Following statements are regarding to the apoptosis which is induced by trophic factors.

A. The presence of specific trophic factors (e.g., NGF) leads to activation of their cognate receptor tyrosine kinases (e.g., TrkA) and activation of the PKB pathway.

B. DNA damage or ultraviolet irradiation leads to induction of synthesis of the BH3-only Puma protein. Puma binds to Bak and Bax as well as to Bcl-2, allowing Bak and Bax to form oligomeric pores.

C. Removal of a cell from its substratum disrupts integrin signaling, leading to release of the BH3-only Bim protein from the cytoskeleton.

D. Binding of extracellular death signals, such as tumor necrosis factor and Fas ligand, to their receptors oligomerizes an associated protein (FADD), which in turn triggers the caspase cascade, leading to cell murder by apoptosis.

Which of the following pathway does not belong to the trophic factor inducing apoptotic pathway?

#Question id: 634

#Unit 1. Molecules and their Interaction Relevant to Biology

An enzyme has a Vmax of 50 micromol product formed (minute x mg protein)-1 and a Km of 10 microM for the substrate. When a reaction mixture contains the enzyme and 5 microM substrate, which of the following percentages of the maximum velocity will be closest to the initial reaction rate?

#Question id: 633

#Unit 1. Molecules and their Interaction Relevant to Biology

An amino acid transporter protein is responsible for the transport of a specific amino acid across a membrane. The KI values of several competitive inhibitors of the amino acid transporter are shown above. Based on these data, which of the following is most likely the amino acid transported by this protein?

#Question id: 631

#Unit 1. Molecules and their Interaction Relevant to Biology

Two curves showing the rate versus substrate concentration are shown below for an enzyme-catalyzed reaction. One curve is for the reaction in the presence of substance X. The other curve is for data in the absence of substance X. Examine the curves and tell which statement below is false.

#Question id: 630

#Unit 1. Molecules and their Interaction Relevant to Biology

In case of competitive inhibition, plots of Km against [Io] fixed [Eo] have

#Question id: 629

#Unit 1. Molecules and their Interaction Relevant to Biology

In the presence of a fixed concentration of a competitive inhibitor, which of the following would best characterize an enzyme-catalyzed reaction when the concentration of the substrate is increased?

#Question id: 628

#Unit 1. Molecules and their Interaction Relevant to Biology

At fixed substrate concentration, which of the following equation is correct for Dixon plot