Biochemistry Exam 1 Material

Noncovalent bonds are critically important to the function of biomolecules. Which of the following is/are (a) valid reason(s) for this importance? A) Noncovalent interactions are made up of hydrogen bonding, electrostatic interactions, and dispersion forces. B) The effect of these weak interactions is cumulative. C) Their bond energies are ~10-100 times weaker than ordinary covalent bonds. D) All of the listed statements are valid reasons for this importance.

D) All of the listed statements are valid reasons for this importance.

Which statement about the various classes of organisms is FALSE? A) Eukaryotes can be unicellular or multicellular organisms. B) Eukaryotic cells are compartmentalized. C) Fungi are eukaryotic organisms. D) Prokaryotes have a well-defined nucleus that houses DNA.

D) Prokaryotes have a well-defined nucleus that houses DNA.

What name is given to the bond between water molecules? A) hydrophobic B)polar covalent C)single (nonpolar) covalent D) ionic E) hydrogen

E) hydrogen

The tendency of an atom to pull electrons toward itself is referred to as its _____.

Electronegativity

Ionic compounds can be readily dissolved in water because the high dielectric constant of water screens and decreases the ________ force between the oppositely charged ions.

Electrostatic

T/F Hypokalemia refers to a low level of calcium

False

When referring to the amino acid sequences of proteins, sequence homology is the same as sequence similarity. True False

False

The weak acid HA is 2% ionized (dissociated) in a 0.20 M solution. What is Ka for this acid?

Ka = 8.2x10⁻⁵

Rank the following substances in order from most soluble in water to least soluble in water: methane, CH4; pentanol, C5H11OH; table salt, NaCl; and butane, C4H10.

Most Soluble→Least Soluble Table salt → pentanol →butane → methane

Which of the following statements is FALSE? In an open system, energy can be converted from one form into another. Organisms are open systems as they can exchange both energy and materials with their environments. Energy can be transferred between a system and the surroundings. In biochemical processes, energy can neither be created or destroyed. Organisms are open systems as they can create energy from their environments.

Organisms are open systems as they can create energy from their environments.

Know the difference between the different types of bonds. -polar covalent -ionic -hydrogen -single (nonpolar) covalent -Hydrophobic effect

Polar Covalent- type of chemical bond where a pair of electrons is unequally shared between two atoms. Ionic- the complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions. Hydrogen- a weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other. Covalent- a chemical bond that involves the sharing of electron pairs between atoms. Hydrophobic Effect- The tendency of nonpolar molecules in a polar solvent (usually water) to interact with one another is called the hydrophobic effect.

A reaction with a large negative free energy of hydrolysis can be coupled to the synthesis of ATP from ADP and Pi. True False

True

Dennis was dehydrated and had an electrolyte imbalance. Assume at time of treatment he is a 75 kg person with a starting osmolality of 300mOsmoles/kg. He was treated with 1 liter of distilled water. Answer the following questions two questions. What is his final Osmolality after treatment with 1 liter of distilled water? a. 293.47 mOsm/kg water b. 13500 mOsm/kg water c. 900 mOsm/kg water d. 30 mOsm/kg water e. There is no change in his osmolarity (300 mOsm/kg water).

a. 293.47 mOsm/kg water

The pharmaceutical company you are working for has developed a new antibiotic to be used in young children. You have been tasked with finding a way to formulate it as a dispersed drug in water. The drug compound is known to be highly lipophilic (hydrophilic). How do you ensure that the drug will be able to enter into the bulk of the solution? Select one or more: a. Add an amphipathic molecule to the formulation that will form into a micelle around the lipophilic drug so that it may disperse in the water. b. It is not possible to do this. A lipophilic compound will never be able to disperse in water. c. Add an amphipathic molecule to the formulation that will form a bilayer vesicle around the lipophilic drug molecule so that it will be able to disperse in the water. Incorrect d. Add an amphipathic molecule to the formulation that will allow for a monolayer of drug to form along the top of the water.

a. Add an amphipathic molecule to the formulation that will form into a micelle around the lipophilic drug so that it may disperse in the water.

