BIOL 11000 Lecture Notes - Lecture 5: Facilitated Diffusion, Ion Transporter, Active Transport
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The table below shows the percent of each type of phospholipid fatty acid tail found in each type of the grass membranes on Oct. 2 and Dec. 8th. The first column in the table shows the length of the fatty acid tail and the number of double-bonds in the fatty acid. For example the fatty acid â16:0â would be a fatty acid that was 16 carbons long and had 0 double-bonds. The second and third columns show the percent of all phospholipid fatty acids that were of this type. For example, in grass collected on October 2nd, 23.9 % of the phospholipid fatty acids were 16 carbons long and had no double-bonds (16:0 type), and in the grass collected on Dec. 8th, 21.0 % of the phospholipid fatty acids were 16 carbons long and had no double-bonds (16:0 type).
| Fatty Acid composition of Phospholipids | October 2 | December 8 |
| % of phospholipids | % of phospholipids | |
| 16:0 | 23.9 | 21.0 |
| 16.1 | 0.4 | 0.7 |
| 18:0 | 0.8 | 0.4 |
| 18:1 | 9.6 | 6.1 |
| 18:2 | 34.4 | 38.6 |
| 18:3 | 30.2 | 32.4 |
| 20:0 | 0.7 | 0.7 |
A. For each date the grass was collected, calculate the total percent of phospholipid fatty acids that were saturated fatty acids and the total percent of phospholipid fatty acids that were unsaturated fatty acids.
B. Draw a column graph that shows the total percent of phospholipid fatty acids that were saturated for each date that grass was collected and the total percent of phospholipids that were unsaturated for each date that grass were collected.
C. Why are the % of saturated and unsaturated fatty acid tails on the phospholipids of the Oct 2nd collected grass and the Dec 8th collected grass not the same? Use your understanding of membrane fluidity to address why these percentages have changed during this time period.
D. During this experiment the concentration of cholesterol found in the membranes of the grass was also measured. On Oct. 2th the concentration of cholesterol was 1.10 umol/mg and on Dec. 8th the concentration of cholesterol was 1.22 umol/mg. Why did the concentration of cholesterol change? Use your understanding of membrane fluidity to address why these concentrations have changed during this time period.