Topic Three (1.3): Movement In and Out of Cells
This topic focuses on ways in which different molecules move in and out of cells. Learning definitions and key points are essential for this topic.
To begin, learn the definition for diffusion and the role of kinetic energy in diffusion. You will need to be able to describe and explain how diffusion is affected by surface area, temperature, concentration gradients, and diffusion distances.
The next area is osmosis. Define osmosis and understand that it is only related to water. It is important that you refer to water potential, rather than importance of osmosis to living organisms, particularly when referring to plants"
You may be asked to apply this knowledge to unfamiliar situations in exam questions. Remember to always state the direction of water movement in relation to water potential.
Reading
Please read through and make notes on pages 10-20 in the textbook. Complete the in-text questions and check your answers. Alternatives are given to the activities (below).
Links
EXPLORE - Transport Across Cell Membranes (Twig) Links to an external site.
EXPLORE - Diffusion Definition (Twig) Links to an external site.
EXPLORE - Osmosis Definition (Twig) Links to an external site.
EXPLORE - Osmosis & Volume (Twig) Links to an external site.
WATCH - Amoeba Sisters: Osmosis (YouTube) Links to an external site.
Download
Download and read through the PowerPoint Movement in and Out of Cells Download Movement in and Out of Cells.
Practical
Please complete the Osmosis Practical Download Osmosis Practical, ‘Investigating how the Concentration of Solution Affects Potato Pieces’. Please remember to review the safety guide Download safety guide. Complete the data table and draw a graph of your results. Answer the Conclusion and Discussion Questions for this practical.
Skills
Representing Osmosis Data in a Graph. You need to be able to graph data from osmosis experiments. These graphs are always line graphs. They have both positive and negative values. When drawing your line ensure that you do not extrapolate beyond the plots. The value where the line intersects the axis is the value when net osmosis is zero and the water potentials are equal.
Example:
Review
Complete Questions on Diffusion and Osmosis on page 17-20. Check your answers.