BIOCHEM 1- Ch 2-1, 2-2, 2-L
Many proteins interact with DNA at physiological pH because: A) proteins are naturally attracted to DNA regardless of the pH. B) the positively charged DNA is electrostatically attracted to negatively charged regions on proteins. C) proteins and DNA interact using mainly hydrophobic interactions. D) the negatively charged DNA is electrostatically attracted to positively charged regions on proteins. E) both proteins and DNA are at their isoelectric points at physiological pH and tend to aggregate.
D) the negatively charged DNA is electrostatically attracted to positively charged regions on proteins.
What happens to these physical properties as the strength of intermolecular forces increases? Drag each item to the bin: boiling point, viscosity, vapor pressure, melting point, surface tension. Decrease? (1)
Decrease: Vapor pressure
Which conjugate pair is suited best to make this buffer?
Dihydrogen phosphate ion H2PO4- and monohydrogen phosphate ion HPO42-
Identify the predominant type of intermolecular force in each of the following compounds. Drag each item to bin: CHF3, HF, CF4, OF2 Dipole-dipole? (2)
Dipole-dipole: -CHF3 -OF2
Which of these DNA molecules is the shortest?
E (The shorter the DNA molecule, the farther it moves.)
TRUE OR FALSE: Amphipathic molecules are not able to interact via van der Waals forces.
FALSE
TRUE OR FALSE: Glycine cannot serve as a buffer because it has two ionizable groups.
FALSE
TRUE OR FALSE: The pKa of each amino acid residue in a protein will not be influenced by the adjacent residue.
FALSE
Identify the predominant type of intermolecular force in each of the following compounds. Drag each item to bin: CHF3, HF, CF4, OF2 Hydrogen bonding? (1)
Hydrogen bonding: HF
What happens to these physical properties as the strength of intermolecular forces increases? Drag each item to the bin: boiling point, viscosity, vapor pressure, melting point, surface tension. Increase? (4)
Increase: melting point boiling point viscosity surface tension
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.
Ionic compounds can be readily dissolved in water because the high dielectric constant of water screens and decreases the electrostatic force between the oppositely charged ions.
The weak acid HA is 2% ionized (dissociated) in a 0.20 M solution. What is Ka for this acid?
Ka = 8.2 x 10^-5
Identify the predominant type of intermolecular force in each of the following compounds. Drag each item to bin: CHF3, HF, CF4, OF2 London? (1)
London: CF4
Substances with weak intermolecular forces tend to be in the gas state at room temperature. Moderate intermolecular forces are required to liquefy or solidify a substance at room temperature. Classify the types of intermolecular forces as moderate or weak. Drag each item to bin: dipole-dipole, hydrogen bonding, ion-dipole, London dispersion Moderate? (2)
Moderate: -hydrogen bonding -ion-dipole
Which set of compounds would form a buffer in aqueous solution? Drag to bin: HCOOH & HCOOK; NaF and NaOH; HCN and NaF; HCN and KCN; HBr and NaBr; NaBr and KBr; NaF and KF Not a Buffer? (5)
Not a Buffer? -NaF and NaOH -HCr and NaBr -NaBr and KBr -NaF and KF -HCN and NaF
What is the molecular basis for the observation that the overall charge on a protein becomes increasingly positive as pH drops and more negative as pH increases? Drag from 4 terms: negatively, decreases, increases, positively 1. Protein molecules in aqueous solution become increasingly protonated as the pH ______.
Protein molecules in aqueous solution become increasingly protonated as the pH decreases.
What is the molecular basis for the observation that the overall charge on a protein becomes increasingly positive as pH drops and more negative as pH increases? Drag from 4 terms: negatively, decreases, increases, positively 3. Proteins become more negatively charged as pH ______, because acidic groups become more _____ charged while the basic groups become less ______ charged.
Proteins become more negatively charged as pH increases, because acidic groups become more negatively charged while the basic groups become less positively charged.
(image: CITRIC ACID) drag the terms to complete sentences: attractions; repulsions; dissociate; increase; associate; decrease Successive depronations _____ the (-) charge density on the resulting anion.
