Laurie met her husband Jim at a support group for families dealing with PKU (phenylketonurea), a recessive genetic disorder. Laurie and Jim both have one sister who is affected with PKU and no other family history of the disorder. They come to you as a genetic counselor to ask what their risk is of having an affected child. What do you tell them?

TLS Online TPP Program

#Question id: 33229

#Unit 1. Molecules and their Interaction Relevant to Biology

The effects of pH on enzymes depends on a combination of factors: 

(a) Most enzymes are active within only a narrow pH range, typically 5 to 9. 

(b) the ionization states of the amino acid residues involved in the catalytic activity of the enzyme

(c) the variation of protein structure (usually significant only at extremes of pH).

Which of the above is correct

TLS Online TPP Program

#Question id: 33230

#Unit 1. Molecules and their Interaction Relevant to Biology

The pH dependence of the rate of the reaction catalyzed by fumarase produces the following curve. Which amino acid/s likely to be present in the active site

TLS Online TPP Program

#Question id: 33231

#Unit 1. Molecules and their Interaction Relevant to Biology

Which character makes concerted acid–base catalysis a common enzymatic mechanism?

TLS Online TPP Program

#Question id: 33232

#Unit 1. Molecules and their Interaction Relevant to Biology

In RNase A 

TLS Online TPP Program

#Question id: 33233

#Unit 1. Molecules and their Interaction Relevant to Biology

The pH dependence of the rate of the RNase A reaction suggests the involvement of 

a. Two ionizable residues with pK values of 5.4 and 6.4

b. Single ionizable residue with pK values 7

c. Cytosine residue in active site

TLS Online TPP Program

#Question id: 33234

#Unit 1. Molecules and their Interaction Relevant to Biology

The form of catalysis is often also called nucleophilic catalysis