1.  A positive result for the starch test is a black or dark purple colour on the food by adding a few drops of iodine solution.  During a test for carbohydrates when the colour of the liquid within the test turns from blue to yellow/orange,  this indicates a positive result. In a lipids test, the food is positive when there is grease or a stain left on the paper.

2.  The starch molecule has building blocks of molecules comprised of monomers, specifically  glucose.


 3. The intensity of the color depends on the concentration of glucose present in the sample. For simple carbohydrates when heated turn to a red or orange solution.  Those that turn red after more than two minutes are probably complex starches and as such take longer to break down. The prolonged exposure to the heat causes the complex molecules to break down and react with the Benedict  solution to form a orange/red solution.

4.   Imagine eating a piece of bread. Once the bread has entered the mouth, the physical digestion of teeth breaking down your food begins. Salivary amylase produced by the salivary glands starts the chemical digestion. After this, the food forms into a bolus and once swallowed, travels down the esophagus. The epiglottis prevents food from traveling to the lungs, and peristalsis pushes the food down the esophagus by muscle contractions. The bolus travels to the cardiac sphincter, the opening at the top of the stomach, and pushes past this. In the stomach, a combination of HCL, pepsin, and mucus break down the food. By the time the stomach has finished churning and chemically attacking the food, very little solid material is left. The stomach contents consist of a very acidic liquid referred to as chyme. The salivary amylase is broken down and the digestion of starch is stopped. At the bottom of the stomach is the pyloric sphincter which squirts the chyme a bit at a time into the duodenum. Secretions from the liver, pancreas, and gall bladder squirt into the duodenum via the bile duct.

The inflow from the pancreas is far more complex. The pancreatic flui is rich in the buffered base sodium bicarbonate which neutralises the HCl from the stomach and makes the duodenum slightly basic. The pancreas also secretes a cocktail of enzymes

 that are responsible for most of the rest of the chemical digestion. From the there, the chyme moves to the small intestine and absorption of the glucose that have been broken down from Maltose which was started by Maltase. The chyme then passes to large intestine, then the rectum, and finally the anus. The absorption Of water and recovery is done by the colon.

 3.