Immobilised enzymes and where enzymes work
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The teaching part (1 min) is free to watch. A free account opens the whole lecture: 4 practice questions, 2 real past-paper questions with the answers explained, the mistakes that lose marks, the full-marks tip, a one-card summary and a quick quiz.
What this lecture covers
- Enzymes at work in the factory
- Where enzymes act
Read the transcript of the teaching part
Last time
Before we start: last time, in Enzyme inhibitors, Vmax and Km, you learned these points. Here they are again on one card. Keep them in mind, because today builds on them.
Enzymes at work in the factory
Making lactose free milk needs an enzyme called lactase. Throw the enzyme into the milk, and you can never get it back, and it ends up in the product. Fix the enzyme to beads instead, and you can pour the milk past it again and again. That idea is called immobilisation.
Where enzymes act
An intracellular enzyme is made and works inside the cell. Catalase, and the enzymes of glycolysis and the Krebs cycle, are intracellular. An extracellular enzyme is made inside the cell but released to work outside it. Digestive enzymes such as amylase and trypsin are extracellular. Extracellular enzymes digest large molecules into small ones that can be absorbed. Examples are in the gut lumen, and in fungi digesting dead material.
Chapter 3: Enzymes
- Enzyme action, the factors and progress curves 6 min
- Enzyme inhibitors, Vmax and Km 6 min
- Immobilised enzymes and where enzymes work 6 min
Also for A Level Biology 9700
Which topics come up most in A Level Biology 9700 past papers, counted from every paper since 2004: Paper 1 topic frequency, Paper 2 topic frequency, Paper 4 topic frequency.