Google Pagerank totally based on Back links

PageRank: 

PageRank based on uniquely democratic nature of the internet contents of web by using its spread link structure & the value of the page. Google evaluates a link from page A to page B as a vote, by page A, for page B.So, you can say that they are mainly based on the backlinks. The pages that have better and high value page links will be considered as high pagerank webpage.  

What are backlinks? 

Backlinks are the incoming links to an website or webpage. Here Page A & Page B have backlinks. 

The life span of a Google query normally lasts less than half a second, yet involves a number of different steps that must be completed before results can be delivered to a person seeking information.

A Diagram from Google Group:

3. The search results are returned to the user in a fraction of a second.			1. The web server sends the query to the index servers. The content inside the index servers is similar to the index in the back of a book – it tells which pages contain the words that match the query.

	2.The query travels to the doc servers, which actually retrieve the stored documents. Snippets are generated to describe each search result.