an interesting point. One of the complex issues with consciousness is that our thoughts are inextricably linked to our evolution and biological instinct. In addition, we are 80% a product of environmental stimulus. A computer could learn to react to its environment and in simple terms i guess it is possible to program a computer to have survival and reproductive instincts. (many virus already display this characteristic)
"life" and "sentient life" are two very different things. However, sentient life would contain all the basic characteristics of life which is
to be born, to grow, to evolve, to reproduce, to interact with environment etc.
Where sentient life differs is in for example its understanding of the "will to live". Sentient life would understand the concept of death, but even simple forms of life can display a will to live in terms of a fight or flight mechanism
Do we need a "computer to replicate the functions of the human brain" ? What is wrong with the human brain then ?
I think, as has been said, that if computers do ever develop some intelligence then we would probably not recognise it as intelligence. If it depends on the ability to learn then it would never need to learn such things as hunger, cold, pain or any emotions like fear or love, so what kind of intelligence would it be ? I can only think of military applications for a machine such as that.