Bio IA

Southville International School and Colleges INTERNATIONAL BACCALAUREATE DIPLOMA PROGRAM School Code: n/a

Julia M. Wong Surface Area to Volume Ratio and Cell’s Efficiency

Julia Wong IB Biology High Level Session Number: n/a

February 19, 2013

The Effect of Surface Area to t o Volume Ratio on Heat Capacity of Different Sized Beakers DESIGN 

Background of the Study

Cells are very small objects. Some may wonder why cells do not grow to larger sizes, especially since growth is one of the main functions of life. However, cells were made to be small for a purpose: to increase their surface area to volume ratio. As a cell gets bigger, the volume of  the cell increases at a much faster rate than its surface area. The surface area is the outermost part of the cell, represented by the cell membrane. The surface area is responsible for providing an area of exchange between substances moving in and out of a cell. As a cell grows larger, the volume grows at a much faster rate than its surface area. Since the volume of the cell depends on the surface area to provide it with the necessary nutrients to function, a rapidly increasing volume would compromise the cell membrane’s ability to function as a provider for the interior of the cell. The cell solves this by dividing, to keep its overall cell size relatively small. As cell size decreases, the surface area to volume ratio increases and vice-versa. Thus, there is an inverse relationship between surface area to volume ratio and cell size. As the surface area to volume ratio increases, there is relatively more membrane surface to allow exchange of wastes  between inside and outside the cell. Thus, the relative amount of membrane available for  exchange is more. If a cell grows too large, the surface area to volume ratio decreases and the result would be a cell dying due to waste accumulation. Within the cell, the rate of heat and waste production, as well as the rate of resource consumption, is highly dependent on its volume. The more substances being exchanged in and out of the cell, there is an increase of waste and heat production. Thus, there will be a higher  demand of energy and oxygen. Smaller cells function more efficiently than larger cells because since the surface area is larger the demand for oxygen and nutrients are easily met. Thus, granting them higher cell efficiency/capacity. This explains why cells must remain small, so that the cell membrane can adequately provide the interior of the cell with nutrients.

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Research Questions 1. What is the effect of size of beaker to the time required for the volume of water to heat up from 30°C to 35°C? (Heat capacity) 2. What is the effect of surface area to volume ratio to the time required for the volume of water  to heat up from 30 °C to 35°C? (Heat capacity)

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Southville International School and Colleges INTERNATIONAL BACCALAUREATE DIPLOMA PROGRAM School Code: n/a

Julia Wong IB Biology High Level Session Number: n/a

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