can a blocked transaction affect the performance of one that is blocking it?

Hi,

Could one transaction (one that should be relatively simple and short) 
cause another complex, long running transaction (involving INSERTS, on a 
table the first transaction may be reading from) to take many orders of 
magnitude longer than it would normally? (short of competing for system 
resources, like CPU time etc, of course)

I don't believe my scenario involved a deadlock but I expect my short 
transaction was probably blocked by my long one. Does it make any sense 
that this could very significantly affect the performance of the 
non-blocked transaction?

Thanks,

Eric