"Several mobile apps makers are concerned about what the outcome of the merger means for them," he said, citing Kayak.com as an example.
Cleland also raised the issue of competition in the search field, a question the Texas attorney general is probing in an investigation of Google.
Google "is not an honest broker in search," Cleland said. It "hides multiple serious conflicts of interest."
He cited the falling popularity of MapQuest after Google started its own mapping application, which he said helped move MapQuest off the first page of search results to become an "also-ran."
"Don't ignore he blue whale in the antitrust space," he said.
"Thank you for adding some passion," Rep. Hank Johnson (D-Ga.), chairman of the subcommittee, said. He had urged in his opening remarks that the hearing not become "a forum for Google-bashing."
Ed Black of CCIA, an association that includes Google, refuted Cleland's point about the company burying the competition in its rankings. He said he went onto Google on Wednesday and searched for "mapping directions" and the top result was not Google.
He characterized the online market for content and applications online as highly competitive.
"Barriers to entry ... just aren't there," he said, noting that Facebook has surpassed Google in "time spent" domestically.
In fact, the tenor of Cleland's Google concerns may be singular to him, Black suggested.
"If Google came up with a cure for cancer, I'm sure Scott would find a reason that's bad for society," he said.
Richard Feinstein, director of the bureau of competition at the Federal Trade Commission (FTC), said Google is attracting competition challenges in part because it is so successful, a traditional pattern for large companies. The commission is "very much aware of Google's presence in many markets," he said.
"Taking a step back, I don't view it as our role to be focused on bashing any particular company, but to promote competition for the benefit of consumers and address clogs on competition wherever we find them," he said.
Lawmakers did not sound like they are on the brink of a heady antitrust push against Internet companies.
"Just because a company is big does not mean it is bad," Rep. Lamar Smith (R-Texas) said in a general remark. "Just because competitors complain about a practice does not mean it is anticompetitive."
The hearing is paused for a vote. GOP questioning starts when it resumes.