This deep dive covers Enzyme Deficiency Disorders within Enzymes in Digestion for GCSE Biology. Enzyme structure and function, digestive enzymes, factors affecting enzyme activity, lock and key model, and practical investigations It is section 10 of 19 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Enzyme Deficiency Disorders
Lactose Intolerance
- Cause: Deficiency in lactase enzyme
- Normal function: Lactase breaks down lactose (milk sugar) → glucose + galactose
- Problem: Undigested lactose remains in intestine
- Symptoms: Bloating, diarrhea, gas, stomach cramps
- Treatment: Avoid dairy or take lactase supplements
- Prevalence: More common in adults (lactase production decreases with age)
Phenylketonuria (PKU)
- Cause: Deficiency in phenylalanine hydroxylase enzyme
- Normal function: Converts phenylalanine → tyrosine
- Problem: Phenylalanine builds up to toxic levels
- Symptoms: Intellectual disability, seizures, skin problems
- Treatment: Strict low-phenylalanine diet from birth
- Detection: Newborn screening (heel prick test)
Celiac Disease
- Cause: Immune reaction to gluten, damages intestinal villi
- Effect: Reduced enzyme production and absorption
- Symptoms: Diarrhea, weight loss, fatigue, nutrient deficiencies
- Treatment: Strict gluten-free diet
Practice questions for Enzymes in Digestion
What are enzymes?
Explain the effect of increasing temperature on enzyme activity.
Quick recall flashcards
What does lipase do?
Breaks down lipids (fats) into fatty acids and glycerol. Produced by pancreas, works in small intestine.
What is an enzyme?
A biological catalyst that speeds up chemical reactions by lowering activation energy. Enzymes are proteins with specific 3D shapes.