Question 5:
Explain the processes that fat molecules undergo starting from the duodenum until it is finally used by body cells.
Answer:
• Lipid digestion begins in the duodenum.
• Bile salts produced by the liver emulsify fats into lipid droplets.
• Pancreas secretes pancreatic juice which contains lipase into the duodenum.
• Lipase hydrolyses lipid droplets to fatty acids and glycerol.
• Lipid + water → Glycerol + fatty acids
• Absorption of fatty acids and glycerol occurs in the small intestine.
• In the epithelial cells of villi, the condensation of fatty acid and glycerol forms lipid.
• Lipid droplets are absorbed into the lacteals of villi.
• Lipid is transported from the lacteal by the lymphatic system into the thoracic duct and finally enters the blood flow through the left subclavian vein.
• Assimilation occurs in the cells.
• Cells use lipids to form the complex compounds of the plasma membrane.
Explain the processes that fat molecules undergo starting from the duodenum until it is finally used by body cells.
Answer:
• Lipid digestion begins in the duodenum.
• Bile salts produced by the liver emulsify fats into lipid droplets.
• Pancreas secretes pancreatic juice which contains lipase into the duodenum.
• Lipase hydrolyses lipid droplets to fatty acids and glycerol.
• Lipid + water → Glycerol + fatty acids
• Absorption of fatty acids and glycerol occurs in the small intestine.
• In the epithelial cells of villi, the condensation of fatty acid and glycerol forms lipid.
• Lipid droplets are absorbed into the lacteals of villi.
• Lipid is transported from the lacteal by the lymphatic system into the thoracic duct and finally enters the blood flow through the left subclavian vein.
• Assimilation occurs in the cells.
• Cells use lipids to form the complex compounds of the plasma membrane.
Question 6:
A teenager had the following for his breakfast.
Explain what happens to the final digested products of his breakfast in his body cells.
Answer:
• Bread contains carbohydrate. The digestion of carbohydrate produces glucose.
• Glucose is transported to body cells and the liver to be oxidised during cellular respiration to yield energy.
• Excess glucose is converted into glycogen for storage.
• The final product of butter is fatty acids and glycerol.
• Lipid is oxidised to produce energy.
• Some of the lipids are stored in adipose tissues.
• The final product of proteins (egg and milk) is amino acids.
• Amino acids are carried to body cells for enzyme synthesis and repair of damaged tissues.
• Apple and milk provide vitamin and mineral salts.
• Vitamins such as vitamin B are used as cofactors. Generally, vitamins and mineral salts maintain optimum health.
• Apple also provides undigested fibre that facilitates defaecation.
A teenager had the following for his breakfast.
Explain what happens to the final digested products of his breakfast in his body cells.
Answer:
• Bread contains carbohydrate. The digestion of carbohydrate produces glucose.
• Glucose is transported to body cells and the liver to be oxidised during cellular respiration to yield energy.
• Excess glucose is converted into glycogen for storage.
• The final product of butter is fatty acids and glycerol.
• Lipid is oxidised to produce energy.
• Some of the lipids are stored in adipose tissues.
• The final product of proteins (egg and milk) is amino acids.
• Amino acids are carried to body cells for enzyme synthesis and repair of damaged tissues.
• Apple and milk provide vitamin and mineral salts.
• Vitamins such as vitamin B are used as cofactors. Generally, vitamins and mineral salts maintain optimum health.
• Apple also provides undigested fibre that facilitates defaecation.