Shiang Chen Ting (24) Sec 313
Introduction
The aim of this experiment is to explore the factors which affect the movement of materials in and out of the cells. The dark red or purple colour of Beetroots is caused by a pigment called betalain that is found within the vacuole of the beetroot cells. The pigment remains intact within the cell if the cells are not “stressed” by the external environment. In this exploration, two factors that affect the movement of the betalain out of the beetroot cells will be explored – surface area of the beetroot and the change in the external environment.
I hypothesize that the 4ml of 50% alcohol in which the beetroot cells are submerged in would contain the most amount of pigments diffused from the beetroot cells. Osmosis, which is the net movement of water particles from a region of higher water potential to a region of lower water potential through a selectively-permeable membrane until equilibrium is reached, occurs the most for the beetroot cells which are submerged in the 4ml of 50% alcohol. This is because, the 4ml of 50% alcohol is the most concentrated solution among the 5 set-ups, hence would be the most hypertonic solution to the beetroot cells. Hence, osmosis would occur more rapidly from the beetroot cells to the solution, resulting in the 4ml of 50% alcohol containing the most amounts of pigments.
Materials and methods
The apparatus needed for the experiment are as follows: o Razor blade/ scalpel o Ruler o 5 test tubes & rack o Labels o Forceps o Distilled water o 25%, 50% alcohol o Beetroot (Beta vulgaris) o White tile (for cutting) o 2 petri dish o 3 droppers (water, 25%, 50% alcohol) o Thermometer o Stop watch o 2 Beakers o Supply of hot water o Spectrophotometer (Data logger)
The methods to carry out the experiment are as follows:
1. Use a ruler and scapel to cut the cylinder of beetroot into 15 discs of 2mm each.
2. Take 3 discs