Prepared to study biology at last (5)
I believe the answer is:
ready
'prepared' is the definition.
(similar in meaning)
'study biology at last' is the wordplay.
'study' becomes 'read' (synonyms).
'at last' suggests the final letters.
The last letter of 'biology' is 'y'.
'read'+'y'='READY'
'to' is the link.
(Other definitions for ready that I've seen before include "Willing (to do something), prepare" , "Waiting" , "Intelligent" , "Suitably prepared" , "Prompt and adequate" .)