Cellular respiration in yeast cells

Káren KrmoyanMrs. Mariam Ohanyan

IB Biology SL27 May 2016

Background: Cellular Respiration “Cellular respiration refers to the breakdown of glucose

and other respiratory substrates to make energy carrying molecules called ATP” ("Cellular Respiration").

“The role of the mitochondria in making stored chemical-bond energy available to cells by completing the breakdown of glucose to carbon dioxide” is important to understand the overall process of cell respiration (Schuster).

“Because oxygen is always in short supply anaerobic respiration dominates the metabolic activities” (“Yeast Propagation”).

Source: http://hyperphysics.phy-astr.gsu.edu/hbase/biology/imgbio/aeresp.gif

Hypothesis: cellular respiration in yeasts

If the concentration of sucrose in the solution rises, the CO2 level in yeasts will

also rise.

Variables

Controlled variables: Sucrose Room Temperature Temperature of the solution

Independent variables: Concentration of sucrose

Dependent variables: Amount of CO2 produced

Materials

Yeast (10.0 ± 0.5 g) Boiled water (2000.0 ml) Sucrose (33.0 ± 0.5 g) Vernier Oxygen Detector Vernier Carbon Dioxide Detector 2 x beakers (500.0 ml), 2 x syringes, 2 x test tubes (500.0 ml).

Procedure

1. Pour 1000.0 ml of water in each of the beakers,

2. Add 3.0 g and 30.0 g of sucrose to each beaker and solve,

3. Add 5.0 g yeast to each of the beakers and solve,

4. Using a syringe, put 5 ml of each of the solutions to different test tubes

Procedure

5. Insert the oxygen and CO2 detectors to the test tube containing 0.3% solution and collect the results using Vernier lab quest

6. Insert the oxygen and CO2 detectors to the test tube containing 3.0% solution and collect the results using Vernier lab quest

Data Processing(0.3% solution)

0 100 200 300 400 500 600 7000

2000

4000

6000

8000

10000

12000Cellular respiration in yeasts- [CO2]

per second

time/s

CO2/ppm

0 100 200 300 400 500 600 70014.814.9

1515.115.215.315.415.515.615.7

Cellular respiration in yeasts- [O2] per second

time/s

O2/ppm

Data Processing(3.0% solution)

0 100 200 300 400 500 6000

20000

40000

60000

80000

100000

120000Cellular respiration in yeasts- [CO2] per second

time/s

CO2/ppm

0 100 200 300 400 500 60015.5

15.55

15.6

15.65

15.7

15.75

15.8Cellular respiration in yeasts- [O2] per

second

time/s

O2/ppm

Evaluation & Conclusion

Overall, oxygen levels dropped, meaning that cellular respiration took place

Carbon dioxide levels, at first, rose showing that respiration took place

HOWEVER, oxygen levels fluctuated and carbon dioxide levels were unstable ~ PROBABLY due to the simultaneous photosynthesis going on [LIMITATION]

Improvements: ensure that photosynthesis does not occur

Works Cited

"Cellular Respiration." BBC Bitesize. BBC, n.d. Web. 8 May 2016. <http://www.bbc.co.uk/education/guides/z2vbb9q/revision>.

Schuster, Tom. "Yeast Respiration." Yeast Respiration. CSUN, n.d. Web. 27 May

2016. <http://www.csun.edu/scied/2-longitudinal/schuster/>."Yeast Propogation with Aerobic Respiration." Woodland Brew. Blogger, 13 Mar.

2013. Web. 27 May 2016. <http://www.woodlandbrew.com/2013/03/yeast-

propogation-with-aerobic.html>.

THANK YOU!