A small team has toiled since early October in a quiet corner of Google Inc.’s sprawling campus in Mountain View, Calif., on a project related to the discovery of human antibodies.

The group is not part of Google and has nothing to do with Google’s flagship Internet search business.

But Google has provided the team — part of the secretive New Hampshire-based biotech company Adimab — with a workspace fitted with top-notch amenities, including high-speed Internet access, conference rooms, even a Ping-Pong table.

Adimab and four other companies are among the first tenants of the new Startup Lab managed by Google’s venture capital arm.

The lab represents the latest expansion of Google Ventures, the search engine’s $100-million-a-year fund launched in March 2009, providing Google with an opportunity to chase the big financial payoffs that can come with venture investing while helping it build ties to the fast-paced world of start-ups.

The on-campus lab is designed to let young companies funded by Google Ventures draw from the deep well of resources within the world’s No. 1 Internet search company. Google staffers offer tips on anything from product design to recruiting, while  providing the startups with a  Silicon Valley presence, said Bill Maris, managing partner of Google Ventures, in an interview at Google’s headquarters this month.

And with growing competition to fund the youngest, early-stage startup companies, Google Ventures wants to set itself apart from other venture firms and angel investors.

“We plan to be very active in 2011 in the seed space,” said Maris, referring to the funding of early-stage companies. “Startup Lab is an expression of that interest.”

The 15,000-square-foot facility can accommodate 100 to 120 people and includes  equipment that Maris and Google Ventures Partner David Krane pulled together over the summer. The pair found a vacant building owned by Google and furnished it with desks from Google’s acquisition of mobile ad firm AdMob.

The lab’s 1-gigabyte broadband network is separate from Google’s network so it can provide a layer of separation and privacy for the labs’ tenants.

In addition to the five startups that use the lab, Google entrepreneur-in-residence Craig Walker, the former group product manager of Google Voice, has also set up shop with a small team as he develops a new company.

“We wanted to have a place where someone like Craig, or other talented entrepreneurs — maybe they don’t even have a company yet — they just want a place to work,” said Maris. At this point, Google Ventures does not plan to bring on further EIRs into the Startup Lab.

The lab’s opening comes as Google’s domination of the Web faces challenges from smaller rivals, like social networking companies Facebook and Twitter. Over the past year, several of Google’s top engineers and executives have defected to Facebook. One such defector, Google Maps co-creator Lars Rasmussen, said in a newspaper interview that it can be “very challenging” to work at a company the size of Google.

The Startup Lab underscores how Google, which has more than 23,000 employees worldwide, is seeking to wield its size as an asset to help it forge ties with entrepreneurs and startups.