GCSE Biology (AQA)
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Active Transport in the Gut
- Cells require some substances in large quantities, making diffusion insufficient.
- Glucose, essential for cell respiration, is an example of such a substance.
- Active transport is crucial for glucose absorption in the small intestine.
- The inner space of the intestine is called the lumen, with projections known as villi that are close to the blood supply.
- Post a sugary meal, glucose concentration might be higher in the lumen than in intestinal cells and blood, allowing diffusion down the concentration gradient.
- At times, glucose concentration in the lumen is lower than in cells, necessitating movement against the concentration gradient via active transport.
- Active transport, unlike diffusion and osmosis, requires energy, as it moves substances against the concentration gradient.
- Understanding the mechanism of sugar absorption by active transport in the gut is important for exams.
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