Question

True or False

a. a buffer consists of any acid and any base mixed together

b. proteins tend to precipitate at high salt concentration

c. Coulomb's law measures the standard reduction potential between charged molecules

d. A compound with a large dipole moment will be non polar

e. beta mercaptoethanol and performic acid are used to reduce disulfide bonds

f. water has a high heat capacity and a high dialectric constant

g. biomolecules with a chiral center will exist in the body as a racemic mixture

h. alanine is a zwitterion at pH 7.0

i . free protons are never observed in aqueous systems

j. electrophoresis seperates molecules based upon partitioning between a mobile and stationary phase

Answer 1

a) false

reason-A buffer consists of a weak conjugate acid-base pair.example acetic acid(weak acid) and sodium acetate (its conjugate base.

b)True

reason-this process is called salting out.As the salt concentration is increases, it compresses the solvation layer and makes proteinn-protien hydrophillic (charged outersurface) to interact with each other and also with the salt.This exposes the inner hydrophobic layer of the protein and makes it fall out of the solution.

c)false

coulomb's law describes the electrostatic interactions between electrically charged particles

d)false

dipole moment is the product of the magnitude of charges and separation between them.Higher dipole moment means more polarity

e)True

they convert -S-S- bonds to two -SH bonds in cystine

f)True

High heat capacity is due to extensive hydrogen bonding between polar water molecules.And high dielectric constant is also the measure of its capacity to form electrostatic bonds with other molecules

g)False

the chirality of some biomolecules are important for biological functions.example replication of DNA depends on chiral centres of biomolecules

h)true

only terminal COOH AND NH2 are present so forms -NH3+ and -COO-

i)true

High dissociation constant of H+ from water molecule due to strong H-bonding between polar molecules

j)false

It separates macromolecules based on its size and charges.