Cell Biology - Cell transport

Question 1

What is diffusion?

Answer 1

The spreading out of particles resulting in a net movement from an area of high to low concentration.

Question 2

What is a concentration gradient?

Answer 2

The difference in concentration between 2 areas.

Question 3

What factors affect the rate of diffusion?

Answer 3

• The concentration gradient = the steeper concentration gradient, the faster the rate of diffusion.
• The membrane surface area = the larger the membrane surface area, the faster the rate of diffusion.
• The temperature = the higher the temp, the faster the rate of diffusion.

Question 4

What is osmosis?

Answer 4

The diffusion of water from a dilute solution to a concentrated through a partially permeable membrane.

Question 5

Where does the water molecules move from and to?

Answer 5

Lower solute concentration area to an area of higher solute concentration.

Question 6

Does diffusion require energy?

Answer 6

No its a passive process.

Question 7

Does osmosis require energy?

Answer 7

No its a passive process.

Question 8

What is active transport?

Answer 8

The movement of particles from a dilute solution to a more concentrated solution using energy from respiration.

Question 9

How do the particles in active transport move?

Answer 9

Against the concentration gradient from an area of low to high concentration.

Question 10

Does active transport require energy?

Answer 10

Yes - using energy released from respiration.

Question 11

What are 2 examples of diffusion in humans?

Answer 11

• Urea diffuses from cells into the blood for excretion by the kidney.
• Nutrients in small intestine diffuse into blood in the capillaries through the villi.

Question 12

What are examples of diffusion in fish?

Answer 12

• Oxygen from water passing over the gills diffuses into the blood in the gill filaments.
• Carbon dioxide diffuses from blood in the gill filaments into the water.

Question 13

What are examples of diffusion in plants?

Answer 13

• Carbon dioxide and oxygen diffuse into the leaves through the stomata.

Question 14

What is an example of osmosis in fish?

Answer 14

Water moves from a dilute solution in the soil to a concentrated solution in the root hair cell.

Question 15

What is an example of active transport in humans?

Answer 15

It allows sugar molecules to be absorbed from the small intestine when the sugar concentration is higher in the blood than in the small intestine.

Question 16

What is an example of active transport in plants?

Answer 16

Used to absorb mineral ions into the root hair cells from more dilute solutions in the soil.

Question 17

Why is the villi in the small intestine adapted?

Answer 17

To absorb nutrients.

Question 18

What are the adaptations of the villi?

Answer 18

• Network of capillaries.
• Large surface area.
• Thin wall + one cell think.
• Good blood supply.

Question 19

Why is the alveoli in the lungs adapted?

Answer 19

For gas exchange.

Question 20

What are the adaptations of the alveoli?

Answer 20

• Network of capillaries provides a good blood supply.
• Large surface area.
• Moist.
• One cell thick.

Question 21

Why are fish gills adapted?

Answer 21

For gas exchange.

Question 22

What are the adaptations of fish gills?

Answer 22

Made of stacks of thin filaments with:

• Large surface area.
• A network of capillaries.

Question 23

Why are root hair cells adapted?

Answer 23

For the uptake of water and minerals.

Question 24

What are the adaptations of root hair cells?

Answer 24

• Lots of mitochondria to take in mineral ions by active transport.
• Large surface area.