A researcher is trying to determine the structure of a lipid present after isolation from sheep brain matter.After chemical analysis, the researcher determines a primary amine is present, a phosphate, a saturated fatty acid chain of $18$ carbons and a second of the same length with $1$ double bond. The researcher is unsure of the configuration or position of the double bond. Draw and label the structure of one possible isomer of this lipid. Include its biochemical name.