These distinctive enzymes function in different ways.
Answer: Insulin does not play a role in the uptake of glucose in the liver but it has other effects. It increases the synthesis of fatty acids, glycogen and protein synthesis. On the other hand it decreases gycogenolysis and the formation of ketone bodies by the liver.
Answer: The digestion of lipids starts in the mouth where it is acted upon by lingual lipase. In the stomach the action of gastric lipase begins. These two lipases are not great contributors in the digestion of lipids and they act mainly on short to medium chain fatty acids which include the milk fats. Small intestine is the main site where lipid digestion takes place. This occurs with the help of pancreatic lipase, phospholipase A2 and cholesterol esterase. The bile salts also play a role in digestion by emulsification which is the breakdown of large fat droplets in to small ones so that the enzymes have a larger surface area to carry out their function.
Answer: Transport of glucose in the small intestine is associated with sodium ions. The sodium ions and glucose share the same transporter and the transport of glucose occurs by cotransport with sodium and is referred to as secondary active transport. The concentration of the sodium in the intestinal cells is low. This causes the movement of sodium in the cells and hence the movement of glucose as it is transported with the sodium ions. The glucose is then moved across the interstitium into the capillaries whereas the sodium ions move into intercellular spaces. The provision of energy for this process is indirect by the active transport of sodium out of the cell. This is the reason why this transport of glucose is referred to as secondary active