PAN Card is not required to apply for passport.
Your PAN Number remains the same and is still tagged to your. It doesn't matter whether you have a PAN Card or not.
An individual is eligible to one PAN number.
You will need to fill out a "Change Request Form" if you lose your PAN card. This request is for the reissuing of your PAN Card. The official website of NSDL PAN Service has the PAN Card Change Request Form.
You will receive a list of documents that you must submit with the form. The card will be issued to you after payment of a small fee. It can take up to 15 days for it to reach your mailbox.
It is strongly recommended that the PAN Card be reissued as soon possible, as most financial transitions today require it to be an original document.