can a SATA2 harddisk work on a SATA1 motherboard?

Answer 1

No you cant, if you are sure it is only sata1, check the manifacturer's website make sure. If there is a chance to use you can find there, read reviews, you may need update drivers to use

Answer 2

SATA II is such a loose term. It depends what you mean by that. The official SATA website says that SATA II is not really a term that is used by them.

Some places think that if an SATA drive has 2nd generation features such as NCQ (Native Command Queuing) or the 3.0 Gbps transfer rate, then that means it's SATA II. However, a drive that is 2nd generation might be fully supported by old SATA 1.5 ports on a motherboard. The NCQ feature is the perfect example of this. Many older SATA ports support it, even though the feature came out a year or so later.

Now a drive rated for the 3.0 Gbps transfer rate should be backwards compatible on older ports. Of course, it will just be using the older rate of 1.5 Gbps instead. Don't be fooled by the speed rating. It is talking about the bandwidth on the channel being wider to allow more traffic through at once. A single drive is like a single car travelling down a 4-lane highway. The extra lanes don't matter to just one car, much like the extra bandwidth to just one drive. It's when you build large drive arrays (RAID) that many company servers have, where you start to see the benefit of the extra bandwidth.