Successive deprotonations INCREASE the (-) charge density on the resulting anion. INCREASE
Classify each statement as an example of adhesion, cohesion, or surface tension. Surface tension? (2)
Surface tension: -A sewing needle floats when it is placed gently on top of water in a bucket. - A water strider runs across a pond without breaking the surface.
TRUE OR FALSE: Hydrogen bonds share features of both covalent and noncovalent bonds.
TRUE
TRUE OR FALSE: The average charge on an amino acid below its pI will be positive.
TRUE
TRUE OR FALSE: Water is both a hydrogen bond donor and acceptor.
TRUE
Why? Drag terms: gel electrophoresis, isoelectric focusing, large, small The single-charge difference would result in a ______ difference in mobility in a normal ___________ experiment (which seperates chains based on size), but would make a detectable difference in pI.
The single-charge difference would result in a SMALL difference in mobility in a normal GEL ELECTROPHORESIS experiment (which separates chains based on size), but would make a detectable difference in pI.
What is the molecular basis for the observation that the overall charge on a protein becomes increasingly positive as pH drops and more negative as pH increases? Drag from 4 terms: negatively, decreases, increases, positively 2. Thus, proteins become more ______ charged because carboxylic acids become less ______ charged as pH drops, whereas amines become more ______ charged.
Thus, proteins become more positively charged because carboxylic acids become less negatively charged as pH drops, whereas amines become more positively charged.
The table shown here lists the specific heat of several substances. (table):Substance vs Specific heatJ/g/∘C Which are true: (4) a) Benzene is more resistant to temperature change than sulfuric acid. b) Ethyl alcohol likely exhibits more hydrogen bonding than water. c) Sulfuric acid is less resistant to temperature change than water. d) More heat is required to raise the temperature of 1 g of water 1 ∘C∘C than to raise the temperature of 1 g of ethyl alcohol 1 ∘C∘C. e) Water has a high specific heat due to the hydrogen bonding between water molecules. f) More heat is required to raise the temperature of 1 g of benzene 1 ∘C∘C than to raise the temperature of 1 g of water 1 ∘C∘C. g) Water is less resistant to temperature change than ethyl alcohol.
True: a) Benzene is more resistant to temperature change than sulfuric acid. c) Sulfuric acid is less resistant to temperature change than water. d) More head is required to raise the temperature of 1g of water 1C than to raise the temperature of 1g of ethyl alcohol 1C. e) Water has a high specific head due to the hydrogen bonding between water molecules.
Substances with weak intermolecular forces tend to be in the gas state at room temperature. Moderate intermolecular forces are required to liquefy or solidify a substance at room temperature. Classify the types of intermolecular forces as moderate or weak. Drag each item to bin: dipole-dipole, hydrogen bonding, ion-dipole, London dispersion Weak? (2)
Weak: -London dispersion -dipole-dipole
(image 2.18, blue chart with 4 blanks).
[Bottom] -COOH group imidazole group pI -NH3+ group [Top]
The hydrides of group 5A are NH3, PH3, AsH3, and SbH3. Arrange them from highest to lowest boiling point. Rank molecules from highest to lowest boiling point: PH3, SbH3, NH3, AsH3
[Highest boiling point] NH3 SbH3 AsH3 PH3 [Lowest boiling point]
Rank these hydrocarbons in order from highest to lowest boiling point: octadecane (C18H38), 2,2-dimethylpropane (C5H12), paraffin (C35H72), pentane (C5H12), propane (C3H8)
[Highest boiling point] Paraffin (C35H72) Octadecane (C18H38) Pentane (C5H12) 2,2-dimethylpropane (C5H12) Propane (C3H8) [Lowest boiling point]
Rank the following compounds in order of decreasing boiling point: sodium chloride (NaCl), methane (CH4), and iodomethane (CH3I). Rank from highest to lowest boiling point: sodium chloride (NaCl), methane (CH4), iodomethane (CH3I)
[Highest boiling point] sodium chloride (NaCl) iodomethane (CH3I) methane (CH4) [Lowest boiling point]
