It is hard to guess at the cause of a noise without seeing a car first hand. A "knocking" sound heard on tight turns (more of a click, click, click sound that increases with the speed of a turn) could be a worn CV joint as your car is front wheel drive.
A knocking sound that you may experience when driving over bumps or uneven road surface may be caused by worn shock absorbers, shock absorber/suspension strut mounts, or sway bar end links.
The 'knocking sound" could even be brake pads shifting about in the brake caliper mount if the noise is experienced during brake application. At any rate it is safest to have the car inspected by an automotive technician for your safety, peace of mind, and to lessen potential damage.