bonds that are in the cis, rather than the trans, configuration. One of the consequences of this is: enhanced ability to pack with saturated fatty acids increasing the Tm of the lipid mixture. a 45° bend in the molecule. a 30° bend in the molecule a change in the overall charge of the molecule.

a 30° bend in the molecule

After the removal of all sugar units from a ganglioside, what molecule remains? phosphate glycerol sphingosine a ceramide L-serine palmitate

a ceramide

Peripheral membrane proteins completely span the membrane. can only be removed from the membrane using detergents. are extracted from the membrane with high salt, change in pH, or using chelating agents. only associate with a membrane after modification with a lipid

are extracted from the membrane with high salt, change in pH, or using chelating agents

For charged species, the free energy content of a concentration gradient is determined by - only the electrochemical potential or voltage difference across the membrane. - both the concentration difference and electrochemical potential across the membrane. - only the concentration difference across the membrane.

both the concentration difference and electrochemical potential across the membrane

Stimulation of phospholipase C activity by Gα-proteins generates what second messengers? - free fatty acids and a molecule in which inositol 4,5 diphosphate is linked via a phosphate to glycerol. - diacylglycerol and inositol 1,4,5-triphosphate. - diacylglycerol phosphate and inositol 4,5-diphosphate. - cAMP

diacylglycerol and inositol 1,4,5-triphosphate

The basic building blocks that make up glycosphingolipids include all of the following except: glycerol sphingosine a fatty acid a mono- or oligo-saccharide

glycerol

For an anabolic reaction to benefit from energetic coupling, its half reactions MUST: be redox reactions. have an overall positive ∆G. have an overall negative ∆G. have an overall zero ∆G. include hydrolysis of ATP.

have an overall negative ∆G

Although the insulin receptor is already a dimer, ligand binding to Receptor Tyrosine Kinases (RTKs) induces dimer formation in other members of the RTK family. The result of this is that - the intracellular domains are changed from a conformation having little organized structure into a highly organized structure that is active. - intracellular protein kinase domains are brought together and activate one another by auto-phosphorylation. - intracellular domains acting as second messengers are proteolytically cleaved and free to move through the cytoplasm.

intracellular protein kinase domains are brought together and activate one another by auto-phosphorylation

Fructose-1-phosphate is cleaved between carbons 3 and 4 to make two 3-carbon intermediates. Before they can proceed on to glycolysis, one intermediate must be and the other must be: reduced, isomerized isomerized, phosphorylated reduced, phosphorylated oxidized, isomerized oxidized, phosphorylated

isomerized, phosphorylated

The GTPase activity of G-proteins is important because - the G-proteins are active only when GDP is bound to them. - it provides a method whereby the initial signal can be terminated - the phosphate released in an important secondary messenger.

it provides a method whereby the initial signal can be terminated

Compared to olive oil, you would expect beef fat to have a higher proportion of: long-chain unsaturated fatty acids. short-chain branched fatty acids. long-chain saturated fatty acids. short-chain unsaturated fatty acids.

long-chain saturated fatty acids

Complete oxidation of all carbons in one mole of which compound would yield the most energy? (Ignore possible energetic contributions of nitrogen) glucose glutamine ribose palmitate sucrose

palmitate

The glycolytic product of the ____ reaction allosterically activates ____ hexokinase, pyruvate kinase phosphofructokinase, pyruvate kinase pyruvate kinase, hexokinase pyruvate kinase, phosphofructokinase GAPDH, phosphoglycerate kinase

phosphofructokinase, pyruvate kinase

When oxygen is low, HIF-1 is _____ and leads to _____ of genes encoding many glycolytic enzymes. stabilized, replication degraded, replication stabilized, transcription stabilized, silencing degraded, transcription degraded, silencing

stabilized, transcription

One mole each of glucose, ribose, glyceraldehyde, and sucrose are oxidized completely to CO2. Rank the molecules by the amount of energy released from highest to lowest (i.e. most kJ released > ... > least kJ released) sucrose > glucose > ribose > glyceraldehyde sucrose > ribose > glucose > glyceraldehyde glucose > sucrose > ribose > glyceraldehyde glyceraldehyde > glucose > ribose > sucrose glyceraldehyde > ribose > glucose > sucrose

sucrose > glucose > ribose > glyceraldehyde

In passive transport, the energy driving the net movement of materials across a membrane is provided by - ATP - nothing, no energy is required for passive transport. - the concentration gradient across the membrane.

the concentration gradient across the membrane

Lipid molecules are said to be amphipathic, meaning that: - they are capable of moving rapidly from one side of a lipid bilayer to the other. - they have a dual nature with part of the molecule being hydrophobic and the other part hydrophilic. - they have asymmetric carbons and can exist in left- and right-handed forms.

they have a dual nature with part of the molecule being hydrophobic and the other part hydrophilic

Which of the following lipids is used for energy storage? triacylglycerols cardiolipins glycerophospholipids sphingolipids

triacylglycerols

What is the name of this molecule? (lect 15 q 5) β-D-ribofuranose β-D-fructopyranose α-D-fructopyranose α-D-ribofuranose α-D-ribopyranose

α-D-ribofuranose

The most common way in which integral membrane proteins span the membrane is by using: β-sheet structures. α-helical segments. single strands with no secondary structure.

α-helical segments