7.3

Physical digestion

Cambridge IGCSE Biology (0610)  · Unit 7: Human nutrition  · 10 flashcards

Physical digestion is topic 7.3 in the Cambridge IGCSE Biology (0610) syllabus , positioned in Unit 7 — Human nutrition , alongside Diet, Digestive system and Chemical digestion.  In one line: Physical digestion is the breakdown of food into smaller pieces without any chemical changes to the food molecules themselves. An example is chewing food in the mouth.

This topic is examined in Paper 1 (multiple-choice) and Papers 3/4 (theory), plus Paper 5 or Paper 6 (practical / alternative to practical).

The deck below contains 10 flashcards — 2 definitions, 6 key concepts and 2 identification cards — covering the precise wording mark schemes reward.  Use the 2 definition cards to lock down command-word answers (define, state), then move on to the concept and application cards to handle explain, describe and compare questions.

Key definition

Physical digestion

Physical digestion is the breakdown of food into smaller pieces without any chemical changes to the food molecules themselves. An example is chewing food in the mouth.

What the Cambridge 0610 syllabus says

Official 2026-2028 spec

These are the exact learning objectives Cambridge sets for this topic. Match the command word (Describe, Explain, State, etc.) in your answer to score full marks.

  1. Describe Describe physical digestion as the breakdown of food into smaller pieces without chemical change to the food molecules
  2. State State that physical digestion increases the surface area of food for the action of enzymes in chemical digestion
  3. Identify Identify in diagrams and images the types of human teeth: incisors, canines, premolars and molars
  4. Describe Describe the structure of human teeth, limited to: enamel, dentine, pulp, nerves, blood vessels and cement, and understand that teeth are embedded in bone and the gums
  5. Describe Describe the functions of the types of human teeth in physical digestion of food
  6. Describe Describe the function of the stomach in physical digestion
  7. Outline Outline the role of bile in emulsifying fats and oils to increase the surface area for chemical digestion Supplement
Definition Flip

What is physical digestion?

Answer Flip

Physical digestion is the breakdown of food into smaller pieces without any chemical changes to the food molecules themselves. An example is chewing food in the mouth.

Key Concept Flip

How does physical digestion aid chemical digestion?

Answer Flip

Physical digestion increases the surface area of food particles. This larger surface area allows digestive enzymes to act more effectively during chemical digestion.

Example: bile emulsifies fats into smaller droplets.
Key Concept Flip

Name the four types of human teeth.

Answer Flip

The four types of human teeth are incisors, canines, premolars, and molars. Each type is adapted for a specific function in physical digestion.

Key Concept Flip

List the main structures of a human tooth.

Answer Flip

A human tooth consists of enamel, dentine, pulp (containing nerves and blood vessels), cement, and is embedded in the jaw bone and gums. Enamel is the hardest outermost layer protecting the tooth.

Key Concept Flip

What is the function of incisors?

Answer Flip

Incisors are chisel-shaped teeth located at the front of the mouth. Their primary function is for biting and cutting food into smaller pieces.

Example: biting into an apple.
Key Concept Flip

What is the function of canines?

Answer Flip

Canines are cone-shaped teeth located next to the incisors. Their main function is tearing and gripping food.

Example: tearing meat.
Key Concept Flip

What is the function of premolars and molars?

Answer Flip

Premolars and molars are located at the back of the mouth and have broad, flat surfaces. They are used for grinding and crushing food into smaller particles, increasing the surface area for enzyme action.

Example: Chewing grains.
Key Concept Flip

What is the role of the stomach in physical digestion?

Answer Flip

The stomach's muscular walls contract and relax to churn food, mixing it with gastric juices and breaking it down physically. This churning action helps to increase the surface area of the food.

Example: mixing food into chyme.
Definition Flip

What is emulsification, and why is it important?

Answer Flip

Emulsification is the process of breaking down large fat globules into smaller droplets, increasing the surface area for lipase enzymes to act upon. Bile, produced by the liver, is essential for emulsifying fats in the small intestine.

Key Concept Flip

Describe the role of bile in fat digestion.

Answer Flip

Bile emulsifies fats and oils into smaller droplets. This increases the surface area of the fats, allowing for more efficient digestion by lipase, an enzyme that breaks down fats.

Example: Fat digestion in the duodenum.

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7.2 Digestive system 7.4 Chemical digestion

Key Questions: Physical digestion

What is physical digestion?

Physical digestion is the breakdown of food into smaller pieces without any chemical changes to the food molecules themselves. An example is chewing food in the mouth.

What is emulsification, and why is it important?

Emulsification is the process of breaking down large fat globules into smaller droplets, increasing the surface area for lipase enzymes to act upon. Bile, produced by the liver, is essential for emulsifying fats in the small intestine.

More topics in Unit 7 — Human nutrition

Physical digestion sits alongside these Biology decks in the same syllabus unit. Each uses the same spaced-repetition system, so progress in one informs the next.

7.1 Diet

12 flashcards
7.2 Digestive system

13 flashcards
7.4 Chemical digestion

10 flashcards
7.5 Absorption

11 flashcards

Cambridge syllabus keywords to use in your answers

These are the official Cambridge 0610 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.

physical digestion chemical digestion mechanical digestion teeth chewing churning bile emulsification amylase protease lipase pepsin trypsin hydrochloric acid

Key terms covered in this Physical digestion deck

Every term below is defined in the flashcards above. Use the list as a quick recall test before your exam — if you can't define one of these in your own words, flip back to that card.

Physical digestion
Emulsification, and why is it important

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How to study this Physical digestion deck

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