In the food industry, bacteria are used to produce yogurt, cheese, pickles, and sauerkraut.

Many use flagella for movement or pili to adhere to surfaces or exchange genetic material. 2. Reproduction and Growth

Scientists use a Gram stain to classify them. Gram-positive bacteria have a thick peptidoglycan layer that retains purple dye, while Gram-negative bacteria have a thinner layer and an outer membrane, appearing pink.