AP BIOLOGY

Detailed explanation-1: -The majority of chemical digestion occurs in the small intestine. Digested chyme from the stomach passes through the pylorus and into the duodenum. Here, chyme will mix with secretions from both the pancreas and the duodenum. Mechanical digestion will still occur to a minor extent as well.

Detailed explanation-2: -Most mechanical and some chemical digestion occur in the stomach. Mechanical digestion occurs as layers of muscle in the stomach lining contract to produce a mixing and churning motion. Chemical digestion is carried out by stomach juices that contain enzymes and hydrochloric acid.

Detailed explanation-3: -Both mechanical and chemical digestion occur in the mouth. Teeth grind and break up food (mechanical), while an enzyme in saliva called amylase begins to break down carbohydrates (chemical). After it is swallowed, the chewed food (now called a bolus) moves down the esophagus.

Detailed explanation-4: -Chemical digestion, through a process called hydrolysis, uses water and digestive enzymes to break down the complex molecules. Digestive enzymes speed up the hydrolysis process, which is otherwise very slow.

Detailed explanation-5: -Mechanical digestion is a purely physical process that does not change the chemical nature of the food. Instead, it makes the food smaller to increase both surface area and mobility. It includes mastication, or chewing, as well as tongue movements that help break food into smaller bits and mix food with saliva.