100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
Previously searched by you
AQA A-Level Biology required practical 4: Investigation into the effect of a named variable on the permeability of cell-surface membranes£7.39
Add to cart
AQA A-Level Biology practical report with data and citations
required practical 4: Investigation into the effect of a named variable on the permeability of cell-surface membranes
4 The effect of a names variable on the permeability of the cell
membrane
The effect of alcohol concentration on the leakage of pigment from beetroot cells.
The cell membrane on the surface of a cell is made of several biological molecules
alongside the phospholipid bilayer, including proteins, carbohydrates and cholesterol. The
phospholipid bilayer causes the cell membrane to be selectively permeable which can be
affected depending on variables such as temperature and the concentration of solvents e.g
ethanol. In this experiment, permeability of a membrane is measured with beetroot cells
which contain betalain (a purple pigment). This means that at a higher permeability there will
be more betalain leakage, allowing us to measure permeability via a colorimeter.
The aim of this experiment is to investigate the effect of alcohol concentration on the
permeability of the cell membrane using beetroot cells.
IV: Alcohol concentration
DV: Leakage of pigment/permeability
Control variables and how they were controlled:
Temperature (can affect membrane permeability so needs to be controlled using a water
bath and measured regularly with a thermometer)
Volume of alcohol (measure the volume using a 5cm² syringe)
size of beetroot (need to be as close to the same size as possible-easier and more accurate
comparison- use a ruler when curing them with a scalpel)
Safety/precaution: Goggles, gloves, caution using scalpel and glass equipment and
hot/scalding water.
Results:
Label 0 2 4 6 8 10
Volume of 0 20 40 60 80 100
beetroot/
cm²
Volume of 100 80 60 40 20 0
water/cm²
%Concentratio 0 20 40 60 80 100
n of extract
Absorbance/ 0 0.37 0.63 0.95 1.30 1.97
colorimeter
What is meant by subjective results and quantitative results and what equipment is
required to gather these results?: Subjective results are based upon opinion and are often
biased. Quantitative results focuses on counting and classifying features using numerical
data and constructing statistical models and figures to explain what is observed, equipment
that allows you to gather measurements would be used.
Experiment
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller laibalsx. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £7.39. You're not tied to anything after your purchase.
