Beta radiation consists of high energy electrons emitted from the nucleus. These electrons have not come from the electron shells or energy levels around the nucleus. Instead, they form when a neutron splits into a proton and an electron. The electron then shoots out of the nucleus at high speed, leaving the new proton behind in the nucleus.
Gamma radiation is very short wavelength, high frequency electromagnetic radiation. This is similar to other types of electromagnetic radiation, such as visible light and X-rays, which can travel long distances.