Biology 2012
Cellular Respiration
(For LUOA Special Project Unit 7 – Lesson 16)
Late Nite Labs
Name:
Date:
Experiment 1: Digestion of Individual Sugars by Yeast Cells
Each box (30) is worth 2 points = 60 points total
IMPORTANT!! For the temperature in degrees Kelvin, add 273 to the Celcius temperature. If you don't,
your calculations will be marked wrong! Do NOT click the thermometer!
Name of the Sugar
Glucose
Maltose
Temperature in
degrees C
T = Temperature in
degrees K (add 273
to the C)
Initial Gas Volume start
Final gas volume at
EXACTLY 5 min
Volume of CO2
Produced in ml
(Subtract initial from
final)
V = Volume of CO2
Produced in liters take the ml and
divide by 1000
Number of
molecules of CO2
produced
2
2
4
6
R = is a given
number called a
constant (Latm/mole-Kelvin)
0.082
0.082
0.082
0.082
P = Pressure in lab
which is 1
atmosphere (atm)
1
1
1
1
180.2
180.2
340.3
504.4
n = Press(P)xVol(V)
0.082 (R)x(TKelvin)
n = PV
RT
n is the number of
moles of CO2 made
MW = Molecular
weight g/mole
Here's how the number of molecules of CO2 produced was calculated:
1. In the background to this experiment, the fermentation reaction is given:
C6H12O6 → 2CH3CH2OH + 2CO2 + energy
The coefficients in front of the molecules tell us in what ratio reactants are used and products are produced.
In this case, 2 CO2 molecules are created for every glucose molecule consumed.
To figure the amount of CO2 produced you are given that
2 CO2 molecules are created for every glucose molecule (monosaccaride) So just multiply each of the
sugars by 2.
 a mono (means 1 sugar) saccharide, 2 CO2 molecules are produced per molecule of sugar
 a di (means 2 sugars) saccharide, 4 CO2 molecules are produced per molecule of sugar
a tri (means 3 sugars) saccharide, 6 CO2 molecules are produced per molecule of sugar.
2. The next step is a little more complicated and it uses the Ideal Gas Law to convert volume of gas to
molecules. To simplify the calculation, we use the mole as our unit number of molecules and the molecular
weight of each sugar.
The ideal gas law relates the moles of CO2 gas molecules to its volume by:
n = (P × V) ÷ (R ×T)
where
n is the number of moles of CO2
R is the gas constant 0.082 L-atm/mole-Kelvin
T is the temperature in Kelvin (equal to degrees Celsius + 273)
V is the volume in liters (divide the mL by 1000)
P is the atmospheric pressure in the lab, which is just 1 atmosphere (atm)
n is the number of moles of CO2 made. To calculate this, take all the red numbers and put them in the
formula: n = Pressure(P) x Volume (V)
0.082 (R) x Temperature (in Kelvin)
simplified:
n = PV
RT
Questions:
= 40 points
1. What is cellular respiration?(4 points)
2. What type of cellular respiration is used in this lab? (4 points)
3. What gas is the yeast giving off? (4 points)
4. What gas is NOT being used in the fermentation of yeast? (4 points)
5. What is the yeast using for it's metabolism (eating)? (4 points)
6. What is the equation for this reaction in formula format and in word format? (8
points)
7. What is the primary product of yeast fermentation? (4 points)
8. Name 2 uses for the by-products of yeast fermentation. (8 points)