Question

D 13. lonotropic receptors stimulate signal transduction cascades, which provide opportunities for signal amplification. True False 14. Consider the three phases of glycolysis: (1) preparation and cleavage (Gly-1 to Gly-5) (2) oxidation (Gly-6 to Gly-7) (3) pyruvate formation (Gly-8 to Gly-10) Which of these phases produces ATP? 2 and 3 1 and 2

Answer 1

13) False

Ionotropic receptors are those which does not help with initiation of signal cascade and hence play no role into amplification of the signals. They are basically type of transmembrane molecules and they open or close and hence it enables the movement of small molecules to travel in and out of it. These receptors enable the binding of the ionic ligands and hence does open or close the ion channel. It however does not lead to initiating cascade of reactions as it is done with help of metabotropic receptors. These types of receptors tend to bind to certain chemical ligand and hence they start cascade of reactions leading to signal amplification. As the ligands bind to the ionotropic receptor, it does not lead to the activation of the secondary molecules and hence there is no signal transduction reactions.

14) The answer is 2 and 3

The glycolysis is a process in which the glucose molecule is broken down and it leads to production of 2 molecules of pyruvate. It is basically a series of 10 reactions through which the glucose is broken into 2 molecules of 3 carbon pyruvate. The first phase is basically is the energy requiring which requires the energy from ATP which starts with the breakdown of the glucose molecules. The preparation and cleavage phase starts from reaction 1 to 5 and within these 2 molecules of ATP is used and it forms ADP. However, in the reaction 7, it produces on molecule of ATP and hence it is energy producing stage where the 1,3 – bisphosphoglycerate into 3-phosphoglycerate and 1 molecule of ATP is produced. The last three reaction leads to production of the pyruvate formation and in the last reaction as the phosphenolpyruvate is converted into pyruvate, it leads to production of ATP.