"Ka" at the end turns a sentence into a question, yes. You get a yes/no question, or you can swap in an interrogative pronoun if you like. This is ignoring pragmatics.
"Sen"... no. The closest is that present-tense polite (teineigo) forms of verbs change from -masu to -masen to make them negative. However, that's basically the only case that rule works. You also often end up changing the rest of the sentence, just like in English or other languages. For example, in English, indefinite pronouns will generally change when you negate, as the negative of "somebody is here" is "nobody is here", not "somebody is not here". And of course, being a natural language, it's full of exceptions (like how "everyone" doesn't follow the pattern of "everything", "every time", etc.)
"Sen"... no. The closest is that present-tense polite (teineigo) forms of verbs change from -masu to -masen to make them negative. However, that's basically the only case that rule works. You also often end up changing the rest of the sentence, just like in English or other languages. For example, in English, indefinite pronouns will generally change when you negate, as the negative of "somebody is here" is "nobody is here", not "somebody is not here". And of course, being a natural language, it's full of exceptions (like how "everyone" doesn't follow the pattern of "everything", "every time", etc.)