Rank from highest to lowest vapor pressure: CH3CH(CH3)CH2CH3, CH3CH2CH2CH2OH, CH4, CH3CH2CH2CH2CH3
[Highest vapor pressure] CH4 CH3CH(CH3)CH2CH3 CH3CH2CH2CH2CH3 CH3CH2CH2CH2OH [Lowest vapor pressure]
Rank the following from most acidic to least acidic. Terms: pH=3; pH=14; [H3O+]=10^-2; pH=5; [H30+]=10^-2
[Most acidic] [H3O+]=10^-2 pH=3 pH=5 [H3O+]=10^-6 pH=14 [Least acidic]
Rank the following substances in order from most soluble in water to least soluble in water:methane (CH4CH4), pentanol (C5H11OHC5H11OH), copper sulfate (CuSO4CuSO4), and butane(C4H10C4H10)
[Most soluble] copper sulfate pentanol butane methane [Least soluble]
Rank the following substances in order from most soluble in water to least soluble in water:octane, C8H18; pentanol, C5H11OH; lithium nitrate, LiNO3; and pentane, C5H12. Rank from most to least soluble in water: pentanol, pentane, lithium nitrate, octane
[Most soluble] lithium nitrate pentanol pentane octane [Least soluble] LPlPO
If Ca2+, Na+, and F− each have ionic radii ∼1.16Å. Which ionic bond is stronger: Ca−F or Na−F? a) Ca-F b) Na-F
a) Ca-F
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? a) Hydrophobic molecules are driven together largely because of forces of attraction between them. b) Water molecules form clathrates or cages that surround nonpolar molecules or particles. c) The hydrophobic effect plays an important role in the folding of proteins and the assembly of lipid bilayers. d) All of the listed statements are true.
a) Hydrophobic molecules are driven together largely because of forces of attraction between them.
An ionic bond involves _____. a) an attraction between ions of opposite charge b) water avoidance c) no atoms other than sodium and chlorine d) the unequal sharing of an electron pair e) the sharing of a single pair of electrons
a) an attraction between ions of opposite charge
Small ions in biological fluids: a) encourage strong electrostatic interactions between oppositely charged macroions at low ionic strengths. b) tend to cluster around macroions of the same charge. c) have no effect on the interactions between oppositely charged macroions. d) have large effects on pH. e) encourage strong electrostatic interactions between oppositely charged macroions at high ionic strengths.
a) encourage strong electrostatic interactions between oppositely charged macroions at low ionic strengths *MACROIONS
What name is given to the bond between water molecules? a) hydrogen b) hydrophobic c) polar covalent d) ionic e) single (nonpolar) covalent
a) hydrogen
If Ca2+ is often bound on the surface of a protein by carboxylic acid functional groups. If the pKa of a particular −COOH group is 4.2, would you predict Ca2+ to be most tightly bound at pH 8, pH 4.2, or pH 3? a) pH 8 b) pH 4.2 c) pH 3
a) pH 8
(image: H2O with + on H, - on O) In this molecule, what type of bond is found between the oxygen and hydrogens? a) polar covalent b) ionic c) nonpolar covalent d) hydrophobic e) hydrophilic
a) polar covalent
Carbonated cola is more acidic than coffee or even orange juice because cola contains phosphoric acid. What is the molar concentration of [H3O+] in a cola that has a pH of 3.120? a) 7.58 × 10^−4 b) 7.59 × 10^−4 c) 7.6 × 10^−4 d) 3.120 × 10^−3 e) 0.494 f) 1.318 × 10^3
b) 7.59x10^-4
Which of the following in biological compounds are sufficiently electronegative to serve as strong donors in a hydrogen bond? a) Hydrogen and oxygen b) Oxygen and nitrogen c) Hydrogen and carbon d) Nitrogen and carbon e) Nitrogen and hydrogen
b) Oxygen and nitrogen
You can neglect contributions from form II. Why? a) Species I can be neglected because they are not involved in the calculations of the pI value. b) Species I can be neglected because they are present at an insignificant concentration. c) Species I can be neglected because they are not charged. d) Species I can be neglected because they are not responsible for the ionization of water.
b) Species I can be neglected because they are present at an significant concentration.
