Personalized Biochemistry Cake Youth T-Shirt. Biochemistry is a piece of cake, unchewable, insoluble cake text with a slices of cake is a funny gift design for back to school. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.