Preheat oven to 350° F. Butter a 9 x 5 inch loaf pan thoroughly on the sides and bottom of the pan. You can also line the bottom with parchment paper for easier removal later, but this is optional.
Grate zucchini and place in a colander lined with cheesecloth or several layers of paper towels. Bundle the zucchini up with the cheesecloth and give it a good couple of squeezes to eliminate excess water.
Combine drained zucchini, sugar, melted butter, eggs, yogurt, vanilla, and lemon juice in a large bowl.
In a separate bowl, whisk together flour, baking soda, baking powder, and salt.
Gently fold dry ingredients into zucchini mixture until no streaks of flour remain. Fold in chocolate chips.
Pour batter into prepared pan. Bake until toothpick inserted in center comes out clean, about 55-65 minutes. The best way to tell if a loaf cake is done is to take it's internal temperature with a meat thermometer - it should come to about 200° - 205° F.
Allow to cool at least 20 minutes before removing cake from pan. Cool cake completely before glazing.