The type of ATP synthesis, traditionally referred to as substrate-level phosphorylation involves the direct transfer of a phosphate group, which reactions perform substrate-level phosphorylation?

a) Conversion of Glyceraldehyde 3-phosphate to 1,3-Bisphosphoglycerate

b) Conversion of Phosphoenol pyruvate to pyruvate

c) Conversion of Fructose 6-phosphate to Fructose 1,6-bisphosphate

d) Conversion of 1,3-Bisphosphoglycerate to 3-Phosphoglycerate

Find the correct one.

#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

#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.

#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?

#Question id: 654

#SCPH01 Biochemistry

Which pair represents different conformations?

#Question id: 654

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

Which pair represents different conformations?

#Question id: 654

#SCPH05 I Biotechnology

Which pair represents different conformations?