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The chemical equation above describes the basis of all living organisms storing and releasing energy. A continual supply of glucose (sugar) is necessary to provide sufficient stored energy, while the oxygen is necessary to 'burn' the sugar. This glucose (sugar) takes many forms:
Simple sugar, table sugar (sucrose), converted to many different forms: maltose, lactose
Intro to Cellular Respiration Discussion
Intro to Cellular Respiration Discussion
The graph above shows the change in O2 levels when 10 Superworms are added to a biochamber @ room temperature. The decrease in O2 levels can be used as an indicator of cellular respiration.
In class discussion:
If you were to change one variable, how would that change the graph?
Suppose you were to put a the following into a biochamber and repeat the data collection process:
a candle.
a mouse.
fish.
mushrooms.
rotting peaches (or any other fruit).
a plant
Do plants carry out Cellular Respiration?
Do plants carry out Cellular Respiration?
In class we watched a video of bean seeds germinating and growing over a 10 day period (240 h). The data collected included:
Light On or Off (21 = On / 20 = Off) The choice of 20/21 was to scale the data the same relative values as the oxygen.
O2 Concentration (%) -
Recorded by a Vernier O2 probe in the tank.
Ranged from 19.5 - 20.9%.
CO2 Concentration (ppm - parts per million)
Recorded by a Vernier CO2 probe within the tank.
Ranged from 420-7500 ppm, graphed using the right y-axis.
Using the interactive data above or the data to the right, what evidence is there that plants consume O2 and produce CO2?
From 0 h to 110 h - the CO2 increases rapidly at the start then begins to level off, while the O2 starts at 20.9% and decreases to a value of ˜19.5%. Based on the cellular respiration equation, this shows that the seeds are consuming O2 and producing CO2. This happens when the light is both on and off.
From 162h to 174h, the light is ON and there are plants growing in the tank. The graph clearly shows and increase in the levels of O2 (19.4% to 20.3%) and a decrease in the levels of CO2.(6931 ppm to 1140 ppm). This would indicate that the process of photosynthesis was occurring.
From 174h to 185h, the light is OFF and there are plants growing in the tank. The graph shows a dramatic increase in the levels of CO2 (1200 ppm to 5000 ppm) and an equal drop in O2 (20.34% to 19.60%). Again, this would indicate that cellular respiration is occurring within the plants.
This cycle continues as the light is turned ON and OFF for the remainder of the data collection (until 240h).
Exothermic Reactions and Cellular Respiration
Exothermic Reactions and Cellular Respiration
Exothermic Reactions -
Exothermic Reactions -
the total energy stored in the bonds of the products is less than the reactants.
energy (HEAT) is released in an exothermic reaction.
Cellular Respiration is an example of an exothermic reaction.
Endothermic Reactions -
Endothermic Reactions -
the total energy stored in the bonds of the products is greater than the energy stored in the reactants.
energy is required to produce this type of reaction.
Photosynthesis is an example of an endothermic reaction.
The photo above shows a model of a GLUCOSE molecule and the six oxygen molecules needed for cellular respiration. Each of these bond (grey bars) will be broken during the process, releasing energy. The amount of energy per bond varies with the type of bond. The amounts of energy per bond are as follows:
GLUCOSE molecule (23 total bonds): -9546 kJ/mol
O=O (double bond): -495 kJ/mol
C=O (double bond in CO2): -745 kJ/mol
H-O (single bond): -467 kJ/mol
A - P - P ~ P ( ~ = bond in ATP) - TBD
kJ/mol means that if you had 1 mol of glucose molecules (6.02x1023 molecules) the reaction would release 9 546 000 Joules of energy (enough to lift a 50 kg person to a height of approximately 20 km (19481m))
Determine the change in energy and direction of energy flow in the reaction.
Most Energy graphs will show the change in energy as shown above. However, it is simply a matter of perspective.
Biology -
QUALITATIVE : Energy (heat) is either entering or exiting the system.
Therefore, it is easiest to show it as a decrease when exothermic and an increase when endothermic.
Chemistry -
QUANTITATIVE: When bonds are broken, energy is released. When bonds are created, energy is absorbed.
Difference in values, The difference in these values, determines if the rxn is exothermic or endothermic, respectively. For our purposes, a NEGATIVE difference (-2048 kJ/mol) is an Exothermic reaction and a positive difference is an endothermic reaction (+2048 kJ/mol)
Yeast Respiration Data Collection
Yeast Respiration Data Collection
Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized.[1][2][3]
Yeast cell magnified 400x. Some cells are in the process of reproducing by the process of budding.
The numbers are not the same but the set-up is similar enough to have the same results.
The conclusions drawn from the graph can be as follows:
Amount of Sugar Available:
Linear Line: The production of CO2 was directly related to the amount of sugar available.
Non-zero y-intercept: Because the solution with no sugar did create some CO2 , it can be hypothesized that the yeast contained some sugar stored in their cells.
Temperature of Solution:
Non-linear line: There is an optimal temperature that yeast produces CO2. Based on the data and research, it can be hypothesized that the CO2 production would decrease as the temperature continued to increase.
Zero y-intercept: when the temperature is 0˚C there is no metabolic activity (cellular respiration) by the yeast cells.
End of Year Summative INFO:
End of Year Summative INFO:
The exam will consist of questions about the following topics:
Reactants and Products of cellular respiration.
Exothermic Reactions
How can you calculate the change in energy in a reaction? (see chart above)
Sugars, O2 consumption and CO2 production.
What is the relationship between with sugars (types, concentrations, temperatures, etc) and the usage of O2 or CO2 production?
Summative Format:
DigiExam
Be sure to have an updated version of DigiExam installed on you computer prior to 09 June. Contact the tech dept if you have questions.
The summative will be in LOCKDOWN mode.
Notes Page:
You will be able to bring 1 sheet of A4 or 8.5x11in paper with you to the summative.
You may put any information on this single piece of paper.
You may write by hand or print from a computer onto the paper.
Bonus points for using the following terms:
therefore, however, nevertheless, furthermore, consequently, likewise, moreover
Info Included on the Summative:
There will be graphs and data tables provided on the summative for you to interpret.
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