Mechanical digestion of protein starts in the mouth with the break down of protein into smaller pieces aided by the biting and crushing action of teeth. Protein then travels to the stomach via the esophagus where chemical digestion starts. Cells lining the stomach secretes hydrochloric acid (HCL) and pepsinogen, a proenzyme into the stomach. Cells […]
The word gluconeogenesis means the creation (genesis) of glucose from new (neo) sources. Under normal circumstances, carbohydrates are broken down to release glucose. However, under special circumstances such as limited availability of carbohydrates, other molecules such as fatty acids, amino acids and pyruvate are converted to glucose. This is important for humans, as we store […]
During periods of fasting the pancreas secretes the hormone glucagon which tells the liver cells to breakdown glucose into its individual glucose molecules. Epinephrine, another hormone tells the muscle cells to do the same thing. Steps in Glycogenolysis Glycogen phosphorylase cleaves α (1, 4) bonds at the non-reducing ends of glucose chains and catalyze transfer […]
Not all the glucose that we eat are converted to energy. Some are converted to glycogen which is a complex carbohydrate with a similar structure to starch in plants. Glycogen can then be broken down to release glucose which is metabolized for energy. Glycogenesis (production of glycogen) is controlled by insulin. When there is enough […]
ATP Synthase is responsible for making ATP at the end of the electron transport chain. The enzyme consists of two major regions; F0 which sits across the membrane, and F1 that projects into the matrix of the mitochondria. The F0 region is where proteins enter via 12 c-subunits that rotate as they associate with protons […]
Following glycolysis, pyruvate moves from the cytosol to the matrix of the mitochondria where it reacts with coenzyme A (CoA) to form acetyl CoA. In the process, one molecule of NADH and one molecule of carbondioxide is produced for each pyruvate made. The process is called pyruvate oxidation of pyruvate decarboxylation 1 Pyruvate + 1 […]
