homework quizzes 0-3

The dissociation constant for an acid with a pKa value of 6.0 is

−1 × 10e−6

1 × 10e6

−1 × 10e6

1 × 10e−6

1 × 10e−6

The inflection point of the titration curve for a weak monoprotic acid is equal to its pK_a

 

True

 

False

True

Ionic compounds and polar covalent compounds tend to dissolve in water because of

 

ion-dipole and dipole-dipole interactions

 

hydrophobic interactions

 

van der Waals bonds

 

dipole-induced dipole interactions

ion-dipole and dipole-dipole interactions

Hydrogen bonds explain which of the following properties of water?

 

Both the abnormal melting and freezing points and that ice expands when frozen.

 

Ice expands when frozen.

 

Water is a great solvent for all ionic and polar molecules.

 

Hydrogen bonds explain all of these properties.

 

Water has high melting and boiling points for its small size.

Hydrogen bonds explain all of these properties.

How does the strength of hydrogen bonds compare with covalent bonds?

 

The question cannot be answered without knowing which covalent bonds are being referred to

 

Hydrogen bonds are much weaker than covalent bonds.

 

Hydrogen bonds and covalent bonds have similar strengths.

 

Hydrogen bonds are much stronger than covalent bonds.

Hydrogen bonds are much weaker than covalent bonds.

Which group consists only of amino acids with polar side chains?

 

serine, threonine, and isoleucine

 

serine, threonine, and cysteine

 

serine, threonine, and valine

 

serine, threonine, and leucine

serine, threonine, and cysteine

Which group consists only of amino acids with basic side chains?

 

arginine and leucine

 

leucine and lysine

 

arginine and isoleucine

 

lysine and arginine

lysine and arginine

The amino and carboxyl groups of amino acids are bonded to which carbon?

 

Both are bonded to the β-carbon.

 

The amino is bonded to the β-carbon, and the carboxyl is bonded to the α-carbon.

 

Both are bonded to the α-carbon.

 

The amino is bonded to the α-carbon, and the carboxyl is bonded to the β-carbon.

Both are bonded to the α-carbon.

Which groups of a pair of amino acids must react to form a peptide bond?

 

the two aminos

 

the two carboxyls

 

the carboxyl of one and the amino of the other

 

the two R-groups

the carboxyl of one and the amino of the other

Which of the following has no L or D configuration?

 

Glycine

 

All of these have an L or D configuration

 

Proline

 

Glyceraldehyde

Glycine

In the Bohr effect the binding of oxygen to hemoglobin

 

is increased by the presence of Na⁺

 

is decreased by the presence of H⁺ and CO₂

 

is unchanged

 

is increased by the presence of H⁺ and CO₂

is decreased by the presence of H⁺ and CO₂

The oxygen binding curve of which of the following is the closest to that of myoglobin?

 

maternal hemoglobin

 

fetal hemoglobin

 

hemoglobin at pH 6.8

 

hemoglobin that lacks BPG

hemoglobin that lacks BPG

A single amino substitution can give rise to a malfunctioning protein.

 

False

 

True

True

Under normal circumstances:

 

Adult Hb binds oxygen more tightly than either fetal Hb or Mb binds.

 

More than one of these statements is correct.

 

Mb has the lowest affinity for oxygen of the 3.

 

Adult Hb binds to oxygen more tightly than Mb binds.

 

Fetal Hb binds oxygen more tightly than adult Hb.

Fetal Hb binds oxygen more tightly than adult Hb.

The protein myoglobin

 

carries oxygen in the bloodstream

 

contains a high degree of β-pleated sheet structure

 

contains no histidine

 

contains a heme group

contains a heme group

In gel filtration chromatography

materials are separated based on their size, the smaller ones eluting first.

materials are separated based on their size, the larger ones eluting first.

materials are separated based on their hydrophobic nature, the less hydrophobic ones eluting first.

materials are separated based on their hydrophobic nature, the more hydrophobic ones eluting first.

materials are separated based on their size, the larger ones eluting first.

The most common way of visualizing the results seen on a protein chip is by use of

Group of answer choices

primary antibodies

using an enzyme-linked reaction involving 4-chloro-1-naphthol

secondary antibodies

fluorescence

fluorescence

Which of the following is not an example of column chromatography?

Group of answer choices

ammonium sulfate fractionation

ion-exchange separation

HPLC

affinity separation

ammonium sulfate fractionation

Which of the following happens as a protein is purified?

Group of answer choices

the percent recovery and the fold purification both decrease

the percent recovery and the fold purification both increase

the percent recovery decreases and the fold purification increases

the percent recovery increases and the fold purification decreases

the percent recovery decreases and the fold purification increases

Which of the following are principles on which to base column chromatography?

Group of answer choices

All of these

Both molecular size and ion exchange

Isoionic pH or pI

Ion exchange

Molecular size

Both molecular size and ion exchange

What tends to happen to the percent recovery during a protein's purification?

 

The number usually steadily increases during the purification.

 

The number usually steadily decreases during the purification.

 

There is no general trend for percent recovery during a protein purification.

 

The number usually stays fairly constant during the purification.

The number usually steadily decreases during the purification.

The isoelectric point is

 

the pH at which a substance has a net positive charge

 

the pH at which a substance has no charge groups of any kind

 

the pH at which a substance has no net charge

 

the pH at which a substance has a net negative charge

the pH at which a substance has no net charge

Which separates on the basis of molecular weight?

 

Cation or anion exchange

 

Affinity chromatography

 

Cation exchange

 

Gel filtration

 

Anion exchange

Gel filtration

In a sample consisting of lysine, leucine, and glutamic acid, which will be eluted last from an anion exchange resin at pH 7?

 

lysine

 

glutamic acid

 

all three will be eluted at the same time

 

leucine

glutamic acid