Plants & Human Affairs (BIOL106)  -  Stephen G. Saupe, Ph.D.; Biology Department, College of St. Benedict/St. John's University, Collegeville, MN 56321; ssaupe@csbsju.edu; http://www.employees.csbsju.edu/ssaupe

name__________________                                                          date __________________________
 

Surface/Volume Ratios:  Post-Lab Assignment

General Directions:  Print a copy of this handout and complete the questions directly on this handout (except where indicated)

Exercise 1

1. Fill-in-the-blank with the appropriate response.
   • As a cube gets larger, its S/V ratio will __________.
   • As a cube gets larger, the surface area of the cube will increase by __________ the linear dimension.
   • As a cube gets larger, the volume of the cube will increase by __________ the linear dimension.
   • As a cube gets larger, the surface area increases __________ the volume.

Exercise 2 & 3.

1. Fill-in-the-blank with the appropriate response.
   1. As a cube is flattened its S/V ratio will __________.
   2. As a cube is elongated its S/V ratio will _________.
       
2. Consider a box made out of clay that is 4 x 5 x 10 cm.  Calculate the following:

volume (cm3)              ____________
surface area (cm2)       ____________
S/V ratio                      ____________

3. If we pulled on the sides of this box to change its shape so that it is 2 x 2 x 50, will the S/V increase, decrease or stay the same?
   
    
4. For each pair, circle the one with the largest S/V ratio.
               human infant  / human adult
               elephant  / mouse

 Exercise 4

1. Fill-in-the-blank with the appropriate response.

a.       The shape with the largest S/V ratio is a _______________

b.      The shape that is exposed to the greatest portion of its environment is a _________________
 

2.      On a separate sheet of paper (preferably graph paper), make a sketch, to scale, of the three objects (sphere, cube, filament).   

Exercise 5

1. Append a copy of Table 5 showing completed calculations.
    
2. Fill-in-the-blank with the appropriate response.
   1. The cell model in which cell the greatest portion will get fed is the _______ one.
   2. The cell model in the greatest danger of starving is the ___________ one.
       
3. Suggest a reason why the rate of cell growth slows as a cell gets larger.
    
4. Suggest a reason why cells divide when they get large.

Exercise 6.

1. Append a completed copy of Table 6.
    
2. Fill-in-the-blank with the appropriate response.

a.       The ___________ beaker lost the most total heat.

b.      The ___________ beaker lost heat at the greatest rate

c.       The ___________ beaker would require the most total heat input to maintain a constant temperature.

d.      The ___________ beaker would require the greatest total heat input relative to its size to maintain a constant temperature.
 

3.      Answer the following questions either “mouse” or “elephant.”

a.       Looses the most heat during a given period of time ___________

b.      Looses the most heat relative to its size during a given time period

c.       Needs to eat the most food _____________

d.      Eats the most food relative to its size _______________

4. Referring to your data, explain why mice have a greater metabolic rate than an elephant.

Last updated:  11/10/2005 © Copyright  by SG Saupe