My teacher teaches me that if one puts an - ing to the end of a verb you will get the gerund of the verb which has the function as a noun. Example: 

> 
> mix-mixing,  
> 
>  understand-understanding. 
> 
> 
> 

But there is also another form noun to the relative verb. Example: 

> 
> mix-mixture. 
> 
> 
> 

Both mixture and mixing have the noun meaning. 

I want to know does every verb have another noun besides gerund. What is the difference between them? Can they be used instead of each other?