"This is a cat."
Translation:To jest kot.
That's because to jest works this way.
I think that you can even say that kot is the subject of this sentence.
Why wouldn't 'ten jest kotem' be correct if ten is 'this' masculine, as is 'kot', please
That could be very specific circumstance- you point out to the specific person/animal and claim this one is the/a cat. Maybe you have litter of house cats and wildcats , and you point one and say' ten jest kotem", "a ten jest żbikiem".
"this is" usually translates to "to jest" These are usually translates to "to są", regardless of the gender of the noun.
also,"to in this sentence, and in the "noun is noun" sentences, makes grammar simpler, you use nominative after to.
Is the to conjugiation of to affected by the gender of the noun it's pointing to?
It "to" is in "this is" sentences, then no "to" is always "to". also "noun is noun" sentences. ( To here never changes and the nouns stay in nominative case)
If it's the cat=this cat/that cat then yes it's ten kot (this cat, masculine word), ta kotka (this female cat-feminine word), to kociątko (this kitten, neuter word).
To here changes with gender, number and case. wiktonary