Gravity affects quarks and leptons in the same way it affects any other particles with mass. According to the theory of general relativity, gravity is the curvature of spacetime caused by the presence of mass and energy. All particles with mass, including quarks and leptons, interact with this curved spacetime and are subject to gravitational forces.
Quarks and leptons are elementary particles that make up matter. Quarks are the building blocks of protons and neutrons, which in turn make up atomic nuclei. Leptons include particles like electrons and neutrinos. These particles have mass, and therefore, they experience gravitational attraction.
The gravitational force between two particles is determined by their masses and the distance between them. In the case of quarks and leptons, their masses are extremely small compared to other particles, such as massive stars or planets. As a result, the gravitational force between individual quarks and leptons is typically negligible in everyday situations.
However, on larger scales or in the presence of extremely massive objects like black holes, the effects of gravity can become significant even for these tiny particles. For example, in the vicinity of a black hole, the strong gravitational field can cause spacetime to be highly curved, leading to extreme phenomena like time dilation and the bending of light.
It's worth noting that our current understanding of gravity comes from general relativity, which describes gravity as a geometric property of spacetime. However, efforts are underway in physics to develop a more fundamental theory, such as a quantum theory of gravity, that could provide a more complete understanding of how gravity interacts with elementary particles at the quantum level.