AQA A-level BIOLOGY 7402/2 Paper 2 Question Paper & Mark scheme June 2023 VERIFIED100%.

AQA A-level BIOLOGY 7402/2 Paper 2 Question Paper & Mark scheme June 2023 VERIFIED100%. Chemical digestion - -Hydrolyses large, insoluble molecules What is digestion - -Physical breakdown Chemical digestion Physical breakdown - --Breakdown of food into absorbable nutrients - By teeth - Stomach muscles - increases SA What is the importance of digestion? - -Hydrolyses large food molecules into smaller molecules Which can move across cell membrane And be absorbed into the blood Oesphagus - -carries food from mouth to stomach. adapted for transport. made up of a thick muscular wall What is hydrolysis? - -Breaking bonds by adding water stomach - -muscular sac between the oesphagus and the small intestine where digestion of food begins produces enzymes ileum - -Part of small intestine Long muscular tube Enzymes from walls and glands digest food Inner walls folded for large SA (have microvilli) large intestine - -Absorbs water and forms feces Rectum - -stores feces Salivary glands - -Contain amylase to hyrdolyse starch into maltose Pancreas - -Pancreatic juice (hydrolyse proteins, lipids and starch) Why are different enzymes needed to catalyse the breakdown of carbohydrates, proteins and lipids? - - Enzymes are proteins with specific tertiary structures Active site complementary to a specific substrate Only specific substrate will bind to active site and form E-S complex Where is amylase produced? - -Pancreas, salivary glands and small intestine Where is amylase secreted? - -Mouth and small intestine What is amylase for - -Hyrdolyses alternate glycosidic bonds of starch molecule to produce maltose Where is maltase produced? - -(In the cell membrane of epithelial cells) Small intestine Maltose - -glucose + glucose Where is maltase secreted? - -Small intestine