Custom single.php per specific post category

Hi all,
I have a problem with the customization a some posts of my site. I’d like to know if there’s a way to assign a specific style and contents, conteined in a specific single.php, to all the posts of a particular category, similarly it is possible to customize the archive page of that category.
For example: I have in my site a series of articles with the category “photo” and I want the page of these articles is different from the page of all the remaining articles, with a different background and sidebar.
How I can get that?
I hope you can help me, searching on internet I haven’t found answers.
Thanks in advance.