Is a kilo a 1000 grams?

Yes, both are different ways of saying "kilogram" The Word "kilo" also means 1000, therefore a kilogram is 1000 grams, a kilometer (KM) is 1000 meters, a kilobyte (KB) is 1000 bytes, etc. however when used on it's own, as in "get me a kilo of sugar" it usually refers to grams/weight.