Active transport / uptake

 

Movement of Minerals across Root Hair Cells by Active Transport.

 

Up take of minerals by the root hair cell is very important for a plant's growth.  However, it does not always uses diffusion.  Plant root hair cells are specialised cells.  They grow into long thin 'hair', giving the plant a large surface to absorb minerals and water.   

 

When the concentration of minerals is higher in the root hair cell than the  surrounding soil, it is unable to absorb these using diffusion.  The plant instead uses a method called ACTIVE TRANSPORT for absorption.  This uptake of minerals is against the concentration gradient and the plant has to spend energy to do this.  The energy used come from respiration.

 

Active transport also happens in animals.  For example, in humans the uptake of glucose from the gut and from the kidney tubules. See below!

Animation of root hair cell absorbing minerals.

 

 

After a large meal, your gut has lots (high concentration) of amino acids, fatty acids, glycerol and glucose.  These get absorbed into the blood stream by simple diffusion.  However, when there are less (low concentration) nutrients in the gut then in the blood and your body needs them, these are then absorbed by active transport.

 

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Osmosis

 

⚡ Knowledge Check: Active Transport

Think you’ve mastered how cells pump substances? Try these 5 questions!

1. Active transport moves substances from an area of ________ concentration to an area of ________ concentration.

• High to Low (down the gradient)
• Low to High (against the gradient)
• Equal to Equal (no gradient)

2. Which of the following is required for active transport to occur?

• Energy from respiration
• Sunlight
• Gravity

3. Root hair cells use active transport to absorb which of these from the soil?

• Water molecules
• Mineral ions (like nitrates)
• Oxygen gas

4. Where is glucose absorbed into the blood via active transport in humans?

• The lungs
• The small intestine
• The stomach

5. Which structure in the cell membrane acts as a "pump" for active transport?

• Lipid layer
• Carrier proteins
• Cell wall

Check Your Answers

1. Low to High (This is why it's called 'active'—it takes effort!)
2. Energy from respiration (Usually in the form of ATP).
3. Mineral ions (Water moves via osmosis, but minerals often need a pump).
4. The small intestine (To ensure no nutrients are wasted).
5. Carrier proteins (They change shape to move the substance across).

Tags:Active transport, Uptake, Diffusion