Consider the various configurations discussed in Page 443 of your text for a DC motor. Which one will you choose to get Constant operating torque For the motor used in hard disk drive or DVD player Solution a)From Speed-Torque characteristics for a constant torque application DC Shunt motor is the best suited motor. b)For operation in DVD Player and Hard Disks, we need variable speed and ability to stop at any position. These requirements are met in stepper motor..

1. Describe the effect cyanide ion, CN-, on oxidative phosphorylation and the citric acid cycle.
Why is cyanide deadly? Please draw, as I have illustrated in class, the basic paradigm between
the intracellular compartment the extracellular compartment and the vascular space. Please
appropriately label the following endothelial cell, interstitial fluid and extracellular matrix, basal
lamina, plasma membrane, nucleus, mitochondria and red blood cell. Compare the resting
membrane potential of a neuron with potassium and sodium equilibrium potentials. Explain how
this comparison relates to the relative permeabilities of the resting plasma membrane to these
two ions.
Solution
Answer
The process in cell metabolism by which respiratory enzymes in the mitochondria synthesize
ATP from ADP and inorganic phosphate (Pi) during the oxidation of NADH+H+ and FADH2 by
molecular oxygen.
The enzymes of respiratory chain or electransport chain are: NADH dehydrogenas, Succinate
dehydrogenase, Ubiquinone-cytochrome c oxidoreductase, Cytochrome c, Cytochrome oxidase
and ATP synthase
Cyanide is rare and potentially deadly poison. It works by making the body unable to use oxygen
which is life sustaining molecule.
Cyanide inhibits electron transfer in electron transport chain by inhibiting the activity of
cytochrome oxidase (Complex IV)
Thus blocks the transfer of electrons from cytochrome oxidase to oxygen, hence oxygen is not
utilized.
This inturn stops the process of ATP synthesis which is a vital molecule of cell, thereby leading
to cell death.
The end product of citric acid cycyle if NADH+H and FADH2 molecules.
More than 90% of the oxygen consumed by the body is used by the electron transport chain to
oxidize NADH+H+ and FADH2.
When electron transport chain is disrupted, this indirectely efffects the citric acid cycle