By David M. Merszenhorn, Senate Democrats and White House officials met on Monday evening to discuss how to merge the two versions of the Senate’s health care legislation,

 and Democratic aides said they were aiming to have a combined bill “mostly baked” by the end of this week.

Once the bills are melded, the Congressional Budget Office will be asked to develop a revised cost analysis, a task that will take several days. At that point, provided everything is in order, the majority leader, Harry Reid of Nevada, will look to start the floor debate.

In the meantime, Democrats are focused on resolving differences on five main issues:

THE PUBLIC OPTION The Senate health committee included in its bill a government-run insurance plan to compete with private insurers. The Finance Committee did not include a public option, and instead proposed the creation of private, nonprofit health cooperatives.

AFFORDABILITY Some Senate Democrats are worried that subsidies to help moderate-income Americans buy health insurance are still not generous enough.

A “CADILLAC” TAX The Finance Committee bill includes a proposed excise tax on high-cost, or “Cadillac,” health insurance policies. The health committee has no jurisdiction over taxes, but some senators are concerned that the tax will hit too many middle-class workers, especially members of labor unions.

AN EMPLOYER MANDATE The health committee requires most employers to provide health insurance or pay a penalty of $750 a year for each full-time employee. The Finance Committee requires employers to contribute toward subsidies for employees who do not get benefits or pay $400 per full-time employee per year, whichever is less.

OTHER SPENDING ITEMS The health committee bill includes authorization for spending on numerous programs including prevention and wellness. But President Obama’s goal of keeping the cost of the legislation to about $900 billion means that some of those proposals must be curtailed.