What might affect the rate of respiration in the experiment?

Variable Organism Type of How respiration Potential

to test to test respiration will be measured problems
Amount The Anaerobic: CO2 sensor: it Yeast might not
of organism respiration: measures amount grow in greater
glucose that used to without oxygen, of carbon dioxide amount of
testing is yeast turns released during glucose.
yeast. glucose into fermentation. As Temperature
alcohol and carbon glucose increases, and pH must
dioxide through CO2 production will be controlled
fermentation, increase as well but for accurate
producing ATP. up optimal point. result.
Temperat The Aerobic: yeast CO2 sensor: Mice might die
ure organism ferments glucose measure how fast due to high
that used to at different CO2 is produced as temperature.
testing is temperatures. As different Temperature
Mice. temperature temperature must be kept
increases increase. Use water constant during
bath (20, 30 and trails.
40) to keep
conditions
consistent.
pH level The Anaerobic: pH CO2 Production or High level of H
organism affect how enzyme pH indicator may kill cells
that used to works. Yeast works change. Less CO2 buffering
testing is best around pH 4.5 means enzyme required to
Yest. to 6.5. activity is low at maintain pH
that pH. through all
 trails.
Oxygen The Aerobic: seeds CO2 uptake using Level of oxygen
organism use oxygen to respirometer which is hard to
that used to break down stored shows how active control the risk
testing is glucose into aerobic respiration of anaerobic
Garmenting energy during is. shift. The
seeds. germination. This temperature
is cellular and seed
respiration in health must be
mitochondria controlled.
producing CO2 and
water.

Aim: To determine the effects of different glucose concentrations on the rate of yeast
fermentation.
Hypothesis: As glucose concentration increases (g), the rate of yeast fermentation
also increases as determined by an increase in CO 2 concentration (ppm).
Independent variable: The amount of glucose (0g, 6g, 10g and 12)
Dependant variable: CO2 concentration (ppm) and Amount of yeast (g)

What is the How will it be controlled? The importance of

controlled variable? its control?
Time taken to reaction The time needs to be controlled for A software
each of them for the reaction to occur. (SPARKVUE) will be
Also, reaction rate decreases over time used allowing each
because reactant concentration treatment runs for 30
decreases as reactant converts to minutes to reaction to
product and reaction rate generally occur.
increases (amrita.olabs.edu.in.2015).
Temperature (°C) The temperature needs to be The experiment will be
controlled to ensure that the conducted at room
respiration rate is the same for all temperature.
treatments. An increase in
temperature would affect the
respiration rate. For example,
increasing the temperature causes
more carbon dioxide to be released
and once they get to certain point (30)
the respiration rate will drop
(amrita.olabs.edu.in.2015).

Volume of water (mL) The volume of water, has to be the 100 mL will be
same for all treatments because a measured out. The
decrease or increase in the volume of same volume will be
the water will affect the respiration used for all
rate. treatments.
Uncontrollable factor(s) Why it cannot be controlled?
Genetic variability amongst yeast Each yeast organism can have genetic
differences in the production of the yeast,
which may affect the respiration rate.
The possible safety Why is it a hazard? How can it be
hazard(s) reduced/minimized?
Working with glass Broken glassware can cut and Ensure full safety
apparatus such as test penetrate through the skin, equipment are worn such
tubes, and beakers. causing harm like bleeding or as safety goggles, apron
irritation due to fragments of and gloves. Glassware has
glass trapped into skin tissue. to be utilised with caution
and care to avoid injuries.
Yeast respiration Yeast perspiration naturally To avoid asphyxiation
process. generate carbon dioxide. Over ensuring the class room
exposure of carbon dioxide may doors are all open.
cause asphyxiation.
Inhalation of glucose The dry small particles of glucose When using glucose add it
powder. can cause irritation to the slowly and carefully and
respiratory system. wear a mask if needed.
Bacteria growth on Glucose is source of food for Ensuring that any spills
spills. bacteria and spilled solutions should be cleaned
may cause unwanted bacteria thoroughly and dispose of
growth. waste properly.

Materials:
300mL beakers x 12
100mL distilled water x 12
Yeast packet (1g per beaker) x 14g total
CO2 sensor x1
Electronic mass balance x1
Big Micros spatula x1

Method: Justification:
Step 1. Set up 6, 300mL beakers with The 6x300mL have been labelled with
100mL of water. their respective volume of sugar (100mL)
and significance number used to ensure
and track measurement in changes to
their volume.
Step 2. Use the electronic mass balance The three different amounts of glucose
and measure 6g 10g and 12g of glucose (6g, 10g and 12g) have been measured
and place into each beaker respectively. out. An electronic mass balance is used for
Two beakers contain no sugar. its high level of precision to ensure the
exact the amount of glucose has been
used for experiment.
Step 3. Swirl each solution until the Each of the solutions has been swirled
glucose has dissolved. In case it is not until the sugar has been dissolved
dissolved, use big Micro’s spatula to completely. A long Micros spatula is used
ensure the glucose dissolves completely. to ensure the glucose dissolves
completely in the water.
Step 4. Connect the data logger to the The data logger was connected to a
computer computer that automatically monitors and
records.
The data in unit of (PPM) allowing the
conditions to be measured, documents,
analysed and valid data is recorded.
Step 5. Measure 1g of yeast into a small One gram of yeast has been measured out
beaker (containing 0g of glucose) using using electronic mass balance. This has
an electronic mass balance. been done to keep a trackable
measurement of the number of yeasts for
all treatments.
Step 6. When instructed, add the yeast One gram of glucose was added to the
to the solution. beaker containing 0g of glucose. The
yeast was poured when the solution ready
to avoid errors.
Step 7. As soon as the yeast has been As soon the yeast was poured in the
poured in put the CO2 sensor in the beaker, the CO2 senor was put in the top
conical flask. of beaker to measure the CO2
concentration that was produced by
glucose.
Step 8. Let the data logger software run By using the SPARK Vue software, the
for 30 minutes data logger runs for 30 minutes, as the
software is noting the number of CO2
concentration.
Step 9. repeat the steps (5,6,7,) for the
beakers containing 10g and 12g of
sugar.

Result table
0 6 10 12
Tim Trai Trai Avera
e Tra Tra Avera Tra Tra Avera Tra Tra Avera l l ge
(s) il 1 il 2 ge il 1 il 1 ge il 1 il 2 ge 1 2

CO2 concentration (ppm)

Amount of sugar Maximu Minimu Standard
Range Mean
(g) m m deviation
0
6
10
12