Active Movement Across Membranes
Biology: IB Diploma Higher Level, topic 6.1.2
Active Transport in Humans and Plants
Active transport uses energy and is in charge of moving ions and molecules across a membrane against the concentration gradient.
Carrier proteins
- An important membrane adaption for active transport is the presence of specific carrier proteins to facilitate movement.
Sugar absorption in the gut
- One example of active transport is sugar (glucose) absorption in the gut.
- Active transport allows glucose molecules, which are needed for cell respiration, to be absorbed into the blood from the gut, even when the glucose concentration of the blood is higher.
Mineral absorption in plants
- Another example of active transport is mineral absorption in plants.
- Active transport in the root hairs of plants allows plants to absorb mineral ions, which are necessary for healthy growth, even though the concentration of minerals is usually lower in the soil than in the root hair.
Rate of active transport
- The main factors that affect the rate of active transport are:
- The surface area of cell membranes.
- The number of carrier proteins in cell membranes.
Test yourself on Active Movement Across Membranes
Which of the following processes does NOT happen via active transport?