Flavor and aroma compounds in hops are volatile. This means the longer they are boiled the more you will remove from the beer. In general 10-20 minute additions add flavor, 0-10 minute additions add aroma.
Right. The longer that hops are boiled (up to about 75 minutes), the more they give bittering. If you want a hoppy beer, you'd want to add more hops LATE in the boil. If you want a very bitter beer, you'd want to add more hops at the beginning.
Generally, you see this type of schedule:
60-30 minute hops: bittering only
20-15 minute hops: flavor mostly, but some bittering imparted
10 minutes: flavor, but aroma as well
5-0 minutes: Mostly aroma, but some flavor as well
Dryhopping: Almost all aroma, but since aroma and flavor are tied together, there is some perceived flavor.
so, to answer your question, if you add all of the recipe's hops at 60 minutes, you'll have a bitter beer without hops flavor or aroma. This is very common in beers like stouts, where there is no hops flavor or aroma to speak of. In some beers, like IPAs, hops are added closer to the end of the boil (besides the bittering hops) to provide hops flavor and aroma.