Cell Transport Mechanisms: Exploring Diffusion Osmosis and Active Transport

The video tutorial explains how substances enter and leave cells through the cell membrane via diffusion, osmosis, and active transport. It focuses on diffusion, describing how molecules move from high to low concentration areas, influenced by factors like temperature, distance, and surface area to volume ratio. The tutorial includes a practical demonstration using agar cubes to illustrate diffusion and surface area effects.

Which of the following is NOT a method by which substances enter and leave a cell?

• Photosynthesis

• Diffusion

• Osmosis

• Active transport

What is the primary driving force behind the movement of molecules in diffusion?

• Gravitational pull

• Kinetic energy

• Magnetic fields

• Electrical charge

How does an increase in temperature affect the rate of diffusion?

• It stops diffusion

• It increases the rate

• It has no effect

• It decreases the rate

Why do alveoli in the lungs have a high rate of diffusion?

• They are very large

• They have a short distance for gas exchange

• They have a thick membrane

• They are filled with liquid

What happens to the rate of diffusion when there is a high concentration gradient?

• It stops

• It increases

• It remains the same

• It decreases

Which organism relies heavily on diffusion due to its large surface area to volume ratio?

• Bacterium

• Elephant

• Human

• Whale

In the practical demonstration, what causes the phenolphthalein indicator to change color?

• Addition of water

• Increase in temperature

• Contact with acid

• Exposure to light

What is the surface area to volume ratio of a 2x2x2 cube?

• 1

• 2

• 3

• 4

Why does the one-centimeter cube lose its color faster in the practical demonstration?

• It has a higher surface area to volume ratio

• It is made of a different material

• It is placed in a stronger acid

• It is heated

What biological structure benefits from a large surface area to facilitate absorption?

• Flower

• Leaf

• Root hair

• Stem