Maximum Cell Size
Maximum Cell Size & Diffusion – Ferris Shaw
Research Question:
How does the surface area to volume ratio affect the diffusion rate in agar cubes?
Hypothesis:
The rate of diffusion in directly related to the surface area to volume ratio of cells and is responsible for the efficiency of absorbing nutrients, oxygen, minerals etc. in the cell. This ratio is specific to cells as they require a ratio that isn’t big enough to take too long to receive the nutrients and oxygen or too small to impair diffusion, known as the maximum sustainable cell size. Due to this it would be expected that the smaller the agar cube the larger the rate of diffusion due to the increased surface area to volume ratio as it increases.
Variables:
Independent Variables: * The length of the agar cubes sides, measured with a calliper (cm)
Dependent Variable: * The diffusion rate of sodium hydroxide (cm/min)
Controlled:
* The concentration of sodium hydroxide (0.4%), same Na OH used throughout. * Temperature (°C), experiment takes place in the same classroom * Time immersed in Na OH (8 min), using the timer * Number of agar cubes in each beaker, excess of Na OH will be used * Concentration of agar cubes (%), same agar cubes used throughout the experiment
Uncontrollable:
* Volume of sodium hydroxide in each beaker (cm3) * Humidity (Pa)
Apparatus: * NaOH solution (0.4%) concentrate * Beaker * Timer ± 0.5s * Agar containing phenolphthalein * Calliper ±0.001 cm * Knife * Mat * Spoon * Stirrer
Method: * Using the knife, cut the agar into 5 cubes with specific measured lengths, widths and heights using the calliper. * Fill a beaker with enough Na OH to cover all 5 agar cubes to be placed, place the agar cubes in the beaker and immediately start the timer. * Leave for 8 mins, stirring every 2 mins to insure all areas of the cubes are covered. * Empty out the cubes from the beaker and
Research Question:
How does the surface area to volume ratio affect the diffusion rate in agar cubes?
Hypothesis:
The rate of diffusion in directly related to the surface area to volume ratio of cells and is responsible for the efficiency of absorbing nutrients, oxygen, minerals etc. in the cell. This ratio is specific to cells as they require a ratio that isn’t big enough to take too long to receive the nutrients and oxygen or too small to impair diffusion, known as the maximum sustainable cell size. Due to this it would be expected that the smaller the agar cube the larger the rate of diffusion due to the increased surface area to volume ratio as it increases.
Variables:
Independent Variables: * The length of the agar cubes sides, measured with a calliper (cm)
Dependent Variable: * The diffusion rate of sodium hydroxide (cm/min)
Controlled:
* The concentration of sodium hydroxide (0.4%), same Na OH used throughout. * Temperature (°C), experiment takes place in the same classroom * Time immersed in Na OH (8 min), using the timer * Number of agar cubes in each beaker, excess of Na OH will be used * Concentration of agar cubes (%), same agar cubes used throughout the experiment
Uncontrollable:
* Volume of sodium hydroxide in each beaker (cm3) * Humidity (Pa)
Apparatus: * NaOH solution (0.4%) concentrate * Beaker * Timer ± 0.5s * Agar containing phenolphthalein * Calliper ±0.001 cm * Knife * Mat * Spoon * Stirrer
Method: * Using the knife, cut the agar into 5 cubes with specific measured lengths, widths and heights using the calliper. * Fill a beaker with enough Na OH to cover all 5 agar cubes to be placed, place the agar cubes in the beaker and immediately start the timer. * Leave for 8 mins, stirring every 2 mins to insure all areas of the cubes are covered. * Empty out the cubes from the beaker and