Intracellular & Extracellular enzymes

• Catalase is..

  -an intracellular enzyme
• What is the role of catalase

  -hydrogen peroxide is a toxic byproduct of metabloism

  -catalase ensures it is broken down into oxygen and water to prevent its accumulation

  -found in both animal and plant tissue
• What is a substrate also known as

  -raw material
• what supplies substrates/raw materials

  -nutrients
• what are nutrients often in the form of

  -polymers e.g proteins and polysaccharides
• Why can nutrients not enter cells via the cell surface membrane

  -they are polymers and therefore too large to enter directly
• How do nutrients get broken down into smaller components

  -enzymes that are extracellular are released from cells to break down these large nutrient molecules into smaller components in the process of DIGESTION
• Where is starch digested

  -begins in mouth continues in the small intestine
• What is step 1 of starch digestion

  -starch polymers are broken down by amylase into the disaccharide maltose
• where is amylase produced

  -by salivary glands and pancreas

  -released in saliva in mouth and in pancreatic juice in the small intestine
• what is step 2 of starch digestion

  -maltose is broken down by maltase into monosaccharide glucose

  -maltase is found in the small intestine

  -Glucose is small enough to be absorbed by cells lining digestive system and is absorbed into blood stream
• How are proteins digested

  -by trypsin which is a protease

  -breaks down proteins into peptides which are broken down into smaller amino acids
• Where is trypsin produced

  -in the pancreas and released with pancreatic juice into small intestine to act on proteins

  -amino acids are absorbed by cells lining digestive system and absorbed into bloodstream
• What are some examples of proteases

  -endopeptidases

  -exopeptidases

  -dipeptides