Digestive System Overview and Enzymes Quiz

Digestive System Overview

• The digestive system is a group of organs working together to process food
• Food is broken down into smaller, absorbable molecules
• These molecules are used for energy or to build other molecules

Alimentary Canal & Accessory Organs

• The alimentary canal is the food passage from mouth to anus
• Digestion occurs within this canal
• Accessory organs produce digestive substances (enzymes, bile) - food doesn't pass through

Enzymes & Metabolism

• Digestive enzymes break down large food molecules
• Metabolism is the sum of all chemical reactions in an organism
• Enzymes are protein catalysts that speed up reactions
• Enzymes bind substrates at the active site, creating products
• Enzymes are not used up in the reaction

Temperature & pH Effects on Enzymes

• Enzyme shape is critical for function, especially at the active site
• Optimal temperature for human enzymes is around 37°C
• High temperatures denature enzymes by breaking bonds.
• pH affects enzyme structure
• Most enzymes have an optimum pH near 7
• Extreme pHs cause denaturation

Chemical Digestion - Carbohydrates

• Carbohydrates are large molecules broken down to simple sugars
• Carbohydrases break down these chains
• Amylase breaks down starch into maltose, then maltase breaks maltose into glucose.
• Amylase is produced in salivary glands, pancreas, and small intestine.

Chemical Digestion - Protein

• Proteases break proteins into amino acids
• Protein digestion occurs in stomach and small intestine
• Pepsin (stomach), and enzymes from the pancreas and small intestine contribute to protein breakdown

Chemical Digestion - Lipids

• Lipids are broken down and absorbed as smaller molecules.
• Lipids are broken down by other enzymes.

Products of Digestion

• Small molecules are absorbed into the bloodstream
• Glucose fuels cellular respiration
• Amino acids are used to build proteins
• Lipid digestion products are used to build cell membranes and hormones