What of the following contributes to the high energy of ATP? Select one: a. Charge-Charge repulsion b. London Dispersion forces c. Ionic bonds d. Charge-dipole interaction e. Charge-Charge attraction

a. Charge-Charge repulsion

Which of the following contributes to enthalpy? I. Work II. Heat III. Temperature IV. Change in internal energy Select one or more: a. I, II, IV b. I, III c. II, IV d. I, IV e. I only

a. I, II, IV

Consider the reaction in the question above, PPi +H2O -> 2Pi deltaGo = -33.5 kJ/mol, which occurs in the ICF. Which of the following change in conditions could result in a change from spontaneous to non-spontaneous? I. Drinking large amounts of distilled water II. Drinking concentrated saline III. Disruption of hydrogen bond network IV. Hypernatremia within the ECF a. II, III, IV b. III only c. II, III d. I only e. II only

a. II, III, IV

A helix has hydrogen bonds between the carbonyl group from residue "n" and the amino group of residue "n+3," which of the following is TRUE? Select one: a. It has fewer residues per turn than an alpha helix. b. It has more residues per turn than an alpha helix.

a. It has fewer residues per turn than an alpha helix.

Patient presents to the emergency room with complaints of drowsiness, confusion and muscle weakness. It is the middle of summer and the patient has been training for a marathon. She states that she has been drinking 2 gallons of water every day in order to prevent dehydration. Her lab results come back and some of the ECF values are as follows: Na: 120 mEq/L, K: 4 mEq/L, Bicarbonate: 27 mEq/L. What is your diagnosis and recommendation? a. Patient is hyponatremic due to excessive sweating and overhydration. Recommend that patient receive a sodium solution via IV to correct for this problem and drink a more moderate amount of water to avoid over hydration. b. Patient is hypokalemic due to excess sweating and overhydration. Recommend that patient takes a potassium supplement daily and moderate the amount of water she is consuming to prevent overhydration. c. Patient is hyponatremic due to dehydration. Recommend that patient drink more fluid following her training sessions to avoid this in the future. d. Patient is hypokalemic due to dehydration. Recommend that patient drink more water following training sessions to prevent this in the future.

a. Patient is hyponatremic due to excessive sweating and overhydration. Recommend that patient receive a sodium solution via IV to correct for this problem and drink a more moderate amount of water to avoid over hydration.

Dehydration can cause a high sodium level (hypernatremia). Which is not an effect of increased levels of sodium? a. Severe vomiting and diarrhea b. Weak, sluggish c. Paralysis d. Confusion

a. Severe vomiting and diarrhea

You are an intern working for your local community pharmacy. A patient come to pick up their prescriptions. The patient also is holding 5 bunches of bananas and tells you that they are changing their diet to eating at least 6 bananas every day. You notice that among their prescriptions is one for Spironolactone. What do you do next? (Hint: Here is some information from Drugs.com about Spironlolactone. Spironolactone is a potassium-sparing diuretic (water pill) that prevents your body from absorbing too much sodium and keeps your potassium levels from getting too low. Spironolactone also treats fluid retention (edema) in people with congestive heart failure, cirrhosis of the liver, or a kidney disorder called nephrotic syndrome. This medication is also used to treat or prevent hypokalemia (low potassium levels in the blood).) a. Tell them they should not eat that many bananas. Spironolactone is going to retain the potassium in their body and can lead to hyperkalemia. b. Encourage the patient to eat more bananas. Spironolactone, like all diuretics, is known to deplete the amount of potassium in their body and you don't want them to become hypokalemic. c. Nothing. Bananas are healthy and part of a balanced diet.

a. Tell them they should not eat that many bananas. Spironolactone is going to retain the potassium in their body and can lead to hyperkalemia.

The disease causing form of the PrP protein Select one: a. results in a protein fold with great beta sheet than the correct fold. b. does not alter the fold of the cellular PrP protein. c. is similar in terms of secondary structure to the cellular PrP protein d. Choice A and Choice B e. All of the above

a. results in a protein fold with great beta sheet than the correct fold.