The activity of an enzyme requires a glutamic acid to display its −COOH functional group in the protonated state. Suppose the pKa of the −COOH group is 4.07. What fraction of the enzymes will be active at pH=4.07? Explain. a) When pH=pKaa the ionizable group is 100% protonated; thus, 100% of the enzymes will be in an active state. b) When pH = pKa the ionizable group is 50% protonated; thus, 50% of the enzymes will be in an active state. c) When pH=pKa the ionizable group is 100% protonated; thus, 0% of the enzymes will be in an active state. d) When pH=pKa the ionizable group is0% protonated; thus, 100% of the enzymes will be in an active state.
b) When pH= pKa the ionizable group is 50% protonated; thus, 50% of the enzymes will be in an active state. 50/50
Is the value of average charge you calculated in part C reasonable, given the pIpI you calculated in part A? Explain your answer. a) No. When the molecule has two amino groups it is predicted to carry a positive charge. b) Yes. When pH<pI the molecule is predicted to carry a positive charge. c) No. When pH<pI the molecule is predicted to carry a negative charge. d) Yes. When the molecule has two amino groups it is predicted to carry a negative charge.
b) YES. When pH<PI the molecule is predicted to carry a POSITIVE charge. *pH < pI *POSITIVE
What pH gradient would you choose for this experiment? a) A pH gradient between 7.0 to 10.0 b) A pH gradient between 2.0 to 7.0 c) A pH gradient between 2.0 to 5.0. d) A pH gradient between 8.0 to 12.0
b) a pH gradient between 2.0 to 7.0
Atoms with the same number of protons but with different electrical charges _____. a) have different numbers of neutrons b) are different ions c) are different isotopes d) have different atomic numbers e) have different atomic masses
b) are different ions
The tendency of an atom to pull electrons toward itself is referred to as its _____. a) covalency b) electronegativity c) ionic potential d) polarity e) tonicity
b) electronegativity
Suppose a chloride ion and a sodium ion are separated by a center-center distance of 5Å5Å. Is the interaction energy (the energy required to pull them infinitely far apart) predicted to be larger if the medium between them is water, or if it is n-pentane? a) water b) n-pentane
b) n-pentane
In gel electrophoresis DNA molecules migrate from _____ to _____ ends of the gel. a) acidic....basic b) negative...positive c) basic...acidic d) long...short e) positive...negative
b) negative...positive
The unequal sharing of electrons within a water molecule makes the water molecule _____. a) hydrophobic b) polar c) have a low surface tension d) change easily from a liquid to gaseous form e) ionic
b) polar
What the animation and identify the correct conditions for forming a hydrogen bond. animation is about Hydrogen bonding. Which are true (3): a) The CH4 molecule exhibits hydrogen bonding. b) A hydrogen atom acquires a partial positive charge when it is covalently bonded to an FF atom. c) A hydrogen bond is possible with only certain hydrogen-containing compounds. d) Hydrogen bonding occurs when a hydrogen atom is covalently bonded to an N, O, or F atom. e) A hydrogen bond is equivalent to a covalent bond.
b, c, d -A hydrogen atom acquires a partial positive charge when it is covalently bonded to an F atom -A hydrogen bond is possible with only certain hydrogen-containing compounds. -Hydrogen bonding occurs when a hydrogen atom is covalently bonded to an N, O, or F atom.
Which of the following statements about noncovalent bonding interactions is NOT true? a) A charge may induce formation of a dipole in a nearby polarizable molecule. b) All noncovalent bond interactions are inherently electrostatic in nature. c) Charge-induced dipole interactions are inversely proportional to the square of the distance between the two atoms. d) Van der Waals interactions, also known as dispersion forces, are the weakest of the attractive noncovalent bonding interactions.
c) Charge-induced dipole interactions are inversely proportional to the square of the distance between the two atoms.
