Food passing into the duodenum causes the production of secretin, which in turn promotes release of alkaline secretions from the pancreas, stops further passage of food into the intestine until the acid is neutralized. Glucose Metabolism Glucose levels in the blood remain fairly stable. The liver absorbs glucose from the blood and stores it as the polysaccharide glycogen. Blood glucose levels are maintained between meals by releasing glucose from glycogen back into the blood. Phototrophs convert sunlight energy into sugar or other organic molecules.
Heterotrophs eat to obtain energy from the breakdown of organic molecules in their food.
Macronutrients are foods required on a large scale each day. These include carbohydrates, lipids, and amino acids. Water is essential, correct water balance is a must for proper functioning of the body. The diet should contain at least 100 grams of carbohydrate every day. Proteins are polymers composed of amino acids.