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13 votes
Explain how active transport works in a cell

User Gero
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2 Answers

14 votes
14 votes

Answer: Active transport is the movement of a substance across a cell membrane against its concentration gradient; From a low to a high concentration.

Explanation:

There are two types of active transport:

1) Primary Active Transport - Primary active transport, also called direct active transport, directly uses energy to transport molecules across a membrane. Most of the enzymes that perform this type of transport are transmembrane ATPases. A primary ATPase universal to all life is the sodium-potassium pump, which helps to maintain the cell potential. Other sources of energy for Primary active transport are redox energy and photon energy (light). An example of primary active transport using Redox energy is the mitochondrial electron transport chain that uses the reduction energy of NADH to move protons across the inner mitochondrial membrane against their concentration gradient. An example of primary active transport using light energy are the proteins involved in photosynthesis that use the energy of photons to create a proton gradient across the thylakoid membrane and also to create reduction power in the form of NADPH.

Secondary Active Transport - In secondary active transport or co-transport, energy is used to transport molecules across a membrane; however, in contrast to primary active transport, there is no direct coupling of ATP; instead, the electrochemical potential difference created by pumping ions out of the cell is used. The two main forms of this are antiport and symport.

User Krishna Vyas
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11 votes
11 votes

Answer:

substances move against the concentration gradient, from an area of low concentration to an area of high concentration

Step-by-step explanation:

User Jeff Paulsen
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