Bluetooth and WLAN operate on the same frequency band (2.4 GHz, so called ISM band). However, they use different mechanisms for selecting the frequency. Bluetooth uses frequency hopping.
Bluetooth and WLAN coexistence is being investigated by the Bluetooth SIG. If same frequency is momentarily used, Bluetooth device selects the next frequency (according to the frequency scheme). So there should not be collisions in data transfer. However, the throughput decreases.
Direct connections between Bluetooth and WLAN are not possible. It is however possible that you have an access point with both Bluetooth and WLAN radios. So you could connect your device to the access point using Bluetooth which then connects you to WLAN or LAN. In this use case LAN Access Profile has to be supported.