Construct a shapefile from information in a dBase file in QGIS

I am using QGIS. I have been provided a dbf file but no shp or index files. Each line in the .dbf file corresponds to a line I wish to show on the map. Each line in the .dbf file has a unique identifier and a start lat lon for the line and an end lat lon for the line. How do I construct a .shp and index files for this data from the .dbf file?