Roll call helps beginners a lot (5)
I believe the answer is:
bunch
'a lot' is the definition.
(I know that lot can be written as bunch)
'roll call helps beginners' is the wordplay.
'roll' becomes 'bun' (synonyms).
'beginners' says to take the initial letters.
The initial letters of 'call helps' is 'ch'.
'bun'+'ch'='BUNCH'
(Other definitions for bunch that I've seen before include "Cluster (of grapes)" , "Gang" , "Group of people (informal)" , "Show silly fondness" , "Grouping of a number of similar things" .)