The equilibrium constant for pyrophosphate at 25oC and pH 7 is 7.4 x 105. Calculate the free energy for pyrophosphate at equilibrium. Equations and Useful Information: pH = pKa + log [A-]/[HA] ΔG=ΔH- TΔS K=e^(-ΔGo/RT) R= 8.314 J/molK Select one: a. (-)45 kJ/mol b. (-)33.5 kJ/mol c. (+)37 kJ/mol d. (+)62 kJ/mol e. (-) 62 kJ/mol

b. (-)33.5 kJ/mol

Which of the following decreases the energy in a compound? Select one: a. A starting compound which contains at least one N-P bond. b. A starting compound (reactant) which is capable of resonance stabilization. c. A starting compound whose hydrolytic products (products of hydrolysis reaction) are capable of resonance stabilization. d. A starting compound whose hydrolytic products are capable of tautomerization. e. A compound with several phosphoanhydride bonds.

b. A starting compound (reactant) which is capable of resonance stabilization.

Which of the following properties of water are responsible for maintaining body temperature? a. High viscosity, High heat of Vaporization b. High Heat of Vaporization, High Heat Capacity c. High Heat Capacity, Low molecular weight d. High dielectric constant, High Heat Capacity

b. High Heat of Vaporization, High Heat Capacity

Which of the following is TRUE regarding entropy? Select one or more: a. It is higher in a liquid than in a gas. b. It is higher in ADP + Pi than in ATP c. It is higher at lower temperatures. d. It is higher if a reaction has a negative delta H e. It is independent of temperature.

b. It is higher in ADP + Pi than in ATP

Which electrolyte imbalance is of a special concern in patients with abnormal heart rhythms (arrhythmias)? a. Magnesium b. Potassium c. Sodium d. Calcium

b. Potassium

A molecule X which normally has no dipole moment comes into close proximity of a strong cation. X now develops partial charges in response to the cation. Which of the following is true? a. X must be an anion. b. X is involved in a charge-induced dipole interaction. c. X is involved in a dipole-dipole interaction. d. X has a permanent dipole. e. X is involved in London dispersion forces

b. X is involved in a charge-induced dipole interaction.

The reaction breakdown of glucose to ethanol (C6H12O6(s) --> 2C2H5OH(l) + 2 CO2(g) ) occurs spontaneously and is Select one or more: a. entropically favored b. both c. enthalpically favored

b. both

Which one of these characteristics is TRUE for the beta sheet? Select one: a. Glycine is every third amino acid residue. b. Proline is commonly found in beta sheets c. Beta strands are parallel if the N-terminus of each strand align d. Hydrogen bonds form between residues n and n+4

c. Beta strands are parallel if the N-terminus of each strand align

A pharmaceutical company has discovered a new molecule that will decrease the dipole-dipole interactions between water molecules. Will this molecule be a likely drug candidate? Select one or more: a. Yes. A molecule that decreases this interaction will result in greater prevention from dehydration and hyperthermia. b. No. These interactions are necessary for ions to exist in biological solutions. c. No. These interactions are necessary for your body to prevent dehydration and prevent hyperthermia. d. Yes. A molecule that will decrease interaction between water molecules will allow for ions to exist in biological solutions.

c. No. These interactions are necessary for your body to prevent dehydration and prevent hyperthermia.

Person A drinks 5 liters of distilled water. Which of the following is TRUE? a. The final ECF volume has decreased b. The final ICF volume has decreased c. The final osmolaity has decreased. d. The final osmolaity has increased. e. The total body osmoles have decreased.

c. The final osmolaity has decreased.

You begin with a solution of 50 mg Drug X in 100 mL of distilled water. You add another 100 mL of distilled water to the solution because you need to dilute the concentration of drug. Does this represent a property of the 2nd law of thermodynamics? a. No. This more accurately represents how work will contribute to enthalpy. b. No. This represents the energy balance that is key to the 1st law of thermodynamics. c. Yes, it does because the increased spatial distribution of particles will result in a positive entropy contribution. d. Yes, because it accurately represents the increased disorder based on state of matter, a positive entropy contribution.

c. Yes, it does because the increased spatial distribution of particles will result in a positive entropy contribution.

Given the following information, why are diamonds not forever? C(diamond) -> C(graphite) ΔGo=(-)2.88 kJ/mol a. Because at high temperature, the reaction is not favored. b. Because the enthalpy change must be positive. c. Because no work is done. d. Because the free energy change is negative.

d. Because the free energy change is negative.

