We do not know if individual cells or a group of cells have consciousness, probably not because of no evidence so far, but assuming that they were aware of themselves, would they be also aware that there exists an even larger consciousness and somehow they are a part of it.
This is essentially the same question as how a human being can become aware of the gods. You could ask the same question about ants--- if you are an ant, can you become aware that there is a colony?
Consciousness is a vague term, and it is hard to know what to make of it. I don't know what "self-aware" means exactly, because it's hard to imagine an objective test for it, but if you have one, give it, and then you can say if cells pass it.
On the other hand, we do have a good model for computation, and computation of a certain type is what is going on in the brain, since it is the most that is allowed by physics, or even by general philosophy, as to what a natural system can do. Computation is rather mystical and unknowable (despite the common perception, which is due to the rather primitive types of computations people see their laptop doing), it is the definition of complexity when it gets large, and the existence of computation in the brain is rather obvious, since computation was defined as the simplest abstraction of the operations a human being can do which still contained the ability to do all logical deductions, and therefore do mathematics.
There is a certain complexity limitation in computation, in that the complexity of a fixed computer program means it can never do certain things which are of a higher complexity, like prove the Kolmogorov complexity of a string whose Kolmogorov complexity is larger than the program. But the real computations in nature have access to a random number generator, and there is no bound on the complexity of a computation with a random oracle, the random oracle, the random number generator, will produce an uncomputable sequence of arbitrarily large Kolmogorov complexity. So using randomness, you have no obvious complexity limits, and when I say "computation", I mean "computation with access to randomness", which is slightly different than "computation with a fixed program".
The issue with cells is that we know how many bits of data can fit in a typical cell, about 1-10 gigabytes, and that's certainly not enough for a human-style consciousness. There is no way this computation is sufficient to read "Hamlet" or to compose, or even listen to, a Beethoven symphony.
But let's pretend.
Under these circumstances, the cell can become aware of the larger organism by noticing the constraints on its behavior, and providential action. For example, imagine this dialog between two cells in my liver:
Liver-cell Louie: I am sick of being a liver cell. I want to be cancer.
Liver-cell Lisa: No! don't become cancer. It's dangerous. I heard a liver cell became cancer last year, and Immune-cell Ingmar ate her!
Louie: I know ingmar. He has a crappy antigen set, I can evade him.
Lisa: But you know you're not going to be a tumor. No one has ever been a tumor before.
Louie: I am sure I can make it. Here I go.(transmute) RAWR! From now on, you call me CANCER CELL CARL!
Carl: I'm replicating already. FEEL THE POWER!
Lisa: I don't know about this Louie, uh, I mean Carl. I have a bad feeling you will be punished by Ron.
Carl: Ron! Ron! That stupid superstition? Have you ever seen Ron? I don't believe in Ron.
Lisa: But look at the blood stream supplying us with nutrients, the nerve cells supplying us with signals. Is that not evidence of Ron?
Carl: It is nothing of the sort, that's Harry the Heart cell and his friends, supplying us with blood, and he won't stop just because I'm cancer. In fact, I have assurances from Stem-cell Stanley and his buddies that they will make a whole new set of blood vessels in case I make a big tumor, and we'll have more nutrients than ever! Even you.
Lisa: I still think this is a bad idea. Ron is going to punish you somehow. I don't know how.
a few months later, Carl is a big tumor.
Carl: Look at me now! I made it, I am a huge tumor, I have vast influence. Blood cells come to me from new vessels specially constructed. Aren't you feeling stupid now for being a liver cell?
Lisa: I still think it's not right. What if everyone became cancer? Wouldn't the whole blood system collapse? Wouldn't we stop getting nerve signals and the bile production would drop... it doesn't feel right.
Carl: Forget about the other cells. I am unique! I have always known it. I always knew I was meant to be cancer.
Then I go to the doctor, and he tells me I have liver cancer. So I have an operation, where the tumor is removed.
Carl: Oh no! What's happening? We are being severed from the blood stream! All is lost.
Lisa: I told you it wasn't a good idea to become cancer, we are being punished by Ron.
Carl: I don't believe in Ron! It's just bad luck.
So the sign of being embedded in a larger collective with consciousness is the traditional religious notion of providence and punishment, that events which seem uncoordinated will provide evidence of a larger intelligence which serves to correct actions which harm the collective.
It is not clear to what extent human collectives are more intelligent than individuals, and the notion of God is even more subtle still, since it imagines a limit of ethical behavior extending upwards through even larger collectives.
These stories I am telling about Lisa, Carl and so on, are parallel to some of Jesus's parables.
I seriously doubt the individual cell has consciousness.
The entire "field" of that type of cell, across the span of many lifetimes, I'm not so sure. I think they might.
Of course they don't. It's a parable.