Can I power TTL chips with an USB-powered MB102 board?
Standard USB ports can supply up to 5.25V but could be as low as 4.6V, which is slightly out of spec for TTL but should still work. The total output current should not exceed 100mA, if the goal is to 'just plain work' with whatever the remote student has available. Check the datasheets of all of the devices in the circuit, and add up all of the maximum load currents.