At first glance, it seems that Adwords do not directly affect or improve your page rank. This is because your clickthroughs are not organic- they are bought and users are directed to your site via Adwords. For a better page ranking, you should focus your efforts on optimising your content for search engine results instead.
However, Adwords can help page ranking. In an indirect manner. In reality, all your online marketing efforts are interconnected. The results of your SEO marketing efforts can combine with those of your offline marketing strategies, and all these can also be augmented by your Adwords campaigns as well. You may hence experience a positive collective effect on all fronts if your marketing campaigns are successful. As the clickthrough rate increases for your site via Adwords, your organic web traffic may also increase, and page ranking is therefore improved over time as well.
The adage is true-every little effort counts. However, you need to build a strong foundation so as to enjoy this multiplier effect, which will amplify your already good web traffic results into great page ranking achievements. This is why getting every segment of your marketing mix is crucial when you are dealing with page rank.