TLS Online TPP Program

#Question id: 8704


To apply the principle of maximum parsimony to construction of a phylogenetic tree, ________.

#SCPH05 I Biotechnology
  1. choose the tree that assumes all evolutionary changes are equally probable
  2. choose the tree in which the branch points are based on as many shared derived characters as possible
  3. choose the tree that represents the fewest evolutionary changes, either in DNA sequences or morphology
  4. choose the tree with the fewest branch points
More Questions
TLS Online TPP Program

#Question id: 642

#SCPH05 I Biotechnology

The graphs P, Q and R show the variation of rate constant (k) with temperature. The reactions represented by P, Q and R, respectively, are

TLS Online TPP Program

#Question id: 642

#SCPH05 I Biotechnology

The graphs P, Q and R show the variation of rate constant (k) with temperature. The reactions represented by P, Q and R, respectively, are

TLS Online TPP Program

#Question id: 643

#SCPH05 I Biotechnology

The hydrolysis of lactose is catalysed by b-galactosidase as given below

Which of the following could be correct mechanism for this hydrolysis reaction?

A. Nucleophilic attack by the carboxylate group of Glu/Asp on the C-1 carbon atom of the galactose moiety within glucose, releasing glucose and forming an intermediate with the galactose linked to the enzyme through an ester linkage. Water then attacks this carbon atom, displacing the glutamate carboxylate and releasing galactose.

B. Electrophilic attack by the carboxylate group of Glu/Asp on the C-1 carbon atom of the galactose moiety within glucose, releasing glucose and forming an intermediate with the galactose linked to the enzyme through an ester linkage. Water then attacks this carbon atom, displacing the glutamate carboxylate and releasing galactose.

C. Nucleophilic attack by the carboxylate group of Lys/Arg/His or bivalent cation on the C-1 carbon atom of the galactose moiety within glucose, releasing glucose and forming an intermediate with the galactose linked to the enzyme through an ester linkage. Water then attacks this carbon atom, displacing the glutamate carboxylate and releasing galactose.

TLS Online TPP Program

#Question id: 644

#SCPH05 I Biotechnology

Enzyme X and Enzyme Y are both involved in monosaccharide metabolism. Enzyme X uses glucose as a substrate while Enzyme Y uses fructose as a substrate. At pH=7.0, Enzyme X has a Vmax of 10 μM/s while Enzyme Y has a Vmax of 20 μM/s. Both enzymes have a Km of 3.0 mM for their respective substrates. Which aspects of its reaction will be changed by Enzyme Y?

TLS Online TPP Program

#Question id: 654

#SCPH01 Biochemistry

Which pair represents different conformations?

TLS Online TPP Program

#Question id: 654

#I Life Science/ Life Sciences Group – I-V

Which pair represents different conformations?