FINISH active transport (4.1.3.3)

What is active transport?

Movement of substances from dilute solution to a more concentrated solution,

against the concentration gradient.

Does active transport require energy?

Yes — energy is transferred by respiration.

What is meant by “against the concentration gradient”?

Moving particles from low concentration to high concentration.

What type of transport is active transport?

Active process.

Why is active transport important?

allows cells to absorb substances,

even when concentration is lower outside the cell.

Memory trick Active =

needs energy.

comparing transport processes

What are the three transport processes?

• Diffusion,

• Osmosis,

• Active transport

Which transport process requires energy?

Active transport only.

Which process moves water only?

Osmosis.

Which process can move substances against the concentration gradient?

Active transport.

Which processes are passive?

• Diffusion Osmosis

What does passive mean?

Does not require energy.

active transport in plants

Why do root hair cells use active transport?

To absorb mineral ions from dilute soil.

Why can diffusion not always absorb mineral ions?

Sometimes concentration in soil is lower than inside root cells.

Which mineral ions are absorbed by active transport?

• Nitrate ions Magnesium ions

Why are nitrate ions important?

Needed to make proteins.

Why is magnesium important?

Needed to make chlorophyll.

root hair cell diagram

active transport in humans

Where does active transport happen in humans?

In the small intestine.

Why is active transport needed in the small intestine?

To absorb glucose into the blood when concentration is lower in the gut.

Why is glucose important?

Used in respiration to release energy.

What substances are absorbed by active transport in the gut?

• Glucose Amino acids Some ions

required practical link

What investigation is linked to active transport?

Root hair mineral uptake investigations.

What increases active transport rate?

• More respiration Higher oxygen supply Suitable temperature

Why does active transport slow if respiration slows?

Less energy becomes available.

higher level understanding

Why is active transport especially useful in multicellular organisms?

Cells can still obtain essential substances even when concentrations are low outside.

What organelle provides energy for active transport?

Mitochondria.

What process in mitochondria releases the energy?

Aerobic respiration.

common exam mistakes

remember : It moves from LOW → HIGH concentration.

remember : Always mention energy from respiration.

comparing diffusion, osmosis & active Transport

How is active transport different from diffusion?

• Diffusion moves particles high → low * Active transport moves low → high using energy

How is osmosis different from active transport?

• Osmosis moves water only Active transport moves dissolved substances using energy