A Level Science Kerboodle Biology Practical

TL;DR

This practical explores how temperature affects the permeability of cell membranes using beetroot and colorimetry.

Transcript

[Applause] there are various factors that can affect the permeability of cell membranes in this practical you will investigate the effect of temperature and measure the effects using colorimetry we're going to look at how temperature affects the permeability of membranes using beetroot the first thing that we need to do is we need to cut cause of b... Read More

Key Insights

• ✋ Permeability of cell membranes increases with higher temperatures.
• 🥏 Removing pigments from beetroot discs before the experiment avoids interference with the results.
• ❓ The experiment can be quantitatively analyzed using a colorimeter.
• ✋ The fluidity of the phospholipid bilayer and denaturation of proteins contribute to increased membrane permeability with higher temperatures.
• 😥 Other factors such as pH and solvents can also affect cell membrane permeability.
• 🎮 The experiment reinforces the importance of controlling experimental variables for accurate measurements.
• 😜 The results can be presented qualitatively by ranking the permeability or quantitatively using absorbance values.

Questions & Answers

Q: Why is it necessary to remove the pigments from the beetroot before conducting the experiment?

Removing the pigments ensures that the results are not biased by the presence of other substances that could interfere with the colorimetry measurements. By removing the pigments, we isolate the effect of temperature on membrane permeability.

Q: How does the experiment determine the permeability of cell membranes?

The experiment measures the absorbance of the liquid that leaks out of the beetroot discs. Higher absorbance indicates higher membrane permeability, as more pigment has leaked out due to disrupted cell membranes.

Q: What other factors, besides temperature, can affect cell membrane permeability?

Some factors that can affect cell membrane permeability include pH, solvents, concentration gradients, and the presence of certain ions or drugs. However, this experiment focuses solely on the effect of temperature.

Q: How does membrane permeability change with increasing temperature?

As temperature increases, the phospholipid bilayer of the cell membrane becomes more fluid and increases its permeability. Additionally, heat can cause proteins in the membrane to denature, further disrupting the membrane's integrity.

Summary & Key Takeaways

• The experiment involves cutting beetroot discs and removing the pigments that can affect the results.

• Test tubes with different temperatures are prepared, and beetroot discs are added to each test tube.

• After shaking and measuring the absorbance using a colorimeter, it is observed that membrane permeability increases with higher temperatures.