Topic 5 Digestive System: Intracellular vs Extracellular Digestion

Question 1

• Occurs before excretion

- Animals have 4 main feeding mechanisms: filter feeding, substrate feeding, fluid feeding, and bulk feeding

Answer 1

Digestive System

Question 2

• Takes place within cells and occurs in amoeba, paramecium, and porifera
• Food is usually phagocytized and fuses with food vacuoles and lysosomes to break down nutrients

Answer 2

1. Intracellular Digestion

Question 3

• Takes place outside cells usually in food compartment continuous with animal’s body
• Note that Platyhelminthes and Cnidaria, which have two-way gastrovascular cavities rather than one-way canals, use a combination of extracellular (enzymes secreted into gastrovascular cavity, food broken down) and intracellular (food particles engulfed and digested in food vacuoles)

Answer 3

2. Extracellular Digestion