You can take depreciation (but you don't have to) on the percentage of your home you use for a home office along with a percentage of the other expenses associated with your home. Depreciation is a part of the actual expenses for Vehicle Expense deduction (if you choose to use it) and it is figured into the standard mileage rate. You can leave out depreciation by enter $0 as the value of your vehicle.
If you choose "Home Office" and "Vehicle Expenses" on the screen "Tell us about any expenses for your business", TurboTax will guide you through a series of questions for both areas. You will be prompted to answer questions about the home and vehicle value. Enter $0 if you don't want to depreciate them.