Learn German: Ist die Tasche hier?

In German, just like in English, you form a yes/no question by putting the verb at the very beginning of the sentence. The statement would be Die Tasche ist hier (The bag is here), so swapping the first two words gives us the question Ist die Tasche hier?.

How do I know the gender of Tasche from this sentence?

The word die right before it gives it away! Die is the definite article (the word for "the") used with feminine nouns, so we know Tasche is a feminine noun.

If I wanted to answer this by saying "No, there is no bag here," how would I use the negative article from this lesson?

You could say Nein, hier ist keine Tasche. Because Tasche is feminine, you must use keine instead of kein to say "no bag" or "not a bag".

Why is Tasche capitalized in the middle of the sentence?

In German, every single noun (a person, place, concept, or thing) is always capitalized, no matter where it appears in the sentence. Since Tasche (bag) is a physical thing, it gets a capital T!