In salt, what is the nature of the bond between sodium and chlorine? a) hydrogen b) nonpolar covalent c) ionic d) hydrophobic e) polar covalent
c) ionic
The accompanying graph depicts the interaction energy between two water molecules situated so that their dipole moments are parallel and pointing in the same direction. Which graph?
curved graph
Noncovalent bonds are critically important to the function of biomolecules. Which of the following is/are (a) valid reason(s) for this importance? a) The effect of these weak interactions is cumulative. b) Noncovalent interactions are made up of hydrogen bonding, electrostatic interactions, and dispersion forces. 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 above
Which of the following properties of water make(s) life possible? a) Water is less dense as a solid than as a liquid. b) Water has strong hydrogen bonding interactions between molecules, which allow it to exist at ambient temperature as a liquid. c) Water's high dielectric constant allows it to dissolve polar and charged molecules alike. d) All of the listed properties of water make life possible.
d) All of the above
Noncovalent bonds are critically important to the function of biomolecules. Which of the following is/are (a) valid reason(s) for this importance? a) Their bond energies are ~10-100 times weaker than ordinary covalent bonds. b) The effect of these weak interactions is cumulative. c) Noncovalent interactions are made up of hydrogen bonding, electrostatic interactions, and dispersion forces. d) All of the listed statements are valid reasons for this importance.
d) All of the listed statements are valid reasons for this importance.
For molecules with multiple ionizable groups, such as glycine, which of the following statements is true? a) At a pH near the pI, nearly all the molecules carry a net positive charge. b) When the pH is near the pI, the solution is near its maximum buffering ability. c) At a pH near the pI, nearly all the molecules carry a net negative charge. d) At pH near the pI, nearly all the molecules carry no net charge.
d) At pH near the pI, nearly all the molecules carry no net charge.
Which of the following is FALSE when considering van der Waals interactions? a) Van der Waals radii can determine molecular surfaces. b) The total interaction energy is the sum of the attractive and repulsive forces. c) Molecules that interact by van der Waals forces do not interpenetrate. d) They are not important in determining the stability of three-dimensional structures of proteins.
d) They are not important in determining the stability of three-dimensional structures of proteins
Which of the following statements about acids and bases is INCORRECT? a) A Brønsted base is a proton acceptor. b) Bases need not contain -OH directly; instead, they can increase the concentration of -OH by deprotonating water. c) A strong acid has a weak conjugate base. d) Water acts only as a weak acid.
d) Water acts only as a weak acid
Each of the following is a noncovalent interaction EXCEPT: a) the interaction between an amino and a carboxylate group. b) an interaction between NH3+ and a water molecule.a hydrogen bond. c) a carbon-hydrogen bond. d) a van der Waals interaction.
d) a carbon-hydrogen bond
Each water molecule is joined to _____ other water molecules by ____ bonds. a) two ... polar covalent b) three ... ionic c) four ... polar covalent d) four ... hydrogen e) two ... hydrogen
d) four ... hydrogen
(image): 2 Hydrogen bonds (red with s+ --s- bond) The brackets are indicating a(n)_____ bond a) ionic b) hydrophobic c) polar covalent d) hydrogen e) single (nonpolar) covalent
d) hydrogen
Why isn't this insect drowning? a) The insect is flying just above the water surface. b) It is difficult to change the temperature of water. c) The insect is very light. d) Surface tension. e) The insect is swimming.
d) surface tension
Which of the following is TRUE of hydrophobic molecules? a) Water forms a cage-like structure around them. b) They self-associate by releasing some of the surrounding water molecules. c) They have limited solubility in water. d) Dissolving in water decreases the entropy of the mixture. e) All of the above
e) All of the above
Which would be better for separation: gel electrophoresis or isoelectric focusing? a) gel electrophoresis b) isoelectric focusing
isoelectic focusing
The activity of an enzyme requires a glutamic acid to display its −COOH functional group in the protonated state. Suppose the pKa of the −COOH group is 4.07. Will the enzyme be more active at pH 3.5 or 4.5? Explain. a) pH 3.5, because protonation is favored when pH < pKa b) pH 4.5, because protonzation is favored when pH > pKa
pH 3.5, because protonation is favored w hen pH < pKa
What is the pH of an aqueous solution with the hydronium ion concentration[H3O+] = 2 x 10-14 M ?
pH = 13.7
The weak acid HA is 2% ionized (dissociated) in a 0.20 M solution. What is the pH of this solution?
pH = 2.4
250 mL 0.3 M phosphoric acid plus 250 mL 0.8 M KH2PO4 (pKa=2.14)
pH = 2.6
At what pH will the enzyme show 78% of maximal activity?
pH = 3.52
A 500-mL sample of a 0.100 MM formate buffer, pH 3.75, is treated with 5 mL of 1.00 MM KOH. What is the pH following this addition?
pH = 3.93
100 mL 1 M acetic acid plus 100 mL 0.5 M sodium acetate (pKa=4.76)
pH = 4.5
(image of graph) Calculate the pHpH of the solution that results following addition of 10 mLmL of 1 MNaOHMNaOH to 40 mLmL of 1 MNH4ClMNH4Cl. What is pH?
pH = 4.6
Calculate the pH of a 1 MNH4Cl solution.
pH = 4.6
A solution is made by mixing 9.00 mmolmmol (millimoles) of HAHA and 3.00 mmolmmol of the strong base. What is the pH?
pH = 4.95
(image of graph) Calculate the pHpH of the solution that results following addition of 10 mLmL of 1 MNaOHMNaOH to 40 mLmL of 1 MNH4ClMNH4Cl. What is pH?
pH = 8.8
Calculate the pH of the solution that results following addition of 10 mL of 1 MNaOH to 40 mL of 1 MNH4Cl.
pH = 8.8
Calculate the pH of the solution that results following addition of 30 mL of 1 MNaOH to 40 mL of 1 MNH4Cl.
pH = 9.7
Calculate the isoelectric point of arginine. pI?
pI = 10.7
Calculate the value of pI for histidine.
pI = 7.6
Now assume you wish to make a buffer at the same pHpH, using the same substances, but want the total phosphate molarity ([HPO2−4]+[H2PO−4])([HPO42−]+[H2PO4−]) to equal 0.30. What concentration of the KH2PO4KH2PO4 would be required?
0.13 M
Suppose you wanted to make a buffer of exactly pHpH 7.00 using KH2PO4KH2PO4 and Na2HPO4Na2HPO4. If the final solution was 0.10 MM in KH2PO4KH2PO4, what concentration of Na2HPO4Na2HPO4 would you need? (pKapKa for H3PO4H3PO4, H2PO−4H2PO4−, and HPO2−4HPO42− are 2.14, 6.86, and 12.40, respectively.)
0.14 M
Now assume you wish to make a buffer at the same pHpH, using the same substances, but want the total phosphate molarity ([HPO2−4]+[H2PO−4])([HPO42−]+[H2PO4−]) to equal 0.30. What concentration of the Na2HPO4Na2HPO4 would be required?
0.17 M
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
Describe the preparation of 2.00 L of 0.100 M glycine buffer, pH 9.0, from glycine and 1.00 M NaOH. What mass of glycine is required? The appropriate pKa of glycine is 9.6.
15.0 g
The activity of an enzyme requires a glutamic acid to display its −COOH functional group in the protonated state. Suppose the pKa of the −COOH group is 4.07.
2.19 LOOK BACK
Describe the preparation of 2.00 L of 0.100 M glycine buffer, pH 9.0, from glycine and 1.00 M NaOH. What volume of 1.00 MM NaOH is required? The appropriate pKa of glycine is 9.6.
40 mL
Add to the buffer solution: Add HBr
Add HBr: HBr(aq) + KF(aq) --> HF(aq)+KBr(aq)
Add to the buffer solution: Add KOH
Add KOH: KOH(aq)+HF(aq)--> H2O(l)+KF(aq)
Classify each statement as an example of adhesion, cohesion, or surface tension. Adhesion? (2)
Adhesion: -Water molecules cling to plant cell walls -Water molecules cling to the side of a beaker
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 above
Which set of compounds would form a buffer in aqueous solution? Drag to bin: HCOOH & HCOOK; NaF and NaOH; HCN and NaF; HCN and KCN; HBr and NaBr; NaBr and KBr; NaF and KF BUFFER? (2)
BUFFER: HCOOH and HCOOK HCN and KCN
Classify each statement as an example of adhesion, cohesion, or surface tension. Cohesion? (2)
Cohesion: -A drop of water spilled on a table forms a drop on the table, rather than spreading out over the surface. -Water molecules are attracted to each other