Which of the following drugs would increase the risk of developing electrolyte abnormalities? (you might need to look up the drugs below to determine what type of drug it is) a. Prednisone b. Metoprolol c. Antacids d. Bisacodyl

d. Bisacodyl

Which of the following peptide sequences would be created by cutting a peptide with the cyanogen bromide reaction? Select one: a. Cys-Glu-Arg b. Arg-Met-Phe c. Met-Ser-Cys d. Cys-Ser-Met

d. Cys-Ser-Met

Which of the following is TRUE regarding hydrogen bonds in water? a. They occur because the water molecules are polar. b. They are partially covalent. c. They are partially dipole-dipole interactions. d. They are important because there are so many in our body. e. All of the above.

e. All of the above.

Which of the following contribute favorably (negative contribution of delta G) to Gibbs free energy? I. the release of heat upon a reaction II. an increase in the number of molecules while proceeding from reactants to product III. a decrease in temperature Select one or more: a. II only b. III only c. I only d. II and III e. I and II

e. I and II

During extensive exercise, an individual sweats approximately 0.5 liters of fluid. Which of the following is TRUE? I. The final ECF volume has decreased. II. The final ICF volume has decreased. III. The final osmolality has decreased. IV. The total body osmoles have increased. Select one or more: a. I, II, III b. I, III c. I, II, III, IV d. II, III e. I, II

e. I, II

Dennis was dehydrated and had an electrolyte imbalance. Assume at time of treatment he is a 75 kg person with a starting osmolality of 300mOsmoles/kg. He was treated with 1 liter of distilled water. Answer the following question. What is his change in total body osmoles following the addition of 1 liter of distilled water? a. He went from 4500 mOsm to 13500 mOsm b. He went from 13500 mOsm to 4500 mOsm c. He went from 9000 mOsm to 4500 mOsm d. He went from 13500 mOsm to 9000 mOsm e. There is no change in the number of Osmoles.

e. There is no change in the number of Osmoles.

pH of 0.35 M hydrochloric acid?

pH = 0.46

The weak acid HA is 2% ionized (dissociated) in a 0.20 M solution. What is the pH of this solution?

pH = 2.4

pH of 0.35 M acetic acid?

pH = 2.61

pH of 0.035 M acetic acid?

pH = 3.11

What do you expect the sign of ΔS to be for this process? Explain your answer. This process __________ the entropy of the solvent water, which becomes _________ ordered in the clathrate structures. This is the _____________ effect.

reduces, more, hydrophobic

Under standard conditions, a given reaction is endergonic (i.e., DG >0). Which of the following can render this reaction favorable: using the product immediately in the next step, maintaining a high starting-material concentration, or keeping a high product concentration? -maintaining a high starting-material concentration -using the product immediately in the next step -keeping a high product concentration -using the product immediately in the next step and maintaining a high starting-material concentration

using the product immediately in the next step and maintaining a high starting-material concentration

A biochemical reaction will proceed in the direction as written if: ΔH < 0. ΔG = zero. ΔG < 0. ΔG > 0. ΔH > 0.

ΔG < 0.

The process of a protein folding from an inactive unfolded structure to the active folded structure can be represented by the following equation: unfolded protein <> folded protein The values of ΔH∘ and ΔS∘ for the folding of the protein lysozyme are: ΔH∘=−280kJ/mol ΔS∘=−790J/mol⋅K Calculate the value of ΔG∘ for the folding of lysozyme at 25 ∘C. At what temperature would you expect the unfolding of lysozyme to become favorable?

ΔG∘ = -44.6 kJmol T = 354 K

What must be the sign of ΔS for the change: native → denatured? -ΔS must be positive because the increase in conformations with different energy in the denatured state decreases the entropy of the denatured state relative to the folded state. -ΔS must be positive because the increase in isoenergetic conformations in the denatured state increases the entropy of the denatured state relative to the folded state. -ΔS must be negative because the increase in conformations with different energy in the denatured state increases the entropy of the denatured state relative to the folded state. -ΔS must be negative because the increase in isoenergetic conformations in the denatured state decreases the entropy of the denatured state relative to the folded state.

ΔS must be positive because the increase in isoenergetic conformations in the denatured state increases the entropy of the denatured state relative to the folded state.

Please match the correct term on the left with the appropriate structural feature of proteins listed on the right. 1) primary structure 2) secondary structure 3) tertiary structure 4) quaternary structure A) the interaction between two separate protein strands B) the sequence of AA C) small sections of organized protein structure, such as helices D) the overall fold of a single protein strand, such as the globulin fold -1:B; 2:A; 3:D; 4:C -1:C; 2:D; 3:A; 4:B -1:D; 2:C; 3:B; 4:A -1:B; 2:C; 3:D; 4:A

-1:B; 2:C; 3:D; 4:A

As biochemistry has matured as a science, new branches of the field have developed to maintain the ever-growing database of information. Assign the purpose on the right with the field on the left. A) bioinformatics 1) assess the expression and function of genes B) proteomics 2) determine the intracellular concentrations of small molecules C) metabolomics 3) mathematic analysis of DNA sequence data D) genomics 4) identify the function of proteins -A:3, B:2, C:4, D:1 -A:4, B:3, C:2, D:1 -A:3, B:4, C:1, D:2 -A:3, B:4, C:2, D:1

-A:3, B:4, C:2, D:1

Which of the following is TRUE of hydrophobic molecules? -They have limited solubility in water. -Water forms a cage-like structure around them. -They self-associate by releasing some of the surrounding water molecules. -Dissolving in water decreases the entropy of the mixture. -All of the above

-All of the above

Which of the following properties of water make(s) life possible? -Water's high dielectric constant allows it to dissolve polar and charged molecules alike. -Water has strong hydrogen bonding interactions between molecules, which allow it to exist at ambient temperature as a liquid. -Water is less dense as a solid than as a liquid. -All of the listed properties of water make life possible.

-All of the listed properties of water make life possible.

Which of the following statements is true about a protein that is in an aqueous solution that has a pH equal to the pI of the protein? -At pH = pI, there is no net charge on the protein. -At pH = pI, there is a net positive charge on the protein. -At pH = pI, there is a net negative charge on the protein. -There is not enough information to answer this question.

-At pH = pI, there is no net charge on the protein.

For molecules with multiple ionizable groups, such as glycine, which of the following statements is true? -When the pH is near the pI, the solution is near its maximum buffering ability. -At pH near the pI, nearly all the molecules carry no net charge. -At a pH near the pI, nearly all the molecules carry a net positive charge. -At a pH near the pI, nearly all the molecules carry a net negative charge.

-At pH near the pI, nearly all the molecules carry no net charge

Which of the following statements about noncovalent bonding interactions is NOT true? -A charge may induce formation of a dipole in a nearby polarizable molecule. -Van der Waals interactions, also known as dispersion forces, are the weakest of the attractive noncovalent bonding interactions. -All noncovalent bond interactions are inherently electrostatic in nature. -Charge-induced dipole interactions are inversely proportional to the square of the distance between the two atoms.

-Charge-induced dipole interactions are inversely proportional to the square of the distance between the two atoms.

What are the N-terminal and C-terminal residues for the following peptide sequence? Peptide sequence: EASY -Y is the N-terminal residue; E is the C-terminal residue. -E is the N-terminal residue; Y is the C-terminal residue. -Glutamic acid is the N-terminal residue; tryptophan is the C-terminal residue. -Aspartic acid is the N-terminal residue; tyrosine is the C-terminal residue

-E is the N-terminal residue; Y is the C-terminal residue.

Much is made of water's ability to dissolve a wide variety of molecules and yet, one of its most important characteristics is its effect on nonpolar, uncharged molecules. Which of the following statements is NOT true about this effect? -The hydrophobic effect plays an important role in the folding of proteins and the assembly of lipid bilayers. -Water molecules form clathrates or cages that surround nonpolar molecules or particles. -Hydrophobic molecules are driven together largely because of forces of attraction between them. -All of the listed statements are true.

-Hydrophobic molecules are driven together largely because of forces of attraction between them.

A solution of 2M NaCl in water is separated from pure water by a semipermeable membrane. Which of the following is true? -Water will move from the 2M NaCl solution to the pure water compartment. -Nothing will happen because the system is at ΔG = 0. -The crossing of NaCl is an endergonic process. -NaCl will migrate (diffuse) across the membrane until there is an equal concentration on both sides.

-NaCl will migrate (diffuse) across the membrane until there is an equal concentration on both sides.

Which of the following characteristics are true about a typical peptide (amide) bond? 1) The bond is planar. 2) There is free rotation about the carbonyl carbon and nitrogen bond. 3) There is substantial double-bond character to this bond. 4) There is a net negative charge on nitrogen and net positive charge on oxygen. -Only statements 1 and 3 are correct. -Only statements 2 and 3 are correct. -Only statements 1, 2, and 4 are correct. -All of the listed statements are correct.

-Only statements 1 and 3 are correct.

Which of the following in biological compounds are sufficiently electronegative to serve as strong donors in a hydrogen bond? -Hydrogen and oxygen -Oxygen and nitrogen -Nitrogen and carbon -Nitrogen and hydrogen -Hydrogen and carbon

-Oxygen and nitrogen

Human and sperm whale myoglobin have very similar primary structures. Which of the following statements are correct? 1) The two proteins are very likely related evolutionarily. 2) The differences in the sequences in many instances represent a conservative change (such L for I). 3) The differences in the sequences in many instances represent a nonconservative change (such as D for A). 4) There is no correlation between the two proteins, since they originate from very different species. -Statements 1, 2, and 3 are correct. -Statements 1, 2, and 4 are correct. -Statements 1 and 2 are correct. -All of the listed statements are correct.

-Statements 1 and 2 are correct.

For an amino acid such as aspartic acid, what impact do you expect the two neighboring carboxylic acids to have on the pKa values for each? -The acid with the higher pKa value would decrease the pKa value for the other acid. -The neighboring acids would have no impact on each other's pKa values. -The acid with the lower pKa value would increase the pKa value for the other acid. -The acid with the lower pKa value would decrease the pKa value for the other acid.

-The acid with the lower pKa value would increase the pKa value for the other acid.

The terms Q and K describe mass action for reactions at non-equilibrium and equilibrium conditions, respectively. For a forward reaction to be favored in a living cell, which of the following statements must be true? -The value of Q must be less than that of K. -The value of K must be less than that of Q. -No conclusion can be drawn about Q and K for a favorable process. -None of the listed statements are true; cells are at equilibrium.

-The value of Q must be less than that of K.

A short 8-residue sequence of a polypeptide is determined to have φ angles ranging from -65 degrees to -80 degrees and ψ angles ranging from -40 degrees to -50 degrees. What conclusion can be drawn from this data? -This segment has helical content. -This segment is mostly β sheet. -The sequence has no defined secondary structure. -No conclusion can be drawn.

-This segment has helical content.

From the standpoint of entropy, consider the following processes: water boiling, mixing cola and root beer sodas, and assembling a house of cards. Based on your understanding, which of the following statements is true? -Water boiling is a favorable process, but mixing cola and root beer sodas and assembling a house of cards are not. -Water boiling and mixing cola and root beer sodas are not favorable processes, but assembling a house of cards is. -Water boiling and mixing cola and root beer sodas are favorable processes, but assembling a house of cards is not. -All of the listed processes are favorable.

-Water boiling and mixing cola and root beer sodas are favorable processes, but assembling a house of cards is not.

Based on the thermodynamic functions of enthalpy and entropy, can an unfavorable reaction that has a positive ΔG at RT be made favorable by increasing the reaction temperature? -yes, but only if ΔH is positive and ΔS is negative -only if both ΔH and ΔS are negative -Yes, regardless of the sign of ΔH, if ΔS is positive, a reaction can be rendered favorable by increasing the temperature. -No, an unfavorable reaction cannot be rendered favorable.

-Yes, regardless of the sign of ΔH, if ΔS is positive, a reaction can be rendered favorable by increasing the temperature.

The combustion of palmitic acid in a bomb calorimeter yields energy in the form of heat released upon oxidation. From a thermodynamic perspective and with respect to the calorimeter experiment, what would you expect the combustion of the same amount of palmitic acid in our body to yield? -more energy -less energy -the same amount of energy -The calorimeter experiment is irrelevant to the combustion of palmitic acid in the human body.

-the same amount of energy

Which statements regarding the Henderson-Hasselbalch equation are true? 1) If the pH of the solution is known as is the pKa for the acid, the ratio of conjugate base to acid can be determined. 2) At pH = pK a for an acid, there is an equal amount of conjugate base to acid in solution. 3) At pH >> pK a for an acid, the acid will be mostly ionized. 4) At pH << pK a for an acid, the acid will be mostly ionized.

1, 2, and 3 are true.

Which statements about hydrogen bonds are correct? 1) Hydrogen bonds are the interaction between a hydrogen atom bonded to an electronegative element and the lone pair of electrons on a nearby electronegative atom. 2) The atom to which the hydrogen atom is covalently bonded is the hydrogen-bond donor. 3) The distance between the covalently bound H atom and its hydrogen-bonding donor is the sum of its van der Waals radii. 4) Hydrogen bonds can be stronger interactions than even charge-charge interactions.

1, 2, and 4 are correct.

Match the following characteristics to α helices, β sheets, or both. 1) 5.4Å/turn 2) antiparallel arrangement 3) large dipole moment 4) extensive H-bonding network A) α helices B) β sheets C) both -1:B; 2:B; 3:A; 4:A -1:A; 2:C; 3:A; 4:B -1:A; 2:A; 3:C; 4:B -1:A; 2:B; 3:A; 4:C

1:A; 2:B; 3:A; 4:C

Which of the following is NOT a characteristic of a living system? A) the ability to resist change over generations of progeny B) the ability to replicate and regenerate C) the ability to respond to changes in the environment D) the ability to couple energy-releasing reactions with energy-requiring processes, thereby allowing the creation of complex molecules

A) the ability to resist change over generations of progeny

Classify each statement as an example of adhesion, cohesion, or surface tension. -A sewing needle floats when it is placed gently on top of water in a bucket. -Water molecules cling to the side of a beaker. -A drop of water spilled on a table forms a drop on the table, rather than spreading out over the surface. -Water molecules cling to plant cell walls. -A water strider runs across a pond without breaking the surface. -Water molecules are attracted to each other.

Adhesion: Water molecules cling to the side of a beaker; Water molecules cling to plant cell walls. Cohesion: Water molecules are attracted to each other; A drop of water spilled on a table forms a drop on the table, rather than spreading out over the surface. Surface Tension: A water strider runs across a pond without breaking the surface; A sewing needle floats when it is placed gently on top of water in a bucket.

Which statements about lipid bilayers are true? 1) Their formation is driven by the hydrophobic effect. 2) The amphipathic molecules that make up the bilayers orient themselves such that their polar head groups point out toward the aqueous solvent and their hydrophobic tails are pointed toward the interior of the bilayer. 3) They serve the role of physical compartmentalization of components within a cell. 4) They are made primarily from phospholipids.

All of the listed statements are true.

Which of the following is NOT a function of an organelle? A) Mitochondria specialize in oxidative metabolism. B) Lysozymes are used for storage and replication. C) Ribosomes are involved in protein synthesis. D) Chloroplasts are the sites for photosynthesis.

B) Lysozymes are used for storage and replication.

Which of the following statements is FALSE? Biological systems expend energy to overcome entropy. The entropy of a biological system can decrease. Biological systems are highly ordered so entropy changes are not relevant. Entropy is a measure of disorder. The entropy of an isolated system will tend to increase to a maximum value.

Biological systems are highly ordered so entropy changes are not relevant.

Which of the following statements is NOT true about adaptability? A)It is the capacity to change in response to environmental changes. B) It is the capacity of individual representatives of an organism to respond to environmental changes. C) It is the capacity of populations of organisms to respond to environmental changes. D) It is a characteristic of living organisms.

C) It is the capacity of populations of organisms to respond to environmental changes.

Each of the following is a noncovalent interaction EXCEPT: A) a van der Waals interaction. B) an interaction between NH3+ and a water molecule. C) a carbon-hydrogen bond. D) a hydrogen bond. E) the interaction between an amino and a carboxylate group.

C) a carbon-hydrogen bond.

Homeostasis is __________. A) the ability to maintain nutrient concentrations equal on both sides of the cell membrane B) the same as equilibrium C) the ability to maintain cellular conditions over time D) a function of proteins

C) the ability to maintain cellular conditions over time

A reaction at equilibrium can be driven in one direction or the other by changing the ________ of reactants or products

Concentration