What is alternative? Picking strictly down and up the string. Pick up your pick with your first finger (index) and thumb, and picking down and up with slow movement. You can try to give a little angle to your pick for smoothier playing.
metronome for beginners: 60-150
metronome for others: up to 180
If you're new to this kind of exercises, that will take a few days to adjust, you can start playing two notes per beat. Such lick is very common in rock and metal.
metronome for beginners: 60-100
metronome for others: up to 140
Just be careful in the last beat and accurate. You will learn to change tempo as you play.
metronome for beginners: 60-100
metronome for others: up to 160
metronome for beginners: 60-100
metronome for others: up to 160