Can I put a DDr5 graphic to a DDr3 Motherboard?

Yes you can. The system RAM and graphics RAM are physically different and addressed in different ways. Your motherboard cares about the RAM you install in it, but as it never addresses the RAM on the graphics card directly it doesn't care about that at all. All the communication with the graphics memory is handled by the graphics card itself.

The DDR spec of the motherboard is important because it tells you what memory you can and can't install on it, but the DDR spec of the graphics card is just information about its performance.