Describe the human digestive system as a complex organ system where multiple organs work cooperatively to digest and absorb food.
Describe the nature of biological enzyme molecules and explain how external changes in temperature and pH fundamentally affect their catalytic activity.
Carry out accurate rate calculations for chemical reactions catalysed by enzymes.
Explain how enzymes catalyse specific biological reactions in living organisms due to the unique complementary shape of their active site.
Apply the 'lock and key theory' as a simplified model to correctly illustrate and explain enzyme action.
Identify the primary production sites and describe the specific catalytic actions of amylase, proteases, and lipases within the body.
Understand simple word equations representing these digestive processes.
Explain how digestive enzymes actively convert complex food into small, soluble molecules for ready absorption into the bloodstream.
Describe how carbohydrases break down carbohydrates into simple sugars, highlighting amylase as a specific carbohydrase that breaks down starch.
Describe how proteases break down complex proteins into amino acids.
Describe how lipases break down lipids (fats) into glycerol and fatty acids.
Understand that the end products of digestion are used by the body to build new carbohydrates, lipids, and proteins, with some glucose being allocated for cellular respiration.
Describe the production of bile in the liver and its subsequent storage in the gall bladder.
Explain the critical dual role of bile: neutralising hydrochloric acid from the stomach to provide optimal alkaline conditions, and emulsifying fats into small droplets to increase surface area, thereby increasing the rate of fat breakdown by lipase.
Use qualitative reagents in a laboratory setting to test for carbohydrates, lipids, and proteins, specifically including Benedict’s test for sugars, the iodine test for starch, and Biuret reagent for protein.
Investigate the effect of pH on the rate of reaction of amylase using a continuous sampling technique while carefully controlling temperature using a water bath or electric heater.
