YV4-cells-diffusion

• Biologie
• Middelbare school
• vwo
• Leerjaar 4

Cells & Osmosis

Diffusion

Describe what happens in the video

Diffusion

• Molecules move from a high to a low concentration
• The movement of molecules is random
• This is a form of passive transport, because the energy comes from the molecules themselves

Try to describe what happens using this new information

How does heat affect diffusion?

1. It has no effect
2. More heat means faster diffusion
3. More heat means slower diffusion

What is the effect of distance on diffusion?

The shorter the distance, the faster the molecules will have equal concentrations throughout the space

What is the effect of surface area on diffusion?

The bigger the surface area, the faster the molecules will be evenly distributed over the available area

What is the effect of concentration gradient on diffusion?

The bigger the difference in concentration, the faster diffusion will happen

Misconceptions with diffusion

• Molecules want the concentration to be equal/ try to make the concentrations equal. Molecules have no mind to think with, they move randomly
• Molecules stop moving after the concentrations are equal. Molecules never stop moving, but when concentrations are equal there are equal amounts of molecules moving in every direction.

What is diffusion?

1. The movement of particles from low concentration to high concentration.
2. The movement of particles from high concentration to low concentration.
3. Active movement of particles, requiring energy from respiration.

Which process is responsible for gas exchange in the lungs?

1. Diffusion
2. Osmosis
3. Active transport

What happens to the rate of diffusion as the temperature increases?

1. It decreases
2. It stays the same
3. It increases

What happens to the rate of diffusion as the surface area increases?

1. It increases
2. It decreases
3. It stays the same

What have multi-celled organisms developed in order to provide an increased surface area for gas exchange?

1. A nervous system.
2. A circulatory system.
3. An excretory system.

Why do large multicellular organisms need transport systems while simple unicellular organisms do not?

1. Large organisms have a much smaller surface area to volume ratio compared to smaller ones.
2. Diffusion does not work in large multicellular organisms.
3. Unicellular organisms have a much smaller surface area to volume ratio than multicellular organisms.

Learning Objective

- You can explain the process of diffusion.