Biochem question and answer Assignment Example | Topics and Well Written Essays - 250 words

Biochem question and answer - Assignment Example Milk proteins are digested in the stomach and duodenum by proteolytic enzymes into peptides and finally amino acids that are absorbed in the small intestines. Bile salts emulsify fats after which pancreatic lipase breaks them into fatty acids and glycerol molecules that are absorbed in the ileum. The sucrose is broken down into glucose and fructose in the duodenum by enzyme sucrase, and the monosaccharides are absorbed in the ileum (Digestion and absorption, n.d.). Apples and carrots contain vitamins and mineral salts, which do not undergo digestion, but are directly absorbed into the small intestines. Oxidative phosphorylation is a metabolic pathway, which utilizes energy from the oxidation of food to produce ATP. All the electrons from NADH and FADH2 go to the oxidative phosphorylation cycle following release from the TCA cycle. Oxidative phosphorylation takes electrons from these molecules and transfers them to oxygen, making ATP in the process. This process occurs in the mitochondria. NADH and FADH2 are oxidized into NAD+ and FAD, whereas oxygen is reduced by H+ ions into water. NAD-linked dehydrogenases remove electrons from substrates to NAD in reversible reactions. The malate-aspartate shuttle or the alpha-glycerol phosphate shuttle conveys electrons from NADH outside the mitochondria (the two complexes involved in the process). Blood supplies oxygen to the process. A specific translocase exchanges ADP outside the mitochondria for ATP inside the mitochondria. The end products are water, ATP, and NAD+ or FAD. Cyanide, azide, and CO are metabolic poisons, which are so toxic t o us because they block the transfer of electrons to oxygen hence inhibiting the whole process (Gilbert,