Is folic acid necessary for making ergosterol?

False , folic acid is not  necessary for making ergosterol.

Explanation:

Folic acid is converted to folate by human body when it is taken as dietary supplement. Main function of  the folic acid is to help in making of DNA and RNA, and also helps to metabolise amino acid,that is used in cell division.

Certain fungi like Aspergillus,Penicillum, Cladosporium are commercially grown to extract ergosterol and which can be converted into vitamin D used as dietary supplement and food additive.

oak trees? ? what was listed

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.