Digestion, enzymes and absorption
≈ 48 minDigestion, enzymes and absorption
Digestion breaks large food molecules into small soluble molecules that can cross absorption surfaces. Mechanical digestion increases surface area; chemical digestion uses enzymes. Enzymes have active sites with shapes suited to specific substrates, and their activity is affected by temperature and pH. Most nutrient absorption occurs in the small intestine, whose folds, villi and microvilli create a large surface area and short diffusion path.
Work it through
Amylase begins starch digestion. If food is chewed, it is broken into smaller pieces, increasing contact with enzymes. In the small intestine, glucose molecules cross the thin villus surface into blood for transport to cells.
Mastery target
Connect mechanical digestion, enzyme specificity and villus structure to efficient nutrient uptake.
Why is the small intestine efficient at absorption?
Name the key biological term from Digestion, enzymes and absorption: enter the term that best fits the explanation and visual model.
Why can very high temperature reduce enzyme activity?
Which statement corrects a common misunderstanding in Digestion, enzymes and